You are here

Nelson, Rendon C.

Overview:

Diagnostic Imaging of the Liver; Specifically the Detection and Characterization of Focal and Diffuse Processes by US, CT and MRI.
Percutaneous Image-Guided Thermal Ablation of Hepatic and Renal Tumors

Positions:

Reed and Martha Rice Professor of Radiology, in the School of Medicine

Radiology, Abdominal Imaging
School of Medicine

Professor of Radiology

Radiology, Abdominal Imaging
School of Medicine

Professor in the Department of Mechanical Engineering and Materials Science

Mechanical Engineering and Materials Science
Pratt School of Engineering

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Education:

M.D. 0

M.D. — Kent State University

Grants:

Improved ultrasound imaging using elevated acoustic output

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Faculty Member
Start Date
March 01, 2016
End Date
December 31, 2019

Simulation Tools for 3D and 4D CT and Dosimetry

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
March 01, 2007
End Date
December 31, 2018

Optimization of radiofrequency ablation with electrically conductive particles

Administered By
Radiology, Interventional Radiology
AwardedBy
National Institutes of Health
Role
Collaborator
Start Date
August 14, 2015
End Date
January 31, 2018

Acoustic Radiation Force Based Hepatic Elasticity Quantification and Imaging

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
September 10, 2001
End Date
July 31, 2017

Decreased Variability for Robust Imaging-based Quantification of Tumor Heterogeneity

Administered By
Radiology, Abdominal Imaging
AwardedBy
Radiological Society of North America
Role
Collaborator
Start Date
July 01, 2015
End Date
June 30, 2017

Improved Image Quality of Focal Liver Lesions Using the Coherence of Ultrasound

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
June 15, 2013
End Date
May 31, 2017

Image Rich Radiology Reports: A Value-Based Model to Improve Clinical Workflow

Administered By
Radiology, Abdominal Imaging
AwardedBy
Radiological Society of North America
Role
Collaborator
Start Date
July 01, 2015
End Date
June 30, 2016

Characterization of Early Anti-Angiogensis Treatment Effects in Colorectal Carcinoma

Administered By
Radiology, Abdominal Imaging
AwardedBy
Radiological Society of North America
Role
Principal Investigator
Start Date
July 01, 2014
End Date
June 30, 2015

Mechanisms of Image Quality Improvement via Harmonic Imaging

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
April 01, 2009
End Date
March 31, 2012

Liver Cancer Ablation Guidance by ARFI Imaging

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
May 01, 2005
End Date
March 31, 2012

Biomarker Studies for Novel Anti-Cancer Agents

Administered By
Medicine, Medical Oncology
AwardedBy
National Institutes of Health
Role
Consultant
Start Date
May 28, 2003
End Date
February 29, 2008

Immunotherapy with Renal Tumor RNA Transfected Dendritic Cells

Administered By
Surgery, Urology
AwardedBy
National Institutes of Health
Role
Collaborator
Start Date
February 14, 2001
End Date
January 31, 2005
Show More

Publications:

Image-Rich Radiology Reports: A Value-Based Model to Improve Clinical Workflow.

To determine the value of image-rich radiology reports (IRRR) by evaluating the interest and preferences of referring physicians, potential impact on clinical workflow, and the willingness of radiologists to create them.Referring physicians and radiologists were interviewed in this prospective, HIPAA-compliant study. Subject willingness to participate in the study was determined by an e-mail. A single investigator conducted all interviews using a standard questionnaire. All subjects reviewed a video mockup demonstration of IRRR and three methods for viewing embedded images, as follows: (1) clickable hyperlinks to access a scrollable stack of images, (2) scrollable and enlargeable small-image thumbnails, and (3) scrollable but not enlargeable medium-sized images. Questionnaire responses, free comments, and general impressions were captured and analyzed.Seventy-two physicians (36 clinicians, 36 radiologists) were interviewed. Thirty-one clinicians (86%) expressed interest in using IRRR. Seventy-seven percent of subjects believed IRRR would improve communication. Ten clinicians (28%) preferred method 1, 18 (50%) preferred method 2, and 8 (22%) preferred method 3 for embedding images. Thirty clinicians (83%) stated that IRRR would improve efficiency. Twenty-two radiologists (61%) preferred selecting a tool button with a mouse and right-clicking images to embed them, 13 (36%) preferred pressing a function key, and 11 (31%) preferred dictating series and image numbers. The average time radiologists were willing to expend for embedding images was 66.7 seconds.Referring physicians and radiologist both believe IRRR would add value by improving communication with the potential to improve the workflow efficiency of referring physicians.

Authors
Patel, BN; Lopez, JM; Jiang, BG; Roth, CJ; Nelson, RC
MLA Citation
Patel, BN, Lopez, JM, Jiang, BG, Roth, CJ, and Nelson, RC. "Image-Rich Radiology Reports: A Value-Based Model to Improve Clinical Workflow." Journal of the American College of Radiology : JACR 14.1 (January 2017): 57-64.
PMID
27692807
Source
epmc
Published In
Journal of the American College of Radiology
Volume
14
Issue
1
Publish Date
2017
Start Page
57
End Page
64
DOI
10.1016/j.jacr.2016.07.018

Adoption of Splenic Enhancement to Time and Trigger the Late Hepatic Arterial Phase During MDCT of the Liver: Proof of Concept and Clinical Feasibility.

The purpose of this study was to prospectively investigate the clinical feasibility of adopting splenic enhancement for timing and triggering the acquisition of late hepatic arterial phase images during multiphasic liver MDCT for assessment of hypervascular tumors.Forty-eight patients (33 men, 15 women; median age, 59 years; chronic liver disease, 23 patients; portal venous hypertension, 17 patients) with a total of 81 hypervascular liver tumors underwent liver MDCT by random assignment to one of two scanning protocols. Scanning delay for the late hepatic arterial phase was determined by assessment of time-to-peak splenic enhancement (splenic-triggering protocol) or aortic enhancement (aortic-triggering protocol). Acquisition timing, vascular attenuation, liver attenuation and homogeneity, signal-to-noise ratio, tumor-to-liver contrast, and tumor-to-liver contrast-to-noise ratio were compared. Two blinded independent observers used Likert scales to score timing adequacy (3-point scale), diagnostic confidence (5-point scale), and per lesion conspicuity (4-point scale) for hypervascular tumor detection.The splenic- and aortic-triggering protocols had significant differences in mean late hepatic arterial phase imaging timing (splenic, 36 ± 6 seconds; aortic, 32 ± 3 seconds; p = 0.010). Images obtained with the splenic-triggering protocol had significantly better observer-based judgment of adequacy (splenic, 2.04; aortic, 1.58; p = 0.002). Mean attenuation and signal-to-noise ratios from liver and portal vein were significantly higher with the splenic- than with the aortic-triggering protocol (p < 0.0001). The splenic-triggering protocol was associated with significant improvement in homogeneity of liver attenuation (p < 0.0001). Although the splenic-triggering protocol was associated with significantly higher lesion conspicuity than was the aortic-triggering protocol (p = 0.022), there was no significant difference in tumor detection rate.Our results provide a clinical foundation for and proof of principle that the adoption of splenic enhancement renders an optimal temporal window for late hepatic arterial phase imaging during MDCT of the liver for assessment of hypervascular tumors.

Authors
Mileto, A; Husarik, DB; Bellini, D; Marin, D; Reiner, CS; Nelson, RC
MLA Citation
Mileto, A, Husarik, DB, Bellini, D, Marin, D, Reiner, CS, and Nelson, RC. "Adoption of Splenic Enhancement to Time and Trigger the Late Hepatic Arterial Phase During MDCT of the Liver: Proof of Concept and Clinical Feasibility." AJR. American journal of roentgenology 207.2 (August 2016): 310-320.
PMID
27253268
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
207
Issue
2
Publish Date
2016
Start Page
310
End Page
320
DOI
10.2214/ajr.15.15808

How reader perception of capsule affects interpretation of washout in hypervascular liver nodules in patients at risk for hepatocellular carcinoma.

To determine whether reader perception of a capsule affects reader interpretation of washout in hypervascular liver nodules at dynamic magnetic resonance imaging (MRI) in patients at risk for hepatocellular carcinoma (HCC).This retrospective study was Institutional Review Board (IRB)-approved and Health Insurance Portability and Accountability Act (HIPAA)-compliant, with waiver of informed consent. MRI reports for 111 hypervascular liver nodules (median 2.0 cm, range 1.0-17.8 cm) in 62 patients were reviewed, and the presence/absence of capsule and washout were recorded for one reading. A second independent study reading was also performed. The signal intensity ratio (SIR) for each nodule and liver parenchyma was measured. An objective SIR threshold was identified for nodules without capsules that correctly classified the presence/absence of washout, then applied to nodules with capsules to classify them as having / not having objective washout. Nodules were categorized as definite / not definite HCC using subjective and objective washout, based on LI-RADS, OPTN, AASLD, and EASL criteria, and proportions compared using McNemar's test.Agreement on nodule features was high for Readings 1 and 2 (κ = 0.70-0.82). For Reading 1, 71 nodules lacked capsules (43 with and 28 without subjective washout); an SIR threshold of 0.88 classified the presence/absence of washout correctly in 94% (67/71, P < 0.001). Forty nodules had capsules; although all had subjective washout (100%, 40/40), 75% (30/40) had objective washout (P < 0.05). Using objective washout caused 4.5% (3/66; LI-RADS, OPTN) and 12% (10/83; AASLD, EASL) of nodules to be recategorized from definite HCC to not definite HCC.Reader perception of capsule affects interpretation of washout. This effect can influence nodule categorization using imaging-based diagnostic systems. J. Magn. Reson. Imaging 2016;43:1337-1345.

Authors
Sofue, K; Sirlin, CB; Allen, BC; Nelson, RC; Berg, CL; Bashir, MR
MLA Citation
Sofue, K, Sirlin, CB, Allen, BC, Nelson, RC, Berg, CL, and Bashir, MR. "How reader perception of capsule affects interpretation of washout in hypervascular liver nodules in patients at risk for hepatocellular carcinoma." Journal of magnetic resonance imaging : JMRI 43.6 (June 2016): 1337-1345.
PMID
26559157
Source
epmc
Published In
Journal of Magnetic Resonance Imaging
Volume
43
Issue
6
Publish Date
2016
Start Page
1337
End Page
1345
DOI
10.1002/jmri.25094

Effect of a Noise-Optimized Second-Generation Monoenergetic Algorithm on Image Noise and Conspicuity of Hypervascular Liver Tumors: An In Vitro and In Vivo Study.

The purpose of this study is to investigate whether the reduction in noise using a second-generation monoenergetic algorithm can improve the conspicuity of hypervascular liver tumors on dual-energy CT (DECT) images of the liver.An anthropomorphic liver phantom in three body sizes and iodine-containing inserts simulating hypervascular lesions was imaged with DECT and single-energy CT at various energy levels (80-140 kV). In addition, a retrospective clinical study was performed in 31 patients with 66 hypervascular liver tumors who underwent DECT during the late hepatic arterial phase. Datasets at energy levels ranging from 40 to 80 keV were reconstructed using first- and second-generation monoenergetic algorithms. Noise, tumor-to-liver contrast-to-noise ratio (CNR), and CNR with a noise constraint (CNRNC) set with a maximum noise increase of 50% were calculated and compared among the different reconstructed datasets.The maximum CNR for the second-generation monoenergetic algorithm, which was attained at 40 keV in both phantom and clinical datasets, was statistically significantly higher than the maximum CNR for the first-generation monoenergetic algorithm (p < 0.001) or single-energy CT acquisitions across a wide range of kilovoltage values. With the second-generation monoenergetic algorithm, the optimal CNRNC occurred at 55 keV, corresponding to lower energy levels compared with first-generation algorithm (predominantly at 70 keV). Patient body size did not substantially affect the selection of the optimal energy level to attain maximal CNR and CNRNC using the second-generation monoenergetic algorithm.A noise-optimized second-generation monoenergetic algorithm significantly improves the conspicuity of hypervascular liver tumors.

Authors
Marin, D; Ramirez-Giraldo, JC; Gupta, S; Fu, W; Stinnett, SS; Mileto, A; Bellini, D; Patel, B; Samei, E; Nelson, RC
MLA Citation
Marin, D, Ramirez-Giraldo, JC, Gupta, S, Fu, W, Stinnett, SS, Mileto, A, Bellini, D, Patel, B, Samei, E, and Nelson, RC. "Effect of a Noise-Optimized Second-Generation Monoenergetic Algorithm on Image Noise and Conspicuity of Hypervascular Liver Tumors: An In Vitro and In Vivo Study." AJR. American journal of roentgenology 206.6 (June 2016): 1222-1232.
PMID
27058192
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
206
Issue
6
Publish Date
2016
Start Page
1222
End Page
1232
DOI
10.2214/ajr.15.15512

Can combining triple-arterial phase acquisition with fluoroscopic triggering provide both optimal early and late hepatic arterial phase images during gadoxetic acid-enhanced MRI?

To determine whether triple-arterial phase acquisition with fluoroscopic triggering can provide both well-timed early and late hepatic arterial phase (HAP) images more frequently than when using a fixed-time delay during gadoxetic acid-enhanced magnetic resonance imaging (MRI).Written informed consent was obtained for this Institutional Review Board (IRB)-approved prospective, Health Insurance Portability and Accountability Act (HIPAA)-compliant study. Ninety patients underwent gadoxetic acid-enhanced MRI at 3T with a single-breath-hold triple-arterial phase acquisition using either a fixed-time delay (n = 45) or fluoroscopic triggering injection protocol (n = 45). Three radiologists, blinded to method of timing and other data, independently determined whether well-timed early or late HAP were obtained for each arterial phase image set and assessed for transient severe motion (TSM). Rates of successful HAP acquisitions and of TSM were compared between the two protocols using χ(2) or Fisher's exact test.The rate of successful acquisition of late HAP images was similar in the two groups (93% [42/45] for fixed-time delay vs. 98% [44/45] for fluoroscopic triggering, P = 0.62). There was a trend toward higher rates of successful acquisition of both early and late HAP images in the fluoroscopic triggering group (69% [31/45] vs. 49% [22/45], P = 0.05). TSM occurred in five patients (6% [5/90]) and at similar frequencies in the two groups (2% [1/45] vs. 9% [4/45], P = 0.36).Triple-arterial phase acquisition with fluoroscopic triggering tended to provide both well-timed early and late HAP images more frequently than when using a fixed-time delay during gadoxetic acid-enhanced MRI.

Authors
Sofue, K; Marin, D; Jaffe, TA; Nelson, RC; Bashir, MR
MLA Citation
Sofue, K, Marin, D, Jaffe, TA, Nelson, RC, and Bashir, MR. "Can combining triple-arterial phase acquisition with fluoroscopic triggering provide both optimal early and late hepatic arterial phase images during gadoxetic acid-enhanced MRI?." Journal of magnetic resonance imaging : JMRI 43.5 (May 2016): 1073-1081.
PMID
26469796
Source
epmc
Published In
Journal of Magnetic Resonance Imaging
Volume
43
Issue
5
Publish Date
2016
Start Page
1073
End Page
1081
DOI
10.1002/jmri.25079

Virtual Monochromatic Images from Dual-Energy Multidetector CT: Variance in CT Numbers from the Same Lesion between Single-Source Projection-based and Dual-Source Image-based Implementations.

To determine the variance in virtual monochromatic computed tomography (CT) numbers from the same lesion, comparing the two clinically available dual-energy multidetector CT hardware implementations (single-source projection-based and dual-source image-based), in a phantom-based simulated abdominal environment.This phantom-based study was exempt from institutional review board oversight. Polyethylene terephthalate spheres (15 and 18 mm) with two iodine-to-saline dilutions (0.8 and 1.2 mg of iodine per millilliter) were serially suspended in a cylindrical polypropylene bottle filled with diluted iodinated contrast material. The bottle was placed into a 36-cm-wide torso-shaped water phantom simulating the abdomen of a medium-sized patient. Dual-energy (80/140 kVp) and single-energy (100 and 120 kVp) scans were obtained with single-source and dual-source multidetector CT implementations. Virtual monochromatic images were reconstructed at energy levels of 40-140 keV (in 10-keV increments) in either the projection-space or image-space domain. A multivariate regression analysis approach was used to investigate the effect of energy level, lesion size, lesion iodine content, and implementation type on measured CT numbers.There were significant differences in the attenuation values measured in the simulated lesions with the single-source projection-based platform and the dual-source image-based implementation (P < .001 for all comparisons). The magnitude of these differences was greatest at lower monochromatic energy levels and at lower iodine concentrations (average difference at 40 keV: 25.7 HU; average difference at 140 keV: 7 HU). The monochromatic energy level and the lesion iodine concentration had a significant effect on the difference in the measured attenuation values between the two implementations, which indicates that the two imaging platforms respond differently to changes in investigated variables (P < .001 for all comparisons).There is a statistically significant variance in virtual monochromatic CT numbers from the same lesion examined with single-source projection-based and dual-source image-based implementations. The magnitude of the variance is a function of the selected energy level and the lesion iodine content.

Authors
Mileto, A; Barina, A; Marin, D; Stinnett, SS; Roy Choudhury, K; Wilson, JM; Nelson, RC
MLA Citation
Mileto, A, Barina, A, Marin, D, Stinnett, SS, Roy Choudhury, K, Wilson, JM, and Nelson, RC. "Virtual Monochromatic Images from Dual-Energy Multidetector CT: Variance in CT Numbers from the Same Lesion between Single-Source Projection-based and Dual-Source Image-based Implementations." Radiology 279.1 (April 2016): 269-277.
PMID
26536403
Source
epmc
Published In
Radiology
Volume
279
Issue
1
Publish Date
2016
Start Page
269
End Page
277
DOI
10.1148/radiol.2015150919

Quantitative Features of Liver Lesions, Lung Nodules, and Renal Stones at Multi-Detector Row CT Examinations: Dependency on Radiation Dose and Reconstruction Algorithm.

To determine if radiation dose and reconstruction algorithm affect the computer-based extraction and analysis of quantitative imaging features in lung nodules, liver lesions, and renal stones at multi-detector row computed tomography (CT).Retrospective analysis of data from a prospective, multicenter, HIPAA-compliant, institutional review board-approved clinical trial was performed by extracting 23 quantitative imaging features (size, shape, attenuation, edge sharpness, pixel value distribution, and texture) of lesions on multi-detector row CT images of 20 adult patients (14 men, six women; mean age, 63 years; range, 38-72 years) referred for known or suspected focal liver lesions, lung nodules, or kidney stones. Data were acquired between September 2011 and April 2012. All multi-detector row CT scans were performed at two different radiation dose levels; images were reconstructed with filtered back projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction (MBIR) algorithms. A linear mixed-effects model was used to assess the effect of radiation dose and reconstruction algorithm on extracted features.Among the 23 imaging features assessed, radiation dose had a significant effect on five, three, and four of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). Adaptive statistical iterative reconstruction had a significant effect on three, one, and one of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). MBIR reconstruction had a significant effect on nine, 11, and 15 of the features for liver lesions, lung nodules, and renal stones, respectively (P < .002 for all comparisons). Of note, the measured size of lung nodules and renal stones with MBIR was significantly different than those for the other two algorithms (P < .002 for all comparisons). Although lesion texture was significantly affected by the reconstruction algorithm used (average of 3.33 features affected by MBIR throughout lesion types; P < .002, for all comparisons), no significant effect of the radiation dose setting was observed for all but one of the texture features (P = .002-.998).Radiation dose settings and reconstruction algorithms affect the extraction and analysis of quantitative imaging features in lesions at multi-detector row CT.

Authors
Solomon, J; Mileto, A; Nelson, RC; Roy Choudhury, K; Samei, E
MLA Citation
Solomon, J, Mileto, A, Nelson, RC, Roy Choudhury, K, and Samei, E. "Quantitative Features of Liver Lesions, Lung Nodules, and Renal Stones at Multi-Detector Row CT Examinations: Dependency on Radiation Dose and Reconstruction Algorithm." Radiology 279.1 (April 2016): 185-194.
PMID
26624973
Source
epmc
Published In
Radiology
Volume
279
Issue
1
Publish Date
2016
Start Page
185
End Page
194
DOI
10.1148/radiol.2015150892

Image-guided percutaneous drainage: a review.

Percutaneous abscess drainage (PAD) has been proven to be a safe, effective, and widely used technique for treatment of patients with intra-abdominal fluid collections. Indications for PAD are ever expanding, and most abscesses are amenable to PAD. PAD is routinely used for treatment of simple unilocular abscesses however more complex collections require a collaborative strategy with surgical services for patient management. PAD is also used as a temporizing procedure for patients who will ultimately require operative intervention. A variety of imaging modalities are used for PAD including ultrasound and CT. Several catheter insertion techniques have proven effective. Complications from PAD are relatively uncommon.

Authors
Jaffe, TA; Nelson, RC
MLA Citation
Jaffe, TA, and Nelson, RC. "Image-guided percutaneous drainage: a review." Abdominal radiology (New York) 41.4 (April 2016): 629-636. (Review)
PMID
26826090
Source
epmc
Published In
Abdominal radiology (New York)
Volume
41
Issue
4
Publish Date
2016
Start Page
629
End Page
636
DOI
10.1007/s00261-016-0649-3

How the radiologist can add value in the evaluation of the pre- and post-surgical pancreas.

Disease involving the pancreas can be a significant diagnostic challenge to the interpreting radiologist. Moreover, the majority of disease processes involving the pancreas carry high significant morbidity and mortality either due to their natural process or related to their treatment options. As such, it is critical for radiologists to not only provide accurate information from imaging to guide patient management, but also deliver that information in a clear manner so as to aid the referring physician. This is no better exemplified than in the case of pre-operative staging for pancreatic adenocarcinoma. Furthermore, with the changing healthcare landscape, it is now more important than ever to ensure that the value of radiology service to other providers is high. In this review, we will discuss how the radiologist can add value to the referring physician by employing novel imaging techniques in the pre-operative evaluation as well as how the information can be conveyed in the most meaningful manner through the use of structured reporting. We will also familiarize the radiologist with the imaging appearance of common complications that occur after pancreatic surgery.

Authors
Patel, BN; Gupta, RT; Zani, S; Jeffrey, RB; Paulson, EK; Nelson, RC
MLA Citation
Patel, BN, Gupta, RT, Zani, S, Jeffrey, RB, Paulson, EK, and Nelson, RC. "How the radiologist can add value in the evaluation of the pre- and post-surgical pancreas." Abdominal imaging 40.8 (October 19, 2015): 2932-2944. (Review)
PMID
26482048
Source
epmc
Published In
Abdominal Imaging
Volume
40
Issue
8
Publish Date
2015
Start Page
2932
End Page
2944

Effect of radiologists' experience with an adaptive statistical iterative reconstruction algorithm on detection of hypervascular liver lesions and perception of image quality.

To prospectively evaluate whether clinical experience with an adaptive statistical iterative reconstruction algorithm (ASiR) has an effect on radiologists' diagnostic performance and confidence for the diagnosis of hypervascular liver tumors, as well as on their subjective perception of image quality.Forty patients, having 65 hypervascular liver tumors, underwent contrast-enhanced MDCT during the hepatic arterial phase. Image datasets were reconstructed with filtered backprojection algorithm and ASiR (20%, 40%, 60%, and 80% blending). During two reading sessions, performed before and after a three-year period of clinical experience with ASiR, three readers assessed datasets for lesion detection, likelihood of malignancy, and image quality.For all reconstruction algorithms, there was no significant change in readers' diagnostic accuracy and sensitivity for the detection of liver lesions, between the two reading sessions. However, a 60% ASiR dataset yielded a significant improvement in specificity, lesion conspicuity, and confidence for lesion likelihood of malignancy during the second reading session (P < 0.0001). The 60% ASiR dataset resulted in significant improvement in readers' perception of image quality during the second reading session (P < 0.0001).Clinical experience using an ASiR algorithm may improve radiologists' diagnostic performance for the diagnosis of hypervascular liver tumors, as well as their perception of image quality.

Authors
Marin, D; Mileto, A; Gupta, RT; Ho, LM; Allen, BC; Choudhury, KR; Nelson, RC
MLA Citation
Marin, D, Mileto, A, Gupta, RT, Ho, LM, Allen, BC, Choudhury, KR, and Nelson, RC. "Effect of radiologists' experience with an adaptive statistical iterative reconstruction algorithm on detection of hypervascular liver lesions and perception of image quality." Abdominal imaging 40.7 (October 2015): 2850-2860.
PMID
25783958
Source
epmc
Published In
Abdominal Imaging
Volume
40
Issue
7
Publish Date
2015
Start Page
2850
End Page
2860
DOI
10.1007/s00261-015-0398-8

Impact of CT in elderly patients presenting to the emergency department with acute abdominal pain.

The purpose of the study was to document the clinical impact of CT in elderly patients presenting to the emergency department (ED) with abdominal pain.This retrospective IRB-approved study from 2006 to 2013 evaluated 464 patients ≥80 years (mean 89 years, range 80-100: M150, W314), who presented to the ED with acute abdominal symptoms and underwent CT. CTs were divided into those negative and positive for actionable findings, defined as potentially requiring a change in surgical or medical management. Physician diagnosis, treatment plan, and disposition before and after CT were reviewed in the electronic medical record to assess CT influence on management and disposition. CT diagnosis was confirmed with final clinical diagnosis, surgical intervention, pathology, and follow-up. Descriptive statistics were used.CTs were positive in 55%. The most common diagnoses were SBO (18%), diverticulitis (9%), non-ischemic vascular-related emergency (6%), bowel ischemia (4%), appendicitis (3%), and colonic obstruction (2%). These diagnoses were clinically unsuspected prior to CT in 43% (p < 0.05), with significant difficultly in diagnosing SBO (p < 0.05), diverticulitis (p < 0.01), and colonic obstruction (p < 0.01). Positive CT results influenced treatment plans in 65%, surgical in 48%, and medical in 52%. Disposition from the ED was significantly affected by CT (p < 0.001), 65% of admissions with positive CT (p < 0.001) and 63% of discharges with negative CT (p < 0.001).Utilization of abdominopelvic CT in geriatric patients presenting to the ED with acute abdominal symptoms strongly influences clinical management and significantly affects disposition. As the US population ages, the clinical impact of emergent CT in the elderly will intensify.

Authors
Gardner, CS; Jaffe, TA; Nelson, RC
MLA Citation
Gardner, CS, Jaffe, TA, and Nelson, RC. "Impact of CT in elderly patients presenting to the emergency department with acute abdominal pain." Abdominal imaging 40.7 (October 2015): 2877-2882.
PMID
25862547
Source
epmc
Published In
Abdominal Imaging
Volume
40
Issue
7
Publish Date
2015
Start Page
2877
End Page
2882
DOI
10.1007/s00261-015-0419-7

Percutaneous cryoablation of renal masses under CT fluoroscopy: radiation doses to the patient and interventionalist.

Computed tomographic (CT) fluoroscopy-guided percutaneous cryoablation is an effective therapeutic method used to treat focal renal masses. The purpose of this study is to quantify the radiation dose to the patient and interventional radiologist during percutaneous cryoablation of renal masses using CT fluoroscopic guidance.Over a 1-year period, the CT fluoroscopy time during percutaneous cryoablation of renal masses was recorded in 41 patients. The level of complexity of each procedure was designated as simple, intermediate, or complex. Patient organ radiation doses were estimated using an anthropomorphic model. Dose to the interventional radiologist was estimated using ion chamber survey meters.The average CT fluoroscopy time for technically simple cases was 47 s, 126 s for intermediate cases, and 264 s for complex cases. The relative risk of hematologic stomach and liver malignancy in patients undergoing this procedure was 1.003-1.074. The lifetime attributable risk of cancer ranged from 2 to 58, with the highest risk in younger patients for developing leukemia. The estimated radiation dose to the interventionalist without lead shielding was 390 mR (3.9 mGy) per year of cases.The radiation risk to the patient during CT fluoroscopy-guided percutaneous renal mass cryoablation is, as expected, related to procedure complexity. Quantification of patient organ radiation dose was estimated using an anthropomorphic model. This information, along with the associated relative risk of malignancy, may assist in evaluating risks of the procedure, particularly in younger patients. The radiation dose to the interventionist is low regardless of procedure complexity, but highlights the importance of lead shielding.

Authors
Stewart, JK; Looney, CB; Anderson-Evans, CD; Toncheva, GI; Sopko, DR; Kim, CY; Yoshizumi, TT; Nelson, RC
MLA Citation
Stewart, JK, Looney, CB, Anderson-Evans, CD, Toncheva, GI, Sopko, DR, Kim, CY, Yoshizumi, TT, and Nelson, RC. "Percutaneous cryoablation of renal masses under CT fluoroscopy: radiation doses to the patient and interventionalist." Abdominal imaging 40.7 (October 2015): 2606-2612.
PMID
25989931
Source
epmc
Published In
Abdominal Imaging
Volume
40
Issue
7
Publish Date
2015
Start Page
2606
End Page
2612
DOI
10.1007/s00261-015-0456-2

Diagnostic performance of imaging criteria for distinguishing autoimmune cholangiopathy from primary sclerosing cholangitis and bile duct malignancy.

To determine the diagnostic performance of imaging criteria for distinguishing Ig-G4-associated autoimmune cholangiopathy (IAC) from primary sclerosing cholangitis (PSC) and bile duct malignancy.A medical records search between January 2008 and October 2013 identified 10 patients (8 M, 2 F, mean age 61 years, range 34-82) with a clinical diagnosis of IAC. Fifteen cases of PSC (6 M, 9 F, mean age 50, range 22-65) and 15 cases of biliary malignancy (7 M, 8 F, mean age 65, range 48-84) were randomly selected for comparative analysis. Three abdominal radiologists independently reviewed MRI with MRCP (n = 32) or CT (n = 8) and ERCP (n = 8) for the following IAC imaging predictors: single-wall bile duct thickness >2.5 mm, continuous biliary involvement, gallbladder involvement, liver disease, peribiliary mass, or pancreatic and renal abnormalities. Each radiologist provided an imaging-based diagnosis (IAC, PSC, or cancer). Imaging predictor sensitivity, specificity, accuracy, and association with IAC using Fisher's exact test. Inter-reader agreement determined using Fleiss' kappa statistics.For diagnosis of IAC, sensitivities and specificities were high (70-93%). Pancreatic abnormality was strongest predictor for distinguishing IAC from PSC and cancer, with high diagnostic performance (70-80% sensitivity, 87-97% specificity), significant association (p < 0.01), and moderate inter-reader agreement (κ = 0.59). Continuous biliary involvement was moderately predictive (50-100% sensitivity, 53-83% specificity) and trended toward significant association in distinguishing from PSC (p = 0.01-0.19), but less from cancer (p = 0.06-0.62).It remains difficult to distinguish IAC from PSC or bile duct malignancy based on imaging features alone. The presence of pancreatic abnormalities, including peripancreatic rind, atrophy, abnormal enhancement, or T2 signal intensity, strongly favors a diagnosis of IAC.

Authors
Gardner, CS; Bashir, MR; Marin, D; Nelson, RC; Choudhury, KR; Ho, LM
MLA Citation
Gardner, CS, Bashir, MR, Marin, D, Nelson, RC, Choudhury, KR, and Ho, LM. "Diagnostic performance of imaging criteria for distinguishing autoimmune cholangiopathy from primary sclerosing cholangitis and bile duct malignancy." Abdominal imaging 40.8 (October 2015): 3052-3061.
PMID
26350286
Source
epmc
Published In
Abdominal Imaging
Volume
40
Issue
8
Publish Date
2015
Start Page
3052
End Page
3061
DOI
10.1007/s00261-015-0543-4

High-Pitch Dual-Source MDCT for Imaging of the Thoracoabdominal Aorta: Relationships Among Radiation Dose, Noise, Pitch, and Body Size in a Phantom Experiment and Clinical Study.

The purpose of this study was to investigate, both in a phantom experiment and a within-patient clinical study the relationships among radiation dose, image noise, pitch, and body size in MDCT angiography of the thoracoabdominal aorta, with the use of high-pitch dual-source and standard-pitch single-source acquisitions.A proprietary tapered phantom consisting of four ultrahigh-molecular-weight polyethylene cylinders was used to mimic the body size ranges (small, medium, large, and extra large) of patients in the United States. The phantom was imaged using both standard-pitch (0.8) and various high-pitch (range, 2.0-3.2 [in increments of 0.4]) settings. Standard-pitch and high-pitch acquisitions were also performed in 45 patients (27 men, 18 women; mean age, 67.6 years).At standard pitch, the volume CT dose index (CTDIvol) increased with phantom size, in a logistic sigmoid relationship. At high-pitch settings, the CTDIvol increased gradually in relation to phantom size, up to a threshold (denoted by tCTDI[pitch] ≈ 48.3-7.5 pitch), which linearly decreased (R(2) = 0.99) with pitch (maximum CTDIvol output at pitch [maxCTDI(pitch)] ≈ 18.9-3.9 pitch). A linear decrease in the size-specific dose estimate (SSDE) was observed beyond phantom size thresholds (tSSDE[pitch] ≈ 47.6-8.6 pitch) linearly decreasing (R(2) = 0.98) with pitch (maximum SSDE output at pitch [maxSSDE(pitch)] ≈ 15.5-1.3 pitch). Image noise was statistically significantly lower at standard pitch than at high-pitch settings (p = 0.01). In patients, statistically significant differences were noted between standard and high-pitch settings in the mean CTDIvol(10.8 ± 2.6 and 8.3 ± 0.7 mGy, respectively), SSDE (11.3 ± 2.1 and 8.8 ± 1.5 mGy, respectively), and noise (9.7 ± 2.2 and 14 ± 4.2, respectively) (p < .0001, for all comparisons).Lower radiation dose levels achieved with the use of a high-pitch technique reflect limitations in tube output occurring for medium to large body sizes, with an associated exponential increase in noise. The standard- and high-pitch techniques yield similar radiation dose levels for small body sizes.

Authors
Mileto, A; Ramirez-Giraldo, JC; Nelson, RC; Hurwitz, LM; Choudhury, KR; Seaman, DM; Marin, D
MLA Citation
Mileto, A, Ramirez-Giraldo, JC, Nelson, RC, Hurwitz, LM, Choudhury, KR, Seaman, DM, and Marin, D. "High-Pitch Dual-Source MDCT for Imaging of the Thoracoabdominal Aorta: Relationships Among Radiation Dose, Noise, Pitch, and Body Size in a Phantom Experiment and Clinical Study." AJR. American journal of roentgenology 205.4 (October 2015): 834-839.
PMID
26397333
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
205
Issue
4
Publish Date
2015
Start Page
834
End Page
839
DOI
10.2214/ajr.15.14334

Dual-Energy Multidetector-Row Computed Tomography of the Hepatic Arterial System: Optimization of Energy and Material-Specific Reconstruction Techniques.

To investigate the optimal dual-energy reconstruction technique for the visualization of the hepatic arterial system during dual-energy multidetector computed tomographic (MDCT) angiography of the liver.Twenty-nine nonconsecutive patients underwent dual-energy MDCT angiography of the liver. Synthesized monochromatic (40, 50, 60, and 80 keV) and iodine density data sets were reconstructed. Aortic attenuation, noise, and contrast-to-noise ratio (CNR) were measured. In addition, volume-rendered images were generated and qualitatively assessed by 2 independent readers, blinded to technique. The impact of body size on the readers' scores was also assessed.Aortic attenuation, noise, and CNR increased progressively with decreasing keV and were significantly higher between 40 and 60 keV (P < 0.001). There was a significant improvement of readers' visualization of arterial anatomy at lower monochromatic energies (P < 0.001). Iodine density images yielded significantly higher CNR compared with all monochromatic data sets (P < 0.001). However, iodine density images were scored nondiagnostic by the 2 readers.Synthesized monochromatic images between 40 and 60 keV maximize the magnitude of arterial enhancement and improve visualization of hepatic arterial anatomy at dual-energy MDCT angiography of the liver. Larger body sizes may counteract the benefits of using lower monochromatic energies.

Authors
Marin, D; Caywood, DT; Mileto, A; Reiner, CS; Seaman, DM; Patel, BN; Boll, DT; Nelson, RC
MLA Citation
Marin, D, Caywood, DT, Mileto, A, Reiner, CS, Seaman, DM, Patel, BN, Boll, DT, and Nelson, RC. "Dual-Energy Multidetector-Row Computed Tomography of the Hepatic Arterial System: Optimization of Energy and Material-Specific Reconstruction Techniques." Journal of computer assisted tomography 39.5 (September 2015): 721-729.
PMID
25938210
Source
epmc
Published In
Journal of Computer Assisted Tomography
Volume
39
Issue
5
Publish Date
2015
Start Page
721
End Page
729
DOI
10.1097/rct.0000000000000259

Concordance of hypervascular liver nodule characterization between the organ procurement and transplant network and liver imaging reporting and data system classifications.

To determine the rate of agreement between the Organ Procurement and Transplant Network (OPTN) and Liver Imaging Reporting and Data System (LI-RADS) classifications for hypervascular liver nodules at least 1 cm in diameter, and for patient eligibility for hepatocellular/MELD (Model for Endstage Liver Disease) exception points.This retrospective study was approved by our Institutional Review Board and was compliant with the Health Insurance Portability and Accountability Act. The requirement for informed consent was waived. This study included 200 hypervascular hepatocellular nodules at least 1 cm in diameter on computed tomography (CT) or magnetic resonance imaging (MRI) examinations in 105 patients with chronic liver disease. Three radiologists blinded to clinical data independently evaluated nodule characteristics, including washout, capsule, size, and size on prior examination. Based on those characteristics, nodules were automatically classified as definite hepatocellular carcinoma (HCC) or not definite HCC using both the OPTN and LI-RADS classifications. Using these classifications and the Milan criteria, each examination was determined to be "below transplant criteria," "within transplant criteria," or "beyond transplant criteria." Agreement was assessed between readers and classification systems, using Fleiss' kappa, intraclass correlation coefficients (ICCs), and simple proportions.Interreader agreement was moderate for nodule features (κ = 0.59-0.69) and nodule classification (0.66-0.69). The two systems were in nearly complete agreement on nodule category assignment (98.7% [592/600]) and patient eligibility for transplant exemption priority (99.4% [313/315]). A few discrepancies occurred for the nodule feature of growth (1.3% [8/600]) and for nodule category assignment (1.3% [8/600]).Agreement between the OPTN and LI-RADS classifications is very strong for categorization of hypervascular liver nodules at least 1 cm in diameter, and for patient eligibility for hepatocellular/MELD exception points. Interreader variability is much higher than intersystem variability.

Authors
Bashir, MR; Huang, R; Mayes, N; Marin, D; Berg, CL; Nelson, RC; Jaffe, TA
MLA Citation
Bashir, MR, Huang, R, Mayes, N, Marin, D, Berg, CL, Nelson, RC, and Jaffe, TA. "Concordance of hypervascular liver nodule characterization between the organ procurement and transplant network and liver imaging reporting and data system classifications." Journal of magnetic resonance imaging : JMRI 42.2 (August 2015): 305-314.
PMID
25371354
Source
epmc
Published In
Journal of Magnetic Resonance Imaging
Volume
42
Issue
2
Publish Date
2015
Start Page
305
End Page
314
DOI
10.1002/jmri.24793

Comparison of Acute Histologic and Biomechanical Effects of Radiofrequency Ablation and Cryoablation on Periarticular Structures in a Swine Model.

To compare the acute effects of radiofrequency (RF) ablation and cryoablation on the structural integrity of nontarget periarticular tissues that may be placed at risk during percutaneous bone ablation.RF ablation and cryoablation were separately performed on tendon, articular cartilage, and ligament in an ex vivo porcine model by using standard bone ablation protocols. Gross and histopathologic analysis was performed on cartilage and tendon (n = 6 for each treatment group, n = 5 controls). Tendon lengths were measured before and after ablation. Biomechanical tensile testing was performed on each ligament sample after ablation, with quantification of ultimate load at failure and linear stiffness (n = 7 ligaments in treatment and control groups).RF ablation and cryoablation injured chondrocytes within the ablation zones but caused minimal effects on gross and histologic cartilage architecture. Cryoablation resulted in minimal gross and histologic effects on tendon whereas RF ablation resulted in marked disruption of collagen fibers and significant longitudinal shortening (P = .002). Similarly, cryoablation did not alter ligament strength or stiffness compared with control, whereas RF ablation resulted in a significant decrease in tensile strength and stiffness compared with control and cryoablation samples (P < .001).Neither RF ablation nor cryoablation resulted in significant acute changes in cartilage architecture. However, RF ablation resulted in marked disruption of tendon architecture, tendon shortening, ligament weakening, and loss of ligament stiffness, whereas cryoablation had no significant effect on any of these parameters. These findings suggest that cryoablation may have fewer negative acute effects than RF ablation, although long-term outcomes are currently unknown.

Authors
Vikingstad, EM; de Ridder, GG; Glisson, RR; Cardona, DM; DiPalma, D; Eward, WC; Brigman, BE; Nelson, RC; Kim, CY
MLA Citation
Vikingstad, EM, de Ridder, GG, Glisson, RR, Cardona, DM, DiPalma, D, Eward, WC, Brigman, BE, Nelson, RC, and Kim, CY. "Comparison of Acute Histologic and Biomechanical Effects of Radiofrequency Ablation and Cryoablation on Periarticular Structures in a Swine Model." Journal of vascular and interventional radiology : JVIR 26.8 (August 2015): 1221-1228.e1.
PMID
26065927
Source
epmc
Published In
JVIR: Journal of Vascular and Interventional Radiology
Volume
26
Issue
8
Publish Date
2015
Start Page
1221
End Page
1228.e1
DOI
10.1016/j.jvir.2015.04.013

Dual-Energy MDCT for Imaging the Renal Mass.

OBJECTIVE: The purpose of this article is to provide the reader with a comprehensive overview of dual-energy MDCT applications for imaging renal masses. CONCLUSION: Dual-energy MDCT has the potential to substantially improve the ability of radiologists to diagnose renal masses compared with conventional MDCT, potentially streamlining patients' clinical management.

Authors
Mileto, A; Nelson, RC; Paulson, EK; Marin, D
MLA Citation
Mileto, A, Nelson, RC, Paulson, EK, and Marin, D. "Dual-Energy MDCT for Imaging the Renal Mass." AJR. American journal of roentgenology 204.6 (June 2015): W640-W647. (Review)
PMID
25730444
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
204
Issue
6
Publish Date
2015
Start Page
W640
End Page
W647
DOI
10.2214/ajr.14.14094

Impact of CT in elderly patients presenting to the emergency department with acute abdominal pain

© 2015, Springer Science+Business Media New York.Purpose: The purpose of the study was to document the clinical impact of CT in elderly patients presenting to the emergency department (ED) with abdominal pain. Methods: This retrospective IRB-approved study from 2006 to 2013 evaluated 464 patients ≥80 years (mean 89 years, range 80–100: M150, W314), who presented to the ED with acute abdominal symptoms and underwent CT. CTs were divided into those negative and positive for actionable findings, defined as potentially requiring a change in surgical or medical management. Physician diagnosis, treatment plan, and disposition before and after CT were reviewed in the electronic medical record to assess CT influence on management and disposition. CT diagnosis was confirmed with final clinical diagnosis, surgical intervention, pathology, and follow-up. Descriptive statistics were used. Results: CTs were positive in 55%. The most common diagnoses were SBO (18%), diverticulitis (9%), non-ischemic vascular-related emergency (6%), bowel ischemia (4%), appendicitis (3%), and colonic obstruction (2%). These diagnoses were clinically unsuspected prior to CT in 43% (p < 0.05), with significant difficultly in diagnosing SBO (p < 0.05), diverticulitis (p < 0.01), and colonic obstruction (p < 0.01). Positive CT results influenced treatment plans in 65%, surgical in 48%, and medical in 52%. Disposition from the ED was significantly affected by CT (p < 0.001), 65% of admissions with positive CT (p < 0.001) and 63% of discharges with negative CT (p < 0.001). Conclusion: Utilization of abdominopelvic CT in geriatric patients presenting to the ED with acute abdominal symptoms strongly influences clinical management and significantly affects disposition. As the US population ages, the clinical impact of emergent CT in the elderly will intensify.

Authors
Gardner, CS; Jaffe, TA; Nelson, RC
MLA Citation
Gardner, CS, Jaffe, TA, and Nelson, RC. "Impact of CT in elderly patients presenting to the emergency department with acute abdominal pain." Abdominal Imaging 40.7 (April 11, 2015): 2877-2882.
Source
scopus
Published In
Abdominal Imaging
Volume
40
Issue
7
Publish Date
2015
Start Page
2877
End Page
2882
DOI
10.1007/s00261-015-0419-7

Emerging applications for ferumoxytol as a contrast agent in MRI.

Ferumoxytol is an ultrasmall superparamagnetic iron oxide (USPIO) agent initially approved by the Food and Drug Administration (FDA) as an iron replacement therapy for patients with anemia due to chronic renal failure. Recently, ferumoxytol has been investigated extensively as an intravenous contrast agent in magnetic resonance imaging (MRI). Since it causes regional T1 and T2 * shortening in vivo, conventional pulse sequences can be used following ferumoxytol administration to demonstrate signal enhancement or loss. Ferumoxytol can be administered as a rapid bolus and has a long intravascular half-life on the order of 14-15 hours, making it a potentially useful agent for vascular and perfusion-weighted MRI. In comparison to other USPIOs, ferumoxytol is less limited by allergic and idiosyncratic reactions. Furthermore, since ferumoxytol is an iron-based agent with no potential for causing nephrogenic systemic fibrosis, it may be useful as an alternative to gadolinium-based contrast agents in patients with compromised renal function. Ferumoxytol is ultimately taken up by macrophages/the reticuloendothelial system in the liver, spleen, and lymph nodes, and this uptake mechanism is being explored as a novel imaging technique for vascular lesions, tumors, and lymph nodes. This article reviews the properties of ferumoxytol relevant to MRI as well as many of the uses for the agent currently under investigation.

Authors
Bashir, MR; Bhatti, L; Marin, D; Nelson, RC
MLA Citation
Bashir, MR, Bhatti, L, Marin, D, and Nelson, RC. "Emerging applications for ferumoxytol as a contrast agent in MRI." Journal of magnetic resonance imaging : JMRI 41.4 (April 2015): 884-898. (Review)
PMID
24974785
Source
epmc
Published In
Journal of Magnetic Resonance Imaging
Volume
41
Issue
4
Publish Date
2015
Start Page
884
End Page
898
DOI
10.1002/jmri.24691

Interdependencies of acquisition, detection, and reconstruction techniques on the accuracy of iodine quantification in varying patient sizes employing dual-energy CT.

PURPOSE: To assess the impact of patient habitus, acquisition parameters, detector efficiencies, and reconstruction techniques on the accuracy of iodine quantification using dual-source dual-energy CT (DECT). MATERIALS AND METHODS: Two phantoms simulating small and large patients contained 20 iodine solutions mimicking vascular and parenchymal enhancement from saline isodensity to 400 HU and 30 iodine solutions simulating enhancement of the urinary collecting system from 400 to 2,000 HU. DECT acquisition (80/140 kVp and 100/140 kVp) was performed using two DECT systems equipped with standard and integrated electronics detector technologies. DECT raw datasets were reconstructed using filtered backprojection (FBP), and iterative reconstruction (SAFIRE I/V). RESULTS: Accuracy for iodine quantification was significantly higher for the small compared to the large phantoms (9.2 % ± 7.5 vs. 24.3 % ± 26.1, P = 0.0001), the integrated compared to the conventional detectors (14.8 % ± 20.6 vs. 18.8 % ± 20.4, respectively; P = 0.006), and SAFIRE V compared to SAFIRE I and FBP reconstructions (15.2 % ± 18.1 vs. 16.1 % ± 17.6 and 18.9 % ± 20.4, respectively; P ≤ 0.003). A significant synergism was observed when the most effective detector and reconstruction techniques were combined with habitus-adapted dual-energy pairs. CONCLUSION: In a second-generation dual-source DECT system, the accuracy of iodine quantification can be substantially improved by an optimal choice and combination of acquisition parameters, detector, and reconstruction techniques.

Authors
Marin, D; Pratts-Emanuelli, JJ; Mileto, A; Husarik, DB; Bashir, MR; Nelson, RC; Boll, DT
MLA Citation
Marin, D, Pratts-Emanuelli, JJ, Mileto, A, Husarik, DB, Bashir, MR, Nelson, RC, and Boll, DT. "Interdependencies of acquisition, detection, and reconstruction techniques on the accuracy of iodine quantification in varying patient sizes employing dual-energy CT." European radiology 25.3 (March 2015): 679-686.
PMID
25278247
Source
epmc
Published In
European Radiology
Volume
25
Issue
3
Publish Date
2015
Start Page
679
End Page
686
DOI
10.1007/s00330-014-3447-8

Effects of model-based iterative reconstruction on image quality for low-dose computed tomographic angiography of the thoracic aorta in a Swine model.

PURPOSE: The aim of the study was to assess the image quality of multi-detector-row computed tomography (CT) angiographic images of the thoracic aorta reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction, and model-based iterative reconstruction (MBIR) at different kVp and mA settings. METHODS: A healthy 56.1-kg Yorkshire pig underwent sequential arterial CT angiograms on a 64-slice multi-detector-row CT scanner (Discovery CT 750HD; GE Healthcare Inc, Milwaukee, Wis) at progressively lower kVp and mA settings. At 120-, 100-, and 80-kVp levels, the pig was scanned at 700, 400, 200, 100, and 50 mA at, for a total of 15 scans. Each scan was reconstructed with FBP, adaptive statistical iterative reconstruction (50% blend), and MBIR. Relative noise and contrast-to-noise ratio (CNR) were calculated from regions of interest over the aorta and paraspinous muscle. In addition, selected axial and oblique sagittal images were scored subjectively for both aortic wall visibility and for overall image quality. RESULTS: Averaged across all kVp and mA variations, MBIR reduced relative noise by 73.9% and improved CNR by 227% compared with FBP; MBIR reduced relative noise by 63.4% and improved CNR by 107% compared with ASIR. The effects were more pronounced in lower tube output settings. At 100 kVp/700 mA, MBIR reduced noise by 57% compared with FBP and 40% compared with ASIR. At 100 kVp/50 mA, MBIR reduced noise by 82% compared with FBP and 75% compared with ASIR. Subjective improvements in image quality were noted only in higher noise settings. CONCLUSIONS: Model-based iterative reconstruction reduces relative noise and improves CNR compared with ASIR and FBP at all kVp and mA settings, which were significantly greater at lower mA settings.

Authors
Caywood, D; Paxton, B; Boll, D; Nelson, R; Kim, C; Lowry, C; Seaman, D; Roos, JE; Hurwitz, LM
MLA Citation
Caywood, D, Paxton, B, Boll, D, Nelson, R, Kim, C, Lowry, C, Seaman, D, Roos, JE, and Hurwitz, LM. "Effects of model-based iterative reconstruction on image quality for low-dose computed tomographic angiography of the thoracic aorta in a Swine model." Journal of computer assisted tomography 39.2 (March 2015): 196-201.
PMID
25474144
Source
epmc
Published In
Journal of Computer Assisted Tomography
Volume
39
Issue
2
Publish Date
2015
Start Page
196
End Page
201
DOI
10.1097/rct.0000000000000180

Dual-energy multidetector CT for the characterization of incidental adrenal nodules: diagnostic performance of contrast-enhanced material density analysis.

PURPOSE: To determine whether contrast material-enhanced dual-energy multidetector computed tomography (CT) with material decomposition analysis allows differentiation of adrenal adenomas from nonadenomatous lesions and to compare findings with those of nonenhanced multidetector CT. MATERIALS AND METHODS: This retrospective HIPAA-compliant study was approved by the institutional review board of Duke University, with waiver of informed consent. Thirty-eight nonconsecutive patients (22 men and 16 women; mean age, 65 years) with 47 adrenal nodules underwent nonenhanced and contrast-enhanced dual-energy multidetector CT of the abdomen. For each adrenal nodule, nonenhanced attenuation values were recorded; dual-energy density measurements were obtained by using fat-iodine and fat-water material density basis pairs. Mean and median values of nonenhanced attenuation and material densities were compared between adenomas and nonadenomas by using the two-sample t test and Wilcoxon rank sum test, respectively. The diagnostic performance of nonenhanced multidetector CT and dual-energy material densities was assessed by setting the specificity for diagnosis of adenomas at 100%. RESULTS: Adenomas (lipid rich and lipid poor) displayed significantly different mean density values (in milligrams per cubic centimeter) than those of nonadenomas on fat-iodine (970.4 ± 17.2 vs 1012.3 ± 9.3), iodine-fat (2.5 ± 0.3 vs 4.5 ± 1.5), fat-water (-666.7 ± 154.8 vs -2141.8 ± 953.2), and water-fat (1628.4 ± 177.3 vs 3225 ± 986.1) images, respectively (P < .0001). For diagnosis of adenomas, dual-energy material density analysis showed a sensitivity of 96% (23 of 24 lesions) at a specificity of 100% (23 of 23 lesions), yielding significantly improved diagnostic performance compared with nonenhanced multidetector CT attenuation (sensitivity of 67% [16 of 24 lesions] at a specificity of 100% [23 of 23 lesions]) (P = .035). CONCLUSION: Contrast-enhanced dual-energy multidetector CT with material density analysis allows differentiation between adrenal adenomas and nonadenomas, reflecting an improved ability over nonenhanced multidetector CT for diagnosis of lipid-poor adenoma.

Authors
Mileto, A; Nelson, RC; Marin, D; Roy Choudhury, K; Ho, LM
MLA Citation
Mileto, A, Nelson, RC, Marin, D, Roy Choudhury, K, and Ho, LM. "Dual-energy multidetector CT for the characterization of incidental adrenal nodules: diagnostic performance of contrast-enhanced material density analysis." Radiology 274.2 (February 2015): 445-454.
PMID
25207467
Source
epmc
Published In
Radiology
Volume
274
Issue
2
Publish Date
2015
Start Page
445
End Page
454
DOI
10.1148/radiol.14140876

Effects of model-based iterative reconstruction on image quality for low-dose computed tomographic angiography of the thoracic aorta in a swine model

© 2015 Wolters Kluwer Health, Inc.Purpose: The aim of the study was to assess the image quality of multi-detector-row computed tomography (CT) angiographic images of the thoracic aorta reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction, and model-based iterative reconstruction (MBIR) at different kVp and mA settings. Methods: A healthy 56.1-kg Yorkshire pig underwent sequential arterial CT angiograms on a 64-slice multi-detector-row CT scanner (Discovery CT 750HD; GE Healthcare Inc, Milwaukee, Wis) at progressively lower kVp and mA settings. At 120-, 100-, and 80-kVp levels, the pig was scanned at 700, 400, 200, 100, and 50 mA at, for a total of 15 scans. Each scan was reconstructed with FBP, adaptive statistical iterative reconstruction (50% blend), and MBIR. Relative noise and contrast-to-noise ratio (CNR) were calculated from regions of interest over the aorta and paraspinous muscle. In addition, selected axial and oblique sagittal images were scored subjectively for both aortic wall visibility and for overall image quality. Results: Averaged across all kVp and mAvariations, MBIR reduced relative noise by 73.9% and improved CNR by 227% compared with FBP; MBIR reduced relative noise by 63.4% and improved CNR by 107% compared with ASIR. The effects were more pronounced in lower tube output settings. At 100 kVp/700 mA, MBIR reduced noise by 57% compared with FBP and 40% compared with ASIR. At 100 kVp/50 mA, MBIR reduced noise by 82% compared with FBP and 75% compared with ASIR. Subjective improvements in image quality were noted only in higher noise settings. Conclusions:Model-based iterative reconstruction reduces relative noise and improves CNR compared with ASIR and FBP at all kVp and mA settings, which were significantly greater at lower mA settings.

Authors
Caywood, D; Paxton, B; Boll, D; Nelson, R; Kim, C; Lowry, C; Seaman, D; Roos, JE; Hurwitz, LM
MLA Citation
Caywood, D, Paxton, B, Boll, D, Nelson, R, Kim, C, Lowry, C, Seaman, D, Roos, JE, and Hurwitz, LM. "Effects of model-based iterative reconstruction on image quality for low-dose computed tomographic angiography of the thoracic aorta in a swine model." Journal of Computer Assisted Tomography 39.2 (January 1, 2015): 196-201.
Source
scopus
Published In
Journal of Computer Assisted Tomography
Volume
39
Issue
2
Publish Date
2015
Start Page
196
End Page
201
DOI
10.1097/RCT.0000000000000180

Determination of contrast media administration to achieve a targeted contrast enhancement in CT

© 2015 SPIE.Contrast enhancement is a key component of CT imaging and offer opportunities for optimization. The design and optimization of new techniques however requires orchestration with the scan parameters and further a methodology to relate contrast enhancement and injection function. In this study, we used such a methodology to develop a method, analytical inverse method, to predict the required injection function to achieve a desired contrast enhancement in a given organ by incorporation of a physiologically based compartmental model. The method was evaluated across 32 different target contrast enhancement functions for aorta, kidney, stomach, small intestine, and liver. The results exhibited that the analytical inverse method offers accurate performance with error in the range of 10% deviation between the predicted and desired organ enhancement curves. However, this method is incapable of predicting the injection function based on the liver enhancement. The findings of this study can be useful in optimizing contrast medium injection function as well as the scan timing to provide more consistency in the way that the contrast enhanced CT examinations are performed. To our knowledge, this work is one of the first attempts to predict the contrast material injection function for a desired organ enhancement curve.

Authors
Sahbaee, P; Li, Y; Segars, P; Marin, D; Nelson, R; Samei, E
MLA Citation
Sahbaee, P, Li, Y, Segars, P, Marin, D, Nelson, R, and Samei, E. "Determination of contrast media administration to achieve a targeted contrast enhancement in CT." January 1, 2015.
Source
scopus
Published In
Proceedings of SPIE
Volume
9412
Publish Date
2015
DOI
10.1117/12.2082261

Emerging applications for ferumoxytol as a contrast agent in MRI

© 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.Ferumoxytol is an ultrasmall superparamagnetic iron oxide (USPIO) agent initially approved by the Food and Drug Administration (FDA) as an iron replacement therapy for patients with anemia due to chronic renal failure. Recently, ferumoxytol has been investigated extensively as an intravenous contrast agent in magnetic resonance imaging (MRI). Since it causes regional T1 and T2∗ shortening in vivo, conventional pulse sequences can be used following ferumoxytol administration to demonstrate signal enhancement or loss. Ferumoxytol can be administered as a rapid bolus and has a long intravascular half-life on the order of 14-15 hours, making it a potentially useful agent for vascular and perfusion-weighted MRI. In comparison to other USPIOs, ferumoxytol is less limited by allergic and idiosyncratic reactions. Furthermore, since ferumoxytol is an iron-based agent with no potential for causing nephrogenic systemic fibrosis, it may be useful as an alternative to gadolinium-based contrast agents in patients with compromised renal function. Ferumoxytol is ultimately taken up by macrophages/the reticuloendothelial system in the liver, spleen, and lymph nodes, and this uptake mechanism is being explored as a novel imaging technique for vascular lesions, tumors, and lymph nodes. This article reviews the properties of ferumoxytol relevant to MRI as well as many of the uses for the agent currently under investigation.

Authors
Bashir, MR; Bhatti, L; Marin, D; Nelson, RC
MLA Citation
Bashir, MR, Bhatti, L, Marin, D, and Nelson, RC. "Emerging applications for ferumoxytol as a contrast agent in MRI." Journal of Magnetic Resonance Imaging 41.4 (2015): 884-898.
Source
scival
Published In
Journal of Magnetic Resonance Imaging
Volume
41
Issue
4
Publish Date
2015
Start Page
884
End Page
898
DOI
10.1002/jmri.24691

Using the 3-tiered system for categorizing workup of incidental thyroid nodules detected on CT, MRI, or PET/CT: how many cancers would be missed?

BACKGROUND: A 3-tiered system has been proposed by radiologists for the reporting and workup of incidental thyroid nodules (ITN) detected on computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography/computed tomography (PET/CT). It has been shown to reduce the workup rate, but there remains concern about missed malignancies. This study aims at estimating the proportion of incidental cancers that would be missed relative to all thyroid cancers if the 3-tiered system were applied to ITN seen on CT, MRI, or PET/CT. We also aim to characterize these missed incidental cancers by histology and tumor stage. METHODS: A retrospective review was performed of 680 consecutive patients with thyroid cancer who underwent surgery between January 2003 and December 2012. Medical records were reviewed to identify incidental thyroid cancers detected on imaging. Patients with incidental cancers detected on CT, MRI, or PET/CT were categorized according to the system as 3-tiered system-positive and 3-tiered system-negative. The system recommends that only 3-tiered system-positive ITN undergo further workup with ultrasound. Three-tiered system-negative cancers were the cancers that would have been missed if the system were used in practice. These tumors are described by tumor type, size, and stage to determine the potential impact if the 3-tiered system were adopted. RESULTS: One hundred and one patients had imaging-detected incidental cancers, of whom 64 met the inclusion criteria and were originally detected on CT, MRI, or PET/CT. Eight were 3-tiered system-negative, which represents 13% of the 64 incidental cancers that could be categorized and 1.2% of all thyroid cancers treated at our institution in the 10-year period. Three-tiered system-negative tumors were all papillary in histology and had a median size of 12 mm (interquartile range 10-12 mm). Six tumors (75%) were American Joint Committee on Cancer (AJCC) stage I, one was AJCC stage II, and one was AJCC stage III at diagnosis. CONCLUSIONS: Based on thyroid cancers diagnosed during a decade, incidental malignancies missed by the 3-tiered system represent 1.2% of all thyroid malignancies. Three-tiered system-negative incidental cancers were all small papillary cancers. Given that few cancers would be missed and most are less aggressive, we propose that the 3-tiered system could be adopted in clinical practice to guide the workup of ITN identified on CT, MRI, and PET/CT.

Authors
Bahl, M; Sosa, JA; Eastwood, JD; Hobbs, HA; Nelson, RC; Hoang, JK
MLA Citation
Bahl, M, Sosa, JA, Eastwood, JD, Hobbs, HA, Nelson, RC, and Hoang, JK. "Using the 3-tiered system for categorizing workup of incidental thyroid nodules detected on CT, MRI, or PET/CT: how many cancers would be missed?." Thyroid : official journal of the American Thyroid Association 24.12 (December 2014): 1772-1778.
PMID
25203387
Source
epmc
Published In
Thyroid
Volume
24
Issue
12
Publish Date
2014
Start Page
1772
End Page
1778
DOI
10.1089/thy.2014.0066

ACR Appropriateness Criteria® acute pancreatitis.

The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. The Atlanta Classification by the Acute Pancreatitis Classification Working Group recently modified the terminology for the clinical course and the morphologic changes identified on imaging, primarily contrast- enhanced multidetector computed tomography (MDCT). The two distinct clinical courses of the disease are classified as (1) early phase, which lasts approximately 1 week, and (2) late phase, which starts after the first week and can last for months after the initial episode. The two, primary, morphologic changes are acute, interstitial edematous and necrotizing pancreatitis. Timing of imaging, primarily MDCT, is based on the clinical phases and is, therefore, important for these imaging guidelines. Ultrasound's role is to detect gallstones after the first episode. MDCT plays a primary role in the management of acutely ill patients, only after a minimum of 48-72 hours and generally after one week. MR plays a supplementary role to MDCT. Follow-up MDCT guides management and therapy: percutaneous aspiration of fluid collections and/or placement of large caliber catheters in infected necrosis.

Authors
Baker, ME; Nelson, RC; Rosen, MP; Blake, MA; Cash, BD; Hindman, NM; Kamel, IR; Kaur, H; Piorkowski, RJ; Qayyum, A; Yarmish, GM
MLA Citation
Baker, ME, Nelson, RC, Rosen, MP, Blake, MA, Cash, BD, Hindman, NM, Kamel, IR, Kaur, H, Piorkowski, RJ, Qayyum, A, and Yarmish, GM. "ACR Appropriateness Criteria® acute pancreatitis." Ultrasound quarterly 30.4 (December 2014): 267-273.
PMID
25364960
Source
epmc
Published In
Ultrasound Quarterly
Volume
30
Issue
4
Publish Date
2014
Start Page
267
End Page
273
DOI
10.1097/ruq.0000000000000099

Dual-energy MDCT in hypervascular liver tumors: effect of body size on selection of the optimal monochromatic energy level.

OBJECTIVE: The purpose of this article is to investigate the effect of body size on the selection of optimal monochromatic energy level for maximizing the conspicuity of hypervascular liver tumors during late hepatic arterial phase using dual-energy MDCT. MATERIALS AND METHODS: An anthropomorphic liver phantom in three body sizes and iodine-containing inserts simulating low- and high-contrast hypervascular lesions was imaged with dual- and single-energy MDCT at various energy levels (80, 100, 120, and 140 kVp). Dual-energy MDCT was also performed in 48 patients with 114 hypervascular liver tumors; virtual monochromatic images were reconstructed at energy levels from 40 to 140 keV. The effect of body size and lesion iodine concentration on noise and tumor-to-liver contrast-to-noise ratio was compared among different datasets for phantoms and patients. RESULTS: The highest tumor-to-liver contrast-to-noise ratio was noted at 80 kVp for all phantom sizes. On virtual monochromatic images, the minimum noise was noted at 70 keV for small and medium phantoms and at 80 keV for the large phantom. Tumor-to-liver contrast-to-noise ratio was highest at 50 keV for small and medium phantoms and at 60 keV for the large phantom (p<0.0001). Compared with 80-kVp images, an optimal monochromatic energy level yielded a significantly higher (p<0.0001) tumor-to-liver contrast-to-noise ratio for high-contrast lesions in the large body size and for low-contrast lesions in all phantom sizes. In patients, the optimal monochromatic energy level for tumor-to-liver contrast-to-noise ratio increased proportionally along with body size (p<0.0001). CONCLUSION: Selection of the optimal monochromatic energy level for maximizing the conspicuity of hypervascular liver tumors is significantly affected by patient's body size.

Authors
Mileto, A; Nelson, RC; Samei, E; Choudhury, KR; Jaffe, TA; Wilson, JM; Marin, D
MLA Citation
Mileto, A, Nelson, RC, Samei, E, Choudhury, KR, Jaffe, TA, Wilson, JM, and Marin, D. "Dual-energy MDCT in hypervascular liver tumors: effect of body size on selection of the optimal monochromatic energy level." AJR. American journal of roentgenology 203.6 (December 2014): 1257-1264.
PMID
25415703
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
203
Issue
6
Publish Date
2014
Start Page
1257
End Page
1264
DOI
10.2214/ajr.13.12229

Imaging-detected incidental thyroid nodules that undergo surgery: a single-center experience over 1 year.

Incidental thyroid nodules are commonly seen on imaging, and their work-up can ultimately lead to surgery. We describe characteristics and pathology results of imaging-detected incidental thyroid nodules that underwent surgery.A retrospective review was performed of 303 patients who underwent thyroid surgery over a 1-year period to identify patients who presented with incidental thyroid nodules on imaging. Medical records were reviewed for the types of imaging studies that led to detection, nodule characteristics, and surgical pathology.Of 303 patients, 208 patients (69%) had surgery for thyroid nodules. Forty-seven of 208 patients (23%) had incidental thyroid nodules detected on imaging. The most common technique leading to detection was CT (47%). All patients underwent biopsy before surgery. The cytology results were nondiagnostic (6%), benign (4%), atypia of undetermined significance or follicular neoplasm of undetermined significance (23%), follicular neoplasm or suspicious for follicular neoplasm (19%), suspicious for malignancy (17%), and diagnostic of malignancy (30%). Surgical pathology was benign in 24 of 47 (51%) cases of incidental thyroid nodules. In the 23 incidental cancers, the most common histologic type was papillary (87%), the mean size was 1.4 cm, and nodal metastases were present in 7 of 23 cases (30%). No incidental cancers on imaging had distant metastases.Imaging-detected incidental thyroid nodules led to nearly one-fourth of surgeries for thyroid nodules, and almost half were initially detected on CT. Despite indeterminate or suspicious cytology results that lead to surgery, more than half were benign on final pathology. Guidelines for work-up of incidental thyroid nodules detected on CT could help reduce unnecessary investigations and surgery.

Authors
Bahl, M; Sosa, JA; Nelson, RC; Hoang, JK
MLA Citation
Bahl, M, Sosa, JA, Nelson, RC, and Hoang, JK. "Imaging-detected incidental thyroid nodules that undergo surgery: a single-center experience over 1 year." AJNR. American journal of neuroradiology 35.11 (November 2014): 2176-2180.
PMID
24970551
Source
epmc
Published In
American Journal of Neuroradiology
Volume
35
Issue
11
Publish Date
2014
Start Page
2176
End Page
2180
DOI
10.3174/ajnr.a4004

Dual-energy multi-detector row CT with virtual monochromatic imaging for improving patient-to-patient uniformity of aortic enhancement during CT angiography: an in vitro and in vivo study.

PURPOSE: To determine whether virtual monochromatic imaging from a dual-energy acquisition can improve patient-to-patient uniformity of aortic enhancement during multi-detector row computed tomographic (CT) angiography. MATERIALS AND METHODS: This retrospective single-center HIPAA-compliant study was approved by the institutional review board, with a waiver of informed consent. A proprietary tapered hollow phantom that contained a bone-mimicking insert and a hollow tube insert that mimicked the aorta was used. The aortic insert was filled with different iodine dilutions to mimic various degrees of enhancement. The phantom was imaged with both dual-energy and single-energy multi-detector row CT at four energy levels (80, 100, 120, and 140 kVp). Dual-energy multi-detector row CT was also performed in 62 patients (38 men; mean age, 60 years ± 12.7 [standard deviation]). For both the phantom and the patients, virtual monochromatic images were reconstructed from 40 to 140 keV, at 20-keV increments. The relationship between aortic attenuation and effective diameter was assessed by using a statistical model. RESULTS: For all polychromatic data sets, the mean aortic attenuation decreased proportionally to the effective diameter of the phantom (slope, ≥3.0 HU/cm). For virtual monochromatic data sets ranging from 80 to 140 keV, the regression slopes of aortic attenuation as a function of the phantom's effective diameter were negligible (slope, <1.0 HU/cm) for all iodine-to-water dilutions. In patients, the slope of the regression lines was also negligible (-0.69 < slope < 0.16) for virtual monochromatic data sets ranging from 100 to 140 keV. CONCLUSION: Within an energy range of 100-140 keV, virtual monochromatic images improve patient-to-patient uniformity of aortic enhancement compared with conventional polychromatic acquisitions.

Authors
Marin, D; Fananapazir, G; Mileto, A; Choudhury, KR; Wilson, JM; Nelson, RC
MLA Citation
Marin, D, Fananapazir, G, Mileto, A, Choudhury, KR, Wilson, JM, and Nelson, RC. "Dual-energy multi-detector row CT with virtual monochromatic imaging for improving patient-to-patient uniformity of aortic enhancement during CT angiography: an in vitro and in vivo study." Radiology 272.3 (September 2014): 895-902.
PMID
24814182
Source
epmc
Published In
Radiology
Volume
272
Issue
3
Publish Date
2014
Start Page
895
End Page
902
DOI
10.1148/radiol.14132857

Impact of dual-energy multi-detector row CT with virtual monochromatic imaging on renal cyst pseudoenhancement: in vitro and in vivo study.

PURPOSE: To investigate whether dual-energy multi-detector row computed tomography (CT) with virtual monochromatic imaging can overcome renal cyst pseudoenhancement in a phantom experiment and a clinical study. MATERIALS AND METHODS: This retrospective single-center HIPAA-compliant study was approved by the institutional review board, with waiver of informed consent. Four renal compartments inserted into torso phantoms were filled with saline to simulate the unenhanced state and with iodinated solutions to simulate the three levels of renal parenchyma enhancement (140, 180, and 240 HU). Saline-filled spheres simulating renal cysts (15 and 18 mm in diameter) were serially suspended in the renal compartments and imaged with dual-energy and single-energy multi-detector row CT at four different energy levels (80, 100, 120, and 140 kVp). In addition, 28 patients (mean age, 66 years ± 10; mean body mass index, 31.3 kg/m(2) ± 6.2) with 34 intrarenal cysts were included. Virtual monochromatic images were reconstructed in 10-keV increments at energy levels ranging from 40 to 140 keV. Phantom and clinical data were analyzed by using multivariate regression analysis. RESULTS: In the phantom experiment, all polychromatic image data sets showed pseudoenhancement (postcontrast attenuation increase >10 HU) in all investigated conditions, with a significant effect on cyst size (P <.001), location (P <.001), and renal background attenuation level (P <.001). Virtual monochromatic images at energy levels ranging from 80 to 140 keV did not show pseudoenhancement, with the minimum attenuation increase (mean, 6.1 HU ± 1.6; range, 1.6-7.7 HU) on 80-keV images. In patients, pseudoenhancement never occurred on virtual monochromatic images at energy levels ranging from 90 to 140 keV. Patient body size had a significant effect (P = .007) on selection of the optimal monochromatic energy level. CONCLUSION: Dual-energy multi-detector row CT with reconstruction of virtual monochromatic images at an optimal energy level can overcome renal cyst pseudoenhancement.

Authors
Mileto, A; Nelson, RC; Samei, E; Jaffe, TA; Paulson, EK; Barina, A; Choudhury, KR; Wilson, JM; Marin, D
MLA Citation
Mileto, A, Nelson, RC, Samei, E, Jaffe, TA, Paulson, EK, Barina, A, Choudhury, KR, Wilson, JM, and Marin, D. "Impact of dual-energy multi-detector row CT with virtual monochromatic imaging on renal cyst pseudoenhancement: in vitro and in vivo study." Radiology 272.3 (September 2014): 767-776.
PMID
24844472
Source
epmc
Published In
Radiology
Volume
272
Issue
3
Publish Date
2014
Start Page
767
End Page
776
DOI
10.1148/radiol.14132856

Variability of MDCT dose due to technologist performance: impact of posteroanterior versus anteroposterior localizer image and table height with use of automated tube current modulation.

OBJECTIVE: The purpose of this study was to determine MDCT dose variability due to technologist variability in performing CT studies. MATERIALS AND METHODS: Fifty consecutive adult patients who underwent two portal venous phase CT examinations of the abdomen and pelvis on the same 64-MDCT scanner between January and December 2011 were retrospectively identified. Tube voltage (kVp), tube current (mA), use of automated tube current modulation (ATCM), dose-length product (DLP), volume CT dose index (CTDIvol), table height, whether the localizer image was obtained using the posteroanterior or the anteroposterior technique, arm position, and number of overscanned slices were recorded. RESULTS: For a given patient, the total examination DLP difference comparing the two MDCT studies ranged from 0.1% to 238.0%. For the same patient, total examination DLP was always higher when the localizer image was obtained with the posteroanterior compared with the anteroposterior technique. When table position was closer to the x-ray source, patients appeared magnified in the posteroanterior localizer image (8-29%; average, 14%) and higher tube currents were selected with ATCM. Localizer technique, table height, arm position, number of overscanned slices, and technologist were all significant predictors of dose. CONCLUSION: Patient off-centering closer to the x-ray source resulted in patient magnification in the posteroanterior localizer image, leading to higher tube currents with ATCM and increased DLP. Differences in technologist, arm position, and overscanning also resulted in dose variability.

Authors
Harri, PA; Moreno, CC; Nelson, RC; Fani, N; Small, WC; Duong, PA; Tang, X; Applegate, KE
MLA Citation
Harri, PA, Moreno, CC, Nelson, RC, Fani, N, Small, WC, Duong, PA, Tang, X, and Applegate, KE. "Variability of MDCT dose due to technologist performance: impact of posteroanterior versus anteroposterior localizer image and table height with use of automated tube current modulation." AJR. American journal of roentgenology 203.2 (August 2014): 377-386.
PMID
25055274
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
203
Issue
2
Publish Date
2014
Start Page
377
End Page
386
DOI
10.2214/ajr.13.11608

Trends in incidentally identified thyroid cancers over a decade: a retrospective analysis of 2,090 surgical patients.

BACKGROUND: The aim of this study was to describe trends in the incidence of incidental thyroid cancers and compare their characteristics with clinically presenting cancers. METHODS: We performed a retrospective review of patients with thyroid cancer who underwent thyroid surgery from 2003 to 2012. Patients' initial presentation was categorized as incidental (on imaging or final surgical pathology) or clinical (palpable or symptomatic) cancer. Characteristics of incidental and clinical cancers were compared. RESULTS: Of the 2,090 patients who underwent thyroid surgery, 680 (33 %) were diagnosed with cancer. One hundred ninety (28 %) were incidental cancer, of which 101 were detected on imaging studies and 89 were detected on analysis of the surgical pathology specimens. The incidence of thyroid cancer increased by 7.6-fold from 2003 to 2012. The proportion of incidental cancers on imaging did not increase, but incidental cancers found on pathology steadily increased from 6 % in 2003 to 20 % in 2012. 84 % of the cancers were papillary cancer, and the proportion of papillary cancer was similar for both clinical and incidental cancers. Clinical cancers were larger than incidental cancers on imaging (2.2 vs. 1.8 cm, p = 0.02). Incidental cancers on imaging were less likely to have lateral compartment nodal metastases (7 vs. 13 %, p < 0.001). CONCLUSIONS: Thyroid cancer diagnoses have increased at our institution, but the proportion of incidental cancers identified on imaging relative to clinical cancers has been stable over a decade and is not the sole explanation for the observed increase in thyroid cancer diagnoses. Incidental cancers on imaging are smaller in size and less likely to have lateral compartment nodal metastases than clinical cancers.

Authors
Bahl, M; Sosa, JA; Nelson, RC; Esclamado, RM; Choudhury, KR; Hoang, JK
MLA Citation
Bahl, M, Sosa, JA, Nelson, RC, Esclamado, RM, Choudhury, KR, and Hoang, JK. "Trends in incidentally identified thyroid cancers over a decade: a retrospective analysis of 2,090 surgical patients." World J Surg 38.6 (June 2014): 1312-1317.
PMID
24357246
Source
pubmed
Published In
World Journal of Surgery
Volume
38
Issue
6
Publish Date
2014
Start Page
1312
End Page
1317
DOI
10.1007/s00268-013-2407-9

Venous filling defects on portal venous phase CT of the abdomen and pelvis: clinical implications and positive predictive value for diagnosing deep venous thrombosis.

PURPOSE: To determine the prevalence, resulting clinical decisions, and the positive predictive value (PPV) of venous filling defects detected on portal venous phase (PVP) CT. METHODS: Over a 3-year period, 42412 consecutive patients underwent a PVP abdominopelvic CT; of these, 348 reports mentioned a filling defect concerning for deep venous thrombosis (DVT) in the IVC, iliac, or common femoral veins. Ninety-three patients underwent a reference standard venous imaging study. RESULTS: The prevalence of venous filling defects in CT reports was 0.82% (n = 348). Reports worded with higher degrees of certainty were statistically more likely to result in treatment, while lower certainty was correlated with additional confirmatory imaging. The PPV for detection of DVT was 77%. The presence of peri-vascular stranding or vessel expansion increased the PPV of PVP CT to 95% and 100%, respectively. CONCLUSION: While the PPV for filling defects on PVP CT was modest, it was substantially improved if peri-venous stranding or vessel expansion was present.

Authors
Horvath, JJ; Looney, CB; Nelson, RC; Kim, CY
MLA Citation
Horvath, JJ, Looney, CB, Nelson, RC, and Kim, CY. "Venous filling defects on portal venous phase CT of the abdomen and pelvis: clinical implications and positive predictive value for diagnosing deep venous thrombosis." Abdominal imaging 39.3 (June 2014): 554-561.
PMID
24441580
Source
epmc
Published In
Abdominal Imaging
Volume
39
Issue
3
Publish Date
2014
Start Page
554
End Page
561
DOI
10.1007/s00261-014-0077-1

Thyroid cancers incidentally detected at imaging in a 10-year period: how many cancers would be missed with use of the recommendations from the Society of Radiologists in Ultrasound?

PURPOSE: To estimate the prevalence of incidental thyroid cancer (ITC) among patients undergoing thyroid surgery and to apply the Society of Radiologists in Ultrasound (SRU) guidelines to ITC. MATERIALS AND METHODS: This HIPAA-compliant study was approved by the institutional review board, with waiver of the need to obtain informed consent. A retrospective review of data in patients who underwent thyroid surgery between January 1, 2003, and December 31, 2012, was performed. Imaging studies and reports were reviewed for ITCs that were first detected at either ultrasonography (US) or a different imaging modality and that included US as part of the work-up. ITCs were categorized by using the SRU guidelines to determine the characteristics of SRU criteria-positive and SRU criteria-negative malignancies. Patient demographic data, tumor histologic findings, tumor size, and tumor stage were compared for the SRU criteria-positive and SRU criteria-negative cancers by using the unpaired t test and the χ(2) test. RESULTS: Among 2090 patients who underwent thyroid surgery, 680 had thyroid cancer; of these patients, 101 (15%) had imaging-detected ITC. The SRU recommendations were applied to the findings in 90 of the 101 patients who had undergone US with images or had reports available for review. Sixteen (18%) of the 90 patients had SRU criteria-negative tumors, which represented 2% (16 of 680) of all thyroid cancers. SRU criteria-negative tumors were smaller than SRU criteria-positive tumors (mean, 1.1 cm [range, 0.9-1.4 cm] vs mean, 2.5 cm [range, 1.0-7.6 cm]; P < .001) and were more likely to be stage I (15 [94%] of 16 vs 47 [64%] of 74; P = .02). CONCLUSION: Imaging-detected ITCs are uncommon. Two percent (16 of 680) of malignancies would not undergo fine-needle aspiration biopsy or surgery if the SRU guidelines were used for work-up of incidental thyroid nodules. SRU criteria-negative tumors are lower in stage than SRU criteria-positive tumors.

Authors
Bahl, M; Sosa, JA; Nelson, RC; Hobbs, HA; Wnuk, NM; Hoang, JK
MLA Citation
Bahl, M, Sosa, JA, Nelson, RC, Hobbs, HA, Wnuk, NM, and Hoang, JK. "Thyroid cancers incidentally detected at imaging in a 10-year period: how many cancers would be missed with use of the recommendations from the Society of Radiologists in Ultrasound?." Radiology 271.3 (June 2014): 888-894.
PMID
24475865
Source
epmc
Published In
Radiology
Volume
271
Issue
3
Publish Date
2014
Start Page
888
End Page
894
DOI
10.1148/radiol.13132002

Optimal timing and diagnostic adequacy of hepatocyte phase imaging with gadoxetate-enhanced liver MRI.

RATIONALE AND OBJECTIVES: To evaluate clinical and imaging features associated with adequacy of the hepatocyte phase (HP) in gadoxetate disodium-enhanced liver magnetic resonance imaging (MRI) in patients without chronic liver disease (CLD). MATERIALS AND METHODS: This was a retrospective institutional review board-approved study of 97 patients who underwent liver MRI examinations with gadoxetate disodium and had no history of CLD. Available late dynamic and HP sequences (3-20 minutes postinjection) were independently analyzed by four radiologists for perceived image adequacy and level of biliary enhancement. Signal intensity ratios (SIRs) of liver/inferior vena cava (IVC), liver/spleen, and liver/muscle were measured. The Spearman ρ and receiver operating characteristic analyses were performed correlating various factors with HP adequacy. A rule for predicting HP adequacy was also derived and tested to determine whether overall examination time could be shortened. RESULTS: A visually adequate HP was observed in 12% of subjects by 10 minutes, 80% by 15 minutes, and 93% by 20 minutes. An SIRliver/IVC > 1.8 was the imaging feature that had the strongest correlation with an adequate HP (ρ = 0.813, P < .001), and was more predictive of adequacy of the HP than the time postinjection (ρ = 0.5, P < .001). The time at which an adequate HP was first observed did not correlate with any tested demographic or laboratory values. Stopping imaging when an SIRliver/IVC > 1.8 would have successfully reduced mean postcontrast time to 15:39 ± 4:02 from 20:00 (P < .001), although maintaining HP adequacy. CONCLUSIONS: Most patients without CLD undergoing gadoxetate-enhanced liver MRI achieve adequate HP at 20 minutes. However, a shorter postcontrast stopping time can be used in most patients.

Authors
Bashir, MR; Breault, SR; Braun, R; Do, RK; Nelson, RC; Reeder, SB
MLA Citation
Bashir, MR, Breault, SR, Braun, R, Do, RK, Nelson, RC, and Reeder, SB. "Optimal timing and diagnostic adequacy of hepatocyte phase imaging with gadoxetate-enhanced liver MRI." Academic radiology 21.6 (June 2014): 726-732.
PMID
24717550
Source
epmc
Published In
Academic Radiology
Volume
21
Issue
6
Publish Date
2014
Start Page
726
End Page
732
DOI
10.1016/j.acra.2014.02.005

Safety of an intercostal approach for imaging-guided percutaneous drainage of subdiaphragmatic abscesses.

OBJECTIVE: The objective of our study was to test the hypothesis that an intercostal approach to imaging-guided percutaneous subdiaphragmatic abscess drainage is as safe as a subcostal approach. MATERIALS AND METHODS: A cohort of 258 consecutive patients with one or more subdiaphragmatic abscesses referred for imaging-guided (CT or ultrasound) percutaneous drainage was identified. Demographic characteristics and clinical outcomes were compared between patients who underwent drainage catheter placement via an intercostal approach versus those who underwent drainage catheter placement via a subcostal approach. RESULTS: Percutaneous drainage was performed for 441 abscesses in 258 patients in 409 separate procedures (214 via an intercostal approach, 186 by a subcostal approach, and nine by a combined approach). The total number of pleural complications was significantly higher in the intercostal group (56/214 [26.2%]) than the subcostal group (15/186 [8.1%]; p < 0.001). These complications included a significantly higher pneumothorax rate in the intercostal group than the subcostal group (15/214 [7.0%] vs 0/186 [0%], respectively; p < 0.01) and a higher incidence of new or increased pleural effusions (38/214 [17.8%] vs 14/186 [7.5%]; p < 0.01). The incidence of empyema was low and similar between the two groups (intercostal vs subcostal, 3/214 [1.4%] vs 1/186 [0.5%]; p = 0.63). A few of the complications in the patients who underwent an intercostal-approach drainage were clinically significant. Four of the 15 pneumothoraces required thoracostomy tubes and eight of 38 (21.1%) pleural effusions required thoracentesis, none of which was considered infected. CONCLUSION: An intercostal approach for imaging-guided percutaneous drainage is associated with a higher risk of pleural complications; however, most of these complications are minor and should not preclude use of the intercostal approach.

Authors
Preece, SR; Nelson, RC; Bashir, MR; Jaffe, TA; Kim, CY; Haystead, CM
MLA Citation
Preece, SR, Nelson, RC, Bashir, MR, Jaffe, TA, Kim, CY, and Haystead, CM. "Safety of an intercostal approach for imaging-guided percutaneous drainage of subdiaphragmatic abscesses." AJR. American journal of roentgenology 202.6 (June 2014): 1349-1354.
PMID
24848834
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
202
Issue
6
Publish Date
2014
Start Page
1349
End Page
1354
DOI
10.2214/ajr.13.10712

CT of the retroperitoneum: From conventional to multi-energy imaging

© Springer-Verlag Italia 2014. All rights reserved.This book provides a comprehensive and up-to-date overview of the continuously evolving field of dual-energy CT (DECT). An introductory section presents information on the physical and technical background of DECT and considers nonspecific and specific software advantages. Clinical applications of DECT in the evaluation of retroperitoneal viscera are then addressed in detail with the help of high-quality illustrations. Particular attention is devoted to the most recent DECT study protocols, software, and applications in aortic, renal, pancreatic, and adrenal disease. A number of case studies are reported that elucidate the advantages of DECT, and the relevant literature is extensively discussed. The book closes by considering radiation dose and dose-saving measures. The simple and practical approach offered by this book will assist radiologists in the optimal routine use and interpretation of DECT in different retroperitoneal sites and radiology technologists in the choice of settings and parameters.

Authors
Ascenti, G; Vanzulli, A; Catalano, C; Nelson, RC
MLA Citation
Ascenti, G, Vanzulli, A, Catalano, C, and Nelson, RC. CT of the retroperitoneum: From conventional to multi-energy imaging. May 1, 2014.
Source
scopus
Volume
9788847054691
Publish Date
2014
Start Page
1
End Page
102
DOI
10.1007/978-88-470-5469-1

Adrenal glands

© Springer-Verlag Italia 2014. All rights reserved.The adrenal glands can develop a myriad of abnormalities, which can be fundamentally differentiated into benign or malignant lesions having either hyperfunction or non-hyperfunction (i.e., non-function) [1, 2]. Functioning lesions typically secrete hormonal metabolites and include a variety of tumors, some of which are very rare. These tumors can produce cortisol, aldosterone, and sex hormones as well as adrenergic hormones in the case of pheochromocytomas [1-3]. Non-functioning tumors are far more common and include both benign and malignant lesions. Benign masses include cortical adenomas, myelolipomas, cysts and less commonly ganglioneuromas, hemangioendotheliomas, hemorrhage, and granulomatous disease. Malignant lesions include metastases, lymphoma, neuroblastoma, adrenocortical carcinoma, and some forms of pheochromocytomas [1-3].

Authors
Mileto, A; Marin, D; Ho, LM; Nelson, RC
MLA Citation
Mileto, A, Marin, D, Ho, LM, and Nelson, RC. "Adrenal glands." CT of the Retroperitoneum: From Conventional to Multi-energy Imaging. May 1, 2014. 69-81.
Source
scopus
Volume
9788847054691
Publish Date
2014
Start Page
69
End Page
81
DOI
10.1007/978-88-470-5469-1-6

Current opinions on medical radiation: a survey of oncologists regarding radiation exposure and dose reduction in oncology patients.

PURPOSE: The aim of this study was to evaluate oncologists' opinions about the use of ionizing radiation in medical imaging of oncology patients. METHODS: An electronic survey was e-mailed to 2,725 oncologists at the top 50 National Cancer Institute-funded cancer centers. The survey focused on opinions on CT dose reduction in oncology patients and current philosophies behind long-term imaging in these patients. RESULTS: The response rate was 15% (415 of 2,725). Eighty-two percent of respondents stated that their patients or families have expressed anxiety regarding radiation dose from medical imaging. Although fewer than half of oncologists (48%) did not know whether CT dose reduction techniques were used at their institutions, only 25% were concerned that small lesions may be missed with low-dose CT techniques. The majority of oncologists (63%) follow National Comprehensive Cancer Network guidelines for imaging follow-up, while the remainder follow other national guidelines such as those of the Children's Oncology Group, the American Society of Clinical Oncology, or clinical trials. Ninety percent of respondents believe that long-term surveillance in oncology patients is warranted, particularly in patients with breast cancer, melanoma, sarcoma, and pediatric malignancies. The majority of oncologists would consider the use of low-dose CT imaging in specific patient populations: (1) children and young women, (2) those with malignancies that do not routinely metastasize to the liver, and (3) patients undergoing surveillance imaging. CONCLUSIONS: Cumulative radiation exposure is a concern for patients and oncologists. Among oncologists, there is support for long-term imaging surveillance despite lack of national guidelines.

Authors
Burke, LMB; Bashir, MR; Neville, AM; Nelson, RC; Jaffe, TA
MLA Citation
Burke, LMB, Bashir, MR, Neville, AM, Nelson, RC, and Jaffe, TA. "Current opinions on medical radiation: a survey of oncologists regarding radiation exposure and dose reduction in oncology patients." J Am Coll Radiol 11.5 (May 2014): 490-495.
PMID
24321221
Source
pubmed
Published In
Journal of the American College of Radiology
Volume
11
Issue
5
Publish Date
2014
Start Page
490
End Page
495
DOI
10.1016/j.jacr.2013.08.018

State of the art: dual-energy CT of the abdomen.

Recent technologic advances in computed tomography (CT)--enabling the nearly simultaneous acquisition of clinical images using two different x-ray energy spectra--have sparked renewed interest in dual-energy CT. By interrogating the unique characteristics of different materials at different x-ray energies, dual-energy CT can be used to provide quantitative information about tissue composition, overcoming the limitations of attenuation-based conventional single-energy CT imaging. In the past few years, intensive research efforts have been devoted to exploiting the unique and powerful opportunities of dual-energy CT for a variety of clinical applications. This has led to CT protocol modifications for radiation dose reduction, improved diagnostic performance for detection and characterization of diseases, as well as image quality optimization. In this review, the authors discuss the basic principles, instrumentation and design, examples of current clinical applications in the abdomen and pelvis, and future opportunities of dual-energy CT.

Authors
Marin, D; Boll, DT; Mileto, A; Nelson, RC
MLA Citation
Marin, D, Boll, DT, Mileto, A, and Nelson, RC. "State of the art: dual-energy CT of the abdomen." Radiology 271.2 (May 2014): 327-342.
PMID
24761954
Source
epmc
Published In
Radiology
Volume
271
Issue
2
Publish Date
2014
Start Page
327
End Page
342
DOI
10.1148/radiol.14131480

Applying the society of radiologists in ultrasound recommendations for fine-needle aspiration of thyroid nodules: Effect on workup and malignancy detection

OBJECTIVE. The Society of Radiologists in Ultrasound (SRU) recommendations on thyroid nodules are intended to "diagnose thyroid cancers that have reached clinical significance, while avoiding unnecessary tests and surgery in patients with benign nodules." The aim of our study was to determine the proportion of thyroid nodules undergoing ultrasound-guided fine-needle aspiration (FNA) that do not meet SRU recommendations. MATERIALS AND METHODS. This study is a retrospective study of 400 consecutive ultrasound-guided thyroid FNA encounters from July 2010 through June 2011. An encounter was defined as presentation to the department of radiology on a given date for FNA of one or more thyroid nodules. The criteria for performing biopsy of a nodule were determined by the referring clinicians. Nodules were categorized on the basis of sonographic findings as meeting SRU recommendations for biopsy, which we refer to as "SRU-positive," or not, which we refer to as "SRU-negative." Patients without a definitive pathology diagnosis of Bethesda class benign or malignant nodules were excluded. The characteristics of malignancies were compared for SRU-positive and SRU-negative encounters. RESULTS. The final study group consisted of 360 biopsy encounters for 350 patients and 29 malignancies (8%). Of the 360 biopsy encounters, 86 (24%) were SRU-negative encounters. Malignancy rates in SRU-positive and SRU-negative encounters were 9% (24/274) and 6% (5/86), respectively, and were not significantly different ( p = 0.5). Eighteen malignancies (75%) in the SRU-positive group were localized, whereas the others had nodal metastases (4/24) or distant metastases (2/24). SRU-positive encounters included medullary carcinoma, anaplastic carcinoma, and melanoma metastasis in addition to papillary carcinoma. All SRU-negative malignancies were localized papillary carcinomas. CONCLUSION. One in four thyroid biopsy encounters at our institution did not meet SRU recommendations for biopsy. The application of SRU recommendations reduces the number of benign nodules that undergo workup. Potentially missed malignancies in SRU-negative nodules are less aggressive by histologic type and stage compared with SRU-positive malignancies. © American Roentgen Ray Society.

Authors
Hobbs, HA; Bahl, M; Nelson, RC; Eastwood, JD; Esclamado, RM; Hoang, JK
MLA Citation
Hobbs, HA, Bahl, M, Nelson, RC, Eastwood, JD, Esclamado, RM, and Hoang, JK. "Applying the society of radiologists in ultrasound recommendations for fine-needle aspiration of thyroid nodules: Effect on workup and malignancy detection." American Journal of Roentgenology 202.3 (March 1, 2014): 602-607.
Source
scopus
Published In
AJR. American journal of roentgenology
Volume
202
Issue
3
Publish Date
2014
Start Page
602
End Page
607
DOI
10.2214/AJR.13.11219

ACR appropriateness criteria right upper quadrant pain.

Acute right upper quadrant pain is a common presenting symptom in patients with acute cholecystitis. When acute cholecystitis is suspected in patients with right upper quadrant pain, in most clinical scenarios, the initial imaging modality of choice is ultrasound. Although cholescintigraphy has been shown to have slightly higher sensitivity and specificity for diagnosis, ultrasound is preferred as the initial study for a variety of reasons, including greater availability, shorter examination time, lack of ionizing radiation, morphologic evaluation, confirmation of the presence or absence of gallstones, evaluation of bile ducts, and identification or exclusion of alternative diagnoses. CT or MRI may be helpful in equivocal cases and may identify complications of acute cholecystitis. When ultrasound findings are inconclusive, MRI is the preferred imaging test in pregnant patients who present with right upper quadrant pain. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Authors
Yarmish, GM; Smith, MP; Rosen, MP; Baker, ME; Blake, MA; Cash, BD; Hindman, NM; Kamel, IR; Kaur, H; Nelson, RC; Piorkowski, RJ; Qayyum, A; Tulchinsky, M
MLA Citation
Yarmish, GM, Smith, MP, Rosen, MP, Baker, ME, Blake, MA, Cash, BD, Hindman, NM, Kamel, IR, Kaur, H, Nelson, RC, Piorkowski, RJ, Qayyum, A, and Tulchinsky, M. "ACR appropriateness criteria right upper quadrant pain." Journal of the American College of Radiology : JACR 11.3 (March 2014): 316-322.
PMID
24485592
Source
epmc
Published In
Journal of the American College of Radiology
Volume
11
Issue
3
Publish Date
2014
Start Page
316
End Page
322
DOI
10.1016/j.jacr.2013.11.017

Applying the Society of Radiologists in Ultrasound recommendations for fine-needle aspiration of thyroid nodules: effect on workup and malignancy detection.

OBJECTIVE: The Society of Radiologists in Ultrasound (SRU) recommendations on thyroid nodules are intended to "diagnose thyroid cancers that have reached clinical significance, while avoiding unnecessary tests and surgery in patients with benign nodules." The aim of our study was to determine the proportion of thyroid nodules undergoing ultrasound-guided fine-needle aspiration (FNA) that do not meet SRU recommendations. MATERIALS AND METHODS: This study is a retrospective study of 400 consecutive ultrasound-guided thyroid FNA encounters from July 2010 through June 2011. An encounter was defined as presentation to the department of radiology on a given date for FNA of one or more thyroid nodules. The criteria for performing biopsy of a nodule were determined by the referring clinicians. Nodules were categorized on the basis of sonographic findings as meeting SRU recommendations for biopsy, which we refer to as "SRU-positive," or not, which we refer to as "SRU-negative." Patients without a definitive pathology diagnosis of Bethesda class benign or malignant nodules were excluded. The characteristics of malignancies were compared for SRU-positive and SRU-negative encounters. RESULTS: The final study group consisted of 360 biopsy encounters for 350 patients and 29 malignancies (8%). Of the 360 biopsy encounters, 86 (24%) were SRU-negative encounters. Malignancy rates in SRU-positive and SRU-negative encounters were 9% (24/274) and 6% (5/86), respectively, and were not significantly different (p=0.5). Eighteen malignancies (75%) in the SRU-positive group were localized, whereas the others had nodal metastases (4/24) or distant metastases (2/24). SRU-positive encounters included medullary carcinoma, anaplastic carcinoma, and melanoma metastasis in addition to papillary carcinoma. All SRU-negative malignancies were localized papillary carcinomas. CONCLUSION: One in four thyroid biopsy encounters at our institution did not meet SRU recommendations for biopsy. The application of SRU recommendations reduces the number of benign nodules that undergo workup. Potentially missed malignancies in SRU-negative nodules are less aggressive by histologic type and stage compared with SRU-positive malignancies.

Authors
Hobbs, HA; Bahl, M; Nelson, RC; Eastwood, JD; Esclamado, RM; Hoang, JK
MLA Citation
Hobbs, HA, Bahl, M, Nelson, RC, Eastwood, JD, Esclamado, RM, and Hoang, JK. "Applying the Society of Radiologists in Ultrasound recommendations for fine-needle aspiration of thyroid nodules: effect on workup and malignancy detection." AJR. American journal of roentgenology 202.3 (March 2014): 602-607.
PMID
24555597
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
202
Issue
3
Publish Date
2014
Start Page
602
End Page
607
DOI
10.2214/ajr.13.11219

Dual energy MDCT assessment of renal lesions: an overview.

With the expansion of cross-sectional imaging, the number of renal lesions that are incidentally discovered has increased. Multidetector CT (MDCT) is the investigation of choice for characterising and staging renal lesions. Although a definitive diagnosis can be confidently posed for most of them, a number of renal lesions remain indeterminate following MDCT. Further imaging tests are therefore needed, with subsequent increase of healthcare costs, radiation exposure, and patient anxiety. By addressing most of the issues with conventional MDCT imaging, dual-energy MDCT can improve the diagnosis of renal lesions and, potentially, may represent a paradigm shift from a merely attenuation-based to a material-specific spectral imaging investigation. The purpose of this review is to provide an overview of current clinical applications of dual-energy CT in the evaluation of renal lesions. Key Points • As MDCT expands, an increasing number of renal lesions are serendipitously discovered. • With conventional MDCT, technical issues affect the diagnosis of renal lesions. • Dual-energy CT addresses some of the drawbacks of conventional MDCT. • Dual-energy CT may represent a paradigm shift for renal lesions imaging.

Authors
Mileto, A; Marin, D; Nelson, RC; Ascenti, G; Boll, DT
MLA Citation
Mileto, A, Marin, D, Nelson, RC, Ascenti, G, and Boll, DT. "Dual energy MDCT assessment of renal lesions: an overview." Eur Radiol 24.2 (February 2014): 353-362. (Review)
PMID
24092045
Source
pubmed
Published In
European Radiology
Volume
24
Issue
2
Publish Date
2014
Start Page
353
End Page
362
DOI
10.1007/s00330-013-3030-8

Current opinions on medical radiation: A survey of oncologists regarding radiation exposure and dose reduction in oncology patients

Purpose The aim of this study was to evaluate oncologists' opinions about the use of ionizing radiation in medical imaging of oncology patients. Methods An electronic survey was e-mailed to 2,725 oncologists at the top 50 National Cancer Institute-funded cancer centers. The survey focused on opinions on CT dose reduction in oncology patients and current philosophies behind long-term imaging in these patients. Results The response rate was 15% (415 of 2,725). Eighty-two percent of respondents stated that their patients or families have expressed anxiety regarding radiation dose from medical imaging. Although fewer than half of oncologists (48%) did not know whether CT dose reduction techniques were used at their institutions, only 25% were concerned that small lesions may be missed with low-dose CT techniques. The majority of oncologists (63%) follow National Comprehensive Cancer Network guidelines for imaging follow-up, while the remainder follow other national guidelines such as those of the Children's Oncology Group, the American Society of Clinical Oncology, or clinical trials. Ninety percent of respondents believe that long-term surveillance in oncology patients is warranted, particularly in patients with breast cancer, melanoma, sarcoma, and pediatric malignancies. The majority of oncologists would consider the use of low-dose CT imaging in specific patient populations: (1) children and young women, (2) those with malignancies that do not routinely metastasize to the liver, and (3) patients undergoing surveillance imaging. Conclusions Cumulative radiation exposure is a concern for patients and oncologists. Among oncologists, there is support for long-term imaging surveillance despite lack of national guidelines. © 2014 American College of Radiology.

Authors
Burke, LMB; Bashir, MR; Neville, AM; Nelson, RC; Jaffe, TA
MLA Citation
Burke, LMB, Bashir, MR, Neville, AM, Nelson, RC, and Jaffe, TA. "Current opinions on medical radiation: A survey of oncologists regarding radiation exposure and dose reduction in oncology patients." Journal of the American College of Radiology 11.5 (January 1, 2014): 490-495.
Source
scopus
Published In
Journal of the American College of Radiology
Volume
11
Issue
5
Publish Date
2014
Start Page
490
End Page
495
DOI
10.1016/j.jacr.2013.08.018

Optimal Timing and Diagnostic Adequacy of Hepatocyte Phase Imaging with Gadoxetate-Enhanced Liver MRI

Rationale and Objectives: To evaluate clinical and imaging features associated with adequacy of the hepatocyte phase (HP) in gadoxetate disodium-enhanced liver magnetic resonance imaging (MRI) in patients without chronic liver disease (CLD). Materials and Methods: This was a retrospective institutional review board-approved study of 97 patients who underwent liver MRI examinations with gadoxetate disodium and had no history of CLD. Available late dynamic and HP sequences (3-20 minutes postinjection) were independently analyzed by four radiologists for perceived image adequacy and level of biliary enhancement. Signal intensity ratios (SIRs) of liver/inferior vena cava (IVC), liver/spleen, and liver/muscle were measured. The Spearman ρ and receiver operating characteristic analyses were performed correlating various factors with HP adequacy. A rule for predicting HP adequacy was also derived and tested to determine whether overall examination time could be shortened. Results: A visually adequate HP was observed in 12% of subjects by 10 minutes, 80% by 15 minutes, and 93% by 20 minutes. An SIRliver/IVC > 1.8 was the imaging feature that had the strongest correlation with an adequate HP (ρ = 0.813, P < .001), and was more predictive of adequacy of the HP than the time postinjection (ρ = 0.5, P < .001). The time at which an adequate HP was first observed did not correlate with any tested demographic or laboratory values. Stopping imaging when an SIRliver/IVC > 1.8 would have successfully reduced mean postcontrast time to 15:39 ± 4:02 from 20:00 (P < .001), although maintaining HP adequacy. Conclusions: Most patients without CLD undergoing gadoxetate-enhanced liver MRI achieve adequate HP at 20 minutes. However, a shorter postcontrast stopping time can be used in most patients. © 2014 AUR.

Authors
Bashir, MR; Breault, SR; Braun, R; Do, RK; Nelson, RC; Reeder, SB
MLA Citation
Bashir, MR, Breault, SR, Braun, R, Do, RK, Nelson, RC, and Reeder, SB. "Optimal Timing and Diagnostic Adequacy of Hepatocyte Phase Imaging with Gadoxetate-Enhanced Liver MRI." Academic Radiology 21.6 (January 1, 2014): 726-732.
Source
scopus
Published In
Academic Radiology
Volume
21
Issue
6
Publish Date
2014
Start Page
726
End Page
732
DOI
10.1016/j.acra.2014.02.005

Trends in incidentally identified thyroid cancers over a decade: A retrospective analysis of 2,090 surgical patients

Background: The aim of this study was to describe trends in the incidence of incidental thyroid cancers and compare their characteristics with clinically presenting cancers. Methods: We performed a retrospective review of patients with thyroid cancer who underwent thyroid surgery from 2003 to 2012. Patients' initial presentation was categorized as incidental (on imaging or final surgical pathology) or clinical (palpable or symptomatic) cancer. Characteristics of incidental and clinical cancers were compared. Results: Of the 2,090 patients who underwent thyroid surgery, 680 (33 %) were diagnosed with cancer. One hundred ninety (28 %) were incidental cancer, of which 101 were detected on imaging studies and 89 were detected on analysis of the surgical pathology specimens. The incidence of thyroid cancer increased by 7.6-fold from 2003 to 2012. The proportion of incidental cancers on imaging did not increase, but incidental cancers found on pathology steadily increased from 6 % in 2003 to 20 % in 2012. 84 % of the cancers were papillary cancer, and the proportion of papillary cancer was similar for both clinical and incidental cancers. Clinical cancers were larger than incidental cancers on imaging (2.2 vs. 1.8 cm, p = 0.02). Incidental cancers on imaging were less likely to have lateral compartment nodal metastases (7 vs. 13 %, p < 0.001). Conclusions: Thyroid cancer diagnoses have increased at our institution, but the proportion of incidental cancers identified on imaging relative to clinical cancers has been stable over a decade and is not the sole explanation for the observed increase in thyroid cancer diagnoses. Incidental cancers on imaging are smaller in size and less likely to have lateral compartment nodal metastases than clinical cancers. © 2013 Société Internationale de Chirurgie.

Authors
Bahl, M; Sosa, JA; Nelson, RC; Esclamado, RM; Choudhury, KR; Hoang, JK
MLA Citation
Bahl, M, Sosa, JA, Nelson, RC, Esclamado, RM, Choudhury, KR, and Hoang, JK. "Trends in incidentally identified thyroid cancers over a decade: A retrospective analysis of 2,090 surgical patients." World Journal of Surgery 38.6 (January 1, 2014): 1312-1317.
Source
scopus
Published In
World Journal of Surgery
Volume
38
Issue
6
Publish Date
2014
Start Page
1312
End Page
1317
DOI
10.1007/s00268-013-2407-9

ACR appropriateness criteria right upper quadrant pain

Acute right upper quadrant pain is a common presenting symptom in patients with acute cholecystitis. When acute cholecystitis is suspected in patients with right upper quadrant pain, in most clinical scenarios, the initial imaging modality of choice is ultrasound. Although cholescintigraphy has been shown to have slightly higher sensitivity and specificity for diagnosis, ultrasound is preferred as the initial study for a variety of reasons, including greater availability, shorter examination time, lack of ionizing radiation, morphologic evaluation, confirmation of the presence or absence of gallstones, evaluation of bile ducts, and identification or exclusion of alternative diagnoses. CT or MRI may be helpful in equivocal cases and may identify complications of acute cholecystitis. When ultrasound findings are inconclusive, MRI is the preferred imaging test in pregnant patients who present with right upper quadrant pain. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. © 2014 American College of Radiology.

Authors
Yarmish, GM; Smith, MP; Rosen, MP; Baker, ME; Blake, MA; Cash, BD; Hindman, NM; Kamel, IR; Kaur, H; Nelson, RC; Piorkowski, RJ; Qayyum, A; Tulchinsky, M
MLA Citation
Yarmish, GM, Smith, MP, Rosen, MP, Baker, ME, Blake, MA, Cash, BD, Hindman, NM, Kamel, IR, Kaur, H, Nelson, RC, Piorkowski, RJ, Qayyum, A, and Tulchinsky, M. "ACR appropriateness criteria right upper quadrant pain." Journal of the American College of Radiology 11.3 (January 1, 2014): 316-322.
Source
scopus
Published In
Journal of the American College of Radiology
Volume
11
Issue
3
Publish Date
2014
Start Page
316
End Page
322
DOI
10.1016/j.jacr.2013.11.017

Venous filling defects on portal venous phase CT of the abdomen and pelvis: Clinical implications and positive predictive value for diagnosing deep venous thrombosis

Purpose: To determine the prevalence, resulting clinical decisions, and the positive predictive value (PPV) of venous filling defects detected on portal venous phase (PVP) CT. Methods: Over a 3-year period, 42412 consecutive patients underwent a PVP abdominopelvic CT; of these, 348 reports mentioned a filling defect concerning for deep venous thrombosis (DVT) in the IVC, iliac, or common femoral veins. Ninety-three patients underwent a reference standard venous imaging study. Results: The prevalence of venous filling defects in CT reports was 0.82% (n = 348). Reports worded with higher degrees of certainty were statistically more likely to result in treatment, while lower certainty was correlated with additional confirmatory imaging. The PPV for detection of DVT was 77%. The presence of peri-vascular stranding or vessel expansion increased the PPV of PVP CT to 95% and 100%, respectively. Conclusion: While the PPV for filling defects on PVP CT was modest, it was substantially improved if peri-venous stranding or vessel expansion was present. © 2014 Springer Science+Business Media.

Authors
Horvath, JJ; Looney, CB; Nelson, RC; Kim, CY
MLA Citation
Horvath, JJ, Looney, CB, Nelson, RC, and Kim, CY. "Venous filling defects on portal venous phase CT of the abdomen and pelvis: Clinical implications and positive predictive value for diagnosing deep venous thrombosis." Abdominal Imaging 39.3 (January 1, 2014): 554-561.
Source
scopus
Published In
Abdominal Imaging
Volume
39
Issue
3
Publish Date
2014
Start Page
554
End Page
561
DOI
10.1007/s00261-014-0077-1

ACR appropriateness criteria® acute pancreatitis

© 2014 American College of Radiology.The American College of Radiology Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. The Atlanta Classification by the Acute Pancreatitis Classification Working Group recently modified the terminology for the clinical course and the morphologic changes identified on imaging, primarily contrast- enhanced multidetector computed tomography (MDCT). The two distinct clinical courses of the disease are classified as (1) early phase, which lasts approximately 1 week, and (2) late phase, which starts after the first week and can last for months after the initial episode. The two, primary, morphologic changes are acute, interstitial edematous and necrotizing pancreatitis. Timing of imaging, primarily MDCT, is based on the clinical phases and is, therefore, important for these imaging guidelines. Ultrasound's role is to detect gallstones after the first episode. MDCT plays a primary role in the management of acutely ill patients, only after a minimum of 48Y72 hours and generally after one week. MR plays a supplementary role to MDCT. Follow-up MDCT guides management and therapy: percutaneous aspiration of fluid collections and/or placement of large caliber catheters in infected necrosis.

Authors
Baker, ME; Nelson, RC; Rosen, MP; Blake, MA; Cash, BD; Hindman, NM; Kamel, IR; Kaur, H; Piorkowski, RJ; Qayyum, A; Yarmish, GM
MLA Citation
Baker, ME, Nelson, RC, Rosen, MP, Blake, MA, Cash, BD, Hindman, NM, Kamel, IR, Kaur, H, Piorkowski, RJ, Qayyum, A, and Yarmish, GM. "ACR appropriateness criteria® acute pancreatitis." Ultrasound Quarterly 30.4 (January 1, 2014): 267-273.
Source
scopus
Published In
Ultrasound Quarterly
Volume
30
Issue
4
Publish Date
2014
Start Page
267
End Page
273

Interdependencies of acquisition, detection, and reconstruction techniques on the accuracy of iodine quantification in varying patient sizes employing dual-energy CT

© 2014, European Society of Radiology.Purpose: To assess the impact of patient habitus, acquisition parameters, detector efficiencies, and reconstruction techniques on the accuracy of iodine quantification using dual-source dual-energy CT (DECT). Materials and methods: Two phantoms simulating small and large patients contained 20 iodine solutions mimicking vascular and parenchymal enhancement from saline isodensity to 400 HU and 30 iodine solutions simulating enhancement of the urinary collecting system from 400 to 2,000 HU. DECT acquisition (80/140 kVp and 100/140 kVp) was performed using two DECT systems equipped with standard and integrated electronics detector technologies. DECT raw datasets were reconstructed using filtered backprojection (FBP), and iterative reconstruction (SAFIRE I/V). Results: Accuracy for iodine quantification was significantly higher for the small compared to the large phantoms (9.2 % ± 7.5 vs. 24.3 % ± 26.1, P = 0.0001), the integrated compared to the conventional detectors (14.8 % ± 20.6 vs. 18.8 % ± 20.4, respectively; P = 0.006), and SAFIRE V compared to SAFIRE I and FBP reconstructions (15.2 % ± 18.1 vs. 16.1 % ± 17.6 and 18.9 % ± 20.4, respectively; P ≤ 0.003). A significant synergism was observed when the most effective detector and reconstruction techniques were combined with habitus-adapted dual-energy pairs. Conclusion: In a second-generation dual-source DECT system, the accuracy of iodine quantification can be substantially improved by an optimal choice and combination of acquisition parameters, detector, and reconstruction techniques. Key Points: • Iodine quantification techniques are not immune to error • Systematic deviations between the measured and true iodine concentrations exist • Acquisition parameters, detector efficiencies, and reconstruction techniques impact accuracy of iodine quantification.

Authors
Marin, D; Pratts-Emanuelli, JJ; Mileto, A; Husarik, DB; Bashir, MR; Nelson, RC; Boll, DT
MLA Citation
Marin, D, Pratts-Emanuelli, JJ, Mileto, A, Husarik, DB, Bashir, MR, Nelson, RC, and Boll, DT. "Interdependencies of acquisition, detection, and reconstruction techniques on the accuracy of iodine quantification in varying patient sizes employing dual-energy CT." European Radiology 25.3 (January 1, 2014): 679-686.
Source
scopus
Published In
European Radiology
Volume
25
Issue
3
Publish Date
2014
Start Page
679
End Page
686
DOI
10.1007/s00330-014-3447-8

Journal Club: incidental thyroid nodules detected at imaging: can diagnostic workup be reduced by use of the Society of Radiologists in Ultrasound recommendations and the three-tiered system?

OBJECTIVE: The purpose of this study was to determine the number of thyroid nodule workups that could be eliminated and the number of malignant tumors that would be missed if the Society of Radiologists in Ultrasound (SRU) recommendations and the three-tiered system were applied to incidental thyroid nodules (ITN) detected at imaging. MATERIALS AND METHODS: This retrospective study included ITN in 390 consecutively registered patients who underwent ultrasound-guided fine-needle aspiration of one or more thyroid nodules from July 2010 to June 2011. Images were reviewed, and nodules were categorized according to two workup criteria: ITN seen on ultrasound images were categorized according to SRU recommendations, and those seen on CT, MR, or PET/CT images were classified according to the three-tiered risk-categorization system. RESULTS: In this study 114 of 390 (29%) patients had nodules first detected incidentally during imaging studies, and 107 patients met the inclusion criteria. These patients had 47 ITN seen at ultrasound and 60 ITN seen at either CT, MRI, or PET/CT. If the SRU recommendations had been applied, 14 of 47 (30%) patients with ITN on ultrasound images would not have received fine-needle aspiration and one of four cases of cancer would have been missed. The missed malignant tumor was a 14-mm localized papillary carcinoma. If the three-tiered system had been applied, 21 of 60 (35%) patients with ITN on CT, MR, or PET/CT images would not have received fine-needle aspiration, but none of the three malignancies would have been missed. Overall, 35 of 107 (33%) of patients with ITN did not meet the SRU recommendations or the three-tiered criteria. CONCLUSION: Use of the SRU recommendations and three-tiered system can reduce the workup of ITN by one third compared with current practice without specific guidelines. One case of localized papillary carcinoma was missed when the SRU recommendations were used.

Authors
Hobbs, HA; Bahl, M; Nelson, RC; Kranz, PG; Esclamado, RM; Wnuk, NM; Hoang, JK
MLA Citation
Hobbs, HA, Bahl, M, Nelson, RC, Kranz, PG, Esclamado, RM, Wnuk, NM, and Hoang, JK. "Journal Club: incidental thyroid nodules detected at imaging: can diagnostic workup be reduced by use of the Society of Radiologists in Ultrasound recommendations and the three-tiered system?." AJR Am J Roentgenol 202.1 (January 2014): 18-24.
PMID
24370125
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
202
Issue
1
Publish Date
2014
Start Page
18
End Page
24
DOI
10.2214/AJR.13.10972

Clinical impact of an adaptive statistical iterative reconstruction algorithm for detection of hypervascular liver tumours using a low tube voltage, high tube current MDCT technique

Objectives: To investigate the impact of an adaptive statistical iterative reconstruction (ASiR) algorithm on diagnostic accuracy and confidence for the diagnosis of hypervascular liver tumours, as well as the reader's perception of image quality, using a low tube voltage (80 kVp), high tube current computed tomography (CT) technique. Methods: Forty patients (29 men, 11 women) with 65 hypervascular liver tumours underwent dual energy CT. The 80 kV set of the dual energy acquisition was reconstructed with standard filtered backprojection (FBP) and ASiR at different blending levels. Lesion contrast-to-noise ratio (CNR), reader's confidence for lesion detection and characterisation, and reader's evaluation of image quality were recorded. Results: ASiR yielded significantly higher CNR values compared with FBP (P < 0.0001 for all comparisons). Reader's perception of lesion conspicuity and confidence in the diagnosis of malignancy were also higher with 60 % and 80 % ASiR, compared with FBP (P = 0.01 and < 0.001, respectively). Compared with FBP, ASiR yielded nearly significantly lower specificity for lesion detection and a substantial decrease in the reader's perception of image quality. Conclusions: Compared with the standard FBP algorithm, ASiR significantly improves conspicuity of hypervascular liver lesions. This improvement may come at the cost of decreased specificity and reader's perception of image quality. Key Points: • Adaptive statistical iterative reconstruction algorithms (ASiRs) offer increasing potential in multidetector CT. • An ASiR algorithm significantly improves conspicuity of hypervascular liver lesions at MDCT. • Improved lesion conspicuity translates into increased reader's confidence for diagnosis of malignancy. • False positive findings may increase with ASiR, leading to potentially lower specificity. © 2013 European Society of Radiology.

Authors
Marin, D; Choudhury, KR; Gupta, RT; Ho, LM; Allen, BC; Schindera, ST; Colsher, JG; Samei, E; Nelson, RC
MLA Citation
Marin, D, Choudhury, KR, Gupta, RT, Ho, LM, Allen, BC, Schindera, ST, Colsher, JG, Samei, E, and Nelson, RC. "Clinical impact of an adaptive statistical iterative reconstruction algorithm for detection of hypervascular liver tumours using a low tube voltage, high tube current MDCT technique." European Radiology 23.12 (December 1, 2013): 3325-3335.
Source
scopus
Published In
European Radiology
Volume
23
Issue
12
Publish Date
2013
Start Page
3325
End Page
3335
DOI
10.1007/s00330-013-2964-1

Clinical impact of an adaptive statistical iterative reconstruction algorithm for detection of hypervascular liver tumours using a low tube voltage, high tube current MDCT technique.

OBJECTIVES: To investigate the impact of an adaptive statistical iterative reconstruction (ASiR) algorithm on diagnostic accuracy and confidence for the diagnosis of hypervascular liver tumours, as well as the reader's perception of image quality, using a low tube voltage (80 kVp), high tube current computed tomography (CT) technique. METHODS: Forty patients (29 men, 11 women) with 65 hypervascular liver tumours underwent dual energy CT. The 80 kV set of the dual energy acquisition was reconstructed with standard filtered backprojection (FBP) and ASiR at different blending levels. Lesion contrast-to-noise ratio (CNR), reader's confidence for lesion detection and characterisation, and reader's evaluation of image quality were recorded. RESULTS: ASiR yielded significantly higher CNR values compared with FBP (P < 0.0001 for all comparisons). Reader's perception of lesion conspicuity and confidence in the diagnosis of malignancy were also higher with 60 % and 80 % ASiR, compared with FBP (P = 0.01 and < 0.001, respectively). Compared with FBP, ASiR yielded nearly significantly lower specificity for lesion detection and a substantial decrease in the reader's perception of image quality. CONCLUSIONS: Compared with the standard FBP algorithm, ASiR significantly improves conspicuity of hypervascular liver lesions. This improvement may come at the cost of decreased specificity and reader's perception of image quality.

Authors
Marin, D; Choudhury, KR; Gupta, RT; Ho, LM; Allen, BC; Schindera, ST; Colsher, JG; Samei, E; Nelson, RC
MLA Citation
Marin, D, Choudhury, KR, Gupta, RT, Ho, LM, Allen, BC, Schindera, ST, Colsher, JG, Samei, E, and Nelson, RC. "Clinical impact of an adaptive statistical iterative reconstruction algorithm for detection of hypervascular liver tumours using a low tube voltage, high tube current MDCT technique." Eur Radiol 23.12 (December 2013): 3325-3335.
PMID
23832320
Source
pubmed
Published In
European Radiology
Volume
23
Issue
12
Publish Date
2013
Start Page
3325
End Page
3335
DOI
10.1007/s00330-013-2964-1

Cirrhosis

© 2013 Springer-Verlag Berlin Heidelberg. All rights are reserved.Cirrhosis is a pathologic and clinical entity that occurs following repeated hepatocyte damage and is characterized by extensive fibrosis and innumerable regenerative nodules replacing the normal liver parenchyma. Ultimately, the process can lead to liver failure.

Authors
Marin, D; Nelson, R
MLA Citation
Marin, D, and Nelson, R. "Cirrhosis." Abdominal Imaging. November 1, 2013. 1013-1026.
Source
scopus
Publish Date
2013
Start Page
1013
End Page
1026
DOI
10.1007/978-3-642-13327-5_78

Pancreas

© Springer-Verlag Italia 2014. All rights reserved.Imaging of the pancreas is challenging because of its anatomic location in the retroperitoneum and its intricate relationship with major blood vessels and bowel [1]. In the United States, acute pancreatitis, chronic pancreatitis, and pancreatic cancer are the most common pancreatic disorders [2]. Gallstone disease, which is strongly associated with obesity and the excessive consumption of alcohol, is the major risk factor for benign pancreatic disease, whereas smoking is the most important risk factor for pancreatic cancer [2].

Authors
Mileto, A; Marin, D; Nelson, RC
MLA Citation
Mileto, A, Marin, D, and Nelson, RC. "Pancreas." CT of the Retroperitoneum: From Conventional to Multi-energy Imaging. May 1, 2013. 83-100.
Source
scopus
Publish Date
2013
Start Page
83
End Page
100
DOI
10.1007/978-88-470-5469-1-7

Precision of iodine quantification in hepatic CT: effects of iterative reconstruction with various imaging parameters.

OBJECTIVE: The objective of this study was to evaluate the feasibility of using iterative reconstructions in hepatic CT to improve the precision of Hounsfield unit quantification, which is the degree to which repeated measurements under unchanged conditions provide consistent results. MATERIALS AND METHODS: An anthropomorphic liver phantom with iodinated lesions designed to simulate the enhancement of hypervascular tumors during the late hepatic arterial phase was imaged, and images were reconstructed with both filtered back projection (FBP) and iterative reconstructions, such as adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR). This protocol was further expanded into various dose levels, tube voltages, and slice thicknesses to investigate the effect of iterative reconstructions under all these conditions. The iodine concentrations of the lesions were quantified, with their precision calculated in terms of repeatability coefficient. RESULTS: ASIR reduced image noise by approximately 35%, and improved the quantitative precision by approximately 5%, compared with FBP. MBIR reduced noise by more than 65% and improved the precision by approximately 25% compared with the routine protocol. MBIR consistently showed better precision across a thinner slice thickness, lower tube voltage, and larger patient, achieving the target precision level at a dose lower (≥ 40%) than that of FBP. CONCLUSION: ASIR blended with 50% of FBP indicated a moderate gain in quantitative precision compared with FBP but could achieve more with a higher percentage. A higher gain was achieved by MBIR. These findings may be used to reduce the dose required for reliable quantification and may further serve as a basis for protocol optimization in terms of iodine quantification.

Authors
Chen, B; Marin, D; Richard, S; Husarik, D; Nelson, R; Samei, E
MLA Citation
Chen, B, Marin, D, Richard, S, Husarik, D, Nelson, R, and Samei, E. "Precision of iodine quantification in hepatic CT: effects of iterative reconstruction with various imaging parameters." AJR. American journal of roentgenology 200.5 (May 2013): W475-W482.
PMID
23617515
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
200
Issue
5
Publish Date
2013
Start Page
W475
End Page
W482
DOI
10.2214/ajr.12.9658

Incidental detection of nutcracker phenomenon on multidetector CT in an asymptomatic population: prevalence and associated findings.

OBJECTIVE: To determine the prevalence of nutcracker phenomenon (left renal vein compression by the superior mesenteric artery) and secondary anatomic findings using multidetector computed tomographic (CT) angiography in an asymptomatic population. METHODS: Ninety-nine consecutive CT angiograms for potential renal transplant donors (mean age, 39.0 years; 42 males) without variant renal vein anatomy were reviewed retrospectively. The diameters of the maximal left renal vein, left renal vein between the aorta and superior mesenteric artery, and draining gonadal and lumbar veins were measured. Sex, age, hematuria, proteinuria, and abdominal or flank pain were recorded. RESULTS: Twenty-three patients had 50% to 70% stenosis, and 4 patients had greater than 70% stenosis of the left renal vein. Dilated gonadal and lumbar veins were found in 16 and 28 patients, respectively. Four patients had hematuria. These findings were not significantly associated with left renal vein compression. CONCLUSIONS: Nutcracker phenomenon and dilated veins originating from the left renal vein are common incidental CT findings and nonspecific for the diagnosis of nutcracker syndrome.

Authors
Grimm, LJ; Engstrom, BI; Nelson, RC; Kim, CY
MLA Citation
Grimm, LJ, Engstrom, BI, Nelson, RC, and Kim, CY. "Incidental detection of nutcracker phenomenon on multidetector CT in an asymptomatic population: prevalence and associated findings." Journal of computer assisted tomography 37.3 (May 2013): 415-418.
PMID
23674014
Source
epmc
Published In
Journal of Computer Assisted Tomography
Volume
37
Issue
3
Publish Date
2013
Start Page
415
End Page
418
DOI
10.1097/rct.0b013e3182873235

The utility of micro-CT and MRI in the assessment of longitudinal growth of liver metastases in a preclinical model of colon carcinoma.

RATIONALE AND OBJECTIVES: Liver is a common site for distal metastases in colon and rectal cancer. Numerous clinical studies have analyzed the relative merits of different imaging modalities for detection of liver metastases. Several exciting new therapies are being investigated in preclinical models. But, technical challenges in preclinical imaging make it difficult to translate conclusions from clinical studies to the preclinical environment. This study addresses the technical challenges of preclinical magnetic resonance imaging (MRI) and micro-computed tomography (CT) to enable comparison of state-of-the-art methods for following metastatic liver disease. MATERIALS AND METHODS: We optimized two promising preclinical protocols to enable a parallel longitudinal study tracking metastatic human colon carcinoma growth in a mouse model: T2-weighted MRI using two-shot PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) and contrast-enhanced micro-CT using a liposomal contrast agent. Both methods were tailored for high throughput with attention to animal support and anesthesia to limit biological stress. RESULTS AND CONCLUSIONS: Each modality has its strengths. Micro-CT permitted more rapid acquisition (<10 minutes) with the highest spatial resolution (88-micron isotropic resolution). But detection of metastatic lesions requires the use of a blood pool contrast agent, which could introduce a confound in the evaluation of new therapies. MRI was slower (30 minutes) and had lower anisotropic spatial resolution. But MRI eliminates the need for a contrast agent and the contrast-to-noise between tumor and normal parenchyma was higher, making earlier detection of small lesions possible. Both methods supported a relatively high-throughput, longitudinal study of the development of metastatic lesions.

Authors
Pandit, P; Johnston, SM; Qi, Y; Story, J; Nelson, R; Johnson, GA
MLA Citation
Pandit, P, Johnston, SM, Qi, Y, Story, J, Nelson, R, and Johnson, GA. "The utility of micro-CT and MRI in the assessment of longitudinal growth of liver metastases in a preclinical model of colon carcinoma." Acad Radiol 20.4 (April 2013): 430-439.
PMID
23498983
Source
pubmed
Published In
Academic Radiology
Volume
20
Issue
4
Publish Date
2013
Start Page
430
End Page
439
DOI
10.1016/j.acra.2012.09.030

In vivo application of short-lag spatial coherence imaging in human liver.

We present the results of a patient study conducted to assess the performance of two novel imaging methods, namely short-lag spatial coherence (SLSC) and harmonic spatial coherence imaging (HSCI), in an in vivo liver environment. Similar in appearance to the B-mode images, SLSC and HSCI images are based solely on the spatial coherence of fundamental and harmonic echo data, respectively, and do not depend on the echo magnitude. SLSC and HSCI suppress incoherent echo signals and thus tend to reduce clutter. The SLSC and HSCI images of 17 patients demonstrated sharper delineation of blood vessel walls, suppressed clutter inside the vessel lumen, and showed reduced speckle in surrounding tissue compared to matched B-modes. Target contrast and contrast-to-noise ratio (CNR) show statistically significant improvements between fundamental B-mode and SLSC imaging and between harmonic B-mode and HSCI imaging (in all cases p < 0.001). The magnitude of improvement in contrast and CNR increases as the overall quality of B-mode images decreases. Poor-quality fundamental B-mode images (where image quality classification is based on both contrast and CNR) exhibit the highest improvements in both contrast and CNR (288% improvement in contrast and 533% improvement in CNR).

Authors
Jakovljevic, M; Trahey, GE; Nelson, RC; Dahl, JJ
MLA Citation
Jakovljevic, M, Trahey, GE, Nelson, RC, and Dahl, JJ. "In vivo application of short-lag spatial coherence imaging in human liver." Ultrasound in medicine & biology 39.3 (March 2013): 534-542.
PMID
23347642
Source
epmc
Published In
Ultrasound in Medicine & Biology
Volume
39
Issue
3
Publish Date
2013
Start Page
534
End Page
542
DOI
10.1016/j.ultrasmedbio.2012.09.022

Lessons learned from 118,970 multidetector computed tomographic intravenous contrast material administrations: impact of catheter dwell time and gauge, catheter location, rate of contrast material administration, and patient age and sex on volume of extravasate.

OBJECTIVES: The aim of this study was to determine the impact of catheter dwell time and gauge, catheter location, rate of contrast material administration, and patient age and sex on volume of extravasate at intravenous contrast-enhanced multidetector computed tomography. METHODS: Incident reports were reviewed for all extravasation events that occurred in adult patients between March 2006 and December 2009 at 2 institutions. Patient age and sex; catheter dwell time, gauge, and location; rate of contrast material administration; and estimated volume of extravasated contrast material were recorded. RESULTS: Three hundred thirty extravasation events were recorded for the 118,970 contrast material administrations (0.3%). Mean volume of extravasated contrast material was statistically significantly less for catheters newly placed in the radiology department, for higher flow rates, for smaller gauge catheters, and for catheters placed in the hand. Mean volume of extravasated contrast material did not vary significantly based on patient age or sex. CONCLUSIONS: The volume of extravasate was likely to be smaller for smaller-gauge catheters in the hand with higher flow rates and for catheters newly placed in the radiology department.

Authors
Moreno, CC; Pinho, D; Nelson, RC; Sahani, DV; Jenkins, M; Zabrycki, M; Chaudhry, H; Kang, J; Chen, Z
MLA Citation
Moreno, CC, Pinho, D, Nelson, RC, Sahani, DV, Jenkins, M, Zabrycki, M, Chaudhry, H, Kang, J, and Chen, Z. "Lessons learned from 118,970 multidetector computed tomographic intravenous contrast material administrations: impact of catheter dwell time and gauge, catheter location, rate of contrast material administration, and patient age and sex on volume of extravasate." J Comput Assist Tomogr 37.2 (March 2013): 286-288.
PMID
23493221
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
37
Issue
2
Publish Date
2013
Start Page
286
End Page
288
DOI
10.1097/RCT.0b013e31828211da

Imaging of the pancreas

Authors
Rialon, K; Coursey, C; Nelson, RC
MLA Citation
Rialon, K, Coursey, C, and Nelson, RC. "Imaging of the pancreas." Contemporary Surgical Management of Liver, Biliary Tract, and Pancreatic Disease. January 1, 2013. 417-434.
Source
scopus
Publish Date
2013
Start Page
417
End Page
434
DOI
10.1142/9789814293068_0036

Early outcomes of empiric embolization of tumor-related gastrointestinal hemorrhage in patients with advanced malignancy.

PURPOSE: To report short-term results of empiric transcatheter embolization for patients with advanced malignancy and gastrointestinal (GI) hemorrhage directly from a tumor invading the GI tract wall. MATERIALS AND METHODS: Between 2005 and 2011, 37 mesenteric angiograms were obtained in 26 patients with advanced malignancy (20 men, six women; mean age, 56.2 y) with endoscopically confirmed symptomatic GI hemorrhage from a tumor invading the GI tract wall. Angiographic findings and clinical outcomes were retrospectively evaluated. Clinical success was defined as absence of signs and symptoms of hemorrhage for at least 30 day following embolization. RESULTS: Active extravasation was demonstrated in three cases. Angiographic abnormalities related to a GI tract tumor were identified on 35 of 37 angiograms, including tumor neovascularity (n = 21), tumor enhancement (n = 24), and luminal irregularity (n = 5). In the absence of active extravasation, empiric embolization with particles and/or coils was performed in 25 procedures. Cessation of hemorrhage (ie, clinical success) occurred more frequently when empiric embolization was performed (17 of 25 procedures; 68%) than when embolization was not performed (two of nine; 22%; P = .03). Empiric embolization resulted in clinical success in 10 of 11 patients with acute GI bleeding (91%), compared with seven of 14 patients (50%) with chronic GI bleeding (P = .04). No ischemic complications were encountered. CONCLUSIONS: In patients with advanced malignancy, in the absence of active extravasation, empiric transcatheter arterial embolization for treatment of GI hemorrhage from a direct tumor source demonstrated a 68% short-term success rate, without any ischemic complications.

Authors
Tandberg, DJ; Smith, TP; Suhocki, PV; Pabon-Ramos, W; Nelson, RC; Desai, S; Branch, S; Kim, CY
MLA Citation
Tandberg, DJ, Smith, TP, Suhocki, PV, Pabon-Ramos, W, Nelson, RC, Desai, S, Branch, S, and Kim, CY. "Early outcomes of empiric embolization of tumor-related gastrointestinal hemorrhage in patients with advanced malignancy." J Vasc Interv Radiol 23.11 (November 2012): 1445-1452.
PMID
23101916
Source
pubmed
Published In
JVIR: Journal of Vascular and Interventional Radiology
Volume
23
Issue
11
Publish Date
2012
Start Page
1445
End Page
1452
DOI
10.1016/j.jvir.2012.08.011

Effectiveness of a breath-hold monitoring system in improving the reproducibility of different breath-hold positions in multiphasic CT imaging.

This study tests whether the utilization of an electronic breath-hold monitoring device improves breath-hold reproducibility during computed tomographic (CT) scanning. Two cohorts of 40 patients underwent dual-phase abdominal CT scans, either with a breath-hold monitoring device or with the standard breath-holding technique. Two blinded readers measured the differences in diaphragmatic position between phases. There was no statistical difference in diaphragmatic position (P=.14) between the monitored (8.5±11.5 mm) and control (5.6±5.2 mm) cohorts. Ten percent of patients from the monitored cohort had greater than 20 mm of deviation, versus 0%-2.5% for the control cohort. Reproduction of breath-holding position remains challenging, even with a monitoring system.

Authors
Grimm, LJ; Feuerlein, S; Bashir, M; Nelson, RC
MLA Citation
Grimm, LJ, Feuerlein, S, Bashir, M, and Nelson, RC. "Effectiveness of a breath-hold monitoring system in improving the reproducibility of different breath-hold positions in multiphasic CT imaging." Clinical imaging 36.6 (November 2012): 754-757.
PMID
23154005
Source
epmc
Published In
Clinical Imaging
Volume
36
Issue
6
Publish Date
2012
Start Page
754
End Page
757
DOI
10.1016/j.clinimag.2012.01.040

Dual-energy CT applications in the abdomen.

OBJECTIVE: The purpose of this article is to give a brief overview of the technical background of dual-energy CT (DECT) imaging and to review various DECT applications in the abdomen that are currently available for clinical practice. In a review of the recent literature, specific DECT applications available for abdominal organs, liver, pancreas, kidneys including renal stones, and adrenal glands, will be discussed in light of reliability and clinical usefulness in replacing true unenhanced imaging, increased lesion conspicuity, iodine extraction, and improved tissue/material characterization (e.g., renal stone composition). Radiation dose considerations will be addressed in comparison with standard abdominal imaging protocols. CONCLUSION: Modern DECT applications for the abdomen expand the use of CT and enable advanced quantitative methods in the clinical routine on the basis of differences in material attenuation observed by imaging at two different distinct photon energies.

Authors
Heye, T; Nelson, RC; Ho, LM; Marin, D; Boll, DT
MLA Citation
Heye, T, Nelson, RC, Ho, LM, Marin, D, and Boll, DT. "Dual-energy CT applications in the abdomen." AJR Am J Roentgenol 199.5 Suppl (November 2012): S64-S70. (Review)
PMID
23097169
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
199
Issue
5 Suppl
Publish Date
2012
Start Page
S64
End Page
S70
DOI
10.2214/AJR.12.9196

Assessment of vascular contrast and depiction of stenoses in abdominopelvic and lower extremity vasculature: comparison of dual-energy MDCT with digital subtraction angiography.

RATIONALE AND OBJECTIVES: To assess whether dual-energy computed tomography (DECT) multidetector computed tomography (MDCT) angiography improves vascular contrast beyond MDCT angiography and digital subtraction angiography (DSA) while preserving the ability to precisely characterize stenoses, using DSA as reference standard. MATERIALS AND METHODS: This prospective, Health Insurance Portability and Accountability Act-compliant, institutional review board-approved study was performed on 25 patients referred for lower extremity DECT angiography and subsequent DSA. Spectral data were postprocessed to create single-energy 120 kVp (MDCT series) and iodine-only (DECT series) datasets. The arterial tree was subdivided into 11 anatomical levels. Contrast-to-noise ratios (CNR) and corresponding coefficient -of variation (CV) of patent vessel segments were evaluated for DECT, MDCT, and DSA using analysis of variance comparisons. Degree of stenoses was determined for DECT, MDCT, and DSA and correlated with t-test, bivariate Pearson comparisons, and Bland-Altman plots. RESULTS: Patent vasculature comprised 230 vessel segments. From infrarenal aorta to distal femoral arteries, DECT showed higher CNR compared to DSA and MDCT (P < .05); distal to the popliteal arteries, DSA achieved higher CNR (P < .05). Analyses of contrast homogeneity showed minimal CV above the knee for MDCT (≤9%) and for DSA below the knee (≤7%). Stenotic vasculature comprised 33 segments. Significant correlations of stenosis severity were found comparing DECT and MDCT with DSA as reference standard showing a 0.04-fold mean underestimation of stenoses on MDCT and no detectable mean variation on DECT compared with DSA. CONCLUSION: DECT angiography improved contrast in vascular abdominopelvic and thigh distributions beyond MDCT angiography and DSA while preserving the ability to precisely assess severity of stenoses, using DSA as an accepted reference standard.

Authors
Huang, SY; Nelson, RC; Miller, MJ; Kim, CY; Lawson, JH; Husarik, DB; Boll, DT
MLA Citation
Huang, SY, Nelson, RC, Miller, MJ, Kim, CY, Lawson, JH, Husarik, DB, and Boll, DT. "Assessment of vascular contrast and depiction of stenoses in abdominopelvic and lower extremity vasculature: comparison of dual-energy MDCT with digital subtraction angiography." Acad Radiol 19.9 (September 2012): 1149-1157.
PMID
22743115
Source
pubmed
Published In
Academic Radiology
Volume
19
Issue
9
Publish Date
2012
Start Page
1149
End Page
1157
DOI
10.1016/j.acra.2012.04.014

Improved aortic enhancement in CT angiography using slope-based triggering with table speed optimization: a pilot study.

To assess whether a scan triggering technique based on the slope of the time-attenuation curve combined with table speed optimization may improve arterial enhancement in aortic CT angiography compared to conventional threshold-based triggering techniques. Measurements of arterial enhancement were performed in a physiologic flow phantom over a range of simulated cardiac outputs (2.2-8.1 L/min) using contrast media boluses of 80 and 150 mL injected at 4 mL/s. These measurements were used to construct computer models of aortic attenuation in CT angiography, using cardiac output, aortic diameter, and CT table speed as input parameters. In-plane enhancement was calculated for normal and aneurysmal aortic diameters. Calculated arterial enhancement was poor (<150 HU) along most of the scan length using the threshold-based triggering technique for low cardiac outputs and the aneurysmal aorta model. Implementation of the slope-based triggering technique with table speed optimization improved enhancement in all scenarios and yielded good- (>200 HU; 13/16 scenarios) to excellent-quality (>300 HU; 3/16 scenarios) enhancement in all cases. Slope-based triggering with table speed optimization may improve the technical quality of aortic CT angiography over conventional threshold-based techniques, and may reduce technical failures related to low cardiac output and slow flow through an aneurysmal aorta.

Authors
Bashir, MR; Weber, PW; Husarik, DB; Howle, LE; Nelson, RC
MLA Citation
Bashir, MR, Weber, PW, Husarik, DB, Howle, LE, and Nelson, RC. "Improved aortic enhancement in CT angiography using slope-based triggering with table speed optimization: a pilot study." Int J Cardiovasc Imaging 28.6 (August 2012): 1533-1543.
PMID
21898186
Source
pubmed
Published In
International Journal of Cardiovascular Imaging
Volume
28
Issue
6
Publish Date
2012
Start Page
1533
End Page
1543
DOI
10.1007/s10554-011-9945-8

Radiation dose reduction in abdominal computed tomography during the late hepatic arterial phase using a model-based iterative reconstruction algorithm: how low can we go?

OBJECTIVE: The aim of this study was to compare the image quality of abdominal computed tomography scans in an anthropomorphic phantom acquired at different radiation dose levels where each raw data set is reconstructed with both a standard convolution filtered back projection (FBP) and a full model-based iterative reconstruction (MBIR) algorithm. MATERIALS AND METHODS: An anthropomorphic phantom in 3 sizes was used with a custom-built liver insert simulating late hepatic arterial enhancement and containing hypervascular liver lesions of various sizes. Imaging was performed on a 64-section multidetector-row computed tomography scanner (Discovery CT750 HD; GE Healthcare, Waukesha, WI) at 3 different tube voltages for each patient size and 5 incrementally decreasing tube current-time products for each tube voltage. Quantitative analysis consisted of contrast-to-noise ratio calculations and image noise assessment. Qualitative image analysis was performed by 3 independent radiologists rating subjective image quality and lesion conspicuity. RESULTS: Contrast-to-noise ratio was significantly higher and mean image noise was significantly lower on MBIR images than on FBP images in all patient sizes, at all tube voltage settings, and all radiation dose levels (P < 0.05). Overall image quality and lesion conspicuity were rated higher for MBIR images compared with FBP images at all radiation dose levels. Image quality and lesion conspicuity on 25% to 50% dose MBIR images were rated equal to full-dose FBP images. CONCLUSION: This phantom study suggests that depending on patient size, clinically acceptable image quality of the liver in the late hepatic arterial phase can be achieved with MBIR at approximately 50% lower radiation dose compared with FBP.

Authors
Husarik, DB; Marin, D; Samei, E; Richard, S; Chen, B; Jaffe, TA; Bashir, MR; Nelson, RC
MLA Citation
Husarik, DB, Marin, D, Samei, E, Richard, S, Chen, B, Jaffe, TA, Bashir, MR, and Nelson, RC. "Radiation dose reduction in abdominal computed tomography during the late hepatic arterial phase using a model-based iterative reconstruction algorithm: how low can we go?." Invest Radiol 47.8 (August 2012): 468-474.
PMID
22717881
Source
pubmed
Published In
Investigative Radiology
Volume
47
Issue
8
Publish Date
2012
Start Page
468
End Page
474
DOI
10.1097/RLI.0b013e318251eafd

Contrast enhancement on computed tomography after renal cryoablation: an evidence of treatment failure?

Renal cryoablation has gained popularity as a treatment option for localized renal masses. Treatment success is typically defined by the absence of contrast enhancement on follow-up imaging. We investigate the evolution of lesions that demonstrate contrast enhancement on CT after renal cryoablation.Retrospective review of records of laparoscopic and percutaneous cryoablation (LCA and PCA) was performed, identifying records with postoperative radiographic enhancement. Imaging studies were reviewed and radiographic (pre- and post-contrast Hounsfield units, pattern and location of enhancement) and clinical data including follow up were collected.One hundred and seventy-two cryoablation procedures were analyzed. Of these, 30 (17.4%) showed enhancement on follow-up CT. In 28 cases, contrast enhancement was demonstrated on the first postoperative study. Seven patients underwent salvage treatments. Spontaneous resolution of enhancement was noted in 17 (56.7%) cases. No association was found between enhancement pattern (diffuse/nodular/rim) and resolution. Of lesions enhancing >35 HU, only 14.3% resolved spontaneously. Delayed enhancement (after negative imaging studies) occurred in two patients; both underwent salvage treatments.Most of the time, contrast-enhancements after cryoablation are evident on the first follow-up imaging study. More than 50% of these resolve spontaneously, and only one of four patients need salvage treatment. Delayed appearance of enhancement after previously negative imaging and highly enhancing lesions (>35 HU) are unlikely to resolve and should be considered suspicious for local recurrence or incomplete ablation. Further investigation is warranted to reach a consensus on a radiographic definition of local recurrence after renal cryoablation.

Authors
Tsivian, M; Kim, CY; Caso, JR; Rosenberg, MD; Nelson, RC; Polascik, TJ
MLA Citation
Tsivian, M, Kim, CY, Caso, JR, Rosenberg, MD, Nelson, RC, and Polascik, TJ. "Contrast enhancement on computed tomography after renal cryoablation: an evidence of treatment failure?." Journal of endourology 26.4 (April 2012): 330-335.
PMID
22070179
Source
epmc
Published In
Journal of Endourology
Volume
26
Issue
4
Publish Date
2012
Start Page
330
End Page
335
DOI
10.1089/end.2011.0337

Contrast-enhanced magnetic resonance angiography: first-pass arterial enhancement as a function of gadolinium-chelate concentration, and the saline chaser volume and injection rate.

OBJECTIVE: To evaluate the effect of the contrast medium (CM) concentration and the saline chaser volume and injection rate on first-pass aortic enhancement characteristics in contrast-enhanced magnetic resonance angiography using a physiologic flow phantom. MATERIALS AND METHODS: Imaging was performed on a 3.0-T magnetic resonance system (MAGNETOM Trio, Siemens Healthcare Solutions, Inc, Erlangen, Germany) using a 2-dimensional fast low angle shot T1-weighted sequence (repetition time, 500 milliseconds; echo time, 1.23 milliseconds; flip angle, 8 degrees; 1 frame/s × 60 seconds). The following CM concentrations injected at 2 mL/s were used with 3 different contrast agents (gadolinium [Gd]-BOPTA, Gd-HP-DO3A, Gd-DTPA): 20 mL of undiluted CM (100%) and 80%, 40%, 20%, 10%, 5%, and 2.5% of the full amount, all diluted in saline to a volume of 20 mL to ensure equal bolus volume. The CM was followed by saline chasers of 20 to 60 mL injected at 2 mL/s and 6 mL/s. Aortic signal intensity (SI) was measured, and normalized SI versus time (SI/Tn) curves were generated. The maximal SI (SI(max)), bolus length, and areas under the SI/Tn curve were calculated. RESULTS: Decreasing the CM concentration from 100% to 40% resulted in a decrease of SI(max) to 86.1% (mean). Further decreasing the CM concentration to 2.5% decreased SI(max) to 5.1% (mean). Altering the saline chaser volume had no significant effect on SI(max). Increasing the saline chaser injection rate had little effect (mean increase, 2.2%) on SI(max) when using ≥40% of CM. There was a larger effect (mean increase, 19.6%) when ≤20% of CM were used. Bolus time length was significantly shorter (P < 0.001), and area under the SI/T(n) curve was significantly smaller (P < 0.01) for the CM protocols followed by a saline chaser injected at 6 mL/s compared with a saline chaser injected at 2 mL/s. CONCLUSION: With 40% of CM and a fast saline chaser, SImax close to that with undiluted CM can be achieved. An increased saline chaser injection rate has a more pronounced effect on aortic enhancement characteristics at lower CM concentrations than at higher CM concentrations.

Authors
Husarik, DB; Bashir, MR; Weber, PW; Nichols, EB; Howle, LE; Merkle, EM; Nelson, RC
MLA Citation
Husarik, DB, Bashir, MR, Weber, PW, Nichols, EB, Howle, LE, Merkle, EM, and Nelson, RC. "Contrast-enhanced magnetic resonance angiography: first-pass arterial enhancement as a function of gadolinium-chelate concentration, and the saline chaser volume and injection rate." Invest Radiol 47.2 (February 2012): 121-127.
PMID
21934516
Source
pubmed
Published In
Investigative Radiology
Volume
47
Issue
2
Publish Date
2012
Start Page
121
End Page
127
DOI
10.1097/RLI.0b013e3182300603

Gastrointestinal imaging

Authors
Nelson, RC; Low, VHS; Hough, DM; Paulson, EK; Seabourn, JT; Freed, KS; Kerner, ML; Keogan, MT; Marin, D; Suhocki, PV
MLA Citation
Nelson, RC, Low, VHS, Hough, DM, Paulson, EK, Seabourn, JT, Freed, KS, Kerner, ML, Keogan, MT, Marin, D, and Suhocki, PV. "Gastrointestinal imaging." Duke Radiology Case Review: Imaging, Differential Diagnosis, and Discussion: 2nd Edition. January 19, 2012. 111-.
Source
scopus
Publish Date
2012
Start Page
111

Preface

Authors
Nelson, RC; Vinson, EN; Provenzale, JM
MLA Citation
Nelson, RC, Vinson, EN, and Provenzale, JM. Preface. January 19, 2012.
Source
scopus
Publish Date
2012
Start Page
vii

Duke radiology case review: Imaging, differential diagnosis, and discussion: 2nd edition

© 2012 by Lippincott Williams & Wilkins, a Wolters Kluwer business. All rights reserved.Residents, fellows and practicing radiologists who are preparing for certification exams (the current ABR Part II oral, the future ABR Core and Certifying, CAQ and MOC) will find the new edition of this case-based review book an indispensable tool for success. Duke Radiology Case Review has long been considered one of the standards in board review, and is a well-known adjunct to the popular and well-attended board review course given by the prestigious Department of Radiology at Duke University. Close to 300 case presentations are structured to align with the way residents are taught to work through patient cases. Divided by body region and including chapters on interventional radiology and nuclear medicine, each case offers a clinical history, relevant images, and bulleted points describing the differential diagnosis. This is followed by the actual diagnosis and key clinical and radiologic facts about the diagnosis and suggested readings. This edition includes a new chapter on cardiac imaging.

Authors
Provenzale, JM; Nelson, RC; Vinson, EN
MLA Citation
Provenzale, JM, Nelson, RC, and Vinson, EN. Duke radiology case review: Imaging, differential diagnosis, and discussion: 2nd edition. January 19, 2012.
Source
scopus
Publish Date
2012
Start Page
1
End Page
688

Gastrointestinal imaging: Case 29

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Gastrointestinal imaging: Case 29." Duke Radiology Case Review: Imaging, Differential Diagnosis, and Discussion: 2nd Edition. January 19, 2012. 168-169.
Source
scopus
Publish Date
2012
Start Page
168
End Page
169

Gastrointestinal imaging: Case 3

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Gastrointestinal imaging: Case 3." Duke Radiology Case Review: Imaging, Differential Diagnosis, and Discussion: 2nd Edition. January 19, 2012. 160-161.
Source
scopus
Publish Date
2012
Start Page
160
End Page
161

Gastrointestinal imaging: Case 28

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Gastrointestinal imaging: Case 28." Duke Radiology Case Review: Imaging, Differential Diagnosis, and Discussion: 2nd Edition. January 19, 2012. 166-167.
Source
scopus
Publish Date
2012
Start Page
166
End Page
167

Gastrointestinal imaging: Case 30

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Gastrointestinal imaging: Case 30." Duke Radiology Case Review: Imaging, Differential Diagnosis, and Discussion: 2nd Edition. January 19, 2012. 170-171.
Source
scopus
Publish Date
2012
Start Page
170
End Page
171

Gastrointestinal imaging: Case 24

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Gastrointestinal imaging: Case 24." Duke Radiology Case Review: Imaging, Differential Diagnosis, and Discussion: 2nd Edition. January 19, 2012. 158-159.
Source
scopus
Publish Date
2012
Start Page
158
End Page
159

Gastrointestinal imaging: Case 27

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Gastrointestinal imaging: Case 27." Duke Radiology Case Review: Imaging, Differential Diagnosis, and Discussion: 2nd Edition. January 19, 2012. 127-128.
Source
scopus
Publish Date
2012
Start Page
127
End Page
128

Effects of aerobic vs. resistance training on visceral and liver fat stores, liver enzymes, and insulin resistance by HOMA in overweight adults from STRRIDE AT/RT.

While the benefits of exercise are clear, many unresolved issues surround the optimal exercise prescription. Many organizations recommend aerobic training (AT) and resistance training (RT), yet few studies have compared their effects alone or in combination. The purpose of this study, part of Studies Targeting Risk Reduction Interventions Through Defined Exercise-Aerobic Training and/or Resistance Training (STRRIDE/AT/RT), was to compare the effects of AT, RT, and the full combination (AT/RT) on central ectopic fat, liver enzymes, and fasting insulin resistance [homeostatic model assessment (HOMA)]. In a randomized trial, 249 subjects [18-70 yr old, overweight, sedentary, with moderate dyslipidemia (LDL cholesterol 130-190 mg/dl or HDL cholesterol ≤ 40 mg/dl for men or ≤ 45 mg/dl for women)] performed an initial 4-mo run-in period. Of these, 196 finished the run-in and were randomized into one of the following 8-mo exercise-training groups: 1) RT, which comprised 3 days/wk, 8 exercises, 3 sets/exercise, 8-12 repetitions/set, 2) AT, which was equivalent to ∼19.2 km/wk (12 miles/wk) at 75% peak O(2) uptake, and 3) full AT + full RT (AT/RT), with 155 subjects completing the intervention. The primary outcome variables were as follows: visceral and liver fat via CT, plasma liver enzymes, and HOMA. AT led to significant reductions in liver fat, visceral fat, alanine aminotransferase, HOMA, and total and subcutaneous abdominal fat (all P < 0.05). RT resulted in a decrease in subcutaneous abdominal fat (P < 0.05) but did not significantly improve the other variables. AT was more effective than RT at improving visceral fat, liver-to-spleen ratio, and total abdominal fat (all P < 0.05) and trended toward a greater reduction in liver fat score (P < 0.10). The effects of AT/RT were statistically indistinguishable from the effects of AT. These data show that, for overweight and obese individuals who want to reduce measures of visceral fat and fatty liver infiltration and improve HOMA and alanine aminotransferase, a moderate amount of aerobic exercise is the most time-efficient and effective exercise mode.

Authors
Slentz, CA; Bateman, LA; Willis, LH; Shields, AT; Tanner, CJ; Piner, LW; Hawk, VH; Muehlbauer, MJ; Samsa, GP; Nelson, RC; Huffman, KM; Bales, CW; Houmard, JA; Kraus, WE
MLA Citation
Slentz, CA, Bateman, LA, Willis, LH, Shields, AT, Tanner, CJ, Piner, LW, Hawk, VH, Muehlbauer, MJ, Samsa, GP, Nelson, RC, Huffman, KM, Bales, CW, Houmard, JA, and Kraus, WE. "Effects of aerobic vs. resistance training on visceral and liver fat stores, liver enzymes, and insulin resistance by HOMA in overweight adults from STRRIDE AT/RT." Am J Physiol Endocrinol Metab 301.5 (November 2011): E1033-E1039.
PMID
21846904
Source
pubmed
Published In
American journal of physiology. Endocrinology and metabolism
Volume
301
Issue
5
Publish Date
2011
Start Page
E1033
End Page
E1039
DOI
10.1152/ajpendo.00291.2011

64-section multidetector CT of the upper abdomen: optimization of a saline chaser injection protocol for improved vascular and parenchymal contrast enhancement.

OBJECTIVES: To prospectively investigate the effect of varying the injection flow rates of a saline chaser on vascular and parenchymal contrast enhancement during abdominal MDCT. METHODS: 100 consecutive patients were randomly assigned to four injection protocols. A fixed dose of contrast medium was administered followed by no saline (Protocol A) or 50 mL of saline at 2, 4, or 8 mL/s (Protocols B, C, and D). Peak, time-to-peak, and duration of 90% peak enhancement were determined for aorta, pancreas, and liver. RESULTS: Aortic peak enhancement was significantly higher for Protocol D (369.5 HU) compared with Protocols A and B (332.9 HU and 326.0 HU, respectively; P < 0.05). Pancreatic peak enhancement was significantly higher for Protocols C and D (110.6 HU and 110.9 HU, respectively) compared to Protocol A (92.5 HU; P < 0.05). Aortic and pancreatic time-to-peak enhancement occurred significantly later for Protocol D compared with Protocol A (42.8 s vs. 36.1 s [P < 0.001] and 49.7 s vs. 45.3 s [P = 0.003]). CONCLUSIONS: Injecting a saline chaser at high flow rates yields significantly higher peak aortic and pancreatic enhancement, with a slight longer time-to-peak enhancement.

Authors
Marin, D; Nelson, RC; Guerrisi, A; Barnhart, H; Schindera, ST; Passariello, R; Catalano, C
MLA Citation
Marin, D, Nelson, RC, Guerrisi, A, Barnhart, H, Schindera, ST, Passariello, R, and Catalano, C. "64-section multidetector CT of the upper abdomen: optimization of a saline chaser injection protocol for improved vascular and parenchymal contrast enhancement." Eur Radiol 21.9 (September 2011): 1938-1947.
PMID
21556911
Source
pubmed
Published In
European Radiology
Volume
21
Issue
9
Publish Date
2011
Start Page
1938
End Page
1947
DOI
10.1007/s00330-011-2139-x

New iterative reconstruction techniques for cardiovascular computed tomography: how do they work, and what are the advantages and disadvantages?

The radiation doses associated with diagnostic CT scans has recently come under scrutiny. In the process of developing protocols with lower doses, it has become apparent that images reconstructed with a filtered back projection (FBP) technique are often inadequate. Although very fast and robust, FBP images are prone to high noise, streak artifacts and poor low contrast detectability in low dose situations. Manufacturers of CT equipment have responded to this limitation by developing new image reconstruction techniques that derive more information from the data set. These techniques are based on the use of maximum likelihood algorithms and are referred to at iterative reconstructions. This iterative process can be used on the slice data alone, a combination of raw and slice data or on the raw data alone. The latter approach, which is referred to as model based iterative reconstruction, is the most computationally demanding as it models the entire process, from the shape of the focal spot on the anode, the shape of the emerging x-ray beam, the three-dimensional interaction of the beam with the voxel in the patient and the two-dimensional interation of the beam with the detector. This article discusses the fundamentals of iterative reconstruction techniques, the pros and cons of the various manufacturer approaches and specific applications, especially to cardiovascular CT.

Authors
Nelson, RC; Feuerlein, S; Boll, DT
MLA Citation
Nelson, RC, Feuerlein, S, and Boll, DT. "New iterative reconstruction techniques for cardiovascular computed tomography: how do they work, and what are the advantages and disadvantages?." J Cardiovasc Comput Tomogr 5.5 (September 2011): 286-292. (Review)
PMID
21875826
Source
pubmed
Published In
Journal of Cardiovascular Computed Tomography
Volume
5
Issue
5
Publish Date
2011
Start Page
286
End Page
292
DOI
10.1016/j.jcct.2011.07.001

Low-dose unenhanced CT for IV contrast bolus timing: is it reliable to assess hepatic steatosis?

RATIONALE AND OBJECTIVES: To determine whether an unenhanced low-dose image acquired during automated contrast bolus timing can be used to assess hepatic steatosis. MATERIALS AND METHODS: Fifty subjects (29 male, 21 female; 26-92 years; mean body mass index (BMI; 26.9) with abdominal multiphasic computed tomography were included. Abdominal diameters and circumferences were derived from anteroposterior and lateral scout radiographs. Hepatic attenuation (HA) was measured on unenhanced low-dose images (120 kV; 40 mA; 0.5 seconds' rotation time) and corresponding unenhanced standard-dose images (120 kV, z-axis automatic tube current modulation, noise index 11.5). Noise estimates were measured in surrounding air. Pearson correlation was calculated between abdominal circumference and BMI. Mean HA assessed on low-dose images and standard-dose images was compared using a paired Student's t-test and Bland Altman plots. RESULTS: Abdominal circumference (mean, 142.8cm) correlated well with BMI (r = 0.83). No significant difference was found for HA on low-dose images (mean +57.7 HU) compared to HA on standard-dose images (+56.0 HU) (P = .077). Image noise (+11.5 HU) was significantly higher on low-dose images compared to image noise (+8.1 HU) on standard-dose images (P < .05). For HA mean difference comparing low- and standard-dose images was -1.7 HU (limits of agreement: -14.6, 11.2). CONCLUSION: In all subjects, hepatic attenuation can be correctly assessed on unenhanced low-dose images.

Authors
Husarik, DB; Boll, DT; Nelson, RC; Merkle, EM
MLA Citation
Husarik, DB, Boll, DT, Nelson, RC, and Merkle, EM. "Low-dose unenhanced CT for IV contrast bolus timing: is it reliable to assess hepatic steatosis?." Acad Radiol 18.7 (July 2011): 822-827.
PMID
21530330
Source
pubmed
Published In
Academic Radiology
Volume
18
Issue
7
Publish Date
2011
Start Page
822
End Page
827
DOI
10.1016/j.acra.2011.02.013

Body CT: technical advances for improving safety.

OBJECTIVE: In this review, we attempt to address many of the issues that are related to ensuring patient benefit in body CT, balancing the use of ionizing radiation and iodinated contrast media. We attempt to not only summarize the literature but also make recommendations relevant to CT protocols, including the technical parameters of both the scanner and the associated contrast media. CONCLUSION: Although CT is a powerful tool that has transformed the practice of medicine, the benefits are accompanied by important risks. Radiologists must understand these risks and the strategies available to minimize them as well as the risks associated with contrast medium delivery in abdominal CT.

Authors
Marin, D; Nelson, RC; Rubin, GD; Schindera, ST
MLA Citation
Marin, D, Nelson, RC, Rubin, GD, and Schindera, ST. "Body CT: technical advances for improving safety." AJR Am J Roentgenol 197.1 (July 2011): 33-41. (Review)
PMID
21701008
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
197
Issue
1
Publish Date
2011
Start Page
33
End Page
41
DOI
10.2214/AJR.11.6755

Decreased detection of hypovascular liver tumors with MDCT in obese patients: a phantom study.

OBJECTIVE: The purpose of this article is to assess the impact of large patient size on the detection of hypovascular liver tumors with MDCT and the effect of a noise filter on image quality and lesion detection in obese patients. MATERIALS AND METHODS: A liver phantom with 45 hypovascular tumors (diameters of 5, 10, and 15 mm) was placed into two water containers mimicking intermediate and large patients. The containers were scanned with a 64-MDCT scanner. The CT dataset from the large phantom was postprocessed using a noise filter. The image noise was measured and the contrast-to-noise ratio (CNR) of the tumors was calculated. Tumor detection was independently performed by three radiologists in a blinded fashion. RESULTS: The application of the noise filter in the large phantom yielded a reduction of image noise by 42% (p < 0.0001). The CNR values of the tumors in the nonfiltered and filtered large phantom were lower than that in the intermediate phantom (p < 0.05). In the non-filtered and filtered large phantom, 25% and 19% fewer tumors, respectively, were detected on average compared with the intermediate phantom (p < 0.01). CONCLUSION: The risk of missing hypovascular liver tumors with CT is substantially increased in large patients. A noise filter improves image quality in obese patients.

Authors
Schindera, ST; Torrente, JC; Ruder, TD; Hoppe, H; Marin, D; Nelson, RC; Szucs-Farkas, Z
MLA Citation
Schindera, ST, Torrente, JC, Ruder, TD, Hoppe, H, Marin, D, Nelson, RC, and Szucs-Farkas, Z. "Decreased detection of hypovascular liver tumors with MDCT in obese patients: a phantom study." AJR Am J Roentgenol 196.6 (June 2011): W772-W776.
PMID
21606267
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
196
Issue
6
Publish Date
2011
Start Page
W772
End Page
W776
DOI
10.2214/AJR.10.5351

Percutaneous cryoablation of renal lesions with radiographic ice ball involvement of the renal sinus: analysis of hemorrhagic and collecting system complications.

OBJECTIVE: The purpose of this study was to determine the incidence of collecting system and hemorrhagic complications resulting from CT-guided percutaneous cryoablation of renal tumors in which the radiographic ice ball abuts or involves the renal sinus. MATERIALS AND METHODS: From November 2005 through July 2009 at our institution, we performed 129 CT-guided percutaneous cryoablation procedures on 107 patients (mean age, 64 years) with renal masses suspicious of being renal cell carcinoma. Radiographic ice balls that abutted or overlapped the renal sinus were classified as central; the other lesions were classified as noncentral. Medical records and follow-up images were retrospectively reviewed for hemorrhage requiring intervention and for evidence of collecting system injury. The mean follow-up period was 9.3 months. RESULTS: The radiographic ice ball was classified as central in 67 cases. In these central ablations, the mean sinus involvement was 6.2 mm (range, 0-19 mm), 41 ice balls overlapping the renal sinus by 6 mm or more (mean, 9.4 mm). No cases of collecting system injury were identified for any ablation. Overall, there was only one hemorrhagic complication requiring intervention, and it occurred in a noncentral ablation. CONCLUSION: CT-guided percutaneous cryoablation of renal masses with ice ball overlap of the renal sinus resulted in no cases of collecting system injury or serious hemorrhagic complications in our series.

Authors
Rosenberg, MD; Kim, CY; Tsivian, M; Suberlak, MN; Sopko, DR; Polascik, TJ; Nelson, RC
MLA Citation
Rosenberg, MD, Kim, CY, Tsivian, M, Suberlak, MN, Sopko, DR, Polascik, TJ, and Nelson, RC. "Percutaneous cryoablation of renal lesions with radiographic ice ball involvement of the renal sinus: analysis of hemorrhagic and collecting system complications." AJR Am J Roentgenol 196.4 (April 2011): 935-939.
PMID
21427348
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
196
Issue
4
Publish Date
2011
Start Page
935
End Page
939
DOI
10.2214/AJR.10.5182

Appendicitis, body mass index, and CT: is CT more valuable for obese patients than thin patients?

The purpose of our study is to determine whether body mass index (BMI = weight in kg/height in meters(2)) was related to the rate of negative appendectomy in patients who underwent preoperative CT. A surgical database search performed using the procedure code for appendectomy identified 925 patients at least 18 years of age who underwent urgent appendectomy between January 1998 and September 2007. BMI was computed for the 703 of these 925 patients for whom height and weight information was available. Patients were stratified based on body mass index (BMI 15-18.49 = underweight; 18.5-24.9 = normal weight; 25-29.9 = overweight; 30-39.9 = obese; ≥ 40 = morbidly obese). Negative appendectomy rates were computed. Negative appendectomy rates for patients who did and did not undergo preoperative CT were 27 per cent and 50 per cent for underweight patients, 10 per cent and 15 per cent for normal weight patients, 12 per cent and 17 per cent for overweight patients, 7 per cent and 30 per cent for obese patients, and 10 per cent and 100 per cent for morbidly obese patients. The difference in negative appendectomy rates for overweight patients, obese patients, and morbidly obese patients who underwent preoperative CT as compared with patients in the same BMI category who did not undergo preoperative CT was statistically significant (P ≤ 0.001). The negative appendectomy rates for overweight patients, obese patients, and morbidly obese patients who underwent preoperative CT were significantly lower than for patients in these same BMI categories who did not undergo preoperative CT.

Authors
Coursey, CA; Nelson, RC; Moreno, RD; Patel, MB; Beam, CA; Vaslef, S
MLA Citation
Coursey, CA, Nelson, RC, Moreno, RD, Patel, MB, Beam, CA, and Vaslef, S. "Appendicitis, body mass index, and CT: is CT more valuable for obese patients than thin patients?." Am Surg 77.4 (April 2011): 471-475.
PMID
21679558
Source
pubmed
Published In
American Surgeon
Volume
77
Issue
4
Publish Date
2011
Start Page
471
End Page
475

Effect of varying contrast material iodine concentration and injection technique on the conspicuity of hepatocellular carcinoma during 64-section MDCT of patients with cirrhosis

Objectives: The aim of this study was to compare the intraindividual effects of contrast material with two different iodine concentrations on the conspicuity of hepatocellular carcinoma (HCC) and vascular and hepatic contrast enhancement during multiphasic, 64-section multidetector row CT (MDCT) in patients with cirrhosis using two contrast medium injection techniques. Methods: Patients were randomly assigned to one of two groups with an equal iodine dose but different contrast material injection techniques: scheme A, fixed injection duration (25 s), and scheme B, fixed injection flow rate (4 ml s -1). For each group, patients were randomised to receive both moderate-concentration contrast medium (MCCM) and high-concentration contrast medium (HCCM) during two CT examinations within 3 months. Enhancement of the aorta, liver and portal vein and the tumour-to-liver contrast-to-noise ratio (CNR) were compared between MCCM and HCCM. Results: 30 patients (mean age 59 years; range 45-80 years; 16 patients in scheme A and 14 in scheme B)with a total of 31 confirmed HCC noduleswere prospectively enrolled. For scheme B, the mean contrast enhancement of the aorta and tumour-to-liver CNR were significantly higher with HCCM than with MCCM during the hepatic arterial phase (+350.5 HU vs +301.1 HU, p50.001, and +7.5 HU vs +5.5 HU, p50.004). For both groups, there was no significant difference between MCCM and HCCMfor all other comparisons. Conclusion: For a constant injection flow rate, HCCM significantly improves the conspicuity of HCC lesions and aortic enhancement during the hepatic arterial phase on 64-section MDCT in patients with cirrhosis. © 2011 The British Institute of Radiology.

Authors
Guerrisi, A; Marin, D; Nelson, RC; Filippis, GD; Martino, MD; Barnhart, H; Masciangelo, R; Guerrisi, I; Passariello, R; Catalano, C
MLA Citation
Guerrisi, A, Marin, D, Nelson, RC, Filippis, GD, Martino, MD, Barnhart, H, Masciangelo, R, Guerrisi, I, Passariello, R, and Catalano, C. "Effect of varying contrast material iodine concentration and injection technique on the conspicuity of hepatocellular carcinoma during 64-section MDCT of patients with cirrhosis." British Journal of Radiology 84.1004 (2011): 698-708.
PMID
21750137
Source
scival
Published In
British Journal of Radiology
Volume
84
Issue
1004
Publish Date
2011
Start Page
698
End Page
708
DOI
10.1259/bjr/21539234

Precision of iodine quantification in hepatic CT: Effects of reconstruction (FBP and MBIR) and imaging parameters

In hepatic CT imaging, the lesion enhancement after the injection of contrast media is of quantitative interest. However, the precision of this quantitative measurement may be dependent on the imaging techniques such as dose and reconstruction algorithm. To determine the impact of different techniques, we scanned an iodinated liver phantom with acquisition protocols of different dose levels, and reconstructed images with different algorithms (FBP and MBIR) and slice thicknesses. The contrast of lesions was quantified from the images, and its precision was calculated for each protocol separately. Results showed that precision was improved by increasing dose, increasing slice thickness, and using MBIR reconstruction. When using MBIR instead of FBP, the same precision can be achieved at 50% less dose. To our knowledge, this is the first investigation of the quantification precision in hepatic CT imaging using iterative reconstructions. © 2011 SPIE.

Authors
Chen, B; Samei, E; Colsher, J; Barnhart, H; Marin, D; Nelson, R
MLA Citation
Chen, B, Samei, E, Colsher, J, Barnhart, H, Marin, D, and Nelson, R. "Precision of iodine quantification in hepatic CT: Effects of reconstruction (FBP and MBIR) and imaging parameters." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 7961 (2011).
Source
scival
Published In
Proceedings of SPIE
Volume
7961
Publish Date
2011
DOI
10.1117/12.878833

Detection of pancreatic tumors, image quality, and radiation dose during the pancreatic parenchymal phase: effect of a low-tube-voltage, high-tube-current CT technique--preliminary results.

PURPOSE: To intraindividually compare a low-tube-voltage (80 kVp), high-tube-current (675 mA) computed tomographic (CT) technique with a high-tube-voltage (140 kVp) CT protocol for the detection of pancreatic tumors, image quality, and radiation dose during the pancreatic parenchymal phase. MATERIALS AND METHODS: This prospective, single-center, HIPAA-compliant study was approved by the institutional review board, and written informed consent was obtained. Twenty-seven patients (nine men, 18 women; mean age, 64 years) with 23 solitary pancreatic tumors underwent dual-energy CT. Two imaging protocols were used: 140 kVp and 385 mA (protocol A) and 80 kVp and 675 mA (protocol B). For both protocols, the following variables were compared during the pancreatic parenchymal phase: contrast enhancement for the aorta, the pancreas, and the portal vein; pancreas-to-tumor contrast-to-noise ratio (CNR); noise; and effective dose. Two blinded, independent readers qualitatively scored the two data sets for tumor detection and image quality. Random-effect analysis of variance tests were used to compare differences between the two protocols. RESULTS: Compared with protocol A, protocol B yielded significantly higher contrast enhancement for the aorta (508.6 HU vs 221.5 HU, respectively), pancreas (151.2 HU vs 67.0 HU), and portal vein (189.7 HU vs 87.3 HU), along with a greater pancreas-to-tumor CNR (8.1 vs 5.9) (P < .001 for all comparisons). No statistically significant difference in tumor detection was observed between the two protocols. Although standard deviation of image noise increased with protocol B (11.5 HU vs 18.6 HU), this protocol significantly reduced the effective dose (from 18.5 to 5.1 mSv; P < .001). CONCLUSION: A low-tube-voltage, high-tube-current CT technique has the potential to improve the enhancement of the pancreas and peripancreatic vasculature, improve tumor conspicuity, and reduce patient radiation dose during the pancreatic parenchymal phase.

Authors
Marin, D; Nelson, RC; Barnhart, H; Schindera, ST; Ho, LM; Jaffe, TA; Yoshizumi, TT; Youngblood, R; Samei, E
MLA Citation
Marin, D, Nelson, RC, Barnhart, H, Schindera, ST, Ho, LM, Jaffe, TA, Yoshizumi, TT, Youngblood, R, and Samei, E. "Detection of pancreatic tumors, image quality, and radiation dose during the pancreatic parenchymal phase: effect of a low-tube-voltage, high-tube-current CT technique--preliminary results." Radiology 256.2 (August 2010): 450-459.
PMID
20656835
Source
pubmed
Published In
Radiology
Volume
256
Issue
2
Publish Date
2010
Start Page
450
End Page
459
DOI
10.1148/radiol.10091819

Effect of beam hardening on arterial enhancement in thoracoabdominal CT angiography with increasing patient size: an in vitro and in vivo study.

PURPOSE: To assess the effect of beam hardening on arterial enhancement in thoracoabdominal computed tomographic (CT) angiography in various body sizes in a phantom and in a clinical study. MATERIALS AND METHODS: An abdominal aortic phantom was placed in three cylindrical water containers simulating a small, an intermediate, and a large patient (diameters of 22, 30, and 40 cm, respectively). CT scanning was performed at 80, 100, and 120 kVp, and aortic attenuation was assessed. In a HIPAA-compliant institutional review board-approved study with waiver of informed consent, thoracoabdominal aortic attenuation was assessed in 100 consecutive patients (75 men, 25 women; mean body weight (BW), 79 kg) undergoing thoracoabdominal 64-section CT angiography at 80 kVp. Overall aortic attenuation in patients grouped according to BW (small patients [n = 26], <70 kg; intermediate patients [n = 41], 70-85 kg; large patients [n = 33], >85 kg) was compared. Overall aortic attenuation was correlated with BW, height, body mass index (BMI), body surface area (BSA), and lateral diameter by using linear regression. RESULTS: Comparison of the intermediate- and large-phantom groups relative to the small-phantom group indicated that mean aortic attenuation decreased by 9.7% and 13.4% at 80 kVp, 9.8% and 15.1% at 100 kVp, and 13.8% and 23.8% at 120 kVp, respectively (P < .001). In the clinical study, the overall aortic attenuation decreased by 11.3% and 20.0% in the intermediate- and large-patient groups relative to the small-patient group, respectively (P < .05). Overall aortic attenuation correlated well with BSA (R = -0.454), height (R = -0.421), and BW (R = -0.414), followed by lateral diameter (R = -0.291) and BMI (R = -0.211). CONCLUSION: Beam hardening may substantially contribute to reduced arterial enhancement in larger patients undergoing thoracoabdominal CT angiography. The beam-hardening effect on arterial enhancement is more pronounced at higher tube voltages.

Authors
Schindera, ST; Tock, I; Marin, D; Nelson, RC; Raupach, R; Hagemeister, M; von Allmen, G; Vock, P; Szucs-Farkas, Z
MLA Citation
Schindera, ST, Tock, I, Marin, D, Nelson, RC, Raupach, R, Hagemeister, M, von Allmen, G, Vock, P, and Szucs-Farkas, Z. "Effect of beam hardening on arterial enhancement in thoracoabdominal CT angiography with increasing patient size: an in vitro and in vivo study." Radiology 256.2 (August 2010): 528-535.
PMID
20656839
Source
pubmed
Published In
Radiology
Volume
256
Issue
2
Publish Date
2010
Start Page
528
End Page
535
DOI
10.1148/radiol.10092086

Complications of laparoscopic and percutaneous renal cryoablation in a single tertiary referral center.

BACKGROUND: Laparoscopic cryoablation (LCA) and percutaneous cryoablation (PCA) of small renal masses have gained popularity, but only limited data exist on the complication rates. OBJECTIVES: In this study, we report on postoperative complications associated with LCA and PCA in a single tertiary center experience. DESIGN, SETTING, AND PARTICIPANTS: We conducted a retrospective review of electronic medical records for patients undergoing LCA or PCA between 2001 and 2008 at our institution. INTERVENTIONS: All patients underwent LCA or PCA. MEASUREMENTS: Demographics, radiographic variables, and complication rates were compared between the two groups. Complications were classified according to the modified Clavien system. RESULTS AND LIMITATIONS: Of a total of 195 patients included in this study, 72 underwent LCA and 123 underwent PCA. There were no differences in demographics between the groups. We observed complications in 10 LCA procedures (13.9%) and 26 PCA procedures (21.1%) (p=0.253). The distribution of the complications differed significantly between the groups with mild complications (grades 1 and 2) more common in the PCA group (20.3% vs 5.6%, respectively; p=0.001), whereas severe events (grades 3 and 4) were more frequent in the LCA group (8.3% vs 0.8%, respectively; p=0.011). On multivariate analysis, age and body mass index were inversely associated with complications, whereas female gender, multiple tumors, and preexisting comorbidities showed a trend toward increased risk. CONCLUSIONS: LCA and PCA, although minimally invasive, are not void of complications. Most of the complications encountered are mild; however, severe (grade 3 or 4) events may occur in up to 3.6% of patients. PCA may be associated with a higher rate of complications, although most of these are mild and transient. However, on multivariate analysis, the chosen ablative approach (laparoscopic or percutaneous) is not associated with the risk of complications.

Authors
Tsivian, M; Chen, VH; Kim, CY; Zilberman, DE; Mouraviev, V; Nelson, RC; Albala, DM; Polascik, TJ
MLA Citation
Tsivian, M, Chen, VH, Kim, CY, Zilberman, DE, Mouraviev, V, Nelson, RC, Albala, DM, and Polascik, TJ. "Complications of laparoscopic and percutaneous renal cryoablation in a single tertiary referral center." Eur Urol 58.1 (July 2010): 142-147.
PMID
20363550
Source
pubmed
Published In
European Urology
Volume
58
Issue
1
Publish Date
2010
Start Page
142
End Page
147
DOI
10.1016/j.eururo.2010.03.035

Dual-energy multidetector CT: how does it work, what can it tell us, and when can we use it in abdominopelvic imaging?

Dual-energy CT provides information about how substances behave at different energies, the ability to generate virtual unenhanced datasets, and improved detection of iodine-containing substances on low-energy images. Knowing how a substance behaves at two different energies can provide information about tissue composition beyond that obtainable with single-energy techniques. The term K edge refers to the spike in attenuation that occurs at energy levels just greater than that of the K-shell binding because of the increased photoelectric absorption at these energy levels. K-edge values vary for each element, and they increase as the atomic number increases. The energy dependence of the photoelectric effect and the variability of K edges form the basis of dual-energy techniques, which may be used to detect substances such as iodine, calcium, and uric acid crystals. The closer the energy level used in imaging is to the K edge of a substance such as iodine, the more the substance attenuates. In the abdomen and pelvis, dual-energy CT may be used in the liver to increase conspicuity of hypervascular lesions; in the kidneys, to distinguish hyperattenuating cysts from enhancing renal masses and to characterize renal stone composition; in the adrenal glands, to characterize adrenal nodules; and in the pancreas, to differentiate between normal and abnormal parenchyma.

Authors
Coursey, CA; Nelson, RC; Boll, DT; Paulson, EK; Ho, LM; Neville, AM; Marin, D; Gupta, RT; Schindera, ST
MLA Citation
Coursey, CA, Nelson, RC, Boll, DT, Paulson, EK, Ho, LM, Neville, AM, Marin, D, Gupta, RT, and Schindera, ST. "Dual-energy multidetector CT: how does it work, what can it tell us, and when can we use it in abdominopelvic imaging?." Radiographics 30.4 (July 2010): 1037-1055.
PMID
20631367
Source
pubmed
Published In
Radiographics : a review publication of the Radiological Society of North America, Inc
Volume
30
Issue
4
Publish Date
2010
Start Page
1037
End Page
1055
DOI
10.1148/rg.304095175

Dual-energy CT for characterization of adrenal nodules: initial experience.

OBJECTIVE: The purpose of this study was to determine whether use of dual-energy technique can improve the diagnostic performance of CT in the differential diagnosis of adrenal adenomas and metastatic lesions. SUBJECTS AND METHODS: Thirty-one adrenal nodules were prospectively identified in 17 patients who underwent dual-energy CT at 140 and 80 kVp. Attenuation measurements were performed for each nodule at both tube voltages. The mean attenuation change (increase or decrease) between 140 kVp and 80 kVp was determined for each adrenal nodule. RESULTS: Twenty-six adrenal nodules were benign adenomas (attenuation less than +10 HU or stability for at least 1 year). Five adrenal nodules were classified as metastatic (rapid growth in 1 year and history of extraadrenal malignancy). The mean attenuation change between 140 kVp and 80 kVp was 0.4 +/- 7.1 HU for adenomas and 9.2 +/- 4.3 HU for metastatic lesions (p < 0.003). Fifty percent of adenomas had an attenuation decrease at 80 kVp. All metastatic lesions had an attenuation increase at 80 kVp. With a decrease in attenuation at 80 kVp as an indicator of intracellular lipid within an adenoma, dual-energy CT has 50% sensitivity, 100% specificity, 100% positive predictive value, and 28% negative predictive value in the diagnosis of adenoma. CONCLUSION: A decrease in attenuation of an adrenal lesion between 140 kVp and 80 kVp is a highly specific sign of adrenal adenoma. However, because an increase in attenuation at 80 kVp is seen with metastatic lesions and some adenomas, the sensitivity of this test is low. These data suggest that dual-energy CT can be used to help differentiate some lipid-poor adrenal adenomas from metastatic lesions.

Authors
Gupta, RT; Ho, LM; Marin, D; Boll, DT; Barnhart, HX; Nelson, RC
MLA Citation
Gupta, RT, Ho, LM, Marin, D, Boll, DT, Barnhart, HX, and Nelson, RC. "Dual-energy CT for characterization of adrenal nodules: initial experience." AJR Am J Roentgenol 194.6 (June 2010): 1479-1483.
PMID
20489086
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
194
Issue
6
Publish Date
2010
Start Page
1479
End Page
1483
DOI
10.2214/AJR.09.3476

Central Venous Catheter Care during Contrast-enhanced CT Response

Authors
Macha, DB; Nelson, RC; Howle, LE; Hollingsworth, JW; Schindera, ST
MLA Citation
Macha, DB, Nelson, RC, Howle, LE, Hollingsworth, JW, and Schindera, ST. "Central Venous Catheter Care during Contrast-enhanced CT Response." RADIOLOGY 255.2 (May 2010): 662-662.
Source
wos-lite
Published In
Radiology
Volume
255
Issue
2
Publish Date
2010
Start Page
662
End Page
662

Carcinoid tumors of the appendix: are these tumors identifiable prospectively on preoperative CT?

The purpose of this study was to determine if carcinoid tumors of the appendix were identified prospectively on preoperative CT at our institution during the last decade. A surgical database search performed using the Current Procedural Terminology codes for appendectomy and colectomy yielded 2108 patients who underwent appendectomy or colectomy with removal of the appendix from January 1998 through September 2007. Pathology reports were reviewed to identify patients in whom an appendiceal carcinoid tumor was identified. Preoperative CT reports and images were reviewed. Twenty-three carcinoid tumors (1.1%; 15 women [65.2%], eight men [34.8%]; average age 54 years [range, 23 to 86 years]) were identified. Ten patients underwent preoperative CT. No tumors were identified prospectively on CT. Images were available for rereview for eight patients. Studies were acquired with 16- (n = 7) and four- (n = 1) slice CT scanners. Average reported tumor size was 6.1 mm (range, 1.5 to 15 mm; n = 18). A tip or distal location was reported for all tumors for which a location was given (n = 15). Carcinoid tumors occurred in 1.1 per cent of appendix specimens. These tumors were all less than or 1.5 cm in size. Likely as a result of their small size, none of these tumors was identified prospectively on preoperative CT.

Authors
Coursey, CA; Nelson, RC; Moreno, RD; Dodd, LG; Patel, MB; Vaslef, S
MLA Citation
Coursey, CA, Nelson, RC, Moreno, RD, Dodd, LG, Patel, MB, and Vaslef, S. "Carcinoid tumors of the appendix: are these tumors identifiable prospectively on preoperative CT?." Am Surg 76.3 (March 2010): 273-275.
PMID
20349655
Source
pubmed
Published In
The American surgeon
Volume
76
Issue
3
Publish Date
2010
Start Page
273
End Page
275

Making the diagnosis of acute appendicitis: do more preoperative CT scans mean fewer negative appendectomies? A 10-year study.

PURPOSE: To determine the frequency of preoperative computed tomography (CT) in the evaluation of patients suspected of having appendicitis at one institution during the past 10 years and to determine whether changes in CT utilization were associated with changes in the negative appendectomy rate. MATERIALS AND METHODS: Institutional review board approval was obtained, and a waiver of informed consent was granted for this HIPAA-compliant study. A surgical database search yielded medical record numbers of 925 patients (526 [ 56.9%] men and 399 [43.1%] women; mean age, 38 years (range, 18-95 years]) who underwent urgent appendectomy between January 1998 and September 2007. Patients who were younger than 18 years of age at the time of surgery were excluded. CT, pathology, and surgery reports were reviewed. By using logistic regression, changes in the proportion of patients undergoing CT and in the proportion of patients undergoing each year appendectomy in which the appendix was healthy were evaluated. Subgroup analyses based on patient age ( 45 years) and sex also were performed. RESULTS: Prior to urgent appendectomy, 18.5% of patients underwent preoperative CT in 1998 compared with 93.2% of patients in 2007. The negative appendectomy rate for women 45 years of age and younger decreased from 42.9% in 1998% to 7.1% in 2007. However, the timing of the decline in negative appendectomy rates for women 45 years and younger could not be proved to be associated with the increase in CT use. There was no significant trend toward a lower negative appendectomy rate for men regardless of age or for women older than 45 years of age with increased use of preoperative CT. The shift from single-detector CT to multidetector CT and the use of decreasing section thickness also correlated with a reduction in false-positive diagnoses. CONCLUSION: Rising utilization of preoperative CT and advances in technology coincided with a decrease in the negative appendectomy rate for women 45 years and younger but not in men of any age or women older than 45 years.

Authors
Coursey, CA; Nelson, RC; Patel, MB; Cochran, C; Dodd, LG; Delong, DM; Beam, CA; Vaslef, S
MLA Citation
Coursey, CA, Nelson, RC, Patel, MB, Cochran, C, Dodd, LG, Delong, DM, Beam, CA, and Vaslef, S. "Making the diagnosis of acute appendicitis: do more preoperative CT scans mean fewer negative appendectomies? A 10-year study." Radiology 254.2 (February 2010): 460-468.
PMID
20093517
Source
pubmed
Published In
Radiology
Volume
254
Issue
2
Publish Date
2010
Start Page
460
End Page
468
DOI
10.1148/radiol.09082298

Focal cystic high-attenuation lesions: characterization in renal phantom by using photon-counting spectral CT--improved differentiation of lesion composition.

PURPOSE: To evaluate the capability of spectral computed tomography (CT) to improve the characterization of cystic high-attenuation lesions in a renal phantom and to test the hypothesis that spectral CT will improve the differentiation of cystic renal lesions with high protein content and those that have undergone hemorrhage or malignant contrast-enhancing transformation. MATERIALS AND METHODS: A renal phantom that contained cystic lesions grouped in nonenhancing cyst and hemorrhage series and an iodine-enhancing series was developed. Spectral CT is based on new detector designs that may possess energy-sensitive photon-counting abilities, thereby facilitating the assessment of quantitative information about the elemental and molecular composition of tissue or contrast materials. Imaging of the renal phantom was performed with a prototype scanner at 20 mAs and 70 keV, allowing characterization of x-ray photons at 25-34, 34-39, 39-44, 44-49, 49-55, and more than 55 keV. Region of interest analysis was used to determine lesion attenuation values at various x-ray energies. Statistical analysis was performed to assess attenuation patterns and identify distinct levels of attenuation on the basis of curve regression analysis with analysis of variance tables. RESULTS: Spectral CT depicted linear clusters for the cyst (P < .001, R(2) > 0.940) and hemorrhage (P < .001, R(2) > 0.962) series without spectral overlap. A distinct linear attenuation profile without spectral overlap was also detected for the iodine-enhancing series (P < .001, R(2) > 0.964), with attenuation values attained in the 34-39-keV energy bin statistically identified as outliers (mean slope variation, >37%), corresponding with iodine k-edge effects at 33.2 keV. CONCLUSION: Spectral CT has the potential to enable distinct characterization of hyperattenuating fluids in a renal phantom by helping identify proteinaceous and hemorrhagic lesions through assessment of their distinct levels of attenuation as well as by revealing iodine-containing lesions through analysis of their specific k-edge discontinuities.

Authors
Boll, DT; Patil, NA; Paulson, EK; Merkle, EM; Nelson, RC; Schindera, ST; Roessl, E; Martens, G; Proksa, R; Fleiter, TR; Schlomka, J-P
MLA Citation
Boll, DT, Patil, NA, Paulson, EK, Merkle, EM, Nelson, RC, Schindera, ST, Roessl, E, Martens, G, Proksa, R, Fleiter, TR, and Schlomka, J-P. "Focal cystic high-attenuation lesions: characterization in renal phantom by using photon-counting spectral CT--improved differentiation of lesion composition." Radiology 254.1 (January 2010): 270-276.
PMID
20032158
Source
pubmed
Published In
Radiology
Volume
254
Issue
1
Publish Date
2010
Start Page
270
End Page
276
DOI
10.1148/radiol.09090068

Successful implementation of a universal 3/2 radiology curriculum.

Authors
Maxfield, CM; Nelson, RC; Gray-Leithe, L; Ravin, CE
MLA Citation
Maxfield, CM, Nelson, RC, Gray-Leithe, L, and Ravin, CE. "Successful implementation of a universal 3/2 radiology curriculum." Acad Radiol 17.1 (January 2010): 116-119.
PMID
19734065
Source
pubmed
Published In
Academic Radiology
Volume
17
Issue
1
Publish Date
2010
Start Page
116
End Page
119
DOI
10.1016/j.acra.2009.07.007

Low-tube-voltage, high-tube-current multidetector abdominal CT: improved image quality and decreased radiation dose with adaptive statistical iterative reconstruction algorithm--initial clinical experience.

PURPOSE: To investigate whether an adaptive statistical iterative reconstruction (ASIR) algorithm improves the image quality at low-tube-voltage (80-kVp), high-tube-current (675-mA) multidetector abdominal computed tomography (CT) during the late hepatic arterial phase. MATERIALS AND METHODS: This prospective, single-center HIPAA-compliant study was institutional review board approved. Informed patient consent was obtained. Ten patients (six men, four women; mean age, 63 years; age range, 51-77 years) known or suspected to have hypervascular liver tumors underwent dual-energy 64-section multidetector CT. High- and low-tube-voltage CT images were acquired sequentially during the late hepatic arterial phase of contrast enhancement. Standard convolution FBP was used to reconstruct 140-kVp (protocol A) and 80-kVp (protocol B) image sets, and ASIR (protocol C) was used to reconstruct 80-kVp image sets. The mean image noise; contrast-to-noise ratio (CNR) relative to muscle for the aorta, liver, and pancreas; and effective dose with each protocol were assessed. A figure of merit (FOM) was computed to normalize the image noise and CNR for each protocol to effective dose. Repeated-measures analysis of variance with Bonferroni adjustment for multiple comparisons was used to compare differences in mean CNR, image noise, and corresponding FOM among the three protocols. The noise power spectra generated from a custom phantom with each protocol were also compared. RESULTS: When image noise was normalized to effective dose, protocol C, as compared with protocols A (P = .0002) and B (P = .0001), yielded an approximately twofold reduction in noise. When the CNR was normalized to effective dose, protocol C yielded significantly higher CNRs for the aorta, liver, and pancreas than did protocol A (P = .0001 for all comparisons) and a significantly higher CNR for the liver than did protocol B (P = .003). Mean effective doses were 17.5 mSv +/- 0.6 (standard error) with protocol A and 5.1 mSv +/- 0.3 with protocols B and C. Compared with protocols A and B, protocol C yielded a small but quantifiable noise reduction across the entire spectrum of spatial frequencies. CONCLUSION: Compared with standard FBP reconstruction, an ASIR algorithm improves image quality and has the potential to decrease radiation dose at low-tube-voltage, high-tube-current multidetector abdominal CT during the late hepatic arterial phase.

Authors
Marin, D; Nelson, RC; Schindera, ST; Richard, S; Youngblood, RS; Yoshizumi, TT; Samei, E
MLA Citation
Marin, D, Nelson, RC, Schindera, ST, Richard, S, Youngblood, RS, Yoshizumi, TT, and Samei, E. "Low-tube-voltage, high-tube-current multidetector abdominal CT: improved image quality and decreased radiation dose with adaptive statistical iterative reconstruction algorithm--initial clinical experience." Radiology 254.1 (January 2010): 145-153.
PMID
20032149
Source
pubmed
Published In
Radiology
Volume
254
Issue
1
Publish Date
2010
Start Page
145
End Page
153
DOI
10.1148/radiol.09090094

Response

Authors
Macha, DB; Nelson, RC; Howle, LE; Hollingsworth, JW; Schindera, ST
MLA Citation
Macha, DB, Nelson, RC, Howle, LE, Hollingsworth, JW, and Schindera, ST. "Response." Radiology 255.2 (2010): 662--.
Source
scival
Published In
Radiology
Volume
255
Issue
2
Publish Date
2010
Start Page
662-
DOI
10.1148/radiol.092152

Central venous catheter integrity during mechanical power injection of iodinated contrast medium.

PURPOSE: To evaluate a widely used nontunneled triple-lumen central venous catheter in order to determine whether the largest of the three lumina (16 gauge) can tolerate high flow rates, such as those required for computed tomographic angiography. MATERIALS AND METHODS: Forty-two catheters were tested in vitro, including 10 new and 32 used catheters (median indwelling time, 5 days). Injection pressures were continuously monitored at the site of the 16-gauge central venous catheter hub. Catheters were injected with 300 and 370 mg of iodine per milliliter of iopamidol by using a mechanical injector at increasing flow rates until the catheter failed. The infusion rate, hub pressure, and location were documented for each failure event. The catheter pressures generated during hand injection by five operators were also analyzed. Mean flow rates and pressures at failure were compared by means of two-tailed Student t test, with differences considered significant at P < .05. RESULTS: Injections of iopamidol with 370 mg of iodine per milliliter generate more pressure than injections of iopamidol with 300 mg of iodine per milliliter at the same injection rate. All catheters failed in the tubing external to the patient. The lowest flow rate at which catheter failure occurred was 9 mL/sec. The lowest hub pressure at failure was 262 pounds per square inch gauge (psig) for new and 213 psig for used catheters. Hand injection of iopamidol with 300 mg of iodine per milliliter generated peak hub pressures ranging from 35 to 72 psig, corresponding to flow rates ranging from 2.5 to 5.0 mL/sec. CONCLUSION: Indwelling use has an effect on catheter material property, but even for used catheters there is a substantial safety margin for power injection with the particular triple-lumen central venous catheter tested in this study, as the manufacturer's recommendation for maximum pressure is 15 psig.

Authors
Macha, DB; Nelson, RC; Howle, LE; Hollingsworth, JW; Schindera, ST
MLA Citation
Macha, DB, Nelson, RC, Howle, LE, Hollingsworth, JW, and Schindera, ST. "Central venous catheter integrity during mechanical power injection of iodinated contrast medium." Radiology 253.3 (December 2009): 870-878.
PMID
19789224
Source
pubmed
Published In
Radiology
Volume
253
Issue
3
Publish Date
2009
Start Page
870
End Page
878
DOI
10.1148/radiol.2533081086

Contrast material administration protocols for 64-MDCT angiography: altering volume and rate and use of a saline chaser to better match the imaging window--physiologic phantom study.

OBJECTIVE: The purpose of our study was to evaluate the effect of varying volumes and rates of contrast material, use of a saline chaser, and cardiac output on aortic enhancement characteristics in MDCT angiography (MDCTA) using a physiologic phantom. MATERIALS AND METHODS: Volumes of 75, 100, and 125 mL of iopamidol, 370 mg I/mL, were administered at rates of 4, 6, and 8 mL/s. The effect of a saline chaser (50 mL of normal saline, 8 mL/s) was evaluated for each volume and rate combination. Normal, reduced (33% and 50%), and increased (25%) cardiac outputs were simulated. Peak aortic enhancement and duration of peak aortic enhancement were recorded. Analysis of variance models were run with these effects, and the estimated mean levels for the sets of factor combinations were determined. RESULTS: Lowering the volume of contrast material resulted in reduced peak enhancement (example, -56.2 HU [p < 0.0001] with 75 vs 125 mL) and reduced duration of 75% peak enhancement (example, -9.0 seconds [p < 0.0001] with 75 vs 125 mL). Increasing the rate resulted in increased peak enhancement (example, 104.5 HU [p < 0.0001] with a rate of 8 vs 4 mL/s) and decreased duration of 75% peak enhancement (example, -13.0 seconds [p < 0.001]). Use of a saline chaser resulted in increased peak enhancement, and this increase was inversely proportional to contrast material volume. Peak enhancement increased when reduced cardiac output was simulated. Peak enhancement decreased when increased cardiac output was simulated. CONCLUSION: Reducing contrast material volume from 125 to 75 mL, increasing the rate to 6 or 8 mL/s, and use of a saline chaser result in an aortic enhancement profile that better matches the approximately 5-second imaging window possible with 64-MDCTA of the abdomen and pelvis. Even smaller volumes of contrast material may be adequate in patients with reduced cardiac output.

Authors
Coursey, CA; Nelson, RC; Weber, PW; Howle, LE; Nichols, EB; Marin, D; DeLong, D
MLA Citation
Coursey, CA, Nelson, RC, Weber, PW, Howle, LE, Nichols, EB, Marin, D, and DeLong, D. "Contrast material administration protocols for 64-MDCT angiography: altering volume and rate and use of a saline chaser to better match the imaging window--physiologic phantom study." AJR Am J Roentgenol 193.6 (December 2009): 1568-1575.
PMID
19933649
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
193
Issue
6
Publish Date
2009
Start Page
1568
End Page
1575
DOI
10.2214/AJR.09.2670

Dual energy versus single energy MDCT: measurement of radiation dose using adult abdominal imaging protocols.

RATIONALE AND OBJECTIVES: The aim of this study was to measure the radiation dose of dual-energy and single-energy multidetector computed tomographic (CT) imaging using adult liver, renal, and aortic imaging protocols. MATERIALS AND METHODS: Dual-energy CT (DECT) imaging was performed on a conventional 64-detector CT scanner using a software upgrade (Volume Dual Energy) at tube voltages of 140 and 80 kVp (with tube currents of 385 and 675 mA, respectively), with a 0.8-second gantry revolution time in axial mode. Parameters for single-energy CT (SECT) imaging were a tube voltage of 140 kVp, a tube current of 385 mA, a 0.5-second gantry revolution time, helical mode, and pitch of 1.375:1. The volume CT dose index (CTDI(vol)) value displayed on the console for each scan was recorded. Organ doses were measured using metal oxide semiconductor field-effect transistor technology. Effective dose was calculated as the sum of 20 organ doses multiplied by a weighting factor found in International Commission on Radiological Protection Publication 60. Radiation dose saving with virtual noncontrast imaging reconstruction was also determined. RESULTS: The CTDI(vol) values were 49.4 mGy for DECT imaging and 16.2 mGy for SECT imaging. Effective dose ranged from 22.5 to 36.4 mSv for DECT imaging and from 9.4 to 13.8 mSv for SECT imaging. Virtual noncontrast imaging reconstruction reduced the total effective dose of multiphase DECT imaging by 19% to 28%. CONCLUSION: Using the current Volume Dual Energy software, radiation doses with DECT imaging were higher than those with SECT imaging. Substantial radiation dose savings are possible with DECT imaging if virtual noncontrast imaging reconstruction replaces precontrast imaging.

Authors
Ho, LM; Yoshizumi, TT; Hurwitz, LM; Nelson, RC; Marin, D; Toncheva, G; Schindera, ST
MLA Citation
Ho, LM, Yoshizumi, TT, Hurwitz, LM, Nelson, RC, Marin, D, Toncheva, G, and Schindera, ST. "Dual energy versus single energy MDCT: measurement of radiation dose using adult abdominal imaging protocols." Acad Radiol 16.11 (November 2009): 1400-1407.
PMID
19596594
Source
pubmed
Published In
Academic Radiology
Volume
16
Issue
11
Publish Date
2009
Start Page
1400
End Page
1407
DOI
10.1016/j.acra.2009.05.002

Radiation dose for body CT protocols: variability of scanners at one institution.

OBJECTIVE: The objective of our study was to determine, using an anthropomorphic phantom, whether patients are subject to variable radiation doses based on scanner assignment for common body CT studies. MATERIALS AND METHODS: Twenty metal oxide semiconductor field effect transistor dosimeters were placed in a medium-sized anthropomorphic phantom of a man. Pulmonary embolism and chest, abdomen, and pelvis protocols were used to scan the phantom three times with GE Healthcare scanners in four configurations and one 64-MDCT Siemens Healthcare scanner. Organ doses were averaged, and effective doses were calculated with weighting factors. RESULTS: The mean effective doses for the pulmonary embolism protocol ranged from 9.9 to 18.5 mSv and for the chest, abdomen, and pelvis protocol from 6.7 to 18.5 mSv. For the pulmonary embolism protocol, the mean effective dose from the Siemens Healthcare 64-MDCT scanner was significantly lower than that from the 16- and 64-MDCT GE Healthcare scanners (p < 0.001). The mean effective dose from the GE 4-MDCT scanner was significantly lower than that for the GE 16-MDCT scanner (p < 0.001) but not the GE 64-MDCT scanner (p = 0.02). For the chest, abdomen, and pelvis protocol, all mean effective doses from the GE scanners were significantly different from one another (p < 0.001), the lowest mean effective dose being found with use of a single-detector CT scanner and the highest with a 4-MDCT scanner. For the chest, abdomen, and pelvis protocols, the difference between the mean effective doses from the GE Healthcare and Siemens Healthcare 64-MDCT scanners was not statistically significant (p = 0.89). CONCLUSION: According to phantom data, patients are subject to different radiation exposures for similar body CT protocols depending on scanner assignment. In general, doses are lowest with use of 64-MDCT scanners.

Authors
Jaffe, TA; Yoshizumi, TT; Toncheva, G; Anderson-Evans, C; Lowry, C; Miller, CM; Nelson, RC; Ravin, CE
MLA Citation
Jaffe, TA, Yoshizumi, TT, Toncheva, G, Anderson-Evans, C, Lowry, C, Miller, CM, Nelson, RC, and Ravin, CE. "Radiation dose for body CT protocols: variability of scanners at one institution." AJR Am J Roentgenol 193.4 (October 2009): 1141-1147.
PMID
19770340
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
193
Issue
4
Publish Date
2009
Start Page
1141
End Page
1147
DOI
10.2214/AJR.09.2330

Modifying peripheral IV catheters with side holes and side slits results in favorable changes in fluid dynamic properties during the injection of iodinated contrast material.

OBJECTIVE: The purpose of this study was to compare a standard peripheral end-hole angiocatheter with those modified with side holes or side slits using experimental optical techniques to qualitatively compare the contrast material exit jets and using numeric techniques to provide flow visualization and quantitative comparisons. MATERIALS AND METHODS: A Schlieren imaging system was used to visualize the angiocatheter exit jet fluid dynamics at two different flow rates. Catheters were modified by drilling through-and-through side holes or by cutting slits into the catheters. A commercial computational fluid dynamics package was used to calculate numeric results for various vessel diameters and catheter orientations. RESULTS: Experimental images showed that modifying standard peripheral IV angiocatheters with side holes or side slits qualitatively changed the overall flow field and caused the exiting jet to become less well defined. Numeric calculations showed that the addition of side holes or slits resulted in a 9-30% reduction of the velocity of contrast material exiting the end hole of the angiocatheter. With the catheter tip directed obliquely to the wall, the maximum wall shear stress was always highest for the unmodified catheter and was always lowest for the four-side-slit catheter. CONCLUSION: Modified angiocatheters may have the potential to reduce extravasation events in patients by reducing vessel wall shear stress.

Authors
Weber, PW; Coursey, CA; Howle, LE; Nelson, RC; Nichols, EB; Schindera, ST
MLA Citation
Weber, PW, Coursey, CA, Howle, LE, Nelson, RC, Nichols, EB, and Schindera, ST. "Modifying peripheral IV catheters with side holes and side slits results in favorable changes in fluid dynamic properties during the injection of iodinated contrast material." AJR Am J Roentgenol 193.4 (October 2009): 970-977.
PMID
19770318
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
193
Issue
4
Publish Date
2009
Start Page
970
End Page
977
DOI
10.2214/AJR.09.2521

Effect of automatic tube current modulation on radiation dose and image quality for low tube voltage multidetector row CT angiography: phantom study.

RATIONALE AND OBJECTIVES: To evaluate the effect of automatic tube current modulation on radiation dose and image quality for low tube voltage computed tomography (CT) angiography. MATERIALS AND METHODS: An anthropomorphic phantom was scanned with a 64-section CT scanner using following tube voltages: 140 kVp (Protocol A), 120 kVp (Protocol B), 100 kVp (Protocol C), and 80 kVp (Protocol D). To achieve similar noise, combined z-axis and xy-axes automatic tube current modulation was applied. Effective dose (ED) for the four tube voltages was assessed. Three plastic vials filled with different concentrations of iodinated solution were placed on the phantom's abdomen to obtain attenuation measurements. The signal-to-noise ratio (SNR) was calculated and a figure of merit (FOM) for each iodinated solution was computed as SNR(2)/ED. RESULTS: The ED was kept similar for the four different tube voltages: (A) 5.4 mSv +/- 0.3, (B) 4.1 mSv +/- 0.6, (C) 3.9 mSv +/- 0.5, and (D) 4.2 mSv +/- 0.3 (P > .05). As the tube voltage decreased from 140 to 80 kVp, image noise was maintained (range, 13.8-14.9 HU) (P > .05). SNR increased as the tube voltage decreased, with an overall gain of 119% for the 80-kVp compared to the 140-kVp protocol (P < .05). The FOM results indicated that with a reduction of the tube voltage from 140 to 120, 100, and 80 kVp, at constant SNR, ED was reduced by a factor of 2.1, 3.3, and 5.1, respectively, (P < .001). CONCLUSIONS: As tube voltage decreases, automatic tube current modulation for CT angiography yields either a significant increase in image quality at constant radiation dose or a significant decrease in radiation dose at a constant image quality.

Authors
Schindera, ST; Nelson, RC; Yoshizumi, T; Toncheva, G; Nguyen, G; DeLong, DM; Szucs-Farkas, Z
MLA Citation
Schindera, ST, Nelson, RC, Yoshizumi, T, Toncheva, G, Nguyen, G, DeLong, DM, and Szucs-Farkas, Z. "Effect of automatic tube current modulation on radiation dose and image quality for low tube voltage multidetector row CT angiography: phantom study." Acad Radiol 16.8 (August 2009): 997-1002.
PMID
19409820
Source
pubmed
Published In
Academic Radiology
Volume
16
Issue
8
Publish Date
2009
Start Page
997
End Page
1002
DOI
10.1016/j.acra.2009.02.021

Hypervascular liver tumors: low tube voltage, high tube current multidetector CT during late hepatic arterial phase for detection--initial clinical experience.

PURPOSE: To intraindividually compare a low tube voltage (80 kVp), high tube current computed tomographic (CT) technique with a standard CT protocol (140 kVp) in terms of image quality, radiation dose, and detection of malignant hypervascular liver tumors during the late hepatic arterial phase. MATERIALS AND METHODS: This prospective single-center HIPAA-compliant study had institutional review board approval, and written informed consent was obtained. Forty-eight patients (31 men, 17 women; age range, 35-77 years) with 60 malignant hypervascular liver tumors (mean diameter, 20.1 mm +/- 16.4 [standard deviation]) were enrolled. Pathologic proof of focal lesions was obtained with histopathologic analysis for 33 nodules and imaging follow-up after a minimum of 12 months for 27 nodules. Patients underwent dual-energy 64-section multi-detector row CT. By using vendor-specific software, two imaging protocols-140 kVp and 385 mA (protocol A) and 80 kVp and 675 mA (protocol B)-were compared during the late hepatic arterial phase of contrast enhancement. Paired t tests were used to compare tumor-to-liver contrast-to-noise ratio (CNR) for each lesion, mean image noise, and effective dose between the two data sets. Three readers qualitatively assessed the two data sets in a blinded and independent fashion. Lesion detection and characterization and reader confidence were recorded, as well as readers' subjective evaluations of image quality. Wilcoxon-Mann-Whitney statistical analysis was performed on this assessment. RESULTS: Image noise increased from 5.7 to 11.4 HU as the tube voltage decreased from 140 to 80 kVp (P < .0001), resulting in a significantly lower image quality score (4.0 vs 3.0, respectively) with protocol B according to all readers (P < .001). At the same time, protocol B yielded significantly higher CNR (8.2 vs 6.4) and lesion conspicuity scores (4.6 vs 4.1) than protocol A, along with a lower effective dose (5.1 vs 17.5 mSv) (P < .001 for all). CONCLUSION: By substantially increasing the tumor-to-liver CNR, a low tube voltage, high tube current CT technique improves the conspicuity of malignant hypervascular liver tumors during the late hepatic arterial phase while significantly reducing patient radiation dose.

Authors
Marin, D; Nelson, RC; Samei, E; Paulson, EK; Ho, LM; Boll, DT; DeLong, DM; Yoshizumi, TT; Schindera, ST
MLA Citation
Marin, D, Nelson, RC, Samei, E, Paulson, EK, Ho, LM, Boll, DT, DeLong, DM, Yoshizumi, TT, and Schindera, ST. "Hypervascular liver tumors: low tube voltage, high tube current multidetector CT during late hepatic arterial phase for detection--initial clinical experience." Radiology 251.3 (June 2009): 771-779.
PMID
19346514
Source
pubmed
Published In
Radiology
Volume
251
Issue
3
Publish Date
2009
Start Page
771
End Page
779
DOI
10.1148/radiol.2513081330

Liver biopsy.

Authors
Rockey, DC; Caldwell, SH; Goodman, ZD; Nelson, RC; Smith, AD; American Association for the Study of Liver Diseases,
MLA Citation
Rockey, DC, Caldwell, SH, Goodman, ZD, Nelson, RC, Smith, AD, and American Association for the Study of Liver Diseases, . "Liver biopsy." Hepatology 49.3 (March 2009): 1017-1044.
PMID
19243014
Source
pubmed
Published In
Hepatology
Volume
49
Issue
3
Publish Date
2009
Start Page
1017
End Page
1044
DOI
10.1002/hep.22742

Radiation dose savings for adult pulmonary embolus 64-MDCT using bismuth breast shields, lower peak kilovoltage, and automatic tube current modulation.

OBJECTIVE: The purpose of this study was to assess whether radiation dose savings using a lower peak kilovoltage (kVp) setting, bismuth breast shields, and automatic tube current modulation could be achieved while preserving the image quality of MDCT scans obtained to assess for pulmonary embolus (PE). MATERIALS AND METHODS: CT angiography (CTA) examinations were performed to assess for the presence or absence of pulmonary artery emboli using a 64-MDCT scanner with automatic tube current modulation (noise level=10 HU), two kVp settings (120 and 140 kVp), and bismuth breast shields. Absorbed organ doses were measured using anthropomorphic phantoms and metal oxide semiconductor field effect transistor (MOSFET) detectors. Image quality was assessed quantitatively as well as qualitatively in various anatomic sites of the thorax. RESULTS: Using a lower kVp (120 vs 140 kVp) and automatic tube current modulation resulted in a dose savings of 27% to the breast and 47% to the lungs. The use of a lower kVp (120 kVp), automatic tube current modulation, and bismuth shields placed directly on the anterior chest wall reduced absorbed breast and lung doses by 55% and 45%, respectively. Qualitative assessment of the images showed no change in image quality of the lungs and mediastinum when using a lower kVp, bismuth shields, or both. CONCLUSION: The use of bismuth breast shields together with a lower kVp and automatic tube current modulation will reduce the absorbed radiation dose to the breast and lungs without degradation of image quality to the organs of the thorax for CTA detection of PE.

Authors
Hurwitz, LM; Yoshizumi, TT; Goodman, PC; Nelson, RC; Toncheva, G; Nguyen, GB; Lowry, C; Anderson-Evans, C
MLA Citation
Hurwitz, LM, Yoshizumi, TT, Goodman, PC, Nelson, RC, Toncheva, G, Nguyen, GB, Lowry, C, and Anderson-Evans, C. "Radiation dose savings for adult pulmonary embolus 64-MDCT using bismuth breast shields, lower peak kilovoltage, and automatic tube current modulation." AJR Am J Roentgenol 192.1 (January 2009): 244-253.
PMID
19098206
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
192
Issue
1
Publish Date
2009
Start Page
244
End Page
253
DOI
10.2214/AJR.08.1066

Reply

Authors
Rockey, DC; Caldwell, SH; Goodman, ZD; Nelson, RC; Smith, AD
MLA Citation
Rockey, DC, Caldwell, SH, Goodman, ZD, Nelson, RC, and Smith, AD. "Reply." Hepatology 50.2 (2009): 655-656.
Source
scival
Published In
Hepatology
Volume
50
Issue
2
Publish Date
2009
Start Page
655
End Page
656
DOI
10.1002/hep.23086

Hepatobiliary imaging by MDCT

Hepatobiliary imaging by computed tomography (CT) has advanced impressively since the introduction of multidetector CT (MDCT) scanners in the late 1990s. Over the last few years, the number of detector rows has increased progressively from four, to eight, to 16, and then up to 64. Two important advantages of MDCT are the routine use of thinner, submillimeter sections, which yield higher spatial resolution, along the Z-axis and decrease in gantry rotation time, which result in a significantly reduced scan time. Sixteen-, 32- and 64-slice scanners allow the acquisition of data sets with nearly isotropic voxels for multiplanar imaging (e.g., coronal and sagittal plane), which has similar spatial resolution compared with axial planes. These off-axis reformations are particularly helpful for evaluating the hepatic vascular anatomy, the biliary system, and the segmental distribution of hepatic lesions. Since thin-section collination also reduces partial volume averaging, sensitivity and specificity for detecting and characterizing increases, especially for small focal hepatic lesions, whether benign or malignant. © 2008 Springer-Verlag Milan.

Authors
Schindera, ST; Nelson, RC
MLA Citation
Schindera, ST, and Nelson, RC. "Hepatobiliary imaging by MDCT." (December 1, 2008): 93-110. (Chapter)
Source
scopus
Publish Date
2008
Start Page
93
End Page
110
DOI
10.1007/978-88-470-0832-8_10

Persistent contrast enhancement several months after laparoscopic cryoablation of the small renal mass may not indicate recurrent tumor.

PURPOSE: We evaluated the clinical implication of persistent contrast enhancement demonstrated several months after laparoscopic renal cryoablation of a small renal mass. PATIENTS AND METHODS: Between September 2000 and May 2007, 30 patients underwent laparoscopic cryosurgery for an organ-confined renal tumor measuring

Authors
Stein, AJ; Mayes, JM; Mouraviev, V; Chen, VH; Nelson, RC; Polascik, TJ
MLA Citation
Stein, AJ, Mayes, JM, Mouraviev, V, Chen, VH, Nelson, RC, and Polascik, TJ. "Persistent contrast enhancement several months after laparoscopic cryoablation of the small renal mass may not indicate recurrent tumor." J Endourol 22.11 (November 2008): 2433-2439.
PMID
18928388
Source
pubmed
Published In
Journal of Endourology
Volume
22
Issue
11
Publish Date
2008
Start Page
2433
End Page
2439
DOI
10.1089/end.2008.0261

In vivo guidance and assessment of liver radio-frequency ablation with acoustic radiation force elastography.

The initial results from clinical trials investigating the utility of acoustic radiation force impulse (ARFI) imaging for use with radio-frequency ablation (RFA) procedures in the liver are presented. To date, data have been collected from 6 RFA procedures in 5 unique patients. Large displacement contrast was observed in ARFI images of both pre-ablation malignancies (mean 7.5 dB, range 5.7-11.9 dB) and post-ablation thermal lesions (mean 6.2 dB, range 5.1-7.5 dB). In general, ARFI images provided superior boundary definition of structures relative to the use of conventional sonography alone. Although further investigations are required, initial results are encouraging and demonstrate the clinical promise of the ARFI method for use in many stages of RFA procedures.

Authors
Fahey, BJ; Nelson, RC; Hsu, SJ; Bradway, DP; Dumont, DM; Trahey, GE
MLA Citation
Fahey, BJ, Nelson, RC, Hsu, SJ, Bradway, DP, Dumont, DM, and Trahey, GE. "In vivo guidance and assessment of liver radio-frequency ablation with acoustic radiation force elastography." Ultrasound Med Biol 34.10 (October 2008): 1590-1603.
Website
http://hdl.handle.net/10161/10364
PMID
18471954
Source
pubmed
Published In
Ultrasound in Medicine and Biology
Volume
34
Issue
10
Publish Date
2008
Start Page
1590
End Page
1603
DOI
10.1016/j.ultrasmedbio.2008.03.006

Effect of varying injection rates of a saline chaser on aortic enhancement in CT angiography: phantom study.

The effect of varying injection rates of a saline chaser on aortic enhancement in computed tomography (CT) angiography was determined. Single-level, dynamic CT images of a physiological flow phantom were acquired between 0 and 50 s after initiation of contrast medium injection. Four injection protocols were applied with identical contrast medium administration (150 ml injected at 5 ml/s). For baseline protocol A, no saline chaser was applied. For protocols B, C, and D, 50 ml of saline was injected at 2.5 ml/s, 5 ml/s, and 10 ml/s, respectively. Injecting the saline chaser at twice the rate as the contrast medium yielded significantly higher peak aortic enhancement values than injecting the saline at half or at the same rate as the contrast medium (P < 0.05). Average peak aortic enhancement (HU) measured 214, 214, 218, and 226 for protocols A, B, C, and D, respectively. The slower the saline-chaser injection rate, the longer the duration of 90% peak enhancement: 13.6, 12.2, and 11.7 s for protocols B, C, and D, respectively (P > 0.05). In CT angiography, saline chaser injected at twice the rate as the contrast medium leads to increased peak aortic enhancement and saline chaser injected at half the rate tends towards prolonging peak aortic enhancement plateau.

Authors
Schindera, ST; Nelson, RC; Howle, L; Nichols, E; DeLong, DM; Merkle, EM
MLA Citation
Schindera, ST, Nelson, RC, Howle, L, Nichols, E, DeLong, DM, and Merkle, EM. "Effect of varying injection rates of a saline chaser on aortic enhancement in CT angiography: phantom study." Eur Radiol 18.8 (August 2008): 1683-1689.
PMID
18351346
Source
pubmed
Published In
European Radiology
Volume
18
Issue
8
Publish Date
2008
Start Page
1683
End Page
1689
DOI
10.1007/s00330-008-0911-3

Early first-trimester fetal radiation dose estimation in 16-MDCT without and with automated tube current modulation.

OBJECTIVE: The objective of our study was to correlate the estimated fetal absorbed radiation dose derived by directly measured uterine doses in the early first trimester and the volume CT dose index (CTDI(vol)) for 16-MDCT of the maternal chest, abdomen, and pelvis. MATERIALS AND METHODS: Estimated absorbed fetal dose was measured using a metal oxide semiconductor field effect transistor (MOSFET) dosimeter that was placed in the uterus of an adult female anthropomorphic phantom. The phantom was scanned on a 16-MDCT scanner using three protocols. The scanning parameters for protocol A (trauma) were detector configuration, 16 x 0.625 mm; pitch, 1.75:1; rotation time, 0.5 second; 140 kVp; and 340 mA. The scanning parameters for protocol B (CT angiography) were detector configuration, 16 x 1.25 mm; pitch, 1.38:1; rotation time, 0.6 second; 140 kVp; and 300 mA. The scanning parameters for protocol C, which is the automated tube current modulation (ATCM) protocol previously used in the literature, were detector configuration, 16 x 1.25 mm; pitch, 0.938:1; rotation time, 0.5 second; 140 kVp; and 380 mA. The protocols were also modified for the ATCM mode; the CTDI(vol) was documented from the scanner's console. Correlation between these data was tested with a goodness-of-fit model. RESULTS: Absorbed fetal radiation dose in the early first trimester correlated with the CTDI(vol) via a linear regression equation. For a constant tube current and peak voltage of 140 kVp, fetal dose (mGy) = 1.665 x CTDI(vol) (mGy) - 7.059. For the ATCM mode and a constant kVp of 140, fetal dose (mGy) = 2.151 x CTDI(vol) (mGy) - 2.200. The goodness of fit (R(2)) for the equations is 0.99 and 0.91, respectively. CONCLUSION: In both the manual and ATCM modes, absorbed fetal radiation dose can be estimated from the CTDI(vol) obtained at the time of scanning independent of pitch and tube current-time product (mAs).

Authors
Jaffe, TA; Yoshizumi, TT; Toncheva, GI; Nguyen, G; Hurwitz, LM; Nelson, RC
MLA Citation
Jaffe, TA, Yoshizumi, TT, Toncheva, GI, Nguyen, G, Hurwitz, LM, and Nelson, RC. "Early first-trimester fetal radiation dose estimation in 16-MDCT without and with automated tube current modulation." AJR Am J Roentgenol 190.4 (April 2008): 860-864.
PMID
18356429
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
190
Issue
4
Publish Date
2008
Start Page
860
End Page
864
DOI
10.2214/AJR.07.2925

Effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation: phantom study.

OBJECTIVE: The purpose of this study was to evaluate in a phantom study the effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation. MATERIALS AND METHODS: One or two 4-cm-thick circumferential layers of fat-equivalent material were added to the abdomen of an anthropomorphic phantom to simulate patients of three sizes: small (cross-sectional dimensions, 18 x 22 cm), average size (26 x 30 cm), and oversize (34 x 38 cm). Imaging was performed with a 64-MDCT scanner with combined z-axis and xy-axis tube current modulation according to two protocols: protocol A had a noise index of 12.5 H, and protocol B, 15.0 H. Radiation doses to three abdominal organs and the skin were assessed. Image noise also was measured. RESULTS: Despite increasing patient size, the image noise measured was similar for protocol A (range, 11.7-12.2 H) and protocol B (range, 13.9-14.8 H) (p > 0.05). With the two protocols, in comparison with the dose of the small patient, the abdominal organ doses of the average-sized patient and the oversized patient increased 161.5-190.6%and 426.9-528.1%, respectively (p < 0.001). The skin dose increased as much as 268.6% for the average-sized patient and 816.3% for the oversized patient compared with the small patient (p < 0.001). CONCLUSION: Oversized patients undergoing abdominal MDCT with tube current modulation receive significantly higher doses than do small patients. The noise index needs to be adjusted to the body habitus to ensure dose efficiency.

Authors
Schindera, ST; Nelson, RC; Toth, TL; Nguyen, GT; Toncheva, GI; DeLong, DM; Yoshizumi, TT
MLA Citation
Schindera, ST, Nelson, RC, Toth, TL, Nguyen, GT, Toncheva, GI, DeLong, DM, and Yoshizumi, TT. "Effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation: phantom study." AJR Am J Roentgenol 190.2 (February 2008): W100-W105.
PMID
18212190
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
190
Issue
2
Publish Date
2008
Start Page
W100
End Page
W105
DOI
10.2214/AJR.07.2891

In vivo visualization of abdominal malignancies with acoustic radiation force elastography.

The utility of acoustic radiation force impulse (ARFI) imaging for real-time visualization of abdominal malignancies was investigated. Nine patients presenting with suspicious masses in the liver (n = 7) or kidney (n = 2) underwent combined sonography/ARFI imaging. Images were acquired of a total of 12 tumors in the nine patients. In all cases, boundary definition in ARFI images was improved or equivalent to boundary definition in B-mode images. Displacement contrast in ARFI images was superior to echo contrast in B-mode images for each tumor. The mean contrast for suspected hepatocellular carcinomas (HCCs) in B-mode images was 2.9 dB (range: 1.5-4.2) versus 7.5 dB (range: 3.1-11.9) in ARFI images, with all HCCs appearing more compliant than regional cirrhotic liver parenchyma. The mean contrast for metastases in B-mode images was 3.1 dB (range: 1.2-5.2) versus 9.3 dB (range: 5.7-13.9) in ARFI images, with all masses appearing less compliant than regional non-cirrhotic liver parenchyma. ARFI image contrast (10.4 dB) was superior to B-mode contrast (0.9 dB) for a renal mass. To our knowledge, we present the first in vivo images of abdominal malignancies in humans acquired with the ARFI method or any other technique of imaging tissue elasticity.

Authors
Fahey, BJ; Nelson, RC; Bradway, DP; Hsu, SJ; Dumont, DM; Trahey, GE
MLA Citation
Fahey, BJ, Nelson, RC, Bradway, DP, Hsu, SJ, Dumont, DM, and Trahey, GE. "In vivo visualization of abdominal malignancies with acoustic radiation force elastography." Phys Med Biol 53.1 (January 7, 2008): 279-293.
Website
http://hdl.handle.net/10161/10363
PMID
18182703
Source
pubmed
Published In
Physics in Medicine and Biology
Volume
53
Issue
1
Publish Date
2008
Start Page
279
End Page
293
DOI
10.1088/0031-9155/53/1/020

Hypervascular liver tumors: low tube voltage, high tube current multi-detector row CT for enhanced detection--phantom study.

PURPOSE: To prospectively evaluate, for the depiction of simulated hypervascular liver lesions in a phantom, the effect of a low tube voltage, high tube current computed tomographic (CT) technique on image noise, contrast-to-noise ratio (CNR), lesion conspicuity, and radiation dose. MATERIALS AND METHODS: A custom liver phantom containing 16 cylindric cavities (four cavities each of 3, 5, 8, and 15 mm in diameter) filled with various iodinated solutions to simulate hypervascular liver lesions was scanned with a 64-section multi-detector row CT scanner at 140, 120, 100, and 80 kVp, with corresponding tube current-time product settings at 225, 275, 420, and 675 mAs, respectively. The CNRs for six simulated lesions filled with different iodinated solutions were calculated. A figure of merit (FOM) for each lesion was computed as the ratio of CNR2 to effective dose (ED). Three radiologists independently graded the conspicuity of 16 simulated lesions. An anthropomorphic phantom was scanned to evaluate the ED. Statistical analysis included one-way analysis of variance. RESULTS: Image noise increased by 45% with the 80-kVp protocol compared with the 140-kVp protocol (P < .001). However, the lowest ED and the highest CNR were achieved with the 80-kVp protocol. The FOM results indicated that at a constant ED, a reduction of tube voltage from 140 to 120, 100, and 80 kVp increased the CNR by factors of at least 1.6, 2.4, and 3.6, respectively (P < .001). At a constant CNR, corresponding reductions in ED were by a factor of 2.5, 5.5, and 12.7, respectively (P < .001). The highest lesion conspicuity was achieved with the 80-kVp protocol. CONCLUSION: The CNR of simulated hypervascular liver lesions can be substantially increased and the radiation dose reduced by using an 80-kVp, high tube current CT technique.

Authors
Schindera, ST; Nelson, RC; Mukundan, S; Paulson, EK; Jaffe, TA; Miller, CM; DeLong, DM; Kawaji, K; Yoshizumi, TT; Samei, E
MLA Citation
Schindera, ST, Nelson, RC, Mukundan, S, Paulson, EK, Jaffe, TA, Miller, CM, DeLong, DM, Kawaji, K, Yoshizumi, TT, and Samei, E. "Hypervascular liver tumors: low tube voltage, high tube current multi-detector row CT for enhanced detection--phantom study." Radiology 246.1 (January 2008): 125-132.
PMID
18096533
Source
pubmed
Published In
Radiology
Volume
246
Issue
1
Publish Date
2008
Start Page
125
End Page
132
DOI
10.1148/radiol.2461070307

Effect of varying injection rates of a saline chaser on aortic enhancement in CT angiography: Phantom study

The effect of varying injection rates of a saline chaser on aortic enhancement in computed tomography (CT) angiography was determined. Single-level, dynamic CT images of a physiological flow phantom were acquired between 0 and 50 s after initiation of contrast medium injection. Four injection protocols were applied with identical contrast medium administration (150 ml injected at 5 ml/s). For baseline protocol A, no saline chaser was applied. For protocols B, C, and D, 50 ml of saline was injected at 2.5 ml/s, 5 ml/s, and 10 ml/s, respectively. Injecting the saline chaser at twice the rate as the contrast medium yielded significantly higher peak aortic enhancement values than injecting the saline at half or at the same rate as the contrast medium (P < -0.05). Average peak aortic enhancement (HU) measured 214, 214, 218, and 226 for protocols A, B, C, and D, respectively. The slower the saline-chaser injection rate, the longer the duration of 90% peak enhancement: 13.6, 12.2, and 11.7 s for protocols B, C, and D, respectively (P > - 0.05). In CT angiography, saline chaser injected at twice the rate as the contrast medium leads to increased peak aortic enhancement and saline chaser injected at half the rate tends towards prolonging peak aortic enhancement plateau. © European Society of Radiology 2008.

Authors
Schindera, ST; Nelson, RC; Howle, L; Nichols, E; DeLong, DM; Merkle, EM
MLA Citation
Schindera, ST, Nelson, RC, Howle, L, Nichols, E, DeLong, DM, and Merkle, EM. "Effect of varying injection rates of a saline chaser on aortic enhancement in CT angiography: Phantom study." European Radiology 18.8 (2008): 1683-1689.
Source
scival
Published In
European Radiology
Volume
18
Issue
8
Publish Date
2008
Start Page
1683
End Page
1689
DOI
10.1007/s00330-008-0911-3

Effect of varying injection rates of a saline chaser on aortic enhancement in CT angiography: phantom study

Authors
Schindera, ST; Nelson, RC; Howle, L; Nichols, E; DeLong, DM; Merkle, EM
MLA Citation
Schindera, ST, Nelson, RC, Howle, L, Nichols, E, DeLong, DM, and Merkle, EM. "Effect of varying injection rates of a saline chaser on aortic enhancement in CT angiography: phantom study." European Radiology (2008): 1-7.
Source
scopus
Published In
European Radiology
Publish Date
2008
Start Page
1
End Page
7

In vivo Acoustic Radiation Force Impulse imaging of abdominal lesions

The initial results from an ongoing clinical study investigating the utility of Acoustic Radiation Force Impulse (ARFI) imaging for in vivo visualization of abdominal lesions are presented. To date, 13 patients with lesions located in the liver (n = 11) or kidney (n = 2) have been included. Preliminary results establish the feasibility of visualizing both primary and secondary liver tumors and primary renal cell tumors with ARFI imaging. For every lesion encountered to date, displacement contrast in ARFI images has exceeded echo contrast in B-mode ultrasound images. In general, boundary definition of lesions in ARFI images is superior to that seen with sonography. © 2007 IEEE.

Authors
Fahey, BJ; Nelson, RC; Hsu, SJ; Bradway, DP; Dumont, DM; Trahey, GE
MLA Citation
Fahey, BJ, Nelson, RC, Hsu, SJ, Bradway, DP, Dumont, DM, and Trahey, GE. "In vivo Acoustic Radiation Force Impulse imaging of abdominal lesions." December 1, 2007.
Source
scopus
Published In
Proceedings of the IEEE Ultrasonics Symposium
Publish Date
2007
Start Page
440
End Page
443
DOI
10.1109/ULTSYM.2007.119

A comparison of the efficacy and safety of iopamidol-370 and iodixanol-320 in patients undergoing multidetector-row computed tomography.

OBJECTIVES: To prospectively compare the effects on heart rate (HR) and contrast enhancement efficacy of iopamidol-370 and iodixanol-320 in contrast-enhanced, multidetector-row computed tomography (CE-MDCT). METHODS: IMPACT is a multicenter, double-blind study involving 166 patients undergoing CE-MDCT of the liver (n = 121) or peripheral arteries (n = 45) randomized to receive equi-iodine doses (40 gI) of iopamidol-370 or iodixanol-320 intravenous at 4 mL/s. CE-MDCT was performed using 16-MDCT scanners according to predefined imaging protocols. HR was measured with the patient in the supine position before and continuously for 5 minutes after contrast medium administration. Mean and peak increases in HR and the proportion of subjects with predefined HR increases (>5 to <10, 10 to <15, 15 to <20, >20 bpm) were compared in the 2 populations. Liver images were assessed by 2 independent, blinded readers for contrast enhancement [Hounsfield unit (HU)], using predefined regions-of-interest during the arterial and portal-venous phase of enhancement. RESULTS: Effects on HR: Eighty-four subjects received iopamidol-370 whereas 82 received iodixanol-320. Mean age, gender distribution, weight, total iodine dose, dose/body weight, concomitant medications and use of beta-blockers were comparable in the 2 groups. Mean baseline HR was similar in the 2 groups (iopamidol-370: 72.3 +/- 12.5 bpm; iodixanol-320: 74.5 +/- 11.9 bpm). Mean changes from baseline to peak postdose were similar in the 2 groups (8.0 +/- 9.3 bpm after iopamidol-370 and 8.4 +/- 14.7 after iodixanol-320, P = 0.72). The proportion of subjects in each group having increases of <5, >5 to <10, 10 to <15, 15 to <20, or >20 bpm was comparable (P = 0.87). Two subjects experienced postcontrast tachycardia (HR increase >70 bpm, peak HR of 146 and 164 bpm), both in the iodixanol-320 group (2.4%). Contrast Enhancement: Of the 121 patients undergoing liver CT, 60 received iopamidol-370 whereas 61 received iodixanol-320. Mean age, gender distribution, weight, total iodine dose, and dose/body weight were comparable in the 2 groups. Iopamidol-370 provided significantly higher HU values in abdominal aorta during the arterial phase of enhancement for both readers [R1: 301.3 +/- 80.2 vs. 273.6 +/- 65.9 HU, 95% confidence interval (6.1-56.8), P = 0.02; R2: 302.0 +/- 73.6 vs. 275.1 +/- 62.9 HU, 95% confidence interval (2.3-51.3), P = 0.03]. No significant difference was observed between the 2 contrast medium during the portal venous phase of enhancement. CONCLUSIONS: When the same injection rate and iodine dose is used, the effects on HR of bolus intravenous injections of iopamidol-370 and iodixanol-320 were similar. Iopamidol-370 provides significantly greater enhancement during the arterial phase and similar enhancement during the portal venous phase compared with iodixanol-320.

Authors
Sahani, DV; Soulez, G; Chen, KM; Lepanto, L; Xu, JR; Nelson, RC; Grazioli, L; Vanzulli, A; Heiken, JP; Investigators of the IMPACT Study,
MLA Citation
Sahani, DV, Soulez, G, Chen, KM, Lepanto, L, Xu, JR, Nelson, RC, Grazioli, L, Vanzulli, A, Heiken, JP, and Investigators of the IMPACT Study, . "A comparison of the efficacy and safety of iopamidol-370 and iodixanol-320 in patients undergoing multidetector-row computed tomography." Invest Radiol 42.12 (December 2007): 856-861.
PMID
18007158
Source
pubmed
Published In
Investigative Radiology
Volume
42
Issue
12
Publish Date
2007
Start Page
856
End Page
861
DOI
10.1097/RLI.0b013e3181514413

Noninvasive Imaging of the Biliary System

Authors
Merkle, EM; Nelson, RC; Petrowsky, H
MLA Citation
Merkle, EM, Nelson, RC, and Petrowsky, H. "Noninvasive Imaging of the Biliary System." (October 25, 2007): 69-96. (Chapter)
Source
scopus
Publish Date
2007
Start Page
69
End Page
96
DOI
10.1002/9780470986981.ch4

Assessment of the optimal temporal window for intravenous CT cholangiography.

The optimal temporal window of intravenous (IV) computed tomography (CT) cholangiography was prospectively determined. Fifteen volunteers (eight women, seven men; mean age, 38 years) underwent dynamic CT cholangiography. Two unenhanced images were acquired at the porta hepatis. Starting 5 min after initiation of IV contrast infusion (20 ml iodipamide meglumine 52%), 15 pairs of images at 5-min intervals were obtained. Attenuation of the extrahepatic bile duct (EBD) and the liver parenchyma was measured. Two readers graded visualization of the higher-order biliary branches. The first biliary opacification in the EBD occurred between 15 and 25 min (mean, 22.3 min +/- 3.2) after initiation of the contrast agent. Biliary attenuation plateaued between the 35- and the 75-min time points. Maximum hepatic parenchymal enhancement was 18.5 HU +/- 2.7. Twelve subjects demonstrated poor or non-visualization of higher-order biliary branches; three showed good or excellent visualization. Body weight and both biliary attenuation and visualization of the higher-order biliary branches correlated significantly (P<0.05). For peak enhancement of the biliary tree, CT cholangiography should be performed no earlier than 35 min after initiation of IV infusion. For a fixed contrast dose, superior visualization of the biliary system is achieved in subjects with lower body weight.

Authors
Schindera, ST; Nelson, RC; Paulson, EK; DeLong, DM; Merkle, EM
MLA Citation
Schindera, ST, Nelson, RC, Paulson, EK, DeLong, DM, and Merkle, EM. "Assessment of the optimal temporal window for intravenous CT cholangiography." Eur Radiol 17.10 (October 2007): 2531-2537.
PMID
17609958
Source
pubmed
Published In
European Radiology
Volume
17
Issue
10
Publish Date
2007
Start Page
2531
End Page
2537
DOI
10.1007/s00330-007-0709-8

Determining contrast medium dose and rate on basis of lean body weight: does this strategy improve patient-to-patient uniformity of hepatic enhancement during multi-detector row CT?

PURPOSE: To prospectively evaluate the use of lean body weight (LBW) as the main determinant of the volume and rate of contrast material administration during multi-detector row computed tomography of the liver. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval. All patients gave written informed consent. Four protocols were compared. Standard protocol involved 125 mL of iopamidol injected at 4 mL/sec. Total body weight (TBW) protocol involved 0.7 g iodine per kilogram of TBW. Calculated LBW and measured LBW protocols involved 0.86 g of iodine per kilogram and 0.92 g of iodine per kilogram calculated or measured LBW for men and women, respectively. Injection rate used for the three experimental protocols was determined proportionally on the basis of the calculated volume of contrast material. Postcontrast attenuation measurements during portal venous phase were obtained in liver, portal vein, and aorta for each group and were summed for each patient. Patient-to-patient enhancement variability in same group was measured with Levene test. Two-tailed t test was used to compare the three experimental protocols with the standard protocol. RESULTS: Data analysis was performed in 101 patients (25 or 26 patients per group), including 56 men and 45 women (mean age, 53 years). Average summed attenuation values for standard, TBW, calculated LBW, and measured LBW protocols were 419 HU +/- 50 (standard deviation), 443 HU +/- 51, 433 HU +/- 50, and 426 HU +/- 33, respectively (P = not significant for all). Levene test results for summed attenuation data for standard, TBW, calculated LBW, and measured LBW protocols were 40 +/- 29, 38 +/- 33 (P = .83), 35 +/- 35 (P = .56), and 26 +/- 19 (P = .05), respectively. CONCLUSION: By excluding highly variable but poorly perfused adipose tissue from calculation of contrast medium dose, the measured LBW protocol may lessen patient-to-patient enhancement variability while maintaining satisfactory hepatic and vascular enhancement.

Authors
Ho, LM; Nelson, RC; Delong, DM
MLA Citation
Ho, LM, Nelson, RC, and Delong, DM. "Determining contrast medium dose and rate on basis of lean body weight: does this strategy improve patient-to-patient uniformity of hepatic enhancement during multi-detector row CT?." Radiology 243.2 (May 2007): 431-437.
PMID
17456869
Source
pubmed
Published In
Radiology
Volume
243
Issue
2
Publish Date
2007
Start Page
431
End Page
437
DOI
10.1148/radiol.2432060390

Multi-detector row CT of the small bowel: peak enhancement temporal window--initial experience.

PURPOSE: To prospectively determine quantitatively and qualitatively the timing of maximal enhancement of the normal small-bowel wall by using contrast material-enhanced multi-detector row computed tomography (CT). MATERIALS AND METHODS: This HIPAA-compliant study was approved by the institutional review board. After information on radiation risk was given, written informed consent was obtained from 25 participants with no history of small-bowel disease (mean age, 58 years; 19 men) who had undergone single-level dynamic CT. Thirty seconds after the intravenous administration of contrast material, a serial dynamic acquisition, consisting of 10 images obtained 5 seconds apart, was performed. Enhancement measurements were obtained over time from the small-bowel wall and the aorta. Three independent readers qualitatively assessed small-bowel conspicuity. Quantitative and qualitative data were analyzed during the arterial phase, the enteric phase (which represented peak small-bowel mural enhancement), and the venous phase. Statistical analysis included paired Student t test and Wilcoxon signed rank test with Bonferroni correction. A P value less than .05 was used to indicate a significant difference. RESULTS: The mean time to peak enhancement of the small-bowel wall was 49.3 seconds +/- 7.7 (standard deviation) and 13.5 seconds +/- 7.6 after peak aortic enhancement. Enhancement values were highest during the enteric phase (P < .05). Regarding small-bowel conspicuity, images obtained during the enteric phase were most preferred qualitatively; there was a significant difference between the enteric and arterial phases (P < .001) but not between the enteric and venous phases (P = .18). CONCLUSION: At multi-detector row CT, peak mural enhancement of the normal small bowel occurs on average about 50 seconds after intravenous administration of contrast material or 14 seconds after peak aortic enhancement.

Authors
Schindera, ST; Nelson, RC; DeLong, DM; Jaffe, TA; Merkle, EM; Paulson, EK; Thomas, J
MLA Citation
Schindera, ST, Nelson, RC, DeLong, DM, Jaffe, TA, Merkle, EM, Paulson, EK, and Thomas, J. "Multi-detector row CT of the small bowel: peak enhancement temporal window--initial experience." Radiology 243.2 (May 2007): 438-444.
PMID
17384239
Source
pubmed
Published In
Radiology
Volume
243
Issue
2
Publish Date
2007
Start Page
438
End Page
444
DOI
10.1148/radiol.2432060534

Abdominal multislice CT for obese patients: effect on image quality and radiation dose in a phantom study.

RATIONALE AND OBJECTIVES: To evaluate the effect of a modified abdominal multislice computed tomography (CT) protocol for obese patients on image quality and radiation dose. MATERIALS AND METHODS: An adult female anthropomorphic phantom was used to simulate obese patients by adding one or two 4-cm circumferential layers of fat-equivalent material to the abdominal portion. The phantom was scanned with a subcutaneous fat thickness of 0, 4, and 8 cm using the following parameters (detector configuration/beam pitch/table feed per rotation/gantry rotation time/kV/mA): standard protocol A: 16 x 0.625 mm/1.75/17.5 mm/0.5 seconds/140/380, and modified protocol B: 16 x 1.25 mm/1.375/27.5 mm/1.0 seconds/140/380. Radiation doses to six abdominal organs and the skin, image noise values, and contrast-to-noise ratios (CNRs) were analyzed. Statistical analysis included analysis of variance, Wilcoxon rank sum, and Student's t-test (P < .05). RESULTS: Applying the modified protocol B with one or two fat rings, the image noise decreased significantly (P < .05), and simultaneously, the CNR increased significantly compared with protocol A (P < .05). Organ doses significantly increased, up to 54.7%, comparing modified protocol B with one fat ring to the routine protocol A with no fat rings (P < .05). However, no significant change in organ dose was seen for protocol B with two fat rings compared with protocol A without fat rings (range -2.1% to 8.1%) (P > .05). CONCLUSIONS: Using a modified abdominal multislice CT protocol for obese patients with 8 cm or more of subcutaneous fat, image quality can be substantially improved without a significant increase in radiation dose to the abdominal organs.

Authors
Schindera, ST; Nelson, RC; Lee, ER; Delong, DM; Ngyen, G; Toncheva, G; Yoshizumi, TT
MLA Citation
Schindera, ST, Nelson, RC, Lee, ER, Delong, DM, Ngyen, G, Toncheva, G, and Yoshizumi, TT. "Abdominal multislice CT for obese patients: effect on image quality and radiation dose in a phantom study." Acad Radiol 14.4 (April 2007): 486-494.
PMID
17368219
Source
pubmed
Published In
Academic Radiology
Volume
14
Issue
4
Publish Date
2007
Start Page
486
End Page
494
DOI
10.1016/j.acra.2007.01.030

Practical approach to diagnostic CT combined with PET.

OBJECTIVE: Protocols for PET/CT are not yet standardized. In particular, image quality, utilization, and reporting of the findings of the CT component of PET/CT can vary widely, making it complicated for physicians to request the appropriate information. In an effort to address this problem, we describe a set of four PET/CT protocols that satisfy a broad range of clinical needs among oncology patients. Current technology allows acquisition of diagnostic-quality CT scans as part of PET/CT examinations, and referring physicians are given the option of requesting formal interpretation of the CT findings. In this case, the PET and CT images are interpreted by the corresponding specialists, and equivocal or discordant findings are adjudicated through joint review of the PET/CT images. CONCLUSIONS: The menu of PET/CT imaging protocols has gained wide acceptance by our referring physicians and have been used successfully in more than 6,000 PET/CT studies. Newer PET/CT protocols will be developed as technology advances. Continued collaboration among oncologists, CT specialists, and nuclear medicine specialists is essential for deriving the maximum clinical benefit from combined PET/CT. Standardization of imaging protocols will become increasingly important as multiple-institution trials are developed for evaluation of present and future applications of PET/CT.

Authors
Wong, TZ; Paulson, EK; Nelson, RC; Patz, EF; Coleman, RE
MLA Citation
Wong, TZ, Paulson, EK, Nelson, RC, Patz, EF, and Coleman, RE. "Practical approach to diagnostic CT combined with PET." AJR Am J Roentgenol 188.3 (March 2007): 622-629. (Review)
PMID
17312045
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
188
Issue
3
Publish Date
2007
Start Page
622
End Page
629
DOI
10.2214/AJR.06.0813

Abdominal pain: coronal reformations from isotropic voxels with 16-section CT--reader lesion detection and interpretation time.

PURPOSE: To retrospectively assess if reader detection of intraabdominal pathologic findings on coronal reformations from isotropic voxels at 16-section computed tomography (CT) was similar to reader detection on transverse scans. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant study, and a waiver of informed consent was obtained. Twenty-nine consecutive patients (12 men, 17 women; mean age, 48 years; age range, 21-93 years) with abdominal pain underwent 16-section CT with coronal reformations. Eight independent readers reviewed randomized scans (transverse and coronal) and identified pathologic findings in multiple organ systems. Timing for each interpretation was recorded. One month later, readers reviewed the scan reformatted in the other imaging plane. Agreement between transverse and coronal scans was measured by using Cohen kappa coefficients. RESULTS: Agreement was moderate to near perfect between transverse and coronal interpretations for intraabdominal anatomic and pathologic findings (kappa=0.59-1.00). For transverse interpretations, more thoracic pathologic findings were noted than for coronal interpretations; for coronal interpretations, more lymph nodes were noted than for transverse interpretations. Mean transverse interpretation time was 4.9 minutes+/-1.1 (standard deviation) (range, 2.9-6.5 minutes); mean coronal interpretation time was 5.1 minutes+/-0.8 (range, 3.3-6.7 minutes). For each reader, there was no statistically significant difference in interpretation time between transverse and coronal scans (P=.06). CONCLUSION: With regard to the presence of intraabdominal pathologic findings, coronal reformations from isotropic voxels are similar to transverse scans in terms of interpretation time and reader agreement.

Authors
Jaffe, TA; Martin, LC; Miller, CM; Franklin, KM; Merkle, EM; Thompson, WM; Nelson, RC; DeLong, DM; Paulson, EK
MLA Citation
Jaffe, TA, Martin, LC, Miller, CM, Franklin, KM, Merkle, EM, Thompson, WM, Nelson, RC, DeLong, DM, and Paulson, EK. "Abdominal pain: coronal reformations from isotropic voxels with 16-section CT--reader lesion detection and interpretation time." Radiology 242.1 (January 2007): 175-181.
PMID
17185667
Source
pubmed
Published In
Radiology
Volume
242
Issue
1
Publish Date
2007
Start Page
175
End Page
181
DOI
10.1148/radiol.2421060015

Erratum: Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: A double-blind comparison of iodixanol and iopamidol (Investigative Radiology (2006) 41, (815821))

Authors
Barrett, BJ; Katzberg, RW; Thomsen, HS; Chen, N; Sahani, D; Soulez, G; Heiken, JP; Lepanto, L; Ni, Z-H; Nelson, R
MLA Citation
Barrett, BJ, Katzberg, RW, Thomsen, HS, Chen, N, Sahani, D, Soulez, G, Heiken, JP, Lepanto, L, Ni, Z-H, and Nelson, R. "Erratum: Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: A double-blind comparison of iodixanol and iopamidol (Investigative Radiology (2006) 41, (815821))." Investigative Radiology 42.2 (2007): 94--.
Source
scival
Published In
Investigative Radiology
Volume
42
Issue
2
Publish Date
2007
Start Page
94-
DOI
10.1097/00004424-200702000-00004

Hepatobiliary imaging by multidetector computed tomography (MDCT)

Hepatobiliary imaging by computed tomography (CT) has advanced impressively since the introduction of multidetector CT (MDCT) scanners in the late 1990s. Over the last few years, the number of detector rows has increased progressively from four, to eight, to 16, and then up to 64. Two important advantages of MDCT are the routine use of thinner, submillimeter sections, which yield higher spatial resolution, along the Z-axis and decrease in gantry rotation time, which result in a significantly reduced scan time. Sixteen-, 32- and 64-slice scanners allow the acquisition of data sets with nearly isotropic voxels for multiplanar imaging (e.g., coronal and sagittal plane), which has similar spatial resolution compared with axial planes. These off-axis reformations are particularly helpful for evaluating the hepatic vascular anatomy, the biliary system, and the segmental distribution of hepatic lesions. © 2006 Springer-Verlag Italia.

Authors
Schindera, ST; Nelson, RC
MLA Citation
Schindera, ST, and Nelson, RC. "Hepatobiliary imaging by multidetector computed tomography (MDCT)." (December 1, 2006): 49-66. (Chapter)
Source
scopus
Publish Date
2006
Start Page
49
End Page
66
DOI
10.1007/88-470-0413-6_6

Multiple nephron-sparing procedures in solitary kidney with recurrent, metachronous, nonfamilial renal cell carcinoma.

Patients with metachronous bilateral renal cell carcinoma pose a significant challenge given the high mortality of renal cell carcinoma and the poor quality of life should dialysis become necessary. In addition, patients may be subject to morbidity due to potential multiple treatments of the multifocal renal tumors. We present the case of a 71-year-old woman with multifocal, bilateral clear cell carcinoma who maintained a minimal change in serum creatinine after undergoing unilateral radical nephrectomy, subsequent percutaneous radiofrequency ablation, percutaneous cryoablation, laparoscopic cryoablation, and open partial nephrectomy for recurrent renal cell carcinoma in a solitary kidney.

Authors
Nosnik, IP; Mouraviev, V; Nelson, R; Polascik, TJ
MLA Citation
Nosnik, IP, Mouraviev, V, Nelson, R, and Polascik, TJ. "Multiple nephron-sparing procedures in solitary kidney with recurrent, metachronous, nonfamilial renal cell carcinoma." Urology 68.6 (December 2006): 1343.e1-1343.e3.
PMID
17141824
Source
pubmed
Published In
Urology
Volume
68
Issue
6
Publish Date
2006
Start Page
1343.e1
End Page
1343.e3
DOI
10.1016/j.urology.2006.09.004

Intrahepatic tumor recurrence after partial hepatectomy: value of percutaneous radiofrequency ablation.

PURPOSE: To determine the risks and benefits of percutaneous radiofrequency (RF) ablation of recurrent hepatic tumors in patients who have undergone hepatic resection. MATERIALS AND METHODS: Retrospective review of the institutional RF ablation database yielded 35 patients with recurrent hepatic tumor after hepatectomy. Sixty-one recurrent hepatic tumors (mean diameter +/- SD, 1.7 +/- 1.1 cm; range, 0.5-5.3 cm) were ablated percutaneously under sonographic guidance or combined guidance with sonographic and fluoroscopic computed tomography (CT). Follow-up CT, magnetic resonance imaging, or both were used for assessment of the primary and secondary therapeutic effectiveness rate and failure of RF ablation. Patients' survival status was determined by contacting the primary care physician or searching the Social Security Death Index. RESULTS: Complete ablation was accomplished in 54 of 61 hepatic tumors (primary therapeutic effectiveness rate, 88.5%). During a mean follow-up time of 18 months (range, 1-65 months), 14.8% of the tumors (n = 9) were incompletely ablated. Three of the nine incompletely ablated tumors were treated with a second RF ablation, all three of which failed (secondary therapeutic effectiveness rate, 0%). Distant intrahepatic tumor progression appeared in 23 of 35 patients (65.7%). One major complication (2.1%, one of 48 sessions) and eight minor complications (16.7%, eight of 48 sessions) were reported. The major complication was hepatic abscess formation. The overall survival rates for all patients at 1, 2, and 3 years were 76%, 68%, and 45%, respectively. For patients with metastases from colorectal cancer (n = 14), the overall survival rates were 72%, 60%, and 60% at 1, 2, and 3 years, respectively; and for patients with hepatocellular carcinoma (n = 8), the overall survival rates were 72%, 58%, and 44% at 1, 2, and 3 years, respectively. CONCLUSION: Percutaneous RF ablation offers a safe and effective treatment option for recurrent hepatic tumors after previous partial hepatectomy.

Authors
Schindera, ST; Nelson, RC; DeLong, DM; Clary, B
MLA Citation
Schindera, ST, Nelson, RC, DeLong, DM, and Clary, B. "Intrahepatic tumor recurrence after partial hepatectomy: value of percutaneous radiofrequency ablation." J Vasc Interv Radiol 17.10 (October 2006): 1631-1637.
PMID
17057005
Source
pubmed
Published In
JVIR: Journal of Vascular and Interventional Radiology
Volume
17
Issue
10
Publish Date
2006
Start Page
1631
End Page
1637
DOI
10.1097/01.RVI.0000239106.98853.B8

Abdominal magnetic resonance imaging at 3.0 T what is the ultimate gain in signal-to-noise ratio?

RATIONALE AND OBJECTIVES: The purpose of this study was to calculate the gain in signal-to-noise ratio (SNR) of four human abdominal tissues at 3.0 Tesla (T) compared with standard 1.5 T and to validate this calculation in vivo. MATERIALS AND METHODS: The expected gain in SNR at 3.0 T in the liver, pancreas, spleen, and kidney compared with standard 1.5 T was approximated theoretically for a T2-weighted HASTE (half-Fourier acquisition single-shot turbo spin-echo) and a T1-weighted gradient-echo in- and opposed-phase sequence. Fifteen healthy male subjects underwent abdominal MR imaging using a 1.5 T and 3.0 T scanner. Coronal T2-weighted HASTE images and axial T1-weighted gradient-echo in- and opposed-phase images were acquired using the sequence parameters optimized by the vendor. RESULTS: Except for opposed-phased imaging of pancreatic tissue, in vivo adjusted SNR values of all abdominal tissues were significantly higher at 3.0 T for all sequences (P < .05). The highest overall gain in SNR was achieved with the HASTE sequence ranging from 3.8-fold for renal imaging to 7.4-fold for hepatic imaging. The theoretical calculation of SNR gain was in good agreement with the experimentally measured gain in SNR for the HASTE and the in-phase sequence. CONCLUSION: High-field abdominal MR imaging at 3.0 T offers significantly higher SNR compared with standard 1.5 T MR imaging.

Authors
Schindera, ST; Merkle, EM; Dale, BM; Delong, DM; Nelson, RC
MLA Citation
Schindera, ST, Merkle, EM, Dale, BM, Delong, DM, and Nelson, RC. "Abdominal magnetic resonance imaging at 3.0 T what is the ultimate gain in signal-to-noise ratio?." Acad Radiol 13.10 (October 2006): 1236-1243.
PMID
16979073
Source
pubmed
Published In
Academic Radiology
Volume
13
Issue
10
Publish Date
2006
Start Page
1236
End Page
1243
DOI
10.1016/j.acra.2006.06.018

Dual gradient-echo in-phase and opposed-phase hepatic MR imaging: a useful tool for evaluating more than fatty infiltration or fatty sparing.

A T1-weighted gradient-echo in-phase and opposed-phase sequence has become a routine part of every hepatic magnetic resonance (MR) imaging protocol. Although this sequence is primarily used to identify common pathologic conditions, such as diffuse or focal steatosis and focal fatty sparing, it is also helpful in detection of pathologic entities associated with T2* effects owing to the double-echo approach. Thus, pathologic conditions such as hemochromatosis or hemosiderosis can be identified and characterized with a high level of confidence. In cases of iron storage disease, the hepatic parenchymal signal intensity decreases on the image with the longer echo time due to the continued decay of the transverse magnetization. In addition, susceptibility artifacts can be easily detected and characterized with in-phase and opposed-phase MR imaging. Metallic objects demonstrate a larger susceptibility artifact on the image with the second or longer echo time, which is usually the in-phase image. Finally, intrahepatic pneumobilia can be identified with the T1-weighted gradient-echo in-phase and opposed-phase sequence because gas also causes a susceptibility artifact, which is more pronounced on the image with the longer echo time. A complete understanding of both the chemical shift cancellation artifact and the T2* effects of the in-phase and opposed-phase sequence is important for correct interpretation of hepatic MR images.

Authors
Merkle, EM; Nelson, RC
MLA Citation
Merkle, EM, and Nelson, RC. "Dual gradient-echo in-phase and opposed-phase hepatic MR imaging: a useful tool for evaluating more than fatty infiltration or fatty sparing." Radiographics 26.5 (September 2006): 1409-1418. (Review)
PMID
16973772
Source
pubmed
Published In
Radiographics : a review publication of the Radiological Society of North America, Inc
Volume
26
Issue
5
Publish Date
2006
Start Page
1409
End Page
1418
DOI
10.1148/rg.265055711

Liver ablation guidance with acoustic radiation force impulse imaging: challenges and opportunities.

Previous studies have established the feasibility of monitoring radiofrequency (RF) ablation procedures with acoustic radiation force impulse (ARFI) imaging. However, questions remained regarding the utility of the technique in clinically realistic scenarios and at scanning depths associated with abdominal imaging in adults. We address several of these issues and detail recent progress towards the clinical relevance of the ARFI technique. Results from in vitro bovine tissues and an in vivo ovine model are presented. Additional experiments were conducted with a tissue-mimicking phantom and parallel receive tracking techniques in order to further support the clinical feasibility of the method. Thermal lesions created during RF ablation are visualized with high contrast in both in vitro and in vivo hepatic tissues, and radial lesion growth can be monitored throughout the duration of the procedure. ARFI imaging is implemented on a diagnostic ultrasonic scanner, and thus may be a convenient option to guide RF ablation procedures, particularly when electrode insertion is also performed with sonographic guidance.

Authors
Fahey, BJ; Hsu, SJ; Wolf, PD; Nelson, RC; Trahey, GE
MLA Citation
Fahey, BJ, Hsu, SJ, Wolf, PD, Nelson, RC, and Trahey, GE. "Liver ablation guidance with acoustic radiation force impulse imaging: challenges and opportunities." Phys Med Biol 51.15 (August 7, 2006): 3785-3808.
PMID
16861781
Source
pubmed
Published In
Physics in Medicine and Biology
Volume
51
Issue
15
Publish Date
2006
Start Page
3785
End Page
3808
DOI
10.1088/0031-9155/51/15/013

Postprocedure sepsis in imaging-guided percutaneous hepatic abscess drainage: how often does it occur?

OBJECTIVE: This retrospective study was conducted to determine the incidence of sepsis at our institution after percutaneous drainage of a hepatic abscess. MATERIALS AND METHODS: Thirty-three patients with a hepatic abscess treated using percutaneous aspiration and drainage from 1995 to 2000 were identified from a search of the interventional database. The patients' charts and CT images were reviewed independently by two radiologists for clinical presentation, relevant medical history, pre- and postprocedure antibiotic regimens, and clinical course after percutaneous aspiration and drainage. The preprocedure images were reviewed for the location and morphology of the abscess. The procedure details including percutaneous approach, guidance technique, catheter size, and immediate postprocedure complications were reviewed. RESULTS: Of the 33 patients, 14 patients underwent only needle aspiration of the abscess. In six (43%) of these 14 patients, the abscesses resolved with aspiration and appropriate antibiotic treatment alone. Eight (57%) of the patients who had aspiration of the abscess initially went on to have drainage catheters placed within a 72-hr period. Nineteen patients had drainage catheters placed from the onset. Of these, 17 patients (89%) had abscess resolution. Of the 27 patients who had catheters placed, a total of seven patients (26%) developed clinical symptoms of septicemia after catheter placement, but all patients, at least initially, responded to supportive treatment. Two patients died from septicemia 3-6 weeks after the procedure. None of the patients who underwent aspiration only developed postprocedure septicemia. CONCLUSION: After placement of a percutaneous drainage catheter in a hepatic abscess, there is a significant risk (26%) of postprocedure sepsis. Although it appears to be a random and unpredictable event in our small series, interventional radiologists and referring physicians should be aware of the risk of sepsis after percutaneous drainage of hepatic abscess.

Authors
Thomas, J; Turner, SR; Nelson, RC; Paulson, EK
MLA Citation
Thomas, J, Turner, SR, Nelson, RC, and Paulson, EK. "Postprocedure sepsis in imaging-guided percutaneous hepatic abscess drainage: how often does it occur?." AJR Am J Roentgenol 186.5 (May 2006): 1419-1422.
PMID
16632739
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
186
Issue
5
Publish Date
2006
Start Page
1419
End Page
1422
DOI
10.2214/AJR.04.1914

Pigtail catheters used for percutaneous fluid drainage: comparison of performance characteristics.

PURPOSE: To compare the performance characteristics of various single-lumen all-purpose pigtail drainage catheters. MATERIALS AND METHODS: The following parameters were compared: flow rates between catheters of the same size, whether changing the fluid viscosity has any effect on catheter comparisons, the effect on flow of leaving an open three-way stopcock in the drainage pathway, the tendency of the catheters to kink, and catheter patency after kinking, as measured according to flow. All-purpose 8.0-, 8.3-, and 8.5-F (collectively referred to as 8-F); 10.0-, 10.2-, and 10.3-F (collectively referred to as 10-F); and 12.0-F pigtail drainage catheters from three manufacturers were evaluated. Data were compared by using two-tailed t tests after normal distributions were confirmed. P < .05 was considered to represent a significant difference. RESULTS: At comparison of the 8-F catheters, the C.R. Bard catheters demonstrated better flow rates than the Cook and Boston Scientific devices. Among the 10-F catheters, there were no significant differences in the flow rates of fluid with viscosity equivalent to that of water between the C.R. Bard and Boston Scientific catheters; however, both these catheter types demonstrated significantly (P < .05) better flow rates than the Cook devices. Among the 12-F catheters, the C.R. Bard catheters demonstrated significantly (P < .05) better flow rates than the other two catheter types. Changing the fluid viscosity caused no changes in comparison results. In all catheter groups, the presence of a stopcock significantly (P < .05) impaired flow. None of the evaluated catheters demonstrated a clear advantage in terms of patency or susceptibility to kinking. CONCLUSION: At comparison of the in vitro performances of catheters from different manufacturers, the C.R. Bard 8.0-F and Cook 10.2-F catheters had comparable flow rates, and flow rates through the C.R. Bard and Boston Scientific 10.0-F catheters were comparable to flow rates through the Cook and Boston Scientific 12.0-F catheters. Varying viscosity had no effect on comparisons of catheter flow rates; however, a stopcock between the vacuum source and the catheter was noted to impair flow rates in all brands and sizes of evaluated catheters.

Authors
Macha, DB; Thomas, J; Nelson, RC
MLA Citation
Macha, DB, Thomas, J, and Nelson, RC. "Pigtail catheters used for percutaneous fluid drainage: comparison of performance characteristics." Radiology 238.3 (March 2006): 1057-1063.
PMID
16505398
Source
pubmed
Published In
Radiology
Volume
238
Issue
3
Publish Date
2006
Start Page
1057
End Page
1063
DOI
10.1148/radiol.2383050578

Optimization of multiplanar reformations from isotropic data sets acquired with 16-detector row helical CT scanner.

Institutional review board approval and waiver of consent were obtained for the patient component of this retrospective HIPAA-compliant study. By using an anthropomorphic phantom and metal oxide semiconductor field effect transistor detectors, radiation dose was determined for one eight-detector row and two 16-detector row computed tomographic (CT) protocols. A custom phantom was scanned by using the three protocols to identify isotropy. Contrast-to-noise ratios (CNRs) were determined for the same protocols by using a third phantom. Seven patients had undergone isotropic 16-detector row CT of the abdomen and pelvis. Anonymized coronal reformations at various thicknesses were ranked qualitatively by three radiologists. Effective dose equivalents were similar for the eight- and 16-detector row protocols. When transverse and coronal reformations of data acquired in the custom phantom were compared, coronal reformations obtained with the 16-detector row and 0.625-mm section thickness protocol were found to be nearly identical to the transverse image for all sets of line pairs. CNRs were consistently highest on 5-mm-thick coronal reformations (CNR range, 1.2-3.3). For qualitative assessment, 2- and 3-mm-thick coronal reformations were consistently preferred.

Authors
Jaffe, TA; Nelson, RC; Johnson, GA; Lee, ER; Yoshizumi, TT; Lowry, CR; Bullard, AB; DeLong, DM; Paulson, EK
MLA Citation
Jaffe, TA, Nelson, RC, Johnson, GA, Lee, ER, Yoshizumi, TT, Lowry, CR, Bullard, AB, DeLong, DM, and Paulson, EK. "Optimization of multiplanar reformations from isotropic data sets acquired with 16-detector row helical CT scanner." Radiology 238.1 (January 2006): 292-299.
PMID
16373774
Source
pubmed
Published In
Radiology
Volume
238
Issue
1
Publish Date
2006
Start Page
292
End Page
299
DOI
10.1148/radiol.2381050404

Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: A double-blind comparison of iodixanol and iopamidol

BACKGROUND: Based on a single clinical trial, it has been suggested that the contrast agent iodixanol, which is isotonic to human plasma, may be less nephrotoxic than other nonionic contrast agents in renally impaired patients after intra-arterial injection. We compared the effects on renal function of iopamidol-370 injection (796 mOsm/kg) and iodixanol-320 (290 mOsm/kg) in patients with chronic kidney disease undergoing contrast-enhanced multidetector computed tomography (CE-MDCT) examinations using a multicenter, double-blind, randomized, parallel-group design. METHODS: A total of 166 patients with stable moderate-to-severe chronic kidney disease (screening and baseline serum creatinine, SCr, ≥1.5 mg/dL and/or creatinine clearance, CrCl, ≤60 mL/min) who were undergoing CE-MDCT of the liver or peripheral arteries were randomized to receive equi-iodine IV doses (40 gI) of either iopamidol-370 (370 mgI/mL) or iodixanol-320 (320 mgI/mL) at 4 mL/s. SCr and CrCl were obtained at screening, baseline, and at 48-72 ± 6 hours after dose (mean, 57.4 hours). Contrast-induced nephropathy (CIN) was defined as an absolute increase ≥0.5 mg/dL (44.2 μmol/L) and/or a relative increase in SCr ≥25% from baseline. RESULTS: A total of 153 patients were included in the final analysis (13 patients excluded because of lack of follow-up, hemodialysis to remove contrast, average daily CrCl variation >1% at screening). The 2 study groups were comparable with regard to age, gender distribution, the presence of diabetes, concomitant medications, hydration, and contrast dose. Mean predose SCr was 1.6 ± 0.4 mg/dL in both groups (P = 0.9). An absolute increase ≥0.5 mg/dL (44.2 μmol/L) in SCr was observed in none of the patients receiving iopamidol-370 and in 2.6% (2/76) of patients receiving iodixanol-320 (95% confidence interval -6.2, 1.0, P = 0.2). A relative increase ≥25% in SCr occurred in 4% (3/77) of patients receiving iopamidol-370 and in 4% (3/76) of the patients receiving iodixanol-320 (95% confidence interval -6.2, 6.1, P = 1.0). CONCLUSION: The rate of CIN was similarly low in risk patients after intravenous administration of iopamidol-370 or iodixanol-320 for CE-MDCT. © 2006 Lippincott Williams & Wilkins, Inc.

Authors
Barrett, BJ; Katzberg, RW; Thomsen, HS; Chen, N; Sahani, D; Soulez, G; Heiken, JP; Lepanto, L; Ni, Z-H; Nelson, R
MLA Citation
Barrett, BJ, Katzberg, RW, Thomsen, HS, Chen, N, Sahani, D, Soulez, G, Heiken, JP, Lepanto, L, Ni, Z-H, and Nelson, R. "Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: A double-blind comparison of iodixanol and iopamidol." Investigative Radiology 41.11 (2006): 815-821.
PMID
17035872
Source
scival
Published In
Investigative Radiology
Volume
41
Issue
11
Publish Date
2006
Start Page
815
End Page
821
DOI
10.1097/01.rli.0000242807.01818.24

Complications after percutaneous radiofrequency ablation of renal tumors.

OBJECTIVES: To evaluate our experience with percutaneous radiofrequency ablation (pRFA) to determine common characteristics of patients with complications, to elucidate possible relative contraindications to therapy. METHODS: Medical records of all patients undergoing pRFA were reviewed for demographic data, medical and surgical history, indication, tumor characteristics, and treatment information (complications and management). The group of patients with complications was analyzed for common characteristics. RESULTS: From January 2000 to September 2003, 24 patients (mean age 61 years, 5:1 male/female) with 32 renal tumors were treated with pRFA. Indications for pRFA included prior renal surgery and/or chronic renal insufficiency, significant medical disease, patient choice, von Hippel-Lindau disease, and treatment of a metastasis. Average pretreatment tumor size was 2.4 cm (range 0.5-8.6 cm). Of the 5 patients experiencing complications from pRFA treatment, 2 developed perinephric hematomas, 1 had a persistent urinoma and proximal ureteral stricture, and 2 had colonic injuries. Among patients with complications, 3 of 5 had undergone prior partial nephrectomy on the pRFA-treated kidney. Two of four patients treated for multiple tumors and 57% of patients (4 of 7) with anteriorly located tumors experienced complications. CONCLUSIONS: Early experience with pRFA for renal tumor seems promising, but patient selection criteria are evolving. On the basis of our limited experience, we recommend caution when using renal pRFA in patients with prior partial nephrectomy, multiple tumors treated in the same setting, and tumors located anteriorly or centrally. Further clinical experience will help establish guidelines for the use of this powerful technology in the management of renal tumors.

Authors
Weizer, AZ; Raj, GV; O'Connell, M; Robertson, CN; Nelson, RC; Polascik, TJ
MLA Citation
Weizer, AZ, Raj, GV, O'Connell, M, Robertson, CN, Nelson, RC, and Polascik, TJ. "Complications after percutaneous radiofrequency ablation of renal tumors." Urology 66.6 (December 2005): 1176-1180.
PMID
16360436
Source
pubmed
Published In
Urology
Volume
66
Issue
6
Publish Date
2005
Start Page
1176
End Page
1180
DOI
10.1016/j.urology.2005.06.125

Acoustic radiation force impulse imaging of the abdomen: demonstration of feasibility and utility.

The feasibility of utilizing acoustic radiation force impulse (ARFI) imaging to assess the mechanical properties of abdominal tissues was investigated. The thermal safety of the technique was also evaluated through the use of finite element method models. ARFI imaging was shown to be capable of imaging abdominal tissues at clinically realistic depths. Correspondence between anatomical structures in B-mode and ARFI images was observed. ARFI images showed similar tumor contrast when compared with B-mode images of ex vivo abdominal cancers. Finite element method models and in vitro measurements confirmed the thermal safety of ARFI imaging at depth. ARFI imaging is inexpensive, safe and convenient and is a promising modality for use in abdominal imaging.

Authors
Fahey, BJ; Nightingale, KR; Nelson, RC; Palmeri, ML; Trahey, GE
MLA Citation
Fahey, BJ, Nightingale, KR, Nelson, RC, Palmeri, ML, and Trahey, GE. "Acoustic radiation force impulse imaging of the abdomen: demonstration of feasibility and utility." Ultrasound Med Biol 31.9 (September 2005): 1185-1198.
PMID
16176786
Source
pubmed
Published In
Ultrasound in Medicine & Biology
Volume
31
Issue
9
Publish Date
2005
Start Page
1185
End Page
1198
DOI
10.1016/j.ultrasmedbio.2005.05.004

Renal cryoablation and radio frequency ablation: an evaluation of worst case scenarios in a porcine model.

PURPOSE: Although ablative technologies, including radio frequency (RF) ablation (RFA) and cryoablation (CA), are being used to treat renal masses, complications associated with injury to vital renal structures are not well understood. We investigated these worst case scenarios by deliberately targeting vital renal structures with CA or RFA in a porcine model. MATERIALS AND METHODS: Following surgical exposure of the right kidney in female pigs a cryoneedle or an RF probe was deliberately placed under visual and ultrasound guidance in the renal pelvis (CA in 5 pigs and RFA in 7), major calix (CA and RFA in 5 each) or subsegmental renal vessels (CA in 5 pigs and RFA in 7). Cryo-energy or RF energy was then applied to create a 3 cm lesion. After 10 days the kidneys underwent gross and histological examination for urine and blood extravasation, cell death and injury. Ex vivo retrograde pyelography was performed to evaluate for urinary fistulas. RESULTS: All pigs tolerated the treatment and no procedure related deaths occurred. No significant bleeding was noted. RFA and CA created reproducible lesions and areas of cell death and necrosis. Despite significant intentional injury to the collecting system no urinary fistulas were demonstrated in CA specimens (0 of 15). In contrast, damage to the renal pelvis (4 of 7) by dry (3 of 4) or wet (1 of 3) RFA was associated with a high likelihood of urinary extravasation. CONCLUSIONS: This short-term study demonstrates that CA is safe, effective and not associated with urinary extravasation. In contrast, RFA to the renal pelvis is associated with urinary extravasation. Further studies are needed to support these findings.

Authors
Brashears, JH; Raj, GV; Crisci, A; Young, MD; Dylewski, D; Nelson, R; Madden, JF; Polascik, TJ
MLA Citation
Brashears, JH, Raj, GV, Crisci, A, Young, MD, Dylewski, D, Nelson, R, Madden, JF, and Polascik, TJ. "Renal cryoablation and radio frequency ablation: an evaluation of worst case scenarios in a porcine model." J Urol 173.6 (June 2005): 2160-2165.
PMID
15879879
Source
pubmed
Published In
The Journal of Urology
Volume
173
Issue
6
Publish Date
2005
Start Page
2160
End Page
2165
DOI
10.1097/01.ju.0000158125.80981.f1

Pancreatic FNA in 1000 cases: a comparison of imaging modalities.

BACKGROUND: Image-guided FNA is a popular method for evaluating pancreatic lesions, but few large studies on pancreatic FNA exist. METHODS: Cytologic material, imaging reports, and clinical follow-up information were reviewed from pancreatic FNA cases performed over a 5-year period. RESULTS: A total of 1050 pancreatic FNAs were obtained by EUS (n = 843), US (n = 140), and CT (n = 67). On-site assessment was performed in 89.2% (n = 937) of cases. Findings were as follows: positive for neoplasm 48.9% (n = 503), negative 29.1% (n = 306), descriptive 10% (n = 105), suspicious 5.9% (n = 62), atypical/inconclusive 4.6% (n = 48), and nondiagnostic/inadequate 1.5% (n = 26). Follow-up in the form of histology or at least 6 months of clinical observation was available for 61.2% (n = 643). There was an overall false-positive rate of 0.3% and a false-negative rate of 14.3%. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were as follows: 79.4, 99.0, 99.4, 67.9, 84.5 for the total series, respectively; 79.9, 98.8, 99.2, 72.5, 86.5 for EUS, respectively; 77.9, 100, 100, 48.6, 81.7 for US, respectively; and 78.6, 100, 100, 47.1, 82.0 for CT, respectively. In general, accuracy was not influenced by lesion size or site, number of FNA passes, or number of procedures per patient. After controlling for lesion size, EUS resulted in greater accuracy than US or CT when evaluating lesions <3 cm ( p = 0.015). CONCLUSIONS: All imaging modalities showed moderate to high sensitivity, specificity, and accuracy. Logistic regression analysis showed that for lesions <3 cm, the EUS method had higher accuracy than US or CT. No statistically significant difference was seen for larger lesions or for the number of FNA passes.

Authors
Volmar, KE; Vollmer, RT; Jowell, PS; Nelson, RC; Xie, HB
MLA Citation
Volmar, KE, Vollmer, RT, Jowell, PS, Nelson, RC, and Xie, HB. "Pancreatic FNA in 1000 cases: a comparison of imaging modalities." Gastrointest Endosc 61.7 (June 2005): 854-861.
PMID
15933687
Source
pubmed
Published In
Gastrointestinal Endoscopy
Volume
61
Issue
7
Publish Date
2005
Start Page
854
End Page
861

Acute appendicitis: added diagnostic value of coronal reformations from isotropic voxels at multi-detector row CT.

PURPOSE: To assess retrospectively the added value of coronal reformations from isotropic voxels obtained with 16-section multi-detector row computed tomography (CT) of the abdomen and pelvis in patients with suspected acute appendicitis. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was waived. One hundred consecutive patients (21 men, 79 women; mean age, 38 years) with suspected appendicitis underwent 16-section multi-detector row CT (section thickness, 0.625 mm; pitch, 1.75; table speed, 35 mm/sec [17.5 mm per rotation, two rotations]; and gantry speed, 0.5 second per rotation), with coronal reformations. Twenty-four patients had appendicitis; 76 did not. Protocol included 150 mL oral iopamidol administered at 3 mL/sec. Transverse scans were reconstructed with 5-mm-thick sections at 5-mm intervals and 0.625-mm-thick sections at 0.625-mm intervals. The second data set was reformatted coronally, with 3-mm-thick sections at 5-mm intervals. Three independent blinded readers interpreted transverse scans alone and then coronal scans; confidence in visualization of any portion of appendix, entire appendix, wall thickening, distention, inflammation, fluid, and appendicitis was scored with 1-5 scale. Sensitivity and specificity were determined for each reader and compared by means of signed rank test. Agreement between readers was determined with kappa statistic. Differences in mean confidence ratings for each finding were determined with Wilcoxon signed rank test. RESULTS: Mean sensitivity and specificity for all three readers together were 96% and 95% for transverse reformations alone and 95% and 94% for combined transverse and coronal reformations (not significant), respectively. Visualization rates for portion or all of appendix were higher for combined transverse and coronal reformations than for transverse reformations alone (higher mean confidence scores: 0.23 higher [P < .009] and 0.51 higher [P < .001], respectively). In patients without appendicitis, transverse and coronal reformations together enhanced confidence in exclusion of wall thickening, distention, and fluid (lower confidence scores: 0.21 lower [P < .001], 0.17 lower [P < .01], 1.00 lower [P < .001], respectively). Combined transverse and coronal reformations enhanced confidence in identification of appendix in mean of 57 patients. Combined transverse and coronal scans helped exclude appendicitis in mean of 38 patients and aided diagnosis of it in 15. CONCLUSION: Sixteen-section multi-detector row CT transverse and coronal reformations are equally sensitive and specific for diagnosis of appendicitis. Coronal reformations improve confidence in visualization of appendix (whether diseased or normal) and in diagnosis or exclusion of appendicitis.

Authors
Paulson, EK; Harris, JP; Jaffe, TA; Haugan, PA; Nelson, RC
MLA Citation
Paulson, EK, Harris, JP, Jaffe, TA, Haugan, PA, and Nelson, RC. "Acute appendicitis: added diagnostic value of coronal reformations from isotropic voxels at multi-detector row CT." Radiology 235.3 (June 2005): 879-885.
PMID
15833993
Source
pubmed
Published In
Radiology
Volume
235
Issue
3
Publish Date
2005
Start Page
879
End Page
885
DOI
10.1148/radiol.2353041231

Classification and staging of lung cancer: A prototype for the development of reference material for electronic media

Authors
Braithwaite, AC; Hirasaki, KK; Heyneman, LE; Nelson, RC
MLA Citation
Braithwaite, AC, Hirasaki, KK, Heyneman, LE, and Nelson, RC. "Classification and staging of lung cancer: A prototype for the development of reference material for electronic media." 2005.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
184
Issue
4
Publish Date
2005
Start Page
80
End Page
81

Comparison of four different strategies for determining the volume and rate of contrast media administration for multidetector helical CT of the abdomen

Authors
Ho, LM; Nelson, RC; Kurylo, LM
MLA Citation
Ho, LM, Nelson, RC, and Kurylo, LM. "Comparison of four different strategies for determining the volume and rate of contrast media administration for multidetector helical CT of the abdomen." 2005.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
184
Issue
4
Publish Date
2005
Start Page
29
End Page
29

Practice patterns in percutaneous image-guided intraabdominal abscess drainage: survey of academic and private practice centers.

PURPOSE: To evaluate current practice patterns of percutaneous image-guided abdominal and pelvic abscess drainage in academic and private practice centers. MATERIALS AND METHODS: The institutional review board did not require approval for this study. In a survey conducted between November 2002 and February 2003, 493 questionnaires were sent to 193 academic and 300 private practice radiology departments in the United States. All recipients were informed of the study purpose. The survey included questions about departmental demographics, patient selection criteria for percutaneous abscess drainage (eg, abscess diameter at imaging, laboratory parameters such as white blood cell count, and clinical indications such as fever), use of analgesia or conscious sedation, drainage method, and imaging technique. The statistical significance of differences between respondent subgroups was analyzed with a Pearson or Mantel-Haenszel chi(2) test. RESULTS: Academic centers returned 95 questionnaires (49%), and private practice centers, 72 (24%). Percutaneous abscess drainage is performed by a fellowship-trained radiologist at 92 (97%) of 95 academic centers and 41 (79%) of 52 private practice centers (P < .001). Among 95 academic respondents and 52 private practice respondents, respectively, 56 (59%) and 33 (63%) do not perform drainage if an abscess has a diameter of less than 3 cm; 30 (32%) and nine (17%), if the white blood cell count is normal; and 16 (17%) and six (12%), if the patient is afebrile. Most (90 [95%] of 95 academic, 45 [87%] of 52 private practice) respondents use conscious sedation. A transabdominal approach and 8-12-F catheters are most frequently used by both groups. Academic respondents more frequently use transvaginal and transrectal approaches (54 [57%] and 51 [54%] of 95, vs 16 [31%] and 15 [29%] of 52 private practice respondents; P = .003) and 14-F catheters (69 [73%] of 95 vs 18 [35%] of 52; P < .001). CONCLUSION: Percutaneous drainage is usually performed by fellowship-trained radiologists in abscesses of more than 3 cm in diameter, for appropriate clinical indications (multiple parameters above the established threshold), by using conscious sedation and 8-12-F catheters.

Authors
Jaffe, TA; Nelson, RC; Delong, DM; Paulson, EK
MLA Citation
Jaffe, TA, Nelson, RC, Delong, DM, and Paulson, EK. "Practice patterns in percutaneous image-guided intraabdominal abscess drainage: survey of academic and private practice centers." Radiology 233.3 (December 2004): 750-756.
PMID
15516608
Source
pubmed
Published In
Radiology
Volume
233
Issue
3
Publish Date
2004
Start Page
750
End Page
756
DOI
10.1148/radiol.2333032063

Dual-phase 3D MDCT angiography for evaluation of the liver before hepatic resection.

OBJECTIVE: We sought to evaluate the accuracy of dual-phase MDCT angiography for assessing the liver before hepatic resection and to compare 2D and 3D images for quality and arterial branch visualization. MATERIALS AND METHODS: Sixty-three patients with colorectal metastases (n = 30), hepatocellular carcinomas (n = 13), giant hemangiomas (n = 5), and other lesions (n = 15) underwent dual-phase MDCT using either a LightSpeed QX/i 4-MDCT (n = 31) or LightSpeed QX/i Ultra 8-MDCT (n = 32) scanner. Contrast material (150 mL of Isovue 370 [iopamidol]) was injected at a rate of 5 mL/sec. The arterial phase images were rendered on a workstation to obtain 3D MDCT angiograms that were assessed by two reviewers who were blinded to the surgical findings. Arterial anatomy was categorized according to the Michels classification. The reviewers assessed the 2D and 3D images for quality, arterial branch visualization, and differences between the 4- and 8-MDCT images. In the 43 patients who underwent resection, imaging findings were correlated with intraoperative findings. RESULTS: The anatomy of hepatic arteries in the 63 patients was classified as follows: Michels type I, 51 patients (80.9%); type III, four patients (6.3%); type V, five patients (7.9%); and types VII, VIII, and IX, one patient (1.6%) each. In 40 (93%) of 43 patients, the surgical findings concurred with MDCT findings. Three discrepancies were due to failure to identify small accessory left hepatic arteries. Branch visualization and image quality of the 2D images were superior to those of the 3D images. No significant difference was found between the 4- and 8-MDCT images in branch visualization and image quality. CONCLUSION: Three-dimensional MDCT angiography is accurate for classification of hepatic arterial anatomy before hepatic resection. Although 2D data sets show small arteries to better advantage than 3D MDCT angiograms, the 3D MDCT angiograms provide a useful overview of hepatic anatomy.

Authors
Stemmler, BJ; Paulson, EK; Thornton, FJ; Winters, SR; Nelson, RC; Clary, BM
MLA Citation
Stemmler, BJ, Paulson, EK, Thornton, FJ, Winters, SR, Nelson, RC, and Clary, BM. "Dual-phase 3D MDCT angiography for evaluation of the liver before hepatic resection." AJR Am J Roentgenol 183.6 (December 2004): 1551-1557.
PMID
15547190
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
183
Issue
6
Publish Date
2004
Start Page
1551
End Page
1557
DOI
10.2214/ajr.183.6.01831551

MDCT of patients with acute abdominal pain: a new perspective using coronal reformations from submillimeter isotropic voxels.

Authors
Paulson, EK; Jaffe, TA; Thomas, J; Harris, JP; Nelson, RC
MLA Citation
Paulson, EK, Jaffe, TA, Thomas, J, Harris, JP, and Nelson, RC. "MDCT of patients with acute abdominal pain: a new perspective using coronal reformations from submillimeter isotropic voxels." AJR Am J Roentgenol 183.4 (October 2004): 899-906.
PMID
15385279
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
183
Issue
4
Publish Date
2004
Start Page
899
End Page
906
DOI
10.2214/ajr.183.4.1830899

Abdominal aortic aneurysms at multi-detector row helical CT: optimization with interactive determination of scanning delay and contrast medium dose.

PURPOSE: To prospectively evaluate a technique for optimizing aortoiliac enhancement at multi-detector row helical computed tomography (CT) with both the scanning delay and contrast medium dose determined by using an interactive method. MATERIALS AND METHODS: Forty-five patients with abdominal aortic aneurysm were randomized to undergo multi-detector row helical CT with either an interactive protocol (n = 23) or a standard protocol (n = 22). Scanning delays in all patients were determined with automated triggering. Patients in the standard protocol group received 150 mL of contrast medium intravenously at 4 mL/sec. The same injection rate was used for the interactive protocol group, but the dose was reduced with discontinuation of injection at start of scanning. Quantities of contrast medium used and contrast-enhanced aortic attenuation achieved were compared. Aortoiliac enhancement was evaluated qualitatively by using a five-point scale (1 = poor, 5 = excellent). Quantitative and qualitative data were analyzed with the two-tailed t test and Wilcoxon rank sum test, respectively, to determine significance of differences (P <.05). RESULTS: Data from six patients were excluded because of technical errors. Data were analyzed from 20 patients in the interactive protocol group and 19 in the standard protocol group. Mean contrast medium volume was 107 mL +/- 20 (standard deviation) in the interactive protocol group and 148 mL +/- 3 in the standard protocol group (P <.001). Mean contrast-enhanced attenuation at initial, peak, and final measurements was 257 HU +/- 38, 285 HU +/- 46, and 269 HU +/- 54, respectively, for the interactive protocol group, and 261 HU +/- 65, 288 HU +/- 66, and 269 HU +/- 61 for the standard protocol group (P >.05). Mean qualitative enhancement scores for interactive and standard protocol groups were 4.47 and 4.44, respectively (P =.47). CONCLUSION: The interactive method is a simple, efficient, and reproducible way to optimize aortoiliac enhancement while reducing contrast medium dose.

Authors
Ho, LM; Nelson, RC; Thomas, J; Gimenez, EI; DeLong, DM
MLA Citation
Ho, LM, Nelson, RC, Thomas, J, Gimenez, EI, and DeLong, DM. "Abdominal aortic aneurysms at multi-detector row helical CT: optimization with interactive determination of scanning delay and contrast medium dose." Radiology 232.3 (September 2004): 854-859.
PMID
15333799
Source
pubmed
Published In
Radiology
Volume
232
Issue
3
Publish Date
2004
Start Page
854
End Page
859
DOI
10.1148/radiol.2323031006

Real-time 3D color flow Doppler for guidance of vibrating interventional devices.

The goal of this investigation was to examine the feasibility of guiding interventional devices using piezoelectric buzzers to create velocity sources, which were imaged and tracked with real-time 3D color flow Doppler. The interventional devices examined in this study included a pacemaker lead, Brockenbrough needle for cardiac septal puncture, cardiac guidewire and radiofrequency ablation needles for cancer therapy. Each was mechanically coupled to a piezoelectric buzzer and was imaged using a commercial real-time 3D ultrasound system with either a 2.5 MHz matrix array transducer or a 5 MHz, 22 F catheter transducer equipped with a tool port. In vitro images acquired in tissue phantoms, excised liver with a 'tumor' target and an excised sheep heart show strong vibration signals in 3D color flow Doppler, enabling real-time tracking and guidance of all the devices in three dimensions. In a sheep model, in vivo tracking of the pacing lead was performed in the superior vena cava as well as the right atrium using RT3D color flow Doppler images. The vibrating rf ablation needles were guided through the liver toward "tumor" targets in vivo with real-time 3D color flow Doppler images.

Authors
Fronheiser, MP; Wolf, PD; Idriss, SF; Nelson, RC; Lee, W; Smith, SW
MLA Citation
Fronheiser, MP, Wolf, PD, Idriss, SF, Nelson, RC, Lee, W, and Smith, SW. "Real-time 3D color flow Doppler for guidance of vibrating interventional devices." Ultrason Imaging 26.3 (July 2004): 173-184.
PMID
15754798
Source
pubmed
Published In
Ultrasonic Imaging
Volume
26
Issue
3
Publish Date
2004
Start Page
173
End Page
184
DOI
10.1177/016173460402600304

Abdominal imaging with multidetector computed tomography: state of the art.

This article is based on lectures which were given at the Multidetector Computed Tomography Conference in Washington, D.C. on September 13-14, 2003. Specifically, this article summarizes the Abdominal Imaging Section of this meeting. It is not an exhaustive review, but it rather attempts to highlight key points related to preoperative MDCT of the liver, MDCT of pancreas, MDCT urography and MDCT of thoracoabdominal and spinal trauma.

Authors
Harris, JP; Nelson, RC
MLA Citation
Harris, JP, and Nelson, RC. "Abdominal imaging with multidetector computed tomography: state of the art." J Comput Assist Tomogr 28 Suppl 1 (July 2004): S17-S19. (Review)
PMID
15258489
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
28 Suppl 1
Publish Date
2004
Start Page
S17
End Page
S19

Adipose tissue density from CTscan: Depot, gender differences and effects of exercise training. Does adipose density reflect fat cell size?

Authors
Slentz, CA; Aiken, LB; Nelson, RC; Tanner, CJ; Houmard, JA; Kraus, WE
MLA Citation
Slentz, CA, Aiken, LB, Nelson, RC, Tanner, CJ, Houmard, JA, and Kraus, WE. "Adipose tissue density from CTscan: Depot, gender differences and effects of exercise training. Does adipose density reflect fat cell size?." March 24, 2004.
Source
wos-lite
Published In
The FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Volume
18
Issue
5
Publish Date
2004
Start Page
A1227
End Page
A1228

Multidetector helical computed tomography of the liver: comparison of hepatic enhancement using two different contrast media strategies.

RATIONALE AND OBJECTIVES: The purpose of this study was to compare hepatic enhancement characteristics using two different contrast media injection protocols with multidetector helical computed tomography. MATERIALS AND METHODS: Twenty-three patients with known or suspected liver lesions scheduled to undergo biphasic hepatic multidetector helical computed tomography were randomized into one of two groups: (1) 150 mL of iopamidol (300 mgI/mL) at 5 mL/second, or (2) 100 mL of iopamidol (370 mgI/mL) at 4 mL/second. Unenhanced images were acquired initially, followed by both hepatic arterial phase (scan delay, 33 seconds) and portal venous phase (PVP; scan delay, 65 seconds) imaging. Three abdominal radiologists independently graded the images on a scale from 1-5 for enhancement and overall scan quality. Time-attenuation curves were generated from operator-defined region-of-interest measurements of liver parenchyma and aorta. RESULTS: Qualitatively, the three reviewers found no significant difference between the two study groups in terms of overall scan quality (P = .23) or aortic enhancement (hepatic arterial phase, P = .9; PVP, P = .24). However, liver enhancement during the PVP was considered to be less in the Isovue 370 group (P = .04). Quantitatively, during the hepatic arterial phase, there was no statistically significant difference between the two injection protocols comparing either aortic or hepatic parenchymal enhancement (P = .62 and .80, respectively). During the PVP, these differences were statistically significant, with both aortic and hepatic parenchymal enhancement lower in the Isovue 370 group (P < .01 and P = .04, respectively). CONCLUSION: It is important to consider the amount of iodine injected per second and the duration of the injection when setting up protocols to achieve target organ enhancement. 100 mL of iopamidol 370 at 4 mL/second can be used to obtain images of the liver with good diagnostic quality compared to more conventional protocols using 150 mL of iopamidol 300 at 5 mL/second. However, the degree of liver parenchymal enhancement during the PVP using the latter injection scheme is lower, which in turn could potentially reduce hepatic lesion conspicuity.

Authors
Smith, JC; Nelson, RC; Gimenez, EI; Heneghan, JP; Thomas, J; Delong, DM; Kurylo, LM
MLA Citation
Smith, JC, Nelson, RC, Gimenez, EI, Heneghan, JP, Thomas, J, Delong, DM, and Kurylo, LM. "Multidetector helical computed tomography of the liver: comparison of hepatic enhancement using two different contrast media strategies." Acad Radiol 11.3 (March 2004): 267-271.
PMID
15035516
Source
pubmed
Published In
Academic Radiology
Volume
11
Issue
3
Publish Date
2004
Start Page
267
End Page
271

Real-time 3D color doppler for guidance of vibrating interventional devices

The goal of this investigation is to examine the feasibility of guiding interventional devices using piezoelectric buzzers to create a velocity source, which is imaged and tracked with real time 3D (RT3D) ultrasound and Color Doppler. Interventional devices include pacemaker lead stylet, cardiac septal puncture needle and RF ablation needles for cancer therapy. The vibrating devices were imaged using a RT3D ultrasound system (Duke U./Volumetrics Medical Imaging) with a 2.5 MHz transducer that scans a 65° pyramid and displays up to 30 volumes per second. The velocities created by the vibrating devices were detected using real RT3D color Doppler. In vitro RT3D Doppler images acquired in tissue phantoms show strong vibration signals in 3D color Doppler mode, enabling real time tracking and guidance of the devices in three dimensions over the entire 65° pyramid at a minimum rate of one 3D color Doppler image volume per second. In an open chest sheep model, in vivo detection of the pacemaker lead stylet was performed in the superior vena cava as well as the right atrium using RT3D color Doppler images. The vibrating RF ablation needles were guided through the liver toward tumor targets in vivo with RT3D color Doppler images in a closed sheep model. From these results, we believe that using a vibrating buzzer to create a velocity source may enable interventional device visualization and guidance in RT3D images using Doppler methods. ©2004 IEEE.

Authors
Fronheiser, MP; Wolf, PD; Idriss, SF; Nelson, RC; Dixon-Tulloch, E; Smith, SW
MLA Citation
Fronheiser, MP, Wolf, PD, Idriss, SF, Nelson, RC, Dixon-Tulloch, E, and Smith, SW. "Real-time 3D color doppler for guidance of vibrating interventional devices." Proceedings - IEEE Ultrasonics Symposium 1 (2004): 149-152.
Source
scival
Published In
Proceedings of the IEEE Ultrasonics Symposium
Volume
1
Publish Date
2004
Start Page
149
End Page
152

Computed tomography

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Computed tomography." Applied Radiology 33.SUPPL. (2004): 5--.
Source
scival
Published In
Applied Radiology
Volume
33
Issue
SUPPL.
Publish Date
2004
Start Page
5-

Thermal lesion conspicuity following radiofrequency ablation of renal cell cancer: A comparison of HASTE, turbo spin-echo T2-weighted, in- and opposed-phase T1-weighted, and dynamic contrast-enhanced T1-weighted MR images at 1.5T

Authors
Merkle, EM; Nour, SN; Nelson, RC; Lewin, JS
MLA Citation
Merkle, EM, Nour, SN, Nelson, RC, and Lewin, JS. "Thermal lesion conspicuity following radiofrequency ablation of renal cell cancer: A comparison of HASTE, turbo spin-echo T2-weighted, in- and opposed-phase T1-weighted, and dynamic contrast-enhanced T1-weighted MR images at 1.5T." 2004.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
182
Issue
4
Publish Date
2004
Start Page
68
End Page
68

Renal radiofrequency ablation: Worst case scenarios in a porcine model

Authors
Brashears, JH; Crisci, A; Nelson, RC; Polascik, TJ
MLA Citation
Brashears, JH, Crisci, A, Nelson, RC, and Polascik, TJ. "Renal radiofrequency ablation: Worst case scenarios in a porcine model." 2004.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
182
Issue
4
Publish Date
2004
Start Page
14
End Page
15

Lower frequency of peritoneal carcinomatosis in patients with pancreatic cancer diagnosed by EUS-guided FNA vs. percutaneous FNA.

BACKGROUND: Studies have suggested an increased risk of peritoneal seeding in patients with pancreatic cancer diagnosed by percutaneous FNA. EUS-FNA is an alternate method of diagnosis. The aim of this study was to compare the frequency of peritoneal carcinomatosis as a treatment failure pattern in patients with pancreatic cancer diagnosed by EUS-FNA vs. percutaneous FNA. METHODS: Retrospective review of patients with non-metastatic pancreatic cancer identified 46 patients in whom the diagnosis was made by EUS-FNA and 43 with the diagnosis established by percutaneous FNA. All had neoadjuvant chemoradiation. Patients underwent restaging CT after completion of therapy, followed by attempted surgical resection if there was no evidence of disease progression. RESULTS: There were no significant differences in tumor characteristics between the two study groups. In the EUS-FNA group, one patient had developed peritoneal carcinomatosis compared with 7 in the percutaneous FNA group (2.2% vs. 16.3%; p<0.025). No patient with a potentially resectable tumor in the EUS-FNA group had developed peritoneal carcinomatosis. CONCLUSIONS: Peritoneal carcinomatosis may occur more frequently in patients who undergo percutaneous FNA compared with those who have EUS-FNA for the diagnosis of pancreatic cancer. A concern for peritoneal seeding of pancreatic cancer via percutaneous FNA is warranted. EUS-guided FNA is recommended as the method of choice for diagnosis in patients with potentially resectable pancreatic cancer.

Authors
Micames, C; Jowell, PS; White, R; Paulson, E; Nelson, R; Morse, M; Hurwitz, H; Pappas, T; Tyler, D; McGrath, K
MLA Citation
Micames, C, Jowell, PS, White, R, Paulson, E, Nelson, R, Morse, M, Hurwitz, H, Pappas, T, Tyler, D, and McGrath, K. "Lower frequency of peritoneal carcinomatosis in patients with pancreatic cancer diagnosed by EUS-guided FNA vs. percutaneous FNA." Gastrointest Endosc 58.5 (November 2003): 690-695.
PMID
14595302
Source
pubmed
Published In
Gastrointestinal Endoscopy
Volume
58
Issue
5
Publish Date
2003
Start Page
690
End Page
695

Helical CT for nephrolithiasis and ureterolithiasis: comparison of conventional and reduced radiation-dose techniques.

PURPOSE: To determine the accuracy of unenhanced helical computed tomography (CT) performed at reduced milliampere-second, and therefore at a reduced patient radiation dose, by using conventional unenhanced helical CT as the standard. MATERIALS AND METHODS: Fifty patients with acute flank pain who weighed less than 200 lb (90 kg) were prospectively recruited for this study. Conventional helical CT scans were obtained with patients in the prone position by using 5-mm-thick sections, 140 kVp, 135-208 mAs (mean, 160 mAs), and a pitch of 1.5 (single-detector row CT) or 0.75 (multi-detector row CT, 4 x 5-mm detector configuration). Conventional CT was immediately followed by low-dose scanning, whereby the tube current was reduced to 100 mA (mean, 76 mAs). All other technical parameters and anatomic coverage remained constant. Three independent readers who were blinded to patient identity interpreted the scans in random order. The observers noted the location, size, and number of calculi; secondary signs of obstruction; and other clinically relevant findings. High- and low-dose scans were compared by using paired t tests and the signed rank test. RESULTS: Calculi were found in 33 (66%) patients; 25 (50%) had renal calculi and 19 (38%) had an obstructing ureteral calculus. The accuracy rates (averaged over the three readers) for determining the various findings on the low-dose scan compared with the high-dose scan were as follows: nephrolithiasis, 91%; ureterolithiasis, 94%; obstruction, 91%; and normal findings, 92%. When interpretations between readers were compared, agreement rates were 90%-95% for standard-dose scans and 90%-92% for reduced-dose scans (P >.5). Uncomplicated mild diverticulitis was found in three patients. No other clinically important abnormality was identified. A reduction in the tube current to 100 mA resulted in a dose reduction of 25% for multi-detector row CT and 42% for single-detector row CT. CONCLUSION: In patients who weighed less than 200 lb, unenhanced helical CT performed at a reduced tube current of 100 mA, and therefore at a reduced patient dose, resulted in scans of high accuracy.

Authors
Heneghan, JP; McGuire, KA; Leder, RA; DeLong, DM; Yoshizumi, T; Nelson, RC
MLA Citation
Heneghan, JP, McGuire, KA, Leder, RA, DeLong, DM, Yoshizumi, T, and Nelson, RC. "Helical CT for nephrolithiasis and ureterolithiasis: comparison of conventional and reduced radiation-dose techniques." Radiology 229.2 (November 2003): 575-580.
PMID
14526095
Source
pubmed
Published In
Radiology
Volume
229
Issue
2
Publish Date
2003
Start Page
575
End Page
580
DOI
10.1148/radiol.2292021261

An invited commentary. Wall thickening in the GI tract on CT, what does it mean?

Authors
Nelson, RC
MLA Citation
Nelson, RC. "An invited commentary. Wall thickening in the GI tract on CT, what does it mean?." Am J Gastroenterol 98.8 (August 2003): 1675-.
PMID
12907317
Source
pubmed
Published In
The American Journal of Gastroenterology (Elsevier)
Volume
98
Issue
8
Publish Date
2003
Start Page
1675
DOI
10.1111/j.1572-0241.2003.07601.x

Optimization of eight-element multi-detector row helical CT technology for evaluation of the abdomen.

PURPOSE: To evaluate protocols for abdominal imaging with an eight-element multi-detector row computed tomographic (CT) scanner. MATERIALS AND METHODS: An eight-element helical CT scanner was used to acquire data in two phantoms with four-element (pitch, 0.75 and 1.5; section thickness, 1.25, 2.5, and 5.0 mm) and eight-element (pitch, 0.625, 0.875, 1.35 and 1.675; section thickness, 1.25 and 2.5 mm) protocols. One phantom was used for low-contrast detectability and streak artifact; the other, for high-contrast performance. Protocols included near constant radiation dose (140 kV and varied tube current, confirmed by using the above protocols to scan a dedicated radiation dose phantom). Data were analyzed by three blinded readers for streak artifacts, contrast-to-noise ratio, and z-axis resolution (contrast-transfer function). Statistical analysis included studentized range tests. RESULTS: Contrast-to-noise ratios for four and eight elements were not consistently different. Qualitative evaluation for streak artifacts revealed fewer artifacts for all eight-element 1.25-mm-thick section protocols, as compared with eight-element 2.5-mm protocols. All eight-element 2.5-mm protocols except that with 27.0 mm per rotation had fewer streak artifacts than did four-element protocols (P =.02-.04). Contrast-transfer functions along the z axis for eight-element protocols were better than those for four-element protocols, demonstrating improved z-axis resolution (P <.05). CONCLUSION: Images acquired at eight sections per rotation demonstrated no sacrifice of contrast-to-noise ratio, improved z-axis resolution, and fewer streak artifacts, even when radiation dose was similar to that for four-element CT.

Authors
Gupta, AK; Nelson, RC; Johnson, GA; Paulson, EK; Delong, DM; Yoshizumi, TT
MLA Citation
Gupta, AK, Nelson, RC, Johnson, GA, Paulson, EK, Delong, DM, and Yoshizumi, TT. "Optimization of eight-element multi-detector row helical CT technology for evaluation of the abdomen." Radiology 227.3 (June 2003): 739-745.
PMID
12702826
Source
pubmed
Published In
Radiology
Volume
227
Issue
3
Publish Date
2003
Start Page
739
End Page
745
DOI
10.1148/radiol.2273020591

Liver imaging with multidetector helical computed tomography.

The speed and flexibility of multidetector computed tomography (MDCT) have led to improvements in liver imaging, particularly related to the detection and characterization of focal lesions. This report discusses the different phase of liver enhancement following the bolus administration of iodinated contrast material, and the enhancement pattern of various liver lesions during these phases. We also propose guidelines for designing protocols for MDCT of the liver and discuss the principles of contrast media delivery.

Authors
Nelson, RC; Spielmann, AL
MLA Citation
Nelson, RC, and Spielmann, AL. "Liver imaging with multidetector helical computed tomography." J Comput Assist Tomogr 27 Suppl 1 (May 2003): S9-16. (Review)
PMID
12908707
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
27 Suppl 1
Publish Date
2003
Start Page
S9
End Page
16

Single versus multi-detector row CT: comparison of radiation doses and dose profiles.

RATIONALE AND OBJECTIVES: The purpose of this study was twofold: (a) to compare the radiation dose profile between computed tomography (CT) with a single detector row (SD) and with a multi-detector row (MD) and (b) to compare specific organ doses between SD CT and MD CT. MATERIALS AND METHODS: Thermoluminescent dosimeters placed within a 32-cm-diameter cylindrical phantom were used to measure and compare dose profiles from one SD CT scanner and from one MD CT scanner. SD CT scanning parameters were 210 mA, 140 kVp, pitch of 1.0, 5-mm section thickness, and 0.8-second gantry rotation speed. MD CT scanning parameters were 130 mA, 140 kVp, pitch of 0.75, 4 x 5-mm section thickness, 15-mm table feed, and 0.8-second gantry rotation speed. To plot radiation dose profile, doses were measured both in the imaging plane and in the area adjacent to the imaging plane. The resultant data were normalized to achieve constant image noise between MD CT and SD CT. Direct doses to individual organs from primary and scattered radiation were measured with an anthropomorphic phantom containing thermoluminescent dosimeters and with a standard pelvic imaging protocol for both MD CT and SD CT. RESULTS: MD CT resulted in a dose profile approximately 27% higher than that from SD CT in the plane of imaging (8.0 vs 6.3 mGy) and 69% higher adjacent to the plane of imaging (6.8 vs 4.0 mGy). The individual doses to the kidneys, uterus, ovaries, and pelvic bone marrow were 92%-180% higher with MD CT than with SD CT. CONCLUSION: With image noise constant between SD CT and MD CT, the radiation dose profile both inside and outside the plane of imaging was higher with MD CT than with SD CT. Organ dose also was higher with MD CT than with SD CT. This difference should be accounted for in the design of MD CT protocols, especially as MD CT technology becomes more widely available for clinical use.

Authors
Thomton, FJ; Paulson, EK; Yoshizumi, TT; Frush, DP; Nelson, RC
MLA Citation
Thomton, FJ, Paulson, EK, Yoshizumi, TT, Frush, DP, and Nelson, RC. "Single versus multi-detector row CT: comparison of radiation doses and dose profiles." Acad Radiol 10.4 (April 2003): 379-385.
PMID
12678177
Source
pubmed
Published In
Academic Radiology
Volume
10
Issue
4
Publish Date
2003
Start Page
379
End Page
385

Differential actions of PAR2 and PAR1 in stimulating human endothelial cell exocytosis and permeability: the role of Rho-GTPases.

Endothelial cell proteinase activated receptors (PARs) belong to a family of heterotrimeric G protein-coupled receptors that are implicated in leukocyte accumulation and potentiation of reperfusion injury. We characterized the effect and the signal transduction pathways recruited after stimulation of endothelial PAR2. We used von Willebrand Factor (vWF) release and monolayer permeability to peroxidase to report Weibel-Palade body (WPB) exocytosis and pore formation, respectively. Human umbilical vein endothelial cells (HUVECs) were stimulated with the selective PAR2 agonist peptide SLIGRL-NH2 or PAR1 agonist peptide TFLLR-NH2. PAR2 stimulation resulted in WPB exocytosis like PAR1 stimulation but, unlike PAR1, failed to increase monolayer permeability. BAPTA-AM inhibited PAR2-induced exocytosis, indicating a PAR2 calcium-dependent signal in ECs. Moreover, PAR2-like PAR1-stimulated exocytosis requires actin cytoskeleton remodeling, because vWF release is inhibited if the cells were pretreated with Jasplakinolide. Rho-GTPase activity is required for PAR-stimulated exocytosis, because inactivation of this family of actin-regulatory proteins with Clostridium difficile toxin B blocked exocytosis. Expression of dominant-negative mutant Cdc42(17N) inhibited exocytosis whereas neither dominant-negative Rac(17N) expression nor C3 exotoxin treatment affected vWF release. PAR2 stimulated RhoA-GTP weakly compared with the PAR1 agonist. We conclude that both PAR2 and PAR1 elicit WP body exocytosis in a calcium and Cdc42 GTPase-dependent manner. In contrast, the differential effect of PAR1 versus PAR2 activation to increase monolayer permeability correlates with weak RhoA activation by the PAR2 agonist.

Authors
Klarenbach, SW; Chipiuk, A; Nelson, RC; Hollenberg, MD; Murray, AG
MLA Citation
Klarenbach, SW, Chipiuk, A, Nelson, RC, Hollenberg, MD, and Murray, AG. "Differential actions of PAR2 and PAR1 in stimulating human endothelial cell exocytosis and permeability: the role of Rho-GTPases." Circ Res 92.3 (February 21, 2003): 272-278.
PMID
12595338
Source
pubmed
Published In
Circulation Research
Volume
92
Issue
3
Publish Date
2003
Start Page
272
End Page
278

Radiation issues with multidetector row helical CT.

Authors
Yoshizumi, TT; Nelson, RC
MLA Citation
Yoshizumi, TT, and Nelson, RC. "Radiation issues with multidetector row helical CT." Crit Rev Comput Tomogr 44.2 (2003): 95-117. (Review)
PMID
12757315
Source
pubmed
Published In
Critical Reviews in Computed Tomography
Volume
44
Issue
2
Publish Date
2003
Start Page
95
End Page
117

An invited commentary

Authors
Nelson, RC
MLA Citation
Nelson, RC. "An invited commentary." American Journal of Gastroenterology 98.8 (2003): 1675--.
Source
scival
Published In
American Journal of Gastroenterology
Volume
98
Issue
8
Publish Date
2003
Start Page
1675-

Introduction: Computed tomography

Authors
Nelson, RC; Tanenbaum, LN
MLA Citation
Nelson, RC, and Tanenbaum, LN. "Introduction: Computed tomography." Applied Radiology 32.6 SUPPL. (2003): 7--.
Source
scival
Published In
Applied Radiology
Volume
32
Issue
6 SUPPL.
Publish Date
2003
Start Page
7-

Image of the month. Menetrier disease with premalignant transformation.

Authors
Warshauer, DM; Thornton, FJ; Nelson, RC; O'Connor, JB
MLA Citation
Warshauer, DM, Thornton, FJ, Nelson, RC, and O'Connor, JB. "Image of the month. Menetrier disease with premalignant transformation." Gastroenterology 123.4 (October 2002): 968-1419.
PMID
12360455
Source
pubmed
Published In
Gastroenterology
Volume
123
Issue
4
Publish Date
2002
Start Page
968
End Page
1419

The role of F-18 FDG positron emission tomography in preoperative assessment of the liver in patients being considered for curative resection of hepatic metastases from colorectal cancer.

PURPOSE: The authors' goal was to determine the sensitivity and specificity of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for identifying patients with hepatic metastases from colorectal cancer and the accuracy of PET for determining the number and distribution of lesions within the liver. Intraoperative sonography and surgical inspection and palpation were used as the reference standard. METHODS: Twenty-three patients being evaluated for surgical resection of hepatic metastases from colorectal carcinoma underwent FDG PET before operation. Findings of the PET studies were reviewed in a blinded, retrospective manner, with the results compared with the findings of intraoperative sonography and surgical exploration. Lesions of all sizes were considered in the analysis. RESULTS: The FDG-PET results were positive in 21 of the 22 patients ultimately found to have metastatic disease to the liver, and they were negative in the single patient without metastases. Therefore, for identification of patients with hepatic metastatic disease, PET has a sensitivity of 95% and a specificity of 100%. In all, 48 metastatic lesions were identified in these patients, of which 38 (79%) were identified on PET images. The probability of lesion detection by PET was directly correlated with lesion size (P < 0.01). The assessment of lobar disease distribution in the liver was discordant between PET and surgery in 3 of 23 (13%) patients. CONCLUSIONS: In patients being evaluated for potential curative resection of hepatic metastases from colorectal cancer, FDG PET is accurate for the identification of the presence or absence of metastatic disease to the liver. However, detection of individual lesions depends on their size, and determination of lesion number and distribution within the liver is more accurately accomplished with intraoperative sonography.

Authors
Rohren, EM; Paulson, EK; Hagge, R; Wong, TZ; Killius, J; Clavien, PA; Nelson, RC
MLA Citation
Rohren, EM, Paulson, EK, Hagge, R, Wong, TZ, Killius, J, Clavien, PA, and Nelson, RC. "The role of F-18 FDG positron emission tomography in preoperative assessment of the liver in patients being considered for curative resection of hepatic metastases from colorectal cancer." Clin Nucl Med 27.8 (August 2002): 550-555.
PMID
12169999
Source
pubmed
Published In
Clinical Nuclear Medicine
Volume
27
Issue
8
Publish Date
2002
Start Page
550
End Page
555
DOI
10.1097/01.RLU.0000020742.66887.67

Thin-section multidetector CT angiography of renal artery stents.

OBJECTIVE: This study was undertaken as a pilot investigation to compare multidetector CT angiography with conventional catheter angiography for the visualization of the renal artery lumen after renal artery stent placement. SUBJECTS AND METHODS: CT angiography was performed within 24-48 hr of renal artery stent placement in 15 patients. Two patients had bilateral stents, resulting in a total of 17 stents. CT angiography was performed using a multidetector scanner and a bolus of IV contrast material with the scanning delay determined by a small-volume timing bolus. A volumetric data set was acquired through the stented arteries in the axial plane using a 4.0 x 1.25 mm detector configuration and a pitch of 3:1. The stent lumen diameter, as measured on direct CT angiography and curved multiplanar reformations in both the axial and coronal planes, was compared with that measured on catheter angiography. RESULTS: The lumina of all 17 stents were well visualized and patent on both CT angiography and catheter angiography. Anatomic definition, including stent position and wall apposition in the renal artery, correlated well with catheter angiography. The diameter of the renal artery stent lumen measured on catheter angiography (mean, 5.9 +/- 1.3 mm) was greater than that on CT angiography (mean stent lumen diameter for direct axial plane was 4.6 +/- 1.0 mm, for curved multiplanar reformations in the axial plane was 4.3 +/- 1.0 mm, and for curved multiplanar reformations in the coronal plane was 4.4 +/- 1.0 mm) in 14 (82%) of 17 stents. CONCLUSION: CT angiography produced interpretable multiplanar images of the renal artery, even with a metallic stent in place, and was adequate for determining stent patency. Compared with catheter angiography, the intrastent luminal diameter was underestimated in most patients who underwent CT angiography.

Authors
Behar, JV; Nelson, RC; Zidar, JP; DeLong, DM; Smith, TP
MLA Citation
Behar, JV, Nelson, RC, Zidar, JP, DeLong, DM, and Smith, TP. "Thin-section multidetector CT angiography of renal artery stents." AJR Am J Roentgenol 178.5 (May 2002): 1155-1159.
PMID
11959722
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
178
Issue
5
Publish Date
2002
Start Page
1155
End Page
1159
DOI
10.2214/ajr.178.5.1781155

Decreasing the radiation dose for renal stone CT: a feasibility study of single- and multidetector CT.

Authors
Spielmann, AL; Heneghan, JP; Lee, LJ; Yoshizumi, T; Nelson, RC
MLA Citation
Spielmann, AL, Heneghan, JP, Lee, LJ, Yoshizumi, T, and Nelson, RC. "Decreasing the radiation dose for renal stone CT: a feasibility study of single- and multidetector CT." AJR Am J Roentgenol 178.5 (May 2002): 1058-1062.
PMID
11959701
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
178
Issue
5
Publish Date
2002
Start Page
1058
End Page
1062
DOI
10.2214/ajr.178.5.1781058

Outcome analysis of patients with acute pancreatitis by using an artificial neural network.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the ability of an artificial neural network (ANN) that uses radiologic and laboratory data to predict the outcome in patients with acute pancreatitis. MATERIALS AND METHODS: An ANN was constructed with data from 92 patients with acute pancreatitis who underwent computed tomography (CT). Input nodes included clinical, laboratory, and CT data. The ANN was trained and tested by using a round-robin technique, and the performance of the ANN was compared with that of linear discriminant analysis and Ranson and Balthazar grading systems by using receiver operating characteristic analysis. The length of hospital stay was used as an outcome measure. RESULTS: Hospital stay ranged from 0 to 45 days, with a mean of 8.4 days. The hospital stay was shorter than the mean for 62 patients and longer than the mean for 30. The 23 input features were reduced by using stepwise linear discriminant analysis, and an ANN was developed with the six most statistically significant parameters (blood pressure, extent of inflammation, fluid aspiration, serum creatinine level, serum calcium level, and the presence of concurrent severe illness). With these features, the ANN successfully predicted whether the patient would exceed the mean length of stay (Az = 0.83 +/- 0.05). Although the Az performance of the ANN was statistically significantly better than that of the Ranson (Az = 0.68 +/- 0.06, P < .02) and Balthazar (Az = 0.62 +/- 0.06, P < .003) grades, it was not significantly better than that of linear discriminant analysis (Az = 0.82 +/- 0.05, P = .53). CONCLUSION: An ANN may be useful for predicting outcome in patients with acute pancreatitis.

Authors
Keogan, MT; Lo, JY; Freed, KS; Raptopoulos, V; Blake, S; Kamel, IR; Weisinger, K; Rosen, MP; Nelson, RC
MLA Citation
Keogan, MT, Lo, JY, Freed, KS, Raptopoulos, V, Blake, S, Kamel, IR, Weisinger, K, Rosen, MP, and Nelson, RC. "Outcome analysis of patients with acute pancreatitis by using an artificial neural network." Acad Radiol 9.4 (April 2002): 410-419.
PMID
11942655
Source
pubmed
Published In
Academic Radiology
Volume
9
Issue
4
Publish Date
2002
Start Page
410
End Page
419

Automated support for pharmacovigilance: a proposed system.

Governments, manufacturers, and other entities are interested in adverse event surveillance of marketed medical products. FDA's Center for Drug Evaluation and Research redesigned the post-marketing adverse reaction surveillance process to use the advantages of new technology. As part of this effort, a 'Pharmacovigilance Working Group' designed a new strategy for the review and analyses of adverse event reports received by FDA. It created requirements which divided signal detection into five tiers: (1) Single 'urgent' reports would be sent to reviewers' workstations nightly for immediate attention. Reviewers would be able to customize definitions of 'urgent' (events that should not wait for aggregate review). (2) Single urgent reports would be placed in a context matrix containing historical counts of similar events to aid in initial interpretation. (3) In this first level of aggregate review, graphical displays would highlight patterns within all the reports, both urgent and non-urgent, and (4) periodic drug-specific tabled-based reports would display the newly received reports across a pre-defined variety of displays. These four tiers would produce passive and criteria-based results which would be presented to safety reviewers' electronic workstations. (5) Active query capabilities (routine, such as age, sex, and year distributions, as well as ad hoc) would be available for exploring alerted issues. The historical database would be migrated into the new format. All historical and new reaction data would be coded with the new MedDRA (Medical Dictionary for Regulatory Activities) scheme. The strategy was to design a full data capture system which effectively exploits current computing advances and technical performance to automate many aspects of initial adverse event review, supporting more efficient and effective clinical assessment of safety signals.

Authors
Bright, RA; Nelson, RC
MLA Citation
Bright, RA, and Nelson, RC. "Automated support for pharmacovigilance: a proposed system." Pharmacoepidemiol Drug Saf 11.2 (March 2002): 121-125.
PMID
11998536
Source
pubmed
Published In
Pharmacoepidemiology and Drug Safety
Volume
11
Issue
2
Publish Date
2002
Start Page
121
End Page
125
DOI
10.1002/pds.684

Comparison of MR cholangiopancreatographic techniques with contrast-enhanced cholangiography in the evaluation of sclerosing cholangitis.

OBJECTIVE: The purpose of our study was to compare MR cholangiopancreatography and contrast-enhanced cholangiography in patients with sclerosing cholangitis. MATERIALS AND METHODS: Twenty patients with sclerosing cholangitis were evaluated on MR cholangiopancreatography using the single-shot fast spin-echo technique at 1.5 T. A group of 19 healthy volunteers underwent MR cholangiopancreatography as controls. Thick-slab (2-cm sections) coronal oblique and thin-slab (5-mm sections) interleaved straight coronal MR images were obtained. All patients with sclerosing cholangitis had an MR cholangiopancreatogram within 12 months of a contrast-enhanced cholangiogram (mean, 3.8 months). Seventy-five percent of patients had an MR cholangiopancreatogram within 3 months of the contrast-enhanced cholangiogram. The MR cholangiopancreatograms and contrast-enhanced cholangiograms were reviewed independently in a random fashion by two radiologists who were unaware of clinical history for the degree of ductal visualization and for the presence and location of strictures of the intrahepatic and extrahepatic bile ducts. All discrepancies were resolved by a consensus, and the contrast-enhanced cholangiograms were regarded as the gold standard. Statistically significant data were calculated using the signed rank test (p < 0.01), and agreement analysis was calculated using Cohen's kappa. RESULTS: All findings on MR cholangiopancreatograms in healthy subjects were interpreted as normal, and all findings on MR cholangiopancreatograms in patients with sclerosing cholangitis were interpreted as abnormal. When compared with the control group, scans of patients with sclerosing cholangitis usually showed good visualization (>50%) of the intrasegmental (86% vs 9%) and peripheral (67% vs 0%) intrahepatic ducts on thick-slab MR cholangiopancreatography. Thick-slab MR cholangiopancreatography showed good visualization in more ducts than contrast cholangiography (84% vs 70%; p = 0.10) and showed more strictured ducts than contrast cholangiography (47% vs 36%; p = 0.22). When comparing those ducts with good visualization on both MR cholangiopancreatography and contrast cholangiography, we found that disagreement occurred regarding 32% of ducts. Most of the discrepancies (60%) resulted when a stricture was noted on MR cholangiopancreatography but not on contrast-enhanced cholangiography. Good interobserver agreement (kappa > 0.4) was noted for detecting strictures of the extrahepatic, left hepatic, left medial, and right posterior ducts, with the greatest agreement for extrahepatic ductal strictures (kappa = 0.8). CONCLUSION: Thick-slab MR cholangiopancreatography is the best technique for depicting normal and strictured bile ducts and allows the differentiation of healthy patients from patients with sclerosing cholangitis. Although endoscopic retrograde cholangiopancreatography was considered the standard, MR cholangiopancreatography was superior for intrahepatic biliary ductal visualization. Therefore, this technique is of value in the diagnosis and follow-up of patients with sclerosing cholangitis.

Authors
Vitellas, KM; Enns, RA; Keogan, MT; Freed, KS; Spritzer, CE; Baillie, J; Nelson, RC
MLA Citation
Vitellas, KM, Enns, RA, Keogan, MT, Freed, KS, Spritzer, CE, Baillie, J, and Nelson, RC. "Comparison of MR cholangiopancreatographic techniques with contrast-enhanced cholangiography in the evaluation of sclerosing cholangitis." AJR Am J Roentgenol 178.2 (February 2002): 327-334.
PMID
11804887
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
178
Issue
2
Publish Date
2002
Start Page
327
End Page
334
DOI
10.2214/ajr.178.2.1780327

Pseudoenhancement of simple renal cysts: a comparison of single and multidetector helical CT.

PURPOSE: The purpose of this work was to compare the extent of pseudoenhancement (artifactual increase in measured attenuation of a simple cyst after contrast medium administration) in a phantom model on single detector and multidetector helical CT scanners. METHOD: The phantom consisted of four water-filled spheres varying in size from 8 to 28 mm, suspended in an aqueous contrast medium bath. Iodine concentration in the bath was varied: 0, 6, 12, and 24 mg/ml corresponding to attenuation values of 0, +108, +180, and +300 HU. The phantom was scanned on single detector and multidetector helical CT scanners during the same session. Collimation (1, 3, and 5 mm) and pitch (1 and 1.5:1, single detector; 3:1 and 6:1, multidetector) were varied at each concentration. All scans were performed at 140 kVp and 170 mA. The region of interest was measured at the center of each sphere. The effects were analyzed using a linear regression model. RESULTS: The degree of pseudoenhancement was more pronounced with increasing iodine concentration, decreasing cyst size, and wider collimation (all p = 0.0001). Pseudoenhancement was also more marked on the multidetector than the single detector scanner (p = 0.0001). At physiological levels of renal enhancement, the average pseudoenhancement was +18 HU for the single detector versus +23 HU for the multidetector scanner. Variation in pitch had no effect. CONCLUSION: Pseudoenhancement is greater on a multidetector than a single detector helical CT scanner and may exceed 20 HU at physiological levels of renal enhancement.

Authors
Heneghan, JP; Spielmann, AL; Sheafor, DH; Kliewer, MA; DeLong, DM; Nelson, RC
MLA Citation
Heneghan, JP, Spielmann, AL, Sheafor, DH, Kliewer, MA, DeLong, DM, and Nelson, RC. "Pseudoenhancement of simple renal cysts: a comparison of single and multidetector helical CT." J Comput Assist Tomogr 26.1 (January 2002): 90-94.
PMID
11801909
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
26
Issue
1
Publish Date
2002
Start Page
90
End Page
94

Liver: single breath-hold dynamic subtraction CT with multi-detector row helical technology feasibility study.

Fifty-two patients with known or suspected hypervascular malignancy were examined to determine the technical feasibility of performing single-breath-hold dynamic subtraction computed tomography (CT) of the liver with multi-detector row helical CT. The precontrast and hepatic arterial CT scans, which were acquired during the same breath hold, were subtracted. The mean liver-to-muscle contrast ratio on the precontrast, hepatic arterial, and subtracted images was 1.3, 1.4, and 2.3, respectively. In 13 patients with lesions, the subtracted images showed a 2.5-fold increase in mean lesion contrast compared with the hepatic arterial CT scans.

Authors
Spielmann, AL; Nelson, RC; Lowry, CR; Johnson, GA; Sundaramoothy, G; Sheafor, DH; Paulson, EK
MLA Citation
Spielmann, AL, Nelson, RC, Lowry, CR, Johnson, GA, Sundaramoothy, G, Sheafor, DH, and Paulson, EK. "Liver: single breath-hold dynamic subtraction CT with multi-detector row helical technology feasibility study." Radiology 222.1 (January 2002): 278-283.
PMID
11756737
Source
pubmed
Published In
Radiology
Volume
222
Issue
1
Publish Date
2002
Start Page
278
End Page
283
DOI
10.1148/radiol.2221010190

Image of the month

Authors
Warshauer, DM; Thornton, FJ; Nelson, RC; O'Connor, JB
MLA Citation
Warshauer, DM, Thornton, FJ, Nelson, RC, and O'Connor, JB. "Image of the month." Gastroenterology 123.4 (2002): 968+1419-.
Source
scival
Published In
Gastroenterology
Volume
123
Issue
4
Publish Date
2002
Start Page
968+1419

Introduction: Computed tomography

Authors
Nelson, RC; Tanenbaum, LN
MLA Citation
Nelson, RC, and Tanenbaum, LN. "Introduction: Computed tomography." Applied Radiology 31.6 SUPPL. (2002): 5--.
Source
scival
Published In
Applied Radiology
Volume
31
Issue
6 SUPPL.
Publish Date
2002
Start Page
5-

Sonographically guided thrombin injection of iatrogenic femoral pseudoaneurysms: further experience of a single institution.

OBJECTIVE: In September 1998, we began to treat iatrogenic femoral pseudoaneurysms with direct thrombin injection under sonographic guidance. Our purpose was to determine the success and complication rate of this technique. SUBJECTS AND METHODS: We treated 114 consecutive patients who had iatrogenic femoral pseudoaneurysms using direct thrombin injection. A 22-gauge spinal needle was placed into the pseudoaneurysm lumen with sonographic guidance, and bovine or human thrombin (mean dose, 306 U; range, 50--1600 U) was injected under continuous color Doppler sonographic visualization. Distal pulses were monitored. Patient demographics, clinical variables, and pseudoaneurysm characteristics were collected. RESULTS: One hundred three (90%) of 114 patients had pseudoaneurysm thrombosis after the first procedure. Of the remaining 11 patients who required a second procedure 1 day later, thrombosis occurred in seven (64%) of 11. Thus, the overall success rate was 96% (110/114). Of the patients who required one injection, the mean thrombosis time was 12 sec (range, 3--90 sec). Three (3%) of 114 patients required conscious sedation. Of the patients with successful thrombosis, 24-hr follow-up sonograms showed no recurrent pseudoaneurysm. Four patients (4%) had potential complications: a "blue toe" 15 hr after the thrombin injection that resolved spontaneously, a groin abscess, leg ischemia that resolved spontaneously after 4 hr, and crampy buttock pain that resolved spontaneously. CONCLUSION: For the treatment of iatrogenic femoral pseudoaneurysms, thrombin injection under sonographic guidance is a quick and effective method of therapy. Failures and complications are infrequent. At our institution, sonographically guided thrombin injection has replaced compression repair.

Authors
Paulson, EK; Nelson, RC; Mayes, CE; Sheafor, DH; Sketch, MH; Kliewer, MA
MLA Citation
Paulson, EK, Nelson, RC, Mayes, CE, Sheafor, DH, Sketch, MH, and Kliewer, MA. "Sonographically guided thrombin injection of iatrogenic femoral pseudoaneurysms: further experience of a single institution." AJR Am J Roentgenol 177.2 (August 2001): 309-316.
PMID
11461851
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
177
Issue
2
Publish Date
2001
Start Page
309
End Page
316
DOI
10.2214/ajr.177.2.1770309

Nonstenotic internal carotid arteries: effects of age and blood pressure at the time of scanning on Doppler US velocity measurements.

PURPOSE: To assess the effects of age and blood pressure at the time of scanning on internal carotid artery velocities and cross-sectional diameter at Doppler ultrasonography (US). MATERIALS AND METHODS: During 12 months, 1,020 consecutive patients underwent internal carotid artery Doppler US. No or minimal arterial disease was found in 142 patients (67 women, 75 men). Blood pressure was recorded prior to examination. The angle-corrected internal carotid artery peak systolic and end-diastolic velocities were obtained. The effects of systolic blood pressure, diastolic blood pressure, pulse pressure, age, chronic hypertension, and medications for hypertension on velocities were evaluated by using linear regression analysis. RESULTS: Peak systolic velocity was influenced by age (P =.008), systolic blood pressure (P =.009), diastolic blood pressure (P =.003), and pulse pressure (P =.017) but not history of hypertension (P =.53) or antihypertensive medication use (P =.77). Increasing age decreased peak systolic velocity by 0.34 cm/sec/y. End-diastolic velocity was influenced by age (P <.001) but not by systolic, diastolic, or pulse pressure (all P values were >.13). CONCLUSION: Internal carotid artery peak systolic velocities decrease with advancing age and increase with increasing pulse pressure. The effects of blood pressure at the time of scanning are small, but isolated systolic hypertension could cause increases in spurious velocity.

Authors
Spencer, EB; Sheafor, DH; Hertzberg, BS; Bowie, JD; Nelson, RC; Carroll, BA; Kliewer, MA
MLA Citation
Spencer, EB, Sheafor, DH, Hertzberg, BS, Bowie, JD, Nelson, RC, Carroll, BA, and Kliewer, MA. "Nonstenotic internal carotid arteries: effects of age and blood pressure at the time of scanning on Doppler US velocity measurements." Radiology 220.1 (July 2001): 174-178.
PMID
11425992
Source
pubmed
Published In
Radiology
Volume
220
Issue
1
Publish Date
2001
Start Page
174
End Page
178
DOI
10.1148/radiology.220.1.r01jl33174

Two-dimensional multiplanar and three-dimensional volume-rendered vascular CT in pancreatic carcinoma: interobserver agreement and comparison with standard helical techniques.

OBJECTIVE: The purpose of this study was to compare two-dimensional curved multiplanar and three-dimensional reconstructions, routine axial presentations, and combined techniques in the assessment of vascular involvement by pancreatic malignancy. MATERIALS AND METHODS: For 44 patients with known pancreatic malignancy a total of 56 arterial phase helical CT scans were obtained. Targeted pancreatic imaging was performed, and reformatted images were generated. Axial source images, reformatted images, and the combination of axial and reformatted images were interpreted independently by three observers. The observers graded the celiac axis, common and proper hepatic, splenic, gastroduodenal, and superior mesenteric arteries for tumor involvement. Grades of vascular involvement were compared by intra- and interobserver variability analyses. RESULTS: Intraobserver agreement averaged over five vessels was good between the axial and combined techniques for each individual observer (0.64 < or kappa < or = 0.66), but intraobserver agreement was poor between the axial and reformatted (kappa = 0.17 and kappa = 0.31, respectively) and the reformatted and combined techniques (kappa = 0.31 and kappa = 0.38, respectively) for two observers. For grading of vascular involvement in each vessel, intraobserver agreement was good to excellent between the axial and combined techniques (0.48 or = kappa < or = 0.82). Interobserver agreement averaged over five vessels was poor for imaging techniques except between observer 2 and observer 3 on the axial (kappa = 0.47) and combined techniques (kappa = 0.47). For grading of vascular involvement in each vessel, interobserver agreement for reformatted technique was poor (0.09 < or = kappa < or = 0.40). CONCLUSION: Multiplanar and volume-rendered techniques showed the highest intra- and interobserver variability in grading vascular involvement by pancreatic malignancy. These images should be used in combination with routine axial images to decrease observer variability.

Authors
Baek, SY; Sheafor, DH; Keogan, MT; DeLong, DM; Nelson, RC
MLA Citation
Baek, SY, Sheafor, DH, Keogan, MT, DeLong, DM, and Nelson, RC. "Two-dimensional multiplanar and three-dimensional volume-rendered vascular CT in pancreatic carcinoma: interobserver agreement and comparison with standard helical techniques." AJR Am J Roentgenol 176.6 (June 2001): 1467-1473.
PMID
11373215
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
176
Issue
6
Publish Date
2001
Start Page
1467
End Page
1473
DOI
10.2214/ajr.176.6.1761467

Compression CT urography: a comparison with IVU in the opacification of the collecting system and ureters.

OBJECTIVE: The purpose of this study was to evaluate opacification of the collecting system and ureters using compression computed tomography (CT) urography compared with conventional intravenous urography (IVU). MATERIALS AND METHODS: Fifty consecutive patients underwent compression CT urography as part of a dedicated renal CT. A compression belt was applied prior to nephrographic phase imaging. Excretory phase scans were acquired through the kidneys 3 minutes post injection with the compression belt in place. The compression belt was then released, and scans were obtained through the ureters. Three independent readers then scored opacification of the collecting system and ureters on a scale of 0-2 (0 = no opacification, 1 = partial opacification, 2 = full opacification and distension). Fifty consecutive nonmatched IVUs were scored by segment by the same readers. Comparison of the two modalities was made using the Mann-Whitney U test. Interobserver agreement was assessed by the Kappa coefficient. RESULTS: CT demonstrated significantly better opacification (p < or = 0.02) of the upper and lower pole pelvicalyceal systems and midureters bilaterally. There was no difference in opacification of the proximal and distal ureters by CT compared with IVU. The Kappa coefficient was 0.53. CONCLUSIONS: Compression CT urography yields equal or better opacification of the collecting system and ureters when compared with IVU, and shows promise for the routine evaluation of the renal excretory system.

Authors
Heneghan, JP; Kim, DH; Leder, RA; DeLong, D; Nelson, RC
MLA Citation
Heneghan, JP, Kim, DH, Leder, RA, DeLong, D, and Nelson, RC. "Compression CT urography: a comparison with IVU in the opacification of the collecting system and ureters." J Comput Assist Tomogr 25.3 (May 2001): 343-347.
PMID
11351181
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
25
Issue
3
Publish Date
2001
Start Page
343
End Page
347

Breath-hold three-dimensional CT of the liver with multi-detector row helical CT.

PURPOSE: To compare image quality on transverse source images and coronal and sagittal reformations to determine the feasibility of using single-breath-hold three-dimensional liver computed tomography (CT) with multi-detector row helical CT in patients suspected of having hepatic metastases. MATERIALS AND METHODS: Fifty-three patients underwent the protocol. Coronal and sagittal reformations were constructed. Images were reviewed for duration of scan acquisition and length and adequacy of z-axis coverage. Reformations were scored for visualization of portal and hepatic vein branches, liver edge sharpness, cardiac pulsation and respiratory motion artifacts, noise due to mottle, and overall impression. RESULTS: Mean z-axis coverage was 207 mm +/- 33 (SD) (range, 145-280 mm), with a mean acquisition time of 10.96 seconds +/- 1.78 (range, 7.73-14.93 seconds). In 44 (83%) patients, the entire liver was imaged on a single helical scan. Artifact from cardiac motion was not identified on the transverse source images in any patient but was identified on coronal images in eight (15%) and on sagittal images in seven (13%). Similarly, noise due to mottle was not identified on the transverse source images but was identified on coronal images in seven (13%) patients and on sagittal images in six (11%). CONCLUSION: It is feasible to perform single-breath-hold three-dimensional liver CT with multi-detector row helical CT technology. Reformations provide a unique perspective with which to view the liver and may improve diagnostic capacity.

Authors
Wong, K; Paulson, EK; Nelson, RC
MLA Citation
Wong, K, Paulson, EK, and Nelson, RC. "Breath-hold three-dimensional CT of the liver with multi-detector row helical CT." Radiology 219.1 (April 2001): 75-79.
PMID
11274537
Source
pubmed
Published In
Radiology
Volume
219
Issue
1
Publish Date
2001
Start Page
75
End Page
79
DOI
10.1148/radiology.219.1.r01ap2475

An electronic device for needle placement during sonographically guided percutaneous intervention.

An electronic device for guiding needle placement during sonographically directed percutaneous intervention was tested in a phantom and then in patients. In the phantom, targeting accuracy was similar for use of the needle guide alone, the needle guide with the device, and freehand techniques with the device, but all were superior to the freehand technique alone (P <.001). In 34 (79%) of 43 patients, the device worked well.

Authors
Howard, MH; Nelson, RC; Paulson, EK; Kliewer, MA; Sheafor, DH
MLA Citation
Howard, MH, Nelson, RC, Paulson, EK, Kliewer, MA, and Sheafor, DH. "An electronic device for needle placement during sonographically guided percutaneous intervention." Radiology 218.3 (March 2001): 905-911.
PMID
11230674
Source
pubmed
Published In
Radiology
Volume
218
Issue
3
Publish Date
2001
Start Page
905
End Page
911
DOI
10.1148/radiology.218.3.r01mr10905

Three-dimensional CT of the genitourinary tract.

The applications of three-dimensional (3D) CT techniques encompass a spectrum from calculus disease to preoperative planning. With proper selection of display windows and levels, accurate measurement of stone size can be achieved, along with volumetric information. A CT scan with reconstruction may help guide the direction of an endopyelotomy incision away from crossing vessels. The benefits of 3D CT in the evaluation of living renal donors include lower cost and decreased patient morbidity. In renal allograft recipients and other patients, the study may be used to investigate hypertension. Also, 3D CT is invaluable in planning nephron-sparing surgery for renal masses. The ultimate role of this modality rests in the hands of clinicians who can benefit from them and the radiologists who must provide the high-quality images and the interpretive expertise.

Authors
Leder, RA; Nelson, RC
MLA Citation
Leder, RA, and Nelson, RC. "Three-dimensional CT of the genitourinary tract." J Endourol 15.1 (February 2001): 37-46. (Review)
PMID
11248918
Source
pubmed
Published In
Journal of Endourology
Volume
15
Issue
1
Publish Date
2001
Start Page
37
End Page
46
DOI
10.1089/08927790150500935

Nonenhanced helical CT and US in the emergency evaluation of patients with renal colic: prospective comparison.

PURPOSE: To compare nonenhanced helical computed tomography (CT) with ultrasonography (US) for the depiction of urolithiasis. MATERIALS AND METHODS: During 9 months, 45 patients (mean age, 44 years; mean weight, 92.5 kg) prospectively underwent both nonenhanced helical CT (5-mm collimation; pitch of 1.5) and US of the kidneys, ureters, and bladder. US evaluation included a careful search for ureteral calculi. Presence of calculi and obstruction and incidental diagnoses were recorded. Clinical, surgical, and/or imaging follow-up data were obtained in all patients. The McNemar test was used to compare groups. RESULTS: Diagnoses included 23 ureteral calculi and one each of renal cell carcinoma, appendicitis, ureteropelvic junction obstruction, renal subcapsular hematoma, cholelithiasis, medullary calcinosis, and myelolipoma. CT depicted 22 of 23 ureteral calculi (sensitivity, 96%). US depicted 14 of 23 ureteral calculi (sensitivity, 61%). Differences in sensitivity were statistically significant (P: =.02). Specificity for each technique was 100%. When modalities were compared for the detection of any clinically relevant abnormality (eg, unilateral hydronephrosis and/or urolithiasis in patients with an obstructing calculus), sensitivities of US and CT increased to 92% and 100%, respectively. One case of appendicitis was missed at US, whereas medullary calcinosis and myelolipoma were missed at CT. CONCLUSION: Nonenhanced CT has a higher sensitivity for the detection of ureteral calculi compared with US.

Authors
Sheafor, DH; Hertzberg, BS; Freed, KS; Carroll, BA; Keogan, MT; Paulson, EK; DeLong, DM; Nelson, RC
MLA Citation
Sheafor, DH, Hertzberg, BS, Freed, KS, Carroll, BA, Keogan, MT, Paulson, EK, DeLong, DM, and Nelson, RC. "Nonenhanced helical CT and US in the emergency evaluation of patients with renal colic: prospective comparison." Radiology 217.3 (December 2000): 792-797.
PMID
11110945
Source
pubmed
Published In
Radiology
Volume
217
Issue
3
Publish Date
2000
Start Page
792
End Page
797
DOI
10.1148/radiology.217.3.r00dc41792

Logistic advantages of four-section helical CT in the abdomen and pelvis.

BACKGROUND: Multisection helical computed tomography (CT) has the potential for providing data sets with better section profiles, more anatomic coverage, and shorter breath-holding periods. Our purpose was to quantitate these advantages in a clinical setting when imaging the abdomen and pelvis. METHODS: CT parameters including collimation, timing, z-axis coverage, and milliamperes were gathered retrospectively for the image set of both single-section (GE CT/i with 0.8-s rotation) and four-section (GE QX/i Lightspeed with 0.8-s rotation) helical CT scanners. Data were recorded for the abdomen and pelvis CT (n = 30 each), dual-phase liver CT including the pelvis (n = 15 each), and dual-phase pancreas CT (n = 15 each). RESULTS: The abdominal and pelvic CT averaged 128.4 +/- 5.4 s for single-section scanners (70-s delay, two breath-holds of 21.1 and 17. 7 s with a 19.5-s interscan delay) and 92.2 +/- 2.2 s for the four-section scanner (70-s delay and a 22.2-s breath-hold; p < 0. 0001). For the dual liver and pelvis CT, single-section scanners averaged 119.9 +/- 7.5 s (30-s delay, 15.8-s arterial phase, 20.0-s interscan delay, 21.2-s venous phase, 19.5-s interscan delay, and 14. 2 s for the remaining abdomen and pelvis), whereas the four-section scanner averaged 86.8 +/- 2.5 s (30-s delay, 6.7-s arterial phase, 27.9-s interscan delay, and 21.8-s venous phase including the pelvis; p < 0.0001). For the dual pancreas CT, single-section scanners averaged 86.7 +/- 2.5 s (20-s delay, 28.3-s arterial phase, 17.8-s interscan delay, 21.7-s venous phase), whereas the four-section scanner averaged 78.0 +/- 2.9 s (20-s delay, 9.7-s arterial phase, 30.7-s interscan delay, 13.0-s venous phase; p < 0. 0001). CONCLUSION: CT scanners having four-section technology can reduce overall data acquisition times by 10-30% and total milliamperes by 50-60% depending on the protocol with thinner slice profiles.

Authors
Killius, JS; Nelson, RC
MLA Citation
Killius, JS, and Nelson, RC. "Logistic advantages of four-section helical CT in the abdomen and pelvis." Abdom Imaging 25.6 (November 2000): 643-650.
PMID
11029100
Source
pubmed
Published In
Abdominal Imaging
Volume
25
Issue
6
Publish Date
2000
Start Page
643
End Page
650

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety).

The short-term safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast-enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 micromol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection-associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%) and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short-term risks from exposure to MnDPDP.

Authors
Federle, MP; Chezmar, JL; Rubin, DL; Weinreb, JC; Freeny, PC; Semelka, RC; Brown, JJ; Borello, JA; Lee, JK; Mattrey, R; Dachman, AH; Saini, S; Harmon, B; Fenstermacher, M; Pelsang, RE; Harms, SE; Mitchell, DG; Halford, HH; Anderson, MW; Johnson, CD; Francis, IR; Bova, JG; Kenney, PJ; Klippenstein, DL; Foster, GS; Turner, DA
MLA Citation
Federle, MP, Chezmar, JL, Rubin, DL, Weinreb, JC, Freeny, PC, Semelka, RC, Brown, JJ, Borello, JA, Lee, JK, Mattrey, R, Dachman, AH, Saini, S, Harmon, B, Fenstermacher, M, Pelsang, RE, Harms, SE, Mitchell, DG, Halford, HH, Anderson, MW, Johnson, CD, Francis, IR, Bova, JG, Kenney, PJ, Klippenstein, DL, Foster, GS, and Turner, DA. "Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: results of the U.S. multicenter phase III clinical trials (safety)." Journal of magnetic resonance imaging : JMRI 12.1 (July 2000): 186-197.
PMID
10931579
Source
epmc
Published In
Journal of Magnetic Resonance Imaging
Volume
12
Issue
1
Publish Date
2000
Start Page
186
End Page
197
DOI
10.1002/1522-2586(200007)12:1<186::aid-jmri21>3.0.co;2-2

MR cholangiopancreatography of bile and pancreatic duct abnormalities with emphasis on the single-shot fast spin-echo technique.

Magnetic resonance cholangiopancreatography (MRCP) is used for noninvasive work-up of patients with pancreaticobiliary disease. MRCP is comparable with invasive endoscopic retrograde cholangiopancreatography (ERCP) for diagnosis of extrahepatic bile duct abnormalities. In patients with choledocholithiasis, calculi appear as dark filling defects within the high-signal-intensity fluid at MRCP. Benign strictures due to sclerosing cholangitis are multifocal and alternate with slight dilatation or normal-caliber bile ducts, producing a beaded appearance. Dilatation of both the pancreatic and bile ducts at MRCP is highly suggestive of a pancreatic head malignancy. Side-branch ectasia is the most prominent and specific feature of chronic pancreatitis. MRCP is more sensitive than ERCP in detection of pancreatic pseudocysts because less than 50% of pseudocysts fill with contrast material. Because the mucin secreted by biliary cystadenomas and cystadenocarcinomas causes filling defects and partial obstruction of contrast material at ERCP, MRCP is potentially more accurate in demonstrating the extent of these tumors. In patients with biliary-enteric anastomoses, MRCP is the imaging modality of choice for the work-up of suspected pancreaticobiliary disease. A potential use of MRCP is the demonstration of aberrant bile duct anatomy before cholecystectomy. MRCP is also accurate in detection of pancreas divisum.

Authors
Vitellas, KM; Keogan, MT; Spritzer, CE; Nelson, RC
MLA Citation
Vitellas, KM, Keogan, MT, Spritzer, CE, and Nelson, RC. "MR cholangiopancreatography of bile and pancreatic duct abnormalities with emphasis on the single-shot fast spin-echo technique." Radiographics 20.4 (July 2000): 939-957. (Review)
PMID
10903685
Source
pubmed
Published In
Radiographics : a review publication of the Radiological Society of North America, Inc
Volume
20
Issue
4
Publish Date
2000
Start Page
939
End Page
957
DOI
10.1148/radiographics.20.4.g00jl23939

Radiologic manifestations of sclerosing cholangitis with emphasis on MR cholangiopancreatography.

Magnetic resonance cholangiopancreatography (MRCP) is a relatively new, noninvasive cholangiographic technique that is comparable with invasive endoscopic retrograde cholangiopancreatography (ERCP) in the detection and characterization of extrahepatic bile duct abnormalities. The role of MRCP in evaluation of the intrahepatic bile ducts, especially in patients with primary or secondary sclerosing cholangitis, is under investigation. The key cholangiographic features of primary sclerosing cholangitis are randomly distributed annular strictures out of proportion to upstream dilatation. As the fibrosing process worsens, strictures increase and the ducts become obliterated, and the peripheral ducts cannot be visualized to the periphery of the liver at ERCP. In addition, the acute angles formed with the central ducts become more obtuse. With further progression, strictures of the central ducts prevent peripheral ductal opacification at ERCP. Cholangiocarcinoma occurs in 10%-15% of patients with primary sclerosing cholangitis; cholangiographic features that suggest cholangiocarcinoma include irregular high-grade ductal narrowing with shouldered margins, rapid progression of strictures, marked ductal dilatation proximal to strictures, and polypoid lesions. Secondary sclerosing and nonsclerosing processes can mimic primary sclerosing cholangitis at cholangiography. These processes include ascending cholangitis, oriental cholangiohepatitis, acquired immunodeficiency syndrome-related cholangitis, chemotherapy-induced cholangitis, ischemic cholangitis after liver transplantation, eosinophilic cholangitis, and metastases.

Authors
Vitellas, KM; Keogan, MT; Freed, KS; Enns, RA; Spritzer, CE; Baillie, JM; Nelson, RC
MLA Citation
Vitellas, KM, Keogan, MT, Freed, KS, Enns, RA, Spritzer, CE, Baillie, JM, and Nelson, RC. "Radiologic manifestations of sclerosing cholangitis with emphasis on MR cholangiopancreatography." Radiographics 20.4 (July 2000): 959-975. (Review)
PMID
10903686
Source
pubmed
Published In
Radiographics : a review publication of the Radiological Society of North America, Inc
Volume
20
Issue
4
Publish Date
2000
Start Page
959
End Page
975
DOI
10.1148/radiographics.20.4.g00jl04959

Multislice helical CT to facilitate combined CT of the neck, chest, abdomen, and pelvis in children.

Authors
Donnelly, LF; Frush, DP; Nelson, RC
MLA Citation
Donnelly, LF, Frush, DP, and Nelson, RC. "Multislice helical CT to facilitate combined CT of the neck, chest, abdomen, and pelvis in children." AJR Am J Roentgenol 174.6 (June 2000): 1620-1622.
PMID
10845495
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
174
Issue
6
Publish Date
2000
Start Page
1620
End Page
1622
DOI
10.2214/ajr.174.6.1741620

Treatment of iatrogenic femoral arterial pseudoaneurysms: comparison of US-guided thrombin injection with compression repair.

PURPOSE: To evaluate and compare the treatment of iatrogenic femoral arterial pseudoaneurysms by using ultrasonographically (US) guided direct thrombin injection with US-guided compression repair. MATERIALS AND METHODS: Twenty-six patients with iatrogenic femoral arterial pseudoaneurysms were treated with direct thrombin injection. With US guidance, a 22-gauge needle was placed into the pseudoaneurysm flow lumen and thrombin (mean volume, 0.35 mL; range, 0.10-0.60 mL) was injected with continuous color Doppler US guidance. Demographics, clinical variables, pseudoaneurysm characteristics, and results in these patients were compared with those in 281 consecutive patients who underwent US-guided compression repair. RESULTS: The success rate of thrombin injection was 96% (25 of 26 patients), which was significantly higher than that of compression, 74% (209 of 281 patients) (P =.013). Twenty of 26 (77%) patients required a single injection, and six (23%) required two injections. Mean thrombosis time for thrombin injection was 6 seconds, compared with 41.5 minutes for compression. For thrombin injection, there were no complications, foot pulses did not change and no patients required conscious sedation. Follow-up US at 24 hours showed no recurrent pseudoaneurysms. CONCLUSION: For the treatment of iatrogenic femoral arterial pseudoaneurysms, thrombin injection with US guidance appears to be superior to compression repair.

Authors
Paulson, EK; Sheafor, DH; Kliewer, MA; Nelson, RC; Eisenberg, LB; Sebastian, MW; Sketch, MH
MLA Citation
Paulson, EK, Sheafor, DH, Kliewer, MA, Nelson, RC, Eisenberg, LB, Sebastian, MW, and Sketch, MH. "Treatment of iatrogenic femoral arterial pseudoaneurysms: comparison of US-guided thrombin injection with compression repair." Radiology 215.2 (May 2000): 403-408.
PMID
10796916
Source
pubmed
Published In
Radiology
Volume
215
Issue
2
Publish Date
2000
Start Page
403
End Page
408
DOI
10.1148/radiology.215.2.r00ap35403

Physician training requirements in sonography: how many cases are needed for competence?

OBJECTIVE: Physician competence in the performance of sonographic studies was assessed after their involvement in predetermined increments of cases to determine whether the case volumes currently required by the American Institute of Ultrasound in Medicine and the American College of Radiology for training in sonography can be lowered substantially. MATERIALS AND METHODS: Sonographic competence tests were administered to 10 first-year diagnostic radiology residents after their involvement in increments of 50 cases, up to a total of 200 cases (four competency tests). Each competency test consisted of the resident's independently scanning and interpreting 10 clinically mandated studies that were scored in comparison with the examination performed by the sonographer and interpreted by an attending radiologist. Trainee studies were graded on the percentage of anatomic landmarks depicted, the number of reporting errors, the number of clinically significant reporting errors, and the percentage of cases receiving a passing score. RESULTS: Although resident performance improved progressively with increasing experience for all parameters assessed, performance of the group was poor even after their involvement in 200 cases. At this testing level, the mean percentage of anatomic landmarks depicted successfully was 56.5%; the mean total reporting errors per case was 1.2; the mean clinically significant errors per case was 0.5; and the mean percentage of cases receiving a passing score was 16%. Impressive performance differences were observed among residents for all parameters assessed, and these differences were not explained by the number of months of radiology training the resident had taken before the sonography rotation. CONCLUSION: Involvement in 200 or fewer cases during the training period is not sufficient for physicians to develop an acceptable level of competence in sonography.

Authors
Hertzberg, BS; Kliewer, MA; Bowie, JD; Carroll, BA; DeLong, DH; Gray, L; Nelson, RC
MLA Citation
Hertzberg, BS, Kliewer, MA, Bowie, JD, Carroll, BA, DeLong, DH, Gray, L, and Nelson, RC. "Physician training requirements in sonography: how many cases are needed for competence?." AJR Am J Roentgenol 174.5 (May 2000): 1221-1227.
PMID
10789766
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
174
Issue
5
Publish Date
2000
Start Page
1221
End Page
1227
DOI
10.2214/ajr.174.5.1741221

Comparison of sonographic and CT guidance techniques: does CT fluoroscopy decrease procedure time?

OBJECTIVE: Procedure times for percutaneous biopsies were compared for various guidance techniques including helical CT, CT fluoroscopy, sonography with an attached needle guide, and freehand sonography with computer guidance. MATERIALS AND METHODS: Three interventional radiologists experienced in CT- and sonographically guided procedures performed biopsies on a phantom model. The phantom simulated hepatic metastases of various sizes and depths with subcostal or intercostal locations. Lesion sizes were 7, 10, and 20 mm, at 3- and 7-cm depths. Using self-aspirating needles, two passes were performed in each lesion. Mean procedure time per biopsy pass was calculated. A two-tailed Student's t test was used to compare guidance techniques. RESULTS: Mean procedure time per biopsy pass for the four guidance techniques was sonography with a needle guide, 36+/-9 sec; sonography with computer guidance, 43+/-10 sec; helical CT, 146+/-42 sec; and CT fluoroscopy, 50+/-18 sec. CT fluoroscopy required 2.6+/-1.0 sec per biopsy. Helical CT required more procedure time than sonography with a needle guide, CT with computer guidance, and CT fluoroscopy (p < 0.0001). Sonography with a needle guide required less procedure time than sonography with computer guidance (p < 0.002) and CT fluoroscopy (p = 0.0003). Procedure times for CT fluoroscopy and sonography with computer guidance were not statistically different (p = 0.06). CT and sonographic guidance were equally effective regardless of lesion size, depth, or location. CONCLUSION: Traditional sonographic biopsy techniques are faster and more cost-effective than traditional CT techniques; however, CT fluoroscopy offers the localization advantages of CT with improved procedure times.

Authors
Sheafor, DH; Paulson, EK; Kliewer, MA; DeLong, DM; Nelson, RC
MLA Citation
Sheafor, DH, Paulson, EK, Kliewer, MA, DeLong, DM, and Nelson, RC. "Comparison of sonographic and CT guidance techniques: does CT fluoroscopy decrease procedure time?." AJR Am J Roentgenol 174.4 (April 2000): 939-942.
PMID
10749226
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
174
Issue
4
Publish Date
2000
Start Page
939
End Page
942
DOI
10.2214/ajr.174.4.1740939

Hepatic parenchymal enhancement during triple-phase helical CT: can it be used to predict which patients with breast cancer will develop hepatic metastases?

PURPOSE: To evaluate the efficacy of hepatic enhancement characteristics for identification of patients with breast cancer who are at risk for future hepatic metastases. MATERIALS AND METHODS: Triple-phase helical computed tomography (CT) was performed in 60 patients with known breast cancer without visible hepatic metastases. Peak hepatic attenuation and enhancement, and attenuation and enhancement at 25 and 30 seconds were obtained. Ratios of hepatic attenuation or enhancement at 25 and 30 seconds to peak hepatic attenuation or enhancement were calculated. A Wilcoxon rank sum test was used to compare patients with and those without subsequent hepatic metastases. RESULTS: During a mean 18-month follow-up, 18 patients (30%) developed hepatic metastases. Decreases in peak hepatic attenuation and enhancement and increases in hepatic attenuation and enhancement ratios at 25 and 30 seconds were seen in patients who developed metastases compared with those who did not (P < .05). When corrected for chemotherapy interval, these differences were not statistically significant. Using a threshold value of 0.40 or more for the enhancement ratio at 30 seconds resulted in sensitivity of 28%, specificity of 92%, and accuracy of 55%. CONCLUSION: Patients with breast cancer who develop subsequent hepatic metastases have higher relative hepatic arterial perfusion during triple-phase CT; however, after correction for chemotherapy interval, this difference was not statistically significant. Threshold values cannot be used reliably to identify patients who will develop metastases.

Authors
Sheafor, DH; Killius, JS; Paulson, EK; DeLong, DM; Foti, AM; Nelson, RC
MLA Citation
Sheafor, DH, Killius, JS, Paulson, EK, DeLong, DM, Foti, AM, and Nelson, RC. "Hepatic parenchymal enhancement during triple-phase helical CT: can it be used to predict which patients with breast cancer will develop hepatic metastases?." Radiology 214.3 (March 2000): 875-880.
PMID
10715061
Source
pubmed
Published In
Radiology
Volume
214
Issue
3
Publish Date
2000
Start Page
875
End Page
880
DOI
10.1148/radiology.214.3.r00mr36875

Helical CT cholangiography with three-dimensional volume rendering using an oral biliary contrast agent: feasibility of a novel technique.

OBJECTIVE: We evaluated the feasibility and image quality of a new noninvasive biliary imaging technique: helical CT cholangiography with three-dimensional volume rendering using an oral biliary contrast agent. SUBJECTS AND METHODS: Nineteen subjects including five healthy volunteers and 14 patients underwent helical CT cholangiography. Subjects ingested 6.0 g of iopanoic acid 6-10 hr before undergoing imaging. Axial data were used to construct three-dimensional volume-rendered cholangiograms. Two radiologists, an endoscopist, and a laparoscopic surgeon reviewed the images and evaluated overall image quality. In the 14 patients, findings from CT cholangiography were compared with those from ERCP, surgery, and intraoperative cholangiography. RESULTS: All segments of the biliary tree were opacified in all volunteers except one, in whom the intrahepatic ducts were not opacified. Image quality was good to excellent in all volunteers. Anomalous cystic duct insertions were seen in two volunteers. Opacification of the biliary tree was rated as acceptable to excellent in nine patients and suboptimal in five. In five patients with good or excellent opacification, the biliary anatomy correlated with findings on intraoperative cholangiography or ERCP. CT cholangiography revealed additional conditions (gallbladder varices and acute pancreatitis) and variant anatomy in three patients. CONCLUSION: Results of this pilot project suggest that obtaining CT cholangiograms using an oral biliary contrast agent is a feasible, noninvasive method for revealing biliary anatomy. However, visualization of the biliary tree was suboptimal in 36% of the patients, which represents a limitation of this technique.

Authors
Caoili, EM; Paulson, EK; Heyneman, LE; Branch, MS; Eubanks, WS; Nelson, RC
MLA Citation
Caoili, EM, Paulson, EK, Heyneman, LE, Branch, MS, Eubanks, WS, and Nelson, RC. "Helical CT cholangiography with three-dimensional volume rendering using an oral biliary contrast agent: feasibility of a novel technique." AJR Am J Roentgenol 174.2 (February 2000): 487-492.
PMID
10658729
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
174
Issue
2
Publish Date
2000
Start Page
487
End Page
492
DOI
10.2214/ajr.174.2.1740487

Evaluation of pseudoenhancement of renal cysts during contrast-enhanced CT.

OBJECTIVE: The purpose of our study was to evaluate renal cyst pseudoenhancement during helical CT in a phantom model and in patients. MATERIALS AND METHODS: Iodine baths containing water-filled spheres and cylinders were constructed to simulate cysts in enhancing renal parenchyma. Iodine concentration, cyst size and location, collimation, and peak kilovoltage were varied and cyst attenuation was measured. Data were analyzed with the mixed linear models and Mantel-Haenszel tests. Subsequently, a paired t test compared CT attenuation values before and after contrast material enhancement in 40 patients with 68 renal cysts (radiographic stability >3 months). RESULTS: The attenuation values of phantom cysts increased when placed in a contrast media bath (p = 0.001). The increase in attenuation values became more pronounced with increasing iodine concentrations, decreasing peak kilovoltage, and smaller sphere sizes. In patients, mean cyst attenuation increased 3.4 +/- 6.2 H after administration of contrast material (p = 0.00002). The attenuation did not increase more than 10 H in any of the 37 cysts larger than 2 cm found in patients. Eight (26%) of the 31 cysts smaller than 2 cm found in patients increased by at least 10 H. CONCLUSION: In a phantom model, at simulated physiologic levels of renal enhancement, cysts may pseudoenhance by more than 10 H. Similarly, in patients, cysts may also pseudoenhance; however, most pseudoenhancement does not exceed 10 H. In patients, pseudoenhancement of at least 10 H is more likely in cysts smaller than 2 cm.

Authors
Coulam, CH; Sheafor, DH; Leder, RA; Paulson, EK; DeLong, DM; Nelson, RC
MLA Citation
Coulam, CH, Sheafor, DH, Leder, RA, Paulson, EK, DeLong, DM, and Nelson, RC. "Evaluation of pseudoenhancement of renal cysts during contrast-enhanced CT." AJR Am J Roentgenol 174.2 (February 2000): 493-498.
PMID
10658730
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
174
Issue
2
Publish Date
2000
Start Page
493
End Page
498
DOI
10.2214/ajr.174.2.1740493

Retrodisplaced gallbladder detected on hepatobiliary scintigraphy.

Authors
Hanson, MW; Nielsen, RB; Davey, IC; Nelson, RC
MLA Citation
Hanson, MW, Nielsen, RB, Davey, IC, and Nelson, RC. "Retrodisplaced gallbladder detected on hepatobiliary scintigraphy." Clin Nucl Med 25.1 (January 2000): 57-59.
PMID
10634535
Source
pubmed
Published In
Clinical Nuclear Medicine
Volume
25
Issue
1
Publish Date
2000
Start Page
57
End Page
59

Pelvic CT morphometry in Down syndrome: implications for prenatal US evaluation--preliminary results.

PURPOSE: To characterize pelvic morphometric differences in patients with and those without Down syndrome by using computed tomography (CT) and to determine useful indexes for ultrasonographic (US) evaluation. MATERIALS AND METHODS: Pelvic CT scans in seven patients with Down syndrome and in 27 patients without Down syndrome were reviewed. Iliac angle, iliac length, sacroiliac joint angle, and anterior iliac wing separation were measured at superior, middle, and inferior transverse sacral levels. The effects of chromosomal status and transverse level were evaluated statistically. RESULTS: Significant differences were found for mean iliac angle (P < .007) and length (P < .005) between patients without Down syndrome (angle, 75 degrees; length, 8.4 cm) and those with Down syndrome (angle, 82 degrees; length, 7.5 cm). Depending on the level of measurement, variations in iliac angle between patients without and those with Down syndrome were as much as 13 degrees and 15 degrees, respectively, and variations in length were as much as 1.6 cm and 0.9 cm, respectively. The greatest differences were at the middle sacral level. Sacroiliac joint angle and the anterior iliac wing separation were not different between groups. CONCLUSION: Patients with Down syndrome had a larger mean iliac angle and a shorter mean iliac length. The most pronounced differences were at the middle sacral level, which suggests that this may be the optimal level for measuring these parameters at prenatal US.

Authors
Freed, KS; Kliewer, MA; Hertzberg, BS; DeLong, DM; Paulson, EK; Nelson, RC
MLA Citation
Freed, KS, Kliewer, MA, Hertzberg, BS, DeLong, DM, Paulson, EK, and Nelson, RC. "Pelvic CT morphometry in Down syndrome: implications for prenatal US evaluation--preliminary results." Radiology 214.1 (January 2000): 205-208.
PMID
10644125
Source
pubmed
Published In
Radiology
Volume
214
Issue
1
Publish Date
2000
Start Page
205
End Page
208
DOI
10.1148/radiology.214.1.r00dc32205

Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: Results of the U.S. Multicenter phase III clinical trials (safety)

The short-term1 safety of mangafodipir trisodium (MnDPDP) injection was studied in 546 adults with known or suspected focal liver lesions. An initial contrast-enhanced computed tomography examination was followed by unenhanced magnetic resonance imaging (MRI), injection of MnDPDP (5 μmol/kg), and enhanced MRI. Adverse events were reported for 23% of the patients; most were mild to moderate in intensity, did not require treatment, and were not drug related. The most commonly reported adverse events were nausea (7%) and headache (4%). The incidence of serious adverse events was low (nine events in six patients) and not drug related. Injection-associated discomfort was reported for 69% of the patients, and the most commonly reported discomforts included heat (49%] and flushing (33%). Changes in laboratory values and vital signs were generally transient, were not clinically significant, and did not require treatment. There were no clinically significant short-term risks from exposure to MnDPDP. (C) 2000 Wiley-Liss, Inc.

Authors
Federle, MP; Chezmar, JL; Rubin, DL; Weinreb, JC; Freeny, PC; Semelka, RC; Brown, JJ; Borrello, JA; Lee, JKT; Mattrey, R; Dachman, AH; Saini, S; Harmon, B; Fenstermacher, M; Pelsang, RE; Harms, SE; Mitchell, DG; III, HHH; Anderson, MW; Johnson, CD; Francis, IR; Bova, JG; Kenney, PJ; Klippenstein, DL; Foster, GS; Turner, DA; Stillman, AE; Nelson, RC; Young, SW; Patt, RH; Rifkin, M; Seltzer, SE; Gay, SB; Robison, RO; Sherwin, PF; Ballerini, R
MLA Citation
Federle, MP, Chezmar, JL, Rubin, DL, Weinreb, JC, Freeny, PC, Semelka, RC, Brown, JJ, Borrello, JA, Lee, JKT, Mattrey, R, Dachman, AH, Saini, S, Harmon, B, Fenstermacher, M, Pelsang, RE, Harms, SE, Mitchell, DG, III, HHH, Anderson, MW, Johnson, CD, Francis, IR, Bova, JG, Kenney, PJ, Klippenstein, DL, Foster, GS, Turner, DA, Stillman, AE, Nelson, RC, Young, SW, Patt, RH, Rifkin, M, Seltzer, SE, Gay, SB, Robison, RO, Sherwin, PF, and Ballerini, R. "Safety and efficacy of mangafodipir trisodium (MnDPDP) injection for hepatic MRI in adults: Results of the U.S. Multicenter phase III clinical trials (safety)." Journal of Magnetic Resonance Imaging 12.1 (2000): 186-197.
Source
scival
Published In
Journal of Magnetic Resonance Imaging
Volume
12
Issue
1
Publish Date
2000
Start Page
186
End Page
197
DOI
10.1002/1522-2586(200007)12:1<186::AID-JMRI21>3.0.CO;2-2

Percutaneous liver biopsy: a cost-benefit analysis comparing sonographic and CT guidance.

OBJECTIVE: We compared the relative cost of a liver biopsy performed with sonographic guidance with that of one performed with CT guidance in a cost-benefit analysis model. MATERIALS AND METHODS: Variables were estimated from a search of the literature and from clinical experience with 437 hepatic biopsies at our institution. Probability variables included the probability of obtaining an adequate sample and the probability of a major complication. Cost variables included the direct and indirect costs, the cost of a major complication, and the opportunity costs of foregone revenue from preempted diagnostic studies. One-way and two-way sensitivity analyses were performed. RESULTS: Using baseline values, CT guidance was 1.89 times more expensive than sonographic guidance. Sensitivity analyses indicate that CT and sonographic guidance costs would be equivalent if the success rate with sonographic guidance was 39.8%, the opportunity costs of CT guidance were 3.13 times less than best estimates, and the opportunity costs of sonography were 3.15 times greater than best estimates. CONCLUSION: Sonographic guidance for hepatic biopsies is substantially more economical than CT guidance across a wide range of estimated costs.

Authors
Kliewer, MA; Sheafor, DH; Paulson, EK; Helsper, RS; Hertzberg, BS; Nelson, RC
MLA Citation
Kliewer, MA, Sheafor, DH, Paulson, EK, Helsper, RS, Hertzberg, BS, and Nelson, RC. "Percutaneous liver biopsy: a cost-benefit analysis comparing sonographic and CT guidance." AJR Am J Roentgenol 173.5 (November 1999): 1199-1202.
PMID
10541088
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
173
Issue
5
Publish Date
1999
Start Page
1199
End Page
1202
DOI
10.2214/ajr.173.5.10541088

PACS in sonography: accuracy of interpretation using film compared with monitor display. Picture archiving and communication systems.

OBJECTIVE: The goal of this study was to determine the relative accuracy of interpretation of sonography when viewed on a monitor or on film. MATERIALS AND METHODS: Four radiologists twice interpreted a series of 440 sonograms using the following sequences of display formats for initial and second interpretations: film-film, film-monitor, monitor-film, and monitor-monitor. Reporting discrepancies between the initial and subsequent interpretation were reviewed by an arbitration panel unaware of the display mode. Results were analyzed for differences in error rate attributable to film versus monitor display format, chronology of interpretation, individual observer, and observer seniority. RESULTS: We found no statistically significant difference in the error rate for film (10.3%) versus monitor display format (14.6%) (p = .09). Likewise, we found no significant differences in the error rates attributable to chronology of interpretation (p = .13), individual observer (p = .54), or observer seniority (p = .87). CONCLUSION: Interpretative accuracy is similar whether sonograms are interpreted on a monitor or on film.

Authors
Hertzberg, BS; Kliewer, MA; Paulson, EK; Sheafor, DH; Freed, KS; Bowie, JD; Carroll, BA; DeLong, DH; Nelson, RC
MLA Citation
Hertzberg, BS, Kliewer, MA, Paulson, EK, Sheafor, DH, Freed, KS, Bowie, JD, Carroll, BA, DeLong, DH, and Nelson, RC. "PACS in sonography: accuracy of interpretation using film compared with monitor display. Picture archiving and communication systems." AJR Am J Roentgenol 173.5 (November 1999): 1175-1179.
PMID
10541084
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
173
Issue
5
Publish Date
1999
Start Page
1175
End Page
1179
DOI
10.2214/ajr.173.5.10541084

Activated lymphocytes promote endothelial cell detachment from matrix: a role for modulation of endothelial cell beta 1 integrin affinity.

In vivo, MHC class I-restricted injury of allogeneic tissue or cells infected by intracellular pathogens occurs in the absence of classical cytolytic effector mechanisms and Ab. Modulation of the target cell adhesion to matrix may be an additional mechanism used to injure vascular or epithelial cells in inflammation. We studied the mechanisms of human umbilical vein endothelial cell (EC) detachment from matrix-coated plastic following contact by concanamycin A-treated lymphocytes as an in vitro model of perforin-independent modulation of EC basement membrane adhesion. Human PBL were depleted of monocytes, stimulated, then added to an EC monolayer plated on either fibronectin or type I collagen matrices. Activated, but not resting, PBL induced progressive EC detachment from the underlying matrix. Injury of the EC monolayer required direct cell contact with the activated lymphocytes because no detachment was seen when the PBL were placed above a Transwell membrane. Moreover plasma membranes prepared from activated but not resting PBL induced EC detachment. Adherent EC stimulated with activated PBL did not show evidence of apoptosis using TUNEL and annexin V staining at time points before EC detachment was observed. Finally, neither the matrix metalloproteinase inhibitors o-phenanthroline and BB-94 nor aprotinin blocked EC detachment. However, activation of EC beta1 integrin using mAb TS2/16 or Mg2+ decreased EC detachment. These data indicate that cell-cell contact between activated PBL and EC reduces adhesion of EC to the underlying matrix, at least in part by inducing changes in the affinity of the endothelial beta 1 integrin.

Authors
Phan, C; McMahon, AW; Nelson, RC; Elliott, JF; Murray, AG
MLA Citation
Phan, C, McMahon, AW, Nelson, RC, Elliott, JF, and Murray, AG. "Activated lymphocytes promote endothelial cell detachment from matrix: a role for modulation of endothelial cell beta 1 integrin affinity." J Immunol 163.8 (October 15, 1999): 4557-4563.
PMID
10510399
Source
pubmed
Published In
Journal of immunology (Baltimore, Md. : 1950)
Volume
163
Issue
8
Publish Date
1999
Start Page
4557
End Page
4563

Multiple fluid collections: CT- or US-guided aspiration--evaluation of microbiologic results and implications for clinical practice.

PURPOSE: To determine if patients with multiple fluid collections need every collection aspirated and if cross-contamination is a risk if separate sterile procedures are not followed for each aspiration. MATERIALS AND METHODS: Records from 1,076 imaging-guided percutaneous aspirations and drainages over 39 months were retrospectively reviewed; 124 patients had multiple fluid collections drained, which yielded 287 aspirates. The patients were divided into two groups: those (n = 82) with multiple collections aspirated on any 1 day, and those (n = 61) with multiple collections aspirated over 10 days. Nineteen patients were included in both groups. Gram stain microscopy and culture results were compared between sequential aspirates in each patient, and their potential effects on antimicrobial therapy and theoretic risk for cross-contamination were evaluated. RESULTS: In 82 patients undergoing multiple aspirations on any 1 day, multiple microorganisms differed in 32 patients, which indicated a need for therapy change in 18 (22%) patients. In 61 patients undergoing aspiration on different days, microorganisms differed in 32 patients, which indicated a need for therapy change in 15 (25%) patients. Cross-contamination could have occurred in 28 of 93 (30%) aspirates from patients with a second or subsequent collection if separate sterile procedures had not been undertaken. CONCLUSION: When multiple fluid collections are identified, aspirates from all collections should be obtained through separate sterile procedures to ensure optimal antimicrobial coverage and avoid cross-contamination.

Authors
Heneghan, JP; Everts, RJ; Nelson, RC
MLA Citation
Heneghan, JP, Everts, RJ, and Nelson, RC. "Multiple fluid collections: CT- or US-guided aspiration--evaluation of microbiologic results and implications for clinical practice." Radiology 212.3 (September 1999): 669-672.
PMID
10478230
Source
pubmed
Published In
Radiology
Volume
212
Issue
3
Publish Date
1999
Start Page
669
End Page
672
DOI
10.1148/radiology.212.3.r99se25669

The oblique pharyngogram: value in the assessment of dysphagia.

BACKGROUND: To evaluate the diagnostic value of oblique views of the pharynx in patients with dysphagia. METHODS: One hundred thirty-three patients with symptoms referable to the cervical region underwent pharyngoesophography that included views of the pharyngoesophageal junction filmed at three frames per second and spot films of the pharynx obtained in distended frontal, lateral, and both oblique projections. Examination was completed with assessment of the entire esophagus and gastric cardia. RESULTS: The oblique views identified abnormalities not shown on the standard views in 5% of patients. The oblique views proved useful in 12%, where the lower pharynx was obscured in the lateral projection by large shoulders, and in 18% to assess the valleculae when this region was obscured by the occiput and mandible in the frontal projection. In 12%, the oblique views proved useful in demonstrating normal structures when artifacts raised the possibility of lesions on the standard projections. In 10%, poor technique impaired visualization of pharyngeal structures on the standard projections, but repeat swallows in the oblique projections proved adequate to assess these regions. Three (27%) of the 11 cases of cervical esophageal webs were best seen on oblique views, and in another three patients the webs were visible only on oblique views. CONCLUSIONS: Oblique views are of value in the assessment of the pharynx. There will be instances when the standard projections are inadequate, and these alternative views will complement the evaluation of this region. The addition of oblique views will sometimes improve the confidence of the interpretation of normality or assist evaluation of the extent of an abnormality.

Authors
Low, VH; Sitarik, KM; Frederick, MG; Nelson, RC
MLA Citation
Low, VH, Sitarik, KM, Frederick, MG, and Nelson, RC. "The oblique pharyngogram: value in the assessment of dysphagia." Abdom Imaging 24.5 (September 1999): 437-443.
PMID
10475922
Source
pubmed
Published In
Abdominal Imaging
Volume
24
Issue
5
Publish Date
1999
Start Page
437
End Page
443

Indeterminate findings on imaging-guided biopsy: should additional intervention be pursued?

OBJECTIVE: Our purpose was to determine the outcome of patients in whom the results of imaging-guided biopsies were indeterminate and to examine factors that may affect outcome. MATERIALS AND METHODS: During a 25-month period, 619 consecutive imaging-guided biopsies (CT, n = 268 [43%]; sonography, n = 351 [57%]) were performed on abdominal lesions. Of these biopsies, findings from 454 biopsies (73%) were positive for malignancy, findings from 21 biopsies (3%) yielded a benign diagnosis, and findings from 15 biopsies (2%) were nondiagnostic. Findings from the remaining 129 biopsies (21%) were considered indeterminate because the pathologic diagnosis revealed benign tissue, inflammation, stromal elements, or atypical cells. The frequency of malignancy in lesions of patients in this indeterminate group was determined. RESULTS: Thirty-eight of the 129 patients were lost to follow-up. Of the remaining 91 patients, 55 (60%) had true-negative (benign) results, and 36 (40%) had false-negative (malignant) results. A history of malignancy had no significant effect on the true- or false-negative rate (p = .799). However, the guidance technique had a statistically significant effect: CT and sonographic guidance yielded 25 (49%) and 11 (28%) false-negative results, respectively (p = .037). The number of needle passes, needle type and gauge, and biopsy site did not have a statistically significant correlation with the false-negative rate. The presence of atypical cells in the cytologic aspirate was highly predictive, with a 71% false-negative rate (p = .008). CONCLUSION: We found a high incidence of malignancy (40%) in lesions deemed indeterminate at the time of biopsy. Thus, close follow-up or additional intervention should be pursued in such cases. Sonographic guidance resulted in a statistically significant decrease in the false-negative rate when compared with CT guidance; however, a history of malignancy, the biopsy site, the needle gauge and type, and the number of passes did not have a significant effect on the false-negative rate.

Authors
Dameron, RD; deLong, DM; Fisher, AJ; DeLong, DM; Dodd, LG; Nelson, RC
MLA Citation
Dameron, RD, deLong, DM, Fisher, AJ, DeLong, DM, Dodd, LG, and Nelson, RC. "Indeterminate findings on imaging-guided biopsy: should additional intervention be pursued?." AJR Am J Roentgenol 173.2 (August 1999): 461-464.
PMID
10430154
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
173
Issue
2
Publish Date
1999
Start Page
461
End Page
464
DOI
10.2214/ajr.173.2.10430154

Extravasation detection accessory: clinical evaluation in 500 patients.

PURPOSE: To assess the ability of an extravasation detection accessory (EDA) to detect clinically important (> or = 10 mL) extravascular injection of iodinated contrast material delivered with an automated power injector. MATERIALS AND METHODS: Five hundred patients referred for contrast material-enhanced body computed tomography (CT) participated in a prospective, multi-institutional, observational study in which the EDA was used to identify and interrupt any injection associated with clinically important extravasation. The presence or absence of extravasation was definitively established with helical CT at the injection site (injection rate, from 1.0 to 5.0 mL/sec; mean, 2.9 mL/sec; median, 3.0 mL/sec). RESULTS: There were four true-positive (extravasation volumes, 13-18 mL), 484 true-negative, 12 false-positive, and no false-negative cases. The prevalence of overall and clinically important (> or = 10 mL) extravasation was 3.6% (18 of 500 cases) and 0.8% (four of 500 cases), respectively. The EDA had a sensitivity of 100% (four of four cases; 95% CI: 51%, 100%) and a specificity of 98% (484 of 496 cases; 95% CI: 96%, 99%) in the detection of clinically important extravasation. CONCLUSION: The EDA is easy to use, safe, and accurate in the monitoring of intravenous injections for extravasation, which could prove especially useful in high-flow-rate CT applications.

Authors
Birnbaum, BA; Nelson, RC; Chezmar, JL; Glick, SN
MLA Citation
Birnbaum, BA, Nelson, RC, Chezmar, JL, and Glick, SN. "Extravasation detection accessory: clinical evaluation in 500 patients." Radiology 212.2 (August 1999): 431-438.
PMID
10429700
Source
pubmed
Published In
Radiology
Volume
212
Issue
2
Publish Date
1999
Start Page
431
End Page
438
DOI
10.1148/radiology.212.2.r99au14431

Fine-needle aspiration with flow cytometric immunophenotyping for primary diagnosis of intra-abdominal lymphomas.

Cytomorphology in conjunction with immunophenotypic characterization is becoming increasingly used for the primary diagnosis of non-Hodgkin's lymphomas (NHL). This combination is especially advantageous for the diagnosis of intra-abdominal and intrathoracic lymphomas, since unlike superficial lesions, open biopsy of deep-seated tissues is more invasive and more costly, and is associated with a higher risk. We report the cytologic and immunophenotypic features of intra-abdominal NHL obtained by fine-needle aspiration (FNA). Twenty-two cases of intra-abdominal lesions obtained by image-guided FNA where flow cytometry was also performed were reviewed. Of the 22 studied cases, 7 were classified as large-cell lymphoma, 5 as follicular center-cell lymphoma, 2 as small noncleaved-cell lymphoma, 2 as lymphoplasmacytoid lymphoma, one as small lymphocytic lymphoma, and one as marginal-zone lymphoma. In the remaining 4 cases where the immunophenotypic pattern was not definitive, the cytomorphologic features were of small cleaved cells in 3 cases and of mixed small cleaved and large cells in one case. We successfully classified 9 of the 10 patients on whom histologic confirmation was obtained. The successful primary classification of most intra-abdominal non-Hodgkin's lymphomas can be done with a combination of cytology and flow cytometry, and this can be the initial approach in patients with deep-seated lesions. Diagn. Cytopathol. 1999;21:98-104.

Authors
Liu, K; Mann, KP; Vitellas, KM; Paulson, EK; Nelson, RC; Gockerman, JP; Dodd, LG
MLA Citation
Liu, K, Mann, KP, Vitellas, KM, Paulson, EK, Nelson, RC, Gockerman, JP, and Dodd, LG. "Fine-needle aspiration with flow cytometric immunophenotyping for primary diagnosis of intra-abdominal lymphomas." Diagn Cytopathol 21.2 (August 1999): 98-104.
PMID
10425046
Source
pubmed
Published In
Diagnostic Cytopathology
Volume
21
Issue
2
Publish Date
1999
Start Page
98
End Page
104

Imaging-guided percutaneous biopsy of focal splenic lesions: update on safety and effectiveness.

OBJECTIVE: The purpose of this study is to determine the safety and effectiveness of percutaneous imaging-guided biopsy in the diagnosis of focal splenic lesions. MATERIALS AND METHODS: From May 1995 to November 1997, 20 imaging-guided biopsies of focal splenic lesions were performed in 18 patients, including seven patients with a prior diagnosis of extrasplenic malignancy (breast cancer, n = 3; lymphoma, n = 2; ovarian cancer, n = 1; and osteogenic sarcoma, n = 1), three immunosuppressed patients (cause of immunosuppression: AIDS, n = 1; liver transplantation, n = 1; and bone marrow transplantation, n = 1), two patients with anemia, one patient with a recent history of IV drug abuse, and five patients with incidentally discovered splenic lesions. Biopsies were performed with an 18-gauge (n = 1), a 20-gauge (n = 8), or a 22-gauge (n = 14) self-aspirating needle or an 18-gauge cutting needle (n = 1). Biopsies were considered successful if a specific diagnosis of benign or malignant disease was made. RESULTS: A specific diagnosis was made in 16 (88.9%) of 18 patients, and no complications occurred. Malignancy was diagnosed in six patients including three patients with lymphoma. Benign conditions were diagnosed in 10 patients: a cyst in two patients; hamartoma in one; lipogranuloma in one; infarct in one; and infection in four, including one case each of Candida albicans, Pneumocystis carinii, Mycobacterium tuberculosis, and mixed flora. The tenth benign diagnosis was a pseudotumor of the spleen related to a bulbous tail of the pancreas that was inseparable from the splenic hilum. Biopsy did not establish a diagnosis in one patient with lymphoma and in one patient with presumed splenic candidiasis. A mean of 1.5 needle passes was made per biopsy. CONCLUSION: Imaging-guided splenic biopsy is a safe technique that provides a specific diagnosis in most patients with focal splenic lesions.

Authors
Keogan, MT; Freed, KS; Paulson, EK; Nelson, RC; Dodd, LG
MLA Citation
Keogan, MT, Freed, KS, Paulson, EK, Nelson, RC, and Dodd, LG. "Imaging-guided percutaneous biopsy of focal splenic lesions: update on safety and effectiveness." AJR Am J Roentgenol 172.4 (April 1999): 933-937.
PMID
10587123
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
172
Issue
4
Publish Date
1999
Start Page
933
End Page
937
DOI
10.2214/ajr.172.4.10587123

With proper imaging technique, is it still necessary to obtain images of the liver before administering contrast material in patients with known tumors who can have hypervascular liver metastases?

Authors
Sheafor, DH; Nelson, RC
MLA Citation
Sheafor, DH, and Nelson, RC. "With proper imaging technique, is it still necessary to obtain images of the liver before administering contrast material in patients with known tumors who can have hypervascular liver metastases?." AJR Am J Roentgenol 172.4 (April 1999): 1135-1136.
PMID
10587163
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
172
Issue
4
Publish Date
1999
Start Page
1135
End Page
1136
DOI
10.2214/ajr.172.4.10587163

Comparison of unenhanced, hepatic arterial-dominant, and portal venous-dominant phase helical CT for the detection of liver metastases in women with breast carcinoma.

OBJECTIVE: The purpose of this study was to evaluate triple-phase helical CT for detection of hepatic metastases from breast carcinoma. SUBJECTS AND METHODS: Breast cancer patients were studied prospectively with triple-phase helical CT in 300 consecutive examinations. Hepatic arterial-dominant and portal venous-dominant phase scans were initiated at 20 and 65 sec, respectively, after IV injection of 175 ml of iopamidol (30 mg/ml) at 5 ml/sec. Three independent observers each reviewed 200 cases of the portal venous-dominant phase for lesion number, conspicuity, and attenuation. Subsequently, portal venous-dominant phase images were reevaluated in conjunction with hepatic arterial-dominant phase or unenhanced images. RESULTS: Hepatic metastases were identified in 79 (26%) of 300 cases. Lesions detected on portal venous-dominant, hepatic arterial-dominant, and unenhanced images were as follows: observer 1, n = 198, 164, and 171; observer 2, n = 254, 233, and 233; and observer 3, n = 291, 270, and 276 (p > .05). The mean total lesion count was 387, with more lesions detected on portal venous-dominant phase than on either hepatic arterial-dominant phase or unenhanced images (p < .001 and p < .0001, respectively). For individual observers, 10-26% of lesions were hypervascular on hepatic arterial-dominant phase images. Two to 4% of lesions were identified only on hepatic arterial-dominant phase or unenhanced images. However, in these few cases, the lesions either were false-positives or were seen in conjunction with additional metastases on portal venous-dominant images. CONCLUSION: Routine use of triple-phase CT in patients with breast carcinoma may not be warranted: Addition of the hepatic arterial-dominant phase or unenhanced images revealed few additional lesions in our group of 300 patients.

Authors
Sheafor, DH; Frederick, MG; Paulson, EK; Keogan, MT; DeLong, DM; Nelson, RC
MLA Citation
Sheafor, DH, Frederick, MG, Paulson, EK, Keogan, MT, DeLong, DM, and Nelson, RC. "Comparison of unenhanced, hepatic arterial-dominant, and portal venous-dominant phase helical CT for the detection of liver metastases in women with breast carcinoma." AJR Am J Roentgenol 172.4 (April 1999): 961-968.
PMID
10587129
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
172
Issue
4
Publish Date
1999
Start Page
961
End Page
968
DOI
10.2214/ajr.172.4.10587129

Magnetic resonance cholangiography: Diagnostic imaging modality of choice in primary sclerosing cholangitis?

Authors
Enns, RA; Vitellas, K; Eloubeidi, MA; Mergener, K; Jowell, PS; Branch, MS; Trotter, JF; Keogan, MT; Freed, KS; Nelson, RC; Baillie, J
MLA Citation
Enns, RA, Vitellas, K, Eloubeidi, MA, Mergener, K, Jowell, PS, Branch, MS, Trotter, JF, Keogan, MT, Freed, KS, Nelson, RC, and Baillie, J. "Magnetic resonance cholangiography: Diagnostic imaging modality of choice in primary sclerosing cholangitis?." GASTROINTESTINAL ENDOSCOPY 49.4 (April 1999): AB216-AB216.
Source
wos-lite
Published In
Gastrointestinal Endoscopy
Volume
49
Issue
4
Publish Date
1999
Start Page
AB216
End Page
AB216

Magnetic resonance cholangiography: Inter-observer agreement in sclerosing cholangitis

Authors
Enns, RA; Eloubeidi, MA; Vitellas, K; Mergener, K; Jowell, PS; Branch, MS; Trotter, JF; Keogan, MT; Freed, KS; Nelson, RC; Baillie, J
MLA Citation
Enns, RA, Eloubeidi, MA, Vitellas, K, Mergener, K, Jowell, PS, Branch, MS, Trotter, JF, Keogan, MT, Freed, KS, Nelson, RC, and Baillie, J. "Magnetic resonance cholangiography: Inter-observer agreement in sclerosing cholangitis." GASTROINTESTINAL ENDOSCOPY 49.4 (April 1999): AB155-AB155.
Source
wos-lite
Published In
Gastrointestinal Endoscopy
Volume
49
Issue
4
Publish Date
1999
Start Page
AB155
End Page
AB155

The introduction of helical CT has allowed imaging of the liver earlier during the arterial phase. With proper imaging technique, is it still necessary to obtain images of the liver before administering contrast material in patients with known tumors who can have hypervascular liver metastases?

Authors
Sheafor, DH; Nelson, RC
MLA Citation
Sheafor, DH, and Nelson, RC. "The introduction of helical CT has allowed imaging of the liver earlier during the arterial phase. With proper imaging technique, is it still necessary to obtain images of the liver before administering contrast material in patients with known tumors who can have hypervascular liver metastases?." AMERICAN JOURNAL OF ROENTGENOLOGY 172.4 (April 1999): 1135-1136.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
172
Issue
4
Publish Date
1999
Start Page
1135
End Page
1136

Pancreatic transplantation using portal venous and enteric drainage: the postoperative appearance of a new surgical procedure.

PURPOSE: To review the normal radiologic appearance of pancreatic transplants that use portal venous and enteric drainage, and to review the appearance of a variety of postoperative complications. METHOD: We retrospectively reviewed the computed tomographic (CT) scans, magnetic resonance (MR) images, and ultrasounds of patients who had undergone pancreatic transplantation using portal venous and enteric drainage. RESULTS: At CT, the normal pancreatic transplant appears as a heterogeneous mass composed of pancreatic parenchyma, vessels, and omental wrap. On MR imaging, a normal transplant demonstrates intermediate signal intensity on T1- and T2-weighted sequences. Sonographic evaluation of a normal transplant reveals a hypoechoic gland that contains readily detectable low-resistance arterial and venous Doppler waveforms. Acute postoperative complications include acute rejection, which has a nonspecific radiologic appearance, and transplant pancreatitis, which is often manifested on CT by stranding of the peritransplant fat. Chronic postoperative complications include small bowel obstructions, graft pancreatitis secondary to obstruction of the Roux loop, and chronic rejection. CONCLUSION: Knowledge of the radiologic appearance of the normal pancreatic transplant is required before transplant-related complications can be detected.

Authors
Heyneman, LE; Keogan, MT; Tuttle-Newhall, JE; Porte, RJ; Leder, RA; Nelson, RC
MLA Citation
Heyneman, LE, Keogan, MT, Tuttle-Newhall, JE, Porte, RJ, Leder, RA, and Nelson, RC. "Pancreatic transplantation using portal venous and enteric drainage: the postoperative appearance of a new surgical procedure." J Comput Assist Tomogr 23.2 (March 1999): 283-290.
PMID
10096339
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
23
Issue
2
Publish Date
1999
Start Page
283
End Page
290

Acute pancreatitis complicated by gland necrosis: spectrum of findings on contrast-enhanced CT.

Authors
Paulson, EK; Vitellas, KM; Keogan, MT; Low, VH; Nelson, RC
MLA Citation
Paulson, EK, Vitellas, KM, Keogan, MT, Low, VH, and Nelson, RC. "Acute pancreatitis complicated by gland necrosis: spectrum of findings on contrast-enhanced CT." AJR Am J Roentgenol 172.3 (March 1999): 609-613.
PMID
10063845
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
172
Issue
3
Publish Date
1999
Start Page
609
End Page
613
DOI
10.2214/ajr.172.3.10063845

A multicenter, randomized, double-blind study to evaluate the safety, tolerability, and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in patients with liver pathology: results of a Phase III clinical trial.

The purpose of this study was to evaluate the safety and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in hepatic MRI of patients with suspected liver pathology. A Phase III, multicenter, randomized, double-blind, parallel group study was performed in adults with suspected liver pathology. All patients underwent contrast-enhanced computed tomography within 3 weeks prior to magnetic resonance scanning. Ninety-nine patients received OptiMARK, and 94 patients received Magnevist at a dose of 0.1 mmol/kg. Precontrast T1- and T2-weighted spin-echo imaging and T1-weighted gradient-echo imaging were performed, followed by T1-weighted gradient-echo imaging at 15-20 seconds, 1 minute, and 5 minutes after intravenous contrast injection. Three primary efficacy endpoints (confidence in lesion diagnosis, level of conspicuity, and lesion border delineation) were evaluated on the precontrast image set and compared with the pre plus postcontrast image set. Vital signs, physical examination, electrocardiograms (ECGs), and laboratory parameters (chemistry, hematology, and urinalysis) were measured at various time points. Adverse events were recorded. The study design and statistical analyses were chosen to demonstrate presumed equivalence of OptiMARK and Magnevist. There were no statistically significant differences in efficacy between OptiMARK and Magnevist as assessed by either blinded readers or the on-site principal investigators. No serious or unexpected adverse events were noted. Of the 193 patients receiving contrast media, 82 experienced a total of 154 adverse events. Thirty-three (21.4%) of these 154 adverse events were felt by the on-site investigators to be probably related to either study agent: 15 events in 9 patients in the OptiMARK group, and 18 events in 13 patients in the Magnevist group. Headache was the most common adverse event, occurring in 10.1% of the OptiMARK patients and 12.8% of the Magnevist patients. No clinically relevant trends were observed in any laboratory parameter or ECG findings in either treatment group. The results demonstrate the safety, efficacy, and equivalence of OptiMARK and Magnevist at a dose of 0.1 mmol/kg in hepatic magnetic resonance imaging of patients with suspected liver pathology.

Authors
Rubin, DL; Desser, TS; Semelka, R; Brown, J; Nghiem, HV; Stevens, WR; Bluemke, D; Nelson, R; Fultz, P; Reimer, P; Ho, V; Kristy, RM; Pierro, JA
MLA Citation
Rubin, DL, Desser, TS, Semelka, R, Brown, J, Nghiem, HV, Stevens, WR, Bluemke, D, Nelson, R, Fultz, P, Reimer, P, Ho, V, Kristy, RM, and Pierro, JA. "A multicenter, randomized, double-blind study to evaluate the safety, tolerability, and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in patients with liver pathology: results of a Phase III clinical trial." Journal of magnetic resonance imaging : JMRI 9.2 (February 1999): 240-250.
PMID
10077020
Source
epmc
Published In
Journal of Magnetic Resonance Imaging
Volume
9
Issue
2
Publish Date
1999
Start Page
240
End Page
250
DOI
10.1002/(sici)1522-2586(199902)9:2<240::aid-jmri14>3.0.co;2-#

A multicenter, randomized, double-blind study to evaluate the safety, tolerability, and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in patients with liver pathology: Results of a phase III clinical trial

The purpose of this study was to evaluate the safety and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in hepatic MRI of patients with suspected liver pathology. A Phase III, multicenter, randomized, double-blind, parallel group study was performed in adults with suspected liver pathology. All patients underwent contrast-enhanced computed tomography within 3 weeks prior to magnetic resonance scanning. Ninety-nine patients received OptiMARK, and 94 patients received Magnevist at a dose of 0.1 mmol/kg. Precontrast T1- and T2-weighted spin-echo imaging and T1-weighted gradient-echo imaging were performed, followed by T1-weighted gradient-echo imaging at 15-20 seconds, 1 minute, and 5 minutes after intravenous contrast injection. Three primary efficacy endpoints (confidence in lesion diagnosis, level of conspicuity, and lesion border delineation) were evaluated on the precontrast image set and compared with the pre plus postcontrast image set. Vital signs, physical examination, electrocardiograms (ECGs), and laboratory parameters (chemistry, hematology, and urinalysis) were measured at various time points. Adverse events were recorded. The study design and statistical analyses were chosen to demonstrate presumed equivalence of OptiMARK and Magnevist. There were no statistically significant differences in efficacy between OptiMARK and Magnevist as assessed by either blinded readers or the on-site principal investigators. No serious or unexpected adverse events were noted. Of the 193 patients receiving contrast media, 82 experienced a total of 154 adverse events. Thirty-three (21.4%) of these 154 adverse events were felt by the on- site investigators to be probably related to either study agent: 15 events in 9 patients in the OptiMARK group, and 18 events in 13 patients in the Magnevist group. Headache was the most common adverse event, occurring in 10.1% of the OptiMARK patients and 12.8% of the Magnevist patients. No clinically relevant trends were observed in any laboratory parameter or ECG findings in either treatment group. The results demonstrate the safety, efficacy, and equivalence of OptiMARK and Magnevist at a dose of 0.1 mmol/kg in hepatic magnetic resonance imaging of patients with suspected liver pathology.

Authors
Rubin, DL; Desser, TS; Semelka, R; Brown, J; Nghiem, HV; Stevens, WR; Bluemke, D; Nelson, R; Fultz, P; Reimer, P; Ho, V; Kristy, RM; Pierro, JA
MLA Citation
Rubin, DL, Desser, TS, Semelka, R, Brown, J, Nghiem, HV, Stevens, WR, Bluemke, D, Nelson, R, Fultz, P, Reimer, P, Ho, V, Kristy, RM, and Pierro, JA. "A multicenter, randomized, double-blind study to evaluate the safety, tolerability, and efficacy of OptiMARK (gadoversetamide injection) compared with Magnevist (gadopentetate dimeglumine) in patients with liver pathology: Results of a phase III clinical trial." Journal of Magnetic Resonance Imaging 9.2 (1999): 240-250.
Source
scival
Published In
Journal of Magnetic Resonance Imaging
Volume
9
Issue
2
Publish Date
1999
Start Page
240
End Page
250
DOI
10.1002/(SICI)1522-2586(199902)9:2<240::AID-JMRI14>3.0.CO;2-#

Use of contrast material in CT of the liver

Authors
Weiss, AJ; Sheafor, DH; Nelson, RC
MLA Citation
Weiss, AJ, Sheafor, DH, and Nelson, RC. "Use of contrast material in CT of the liver." American Journal of Roentgenology 172.4 (1999): 1135-1136.
Source
scival
Published In
AJR. American journal of roentgenology
Volume
172
Issue
4
Publish Date
1999
Start Page
1135
End Page
1136

PACS in sonography: Accuracy of interpretation using film compared with monitor display

OBJECTIVE. The goal of this study was to determine the relative accuracy of interpretation of sonography when viewed on a monitor or on film. MATERIALS AND METHODS. Four radiologists twice interpreted a series of 440 sonograms using the following sequences of display formats for initial and second interpretations: film-film, film-monitor, monitor-film, and monitor- monitor. Reporting discrepancies between the initial and subsequent interpretation were reviewed by an arbitration panel unaware of the display mode. Results were analyzed for differences in error rate attributable to film versus monitor display format, chronology of interpretation, individual observer, and observer seniority. RESULTS. We found no statistically significant difference in the error rate for film (10.3%) versus monitor display format (14.6%) (p = .09). Likewise, we found no significant differences in the error rates attributable to chronology of interpretation (p =. 13), individual observer (p = .54), or observer seniority (p = .87). CONCLUSION. Interpretative accuracy is similar whether sonograms are interpreted on a monitor or on film.

Authors
Hertzberg, BS; Kliewer, MA; Paulson, EK; Sheafor, DH; Freed, KS; Bowie, JD; Carroll, BA; DeLong, DH; Nelson, RC
MLA Citation
Hertzberg, BS, Kliewer, MA, Paulson, EK, Sheafor, DH, Freed, KS, Bowie, JD, Carroll, BA, DeLong, DH, and Nelson, RC. "PACS in sonography: Accuracy of interpretation using film compared with monitor display." American Journal of Roentgenology 173.5 (1999): 1175-1179.
Source
scival
Published In
AJR. American journal of roentgenology
Volume
173
Issue
5
Publish Date
1999
Start Page
1175
End Page
1179

Re: Unenhanced helical computerized tomography for the evaluation of patients with acute flank pain [6]

Authors
Vieweg, J; Teh, C; Freed, K; Leder, RA; Smith, RHA; Nelson, RH; Preminger, GM; Peterson, LJ
MLA Citation
Vieweg, J, Teh, C, Freed, K, Leder, RA, Smith, RHA, Nelson, RH, Preminger, GM, and Peterson, LJ. "Re: Unenhanced helical computerized tomography for the evaluation of patients with acute flank pain [6]." Journal of Urology 161.3 (1999): 926--.
PMID
10022725
Source
scival
Published In
The Journal of Urology
Volume
161
Issue
3
Publish Date
1999
Start Page
926-

Technique and role of ultrasound-guided aspiration of theca lutein cysts

Massive enlargement of the ovary secondary to theca lutein cysts can result in ovarian torsion, cyst rupture, or severe abdominal pain. We report a case of ultrasound-guided aspiration of theca lutein cysts resulting in symptomatic relief.

Authors
Sheafor, DH; Freed, KS; Nelson, RC
MLA Citation
Sheafor, DH, Freed, KS, and Nelson, RC. "Technique and role of ultrasound-guided aspiration of theca lutein cysts." Emergency Radiology 6.2 (1999): 110-112.
Source
scival
Published In
Emergency Radiology
Volume
6
Issue
2
Publish Date
1999
Start Page
110
End Page
112
DOI
10.1007/s101400050034

Helical liver CT with computer-assisted bolus-tracking technology: is it possible to predict which patients will not achieve a threshold of enhancement?

PURPOSE: To determine how often a prescribed threshold of hepatic contrast material enhancement is not reached at helical computed tomography (CT) of the liver in patients in a tertiary teaching hospital-based practice and which variables are predictive of failure. MATERIALS AND METHODS: Hepatic helical CT was performed in 250 consecutive patients with computer-assisted bolus-tracking technology after either mechanical injection at 3 mL/sec (n = 177) or manual injection (n = 73) of 150 mL of iopamidol. Demographic variables were recorded. After 17 seconds, low-milliamperage monitoring scans were obtained every 6 seconds until hepatic enhancement of 50 HU over baseline was achieved. Time-enhancement curves were reviewed. RESULTS: The threshold was not reached by 60 seconds in 88 patients (35%; default group). The success and default groups were similar in most variables and differed only in weight (P = .002), patient status (inpatient, outpatient, or emergency department; P < .001), and injection type (mechanical vs manual; P < .001). Ten patients (4%) did not achieve the threshold because of inappropriate placement of elliptic regions of interest. CONCLUSION: By using computer-assisted bolus-tracking technology, 35% of patients in a tertiary teaching hospital-based practice will not achieve a threshold of 50 HU above baseline by 60 seconds after injection initiation and will require the use of a set delay. Failures are more frequent in patients who are heavy and in inpatients. No historic or demographic factors are strongly predictive of failure.

Authors
Paulson, EK; Fisher, AJ; DeLong, DM; Parker, DD; Nelson, RC
MLA Citation
Paulson, EK, Fisher, AJ, DeLong, DM, Parker, DD, and Nelson, RC. "Helical liver CT with computer-assisted bolus-tracking technology: is it possible to predict which patients will not achieve a threshold of enhancement?." Radiology 209.3 (December 1998): 787-792.
PMID
9844675
Source
pubmed
Published In
Radiology
Volume
209
Issue
3
Publish Date
1998
Start Page
787
End Page
792
DOI
10.1148/radiology.209.3.9844675

Contrast media extravasation during dynamic CT: detection with an extravasation detection accessory.

To detect extravasation of contrast media during mechanical power injection at dynamic computed tomography, a 5 x 8-cm pliable adhesive patch was applied to the skin over the intravenous cannula and connected to the power injector with a cable to monitor electrical skin impedance. If the rate of change or the slope of impedance over time indicated an extravasation event, the power injector was set into a pause mode. In animal and human studies, monitoring with the device was successful. Extravasation of ionic contrast agents decreased impedance and that of nonionic agents increased impedance.

Authors
Nelson, RC; Anderson, FA; Birnbaum, BA; Chezmar, JL; Glick, SN
MLA Citation
Nelson, RC, Anderson, FA, Birnbaum, BA, Chezmar, JL, and Glick, SN. "Contrast media extravasation during dynamic CT: detection with an extravasation detection accessory." Radiology 209.3 (December 1998): 837-843.
PMID
9844684
Source
pubmed
Published In
Radiology
Volume
209
Issue
3
Publish Date
1998
Start Page
837
End Page
843
DOI
10.1148/radiology.209.3.9844684

Hepatic contrast-enhanced CT: Statistical design for prospective analysis - Reply

Authors
Sheafor, DH; Keogan, MT; DeLong, DM; Nelson, RC
MLA Citation
Sheafor, DH, Keogan, MT, DeLong, DM, and Nelson, RC. "Hepatic contrast-enhanced CT: Statistical design for prospective analysis - Reply." RADIOLOGY 209.3 (December 1998): 880-881.
Source
wos-lite
Published In
Radiology
Volume
209
Issue
3
Publish Date
1998
Start Page
880
End Page
881

Interobserver variability in the interpretation of unenhanced helical CT for the diagnosis of ureteral stone disease.

PURPOSE: The purpose of this study was to analyze interobserver agreement in the interpretation of unenhanced helical CT (UHCT) for the evaluation of ureteral stone disease and obstruction. METHOD: One hundred three UHCT examinations were independently and retrospectively reviewed by five readers including attending radiologists, a radiology resident, and an attending urologist. Examinations were interpreted as positive, negative, or indeterminate for ureteral stone disease and obstruction. The Cohen kappa test was used to measure interobserver agreement. The accuracy of the readers was also assessed. RESULTS: The kappa value ranged from 0.67 to 0.71 among the three attending radiologists and from 0.65 to 0.67 among the radiology attending physicians and radiology resident. Although the urologist tended to agree less well with the other readers (kappa range: 0.33-0.46), there was no statistically significant difference (p < 0.05) in the accuracy among all five readers. The percentage of cases interpreted as indeterminate ranged from 8 to 25% and almost invariably involved difficulty distinguishing phleboliths from minimally obstructing distal ureteral calculi. The percentage of UHCT scans correctly interpreted as positive and correctly interpreted as negative ranged from 73% (n = 27) to 86% (n = 32) and 63% (n = 22) to 86% (n = 30), respectively. CONCLUSION: Interobserver agreement was very good among the radiology attending physicians and resident and moderate with the urologist. The examination is an accurate technique in the evaluation of ureteral stone disease, although limitations exist, particularly in the diagnosis of minimally obstructing distal ureteral calculi.

Authors
Freed, KS; Paulson, EK; Frederick, MG; Preminger, GM; Shusterman, DJ; Keogan, MT; Vieweg, J; Smith, RH; Nelson, RC; Delong, DM; Leder, RA
MLA Citation
Freed, KS, Paulson, EK, Frederick, MG, Preminger, GM, Shusterman, DJ, Keogan, MT, Vieweg, J, Smith, RH, Nelson, RC, Delong, DM, and Leder, RA. "Interobserver variability in the interpretation of unenhanced helical CT for the diagnosis of ureteral stone disease." J Comput Assist Tomogr 22.5 (September 1998): 732-737.
PMID
9754108
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
22
Issue
5
Publish Date
1998
Start Page
732
End Page
737

Fat in the inferior vena cava associated with caval injury.

Authors
Sheafor, DH; Foti, TM; Vaslef, SN; Nelson, RC
MLA Citation
Sheafor, DH, Foti, TM, Vaslef, SN, and Nelson, RC. "Fat in the inferior vena cava associated with caval injury." AJR Am J Roentgenol 171.1 (July 1998): 181-182.
PMID
9648784
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
171
Issue
1
Publish Date
1998
Start Page
181
End Page
182
DOI
10.2214/ajr.171.1.9648784

Predictive model for the diagnosis of intraabdominal abscess.

RATIONALE AND OBJECTIVES: The authors investigated the use of an artificial neural network (ANN) to aid in the diagnosis of intraabdominal abscess. MATERIALS AND METHODS: An ANN was constructed based on data from 140 patients who underwent abdominal and pelvic computed tomography (CT) between January and December 1995. Input nodes included data from clinical history, physical examination, laboratory investigation, and radiographic study. The ANN was trained and tested on data from all 140 cases by using a round-robin method and was compared with linear discriminate analysis. A receiver operating characteristic curve was generated to evaluate both predictive models. RESULTS: CT examinations in 50 cases were positive for abscess. This finding was confirmed by means of laboratory culture of aspirations from CT-guided percutaneous drainage in 38 patients, ultrasound-guided percutaneous drainage in five patients, surgery in five patients, and characteristic appearance on CT scans without aspiration in two patients. CT scans in 90 cases were negative for abscess. The sensitivity and specificity of the ANN in predicting the presence of intraabdominal abscess were 90% and 51%, respectively. Receiver operating characteristic analysis showed no statistically significant difference in performance between the two predictive models. CONCLUSION: The ANN is a useful tool for determining whether an intraabdominal abscess is present. It can be used to set priorities for CT examinations in order to expedite treatment in patients believed to be more likely to have an abscess.

Authors
Freed, KS; Lo, JY; Baker, JA; Floyd, CE; Low, VH; Seabourn, JT; Nelson, RC
MLA Citation
Freed, KS, Lo, JY, Baker, JA, Floyd, CE, Low, VH, Seabourn, JT, and Nelson, RC. "Predictive model for the diagnosis of intraabdominal abscess." Acad Radiol 5.7 (July 1998): 473-479.
PMID
9653463
Source
pubmed
Published In
Academic Radiology
Volume
5
Issue
7
Publish Date
1998
Start Page
473
End Page
479

Abdominal percutaneous interventional procedures: comparison of CT and US guidance.

PURPOSE: To compare ultrasound (US) with computed tomography (CT) as a guidance modality for percutaneous interventional procedures. MATERIALS AND METHODS: A database of abdominal interventional procedures was reviewed for the 6 months preceding and 6 months after the opening of a dedicated US interventional suite. Changes in the number and type of procedures performed, room time, number of needle passes, and complication rates were calculated. RESULTS: In the first 6 months, 305 interventional procedures (138 tissue biopsies and 167 fluid aspirations) were performed (CT guidance in 87% [n = 120] and 95% [n = 159], respectively). In the 6 months after installation of the suite, 395 procedures (195 tissue biopsies and 200 fluid aspirations) were performed (US guidance in 76% [n = 148] and 34% [n = 67], respectively). The largest increase in US utilization was for guidance of tissue biopsies, rising from 6% (18 of 305) to 37% (148 of 395) of all procedures. Room time was significantly less for US-guided procedures (mean US room time, 77 minutes +/- 33 [1 standard deviation]; mean CT room time, 99 minutes +/- 38; P < .0001). CONCLUSION: US guidance often allows performance of quicker, more accurate procedures than does CT guidance, probably because of its real-time capabilities.

Authors
Sheafor, DH; Paulson, EK; Simmons, CM; DeLong, DM; Nelson, RC
MLA Citation
Sheafor, DH, Paulson, EK, Simmons, CM, DeLong, DM, and Nelson, RC. "Abdominal percutaneous interventional procedures: comparison of CT and US guidance." Radiology 207.3 (June 1998): 705-710.
PMID
9609893
Source
pubmed
Published In
Radiology
Volume
207
Issue
3
Publish Date
1998
Start Page
705
End Page
710
DOI
10.1148/radiology.207.3.9609893

Doppler sonography of the portal vein and hepatic artery: measurement of a prandial effect in healthy subjects.

PURPOSE: To determine if the prandial effect outweighs variability in the measurement of portal venous blood flow and hepatic arterial resistive index. MATERIALS AND METHODS: Fourteen healthy adult volunteers fasted overnight. For eight of the subjects, two sonographers performed three determinations of portal venous blood flow and hepatic arterial resistive index before and 30 minutes after a liquid meal (5 mg per kilogram of body weight). In the remaining six volunteers, determinations were made at the same time intervals but without a meal. The sonographers were blinded to on-screen measurements and the subject's prandial status. RESULTS: For subjects examined after the meal by sonographers A and B, respectively, portal venous blood flow increased from 144.2 to 201.7 mL/min and from 209.2 to 331.9 mL/min and hepatic arterial resistive index increased from 0.70 to 0.77 and from 0.67 to 0.78. After repeated-measures analysis of variance, ingestion of a meal was estimated to increase portal venous blood flow by 96.3 mL/min (P < .001)--a change in sonographers could affect the measurement by 76.7 mL/min (P < .001)--and to increase hepatic arterial resistive index by 0.089 (P < .001)--a change in sonographers did not affect the measurement (P > .1). CONCLUSION: The prandial effect on portal venous blood flow is only marginally greater than the interobserver variation in the measurement. Hepatic arterial resistive index also increases after a meal, but interobserver differences between sonographers are minimal; therefore, it is a more robust measurement.

Authors
Fisher, AJ; Paulson, EK; Kliewer, MA; DeLong, DM; Nelson, RC
MLA Citation
Fisher, AJ, Paulson, EK, Kliewer, MA, DeLong, DM, and Nelson, RC. "Doppler sonography of the portal vein and hepatic artery: measurement of a prandial effect in healthy subjects." Radiology 207.3 (June 1998): 711-715.
PMID
9609894
Source
pubmed
Published In
Radiology
Volume
207
Issue
3
Publish Date
1998
Start Page
711
End Page
715
DOI
10.1148/radiology.207.3.9609894

Renal excretion of gadolinium mimicking calculi on non-contrast CT.

Authors
Donnelly, LF; Nelson, RC
MLA Citation
Donnelly, LF, and Nelson, RC. "Renal excretion of gadolinium mimicking calculi on non-contrast CT." Pediatr Radiol 28.6 (June 1998): 417-.
PMID
9634454
Source
pubmed
Published In
Pediatric Radiology
Volume
28
Issue
6
Publish Date
1998
Start Page
417
DOI
10.1007/s002470050374

Urolithiasis: detection and management with unenhanced spiral CT--a urologic perspective.

Authors
Preminger, GM; Vieweg, J; Leder, RA; Nelson, RC
MLA Citation
Preminger, GM, Vieweg, J, Leder, RA, and Nelson, RC. "Urolithiasis: detection and management with unenhanced spiral CT--a urologic perspective." Radiology 207.2 (May 1998): 308-309.
PMID
9577473
Source
pubmed
Published In
Radiology
Volume
207
Issue
2
Publish Date
1998
Start Page
308
End Page
309
DOI
10.1148/radiology.207.2.9577473

Fine-needle aspiration of gastrointestinal stromal tumors.

Gastrointestinal stromal tumors are a group of neoplasms encompassing leiomyoma, leiomyosarcoma, and an epithelioid variant of leiomyosarcoma, as well as lesions expressing neural differentiation. These neoplasms are rare and account for 1% of all gastrointestinal tumors. With increasing frequency, fine-needle aspiration (FNA) has been used to diagnose intra-abdominal neoplasms before institution of definitive treatment. We encountered four patients with gastrointestinal stromal tumors diagnosed by FNA who ultimately underwent surgical excision of their tumors. The age of the patients ranged from 57 to 88 years. Smears from the aspirates were cellular and consisted of numerous small spindle cells distributed as cohesive fragments and individual cells. The dispersed cell population appeared largely as stripped nuclei. Several nuclei had perinuclear or paranuclear vacuoles, similar to the "halos" seen in sections. Cytologic evidence of malignancy (pleomorphism, nuclear irregularity, mitoses) were not identified in smears. Corresponding histologic sections demonstrated varying degrees of malignancy ranging from benign or low grade to frankly sarcomatous gastrointestinal stromal tumors. We conclude that the diagnosis of gastrointestinal stromal tumors can be made with a certain degree of confidence by using FNA findings. However, predictions about potential aggressiveness are best reserved for gross and histologic examination of the resected specimen.

Authors
Dodd, LG; Nelson, RC; Mooney, EE; Gottfried, M
MLA Citation
Dodd, LG, Nelson, RC, Mooney, EE, and Gottfried, M. "Fine-needle aspiration of gastrointestinal stromal tumors." Am J Clin Pathol 109.4 (April 1998): 439-443.
PMID
9535398
Source
pubmed
Published In
American Journal of Clinical Pathology
Volume
109
Issue
4
Publish Date
1998
Start Page
439
End Page
443

Doppler sonographic measurement of portal venous flow: What went wrong? response

Authors
Paulson, EK; Kliewer, MA; Nelson, RC
MLA Citation
Paulson, EK, Kliewer, MA, and Nelson, RC. "Doppler sonographic measurement of portal venous flow: What went wrong? response." RADIOLOGY 206.3 (March 1998): 845-846.
Source
wos-lite
Published In
Radiology
Volume
206
Issue
3
Publish Date
1998
Start Page
845
End Page
846

Dynamic helical CT of the abdomen: prospective comparison of pre- and postprandial contrast enhancement.

PURPOSE: To investigate effects of a liquid meal on contrast material enhancement at dynamic helical computed tomography (CT). MATERIALS AND METHODS: Twenty healthy, fasting subjects underwent intravenous injection of nonionic contrast material at 4 mL/sec. Axial CT sections were obtained at a single level 15 seconds after injection, then every 5 seconds for 2 minutes. This protocol was repeated 1 week later, after ingestion of a 360-calorie liquid meal. Hepatic, splenic, and aortic attenuation were measured before and after contrast material administration. Peak enhancement level, time to peak enhancement, slope of hepatic enhancement, and hepatic, splenic, and aortic enhancement ratios were determined. RESULTS: Postprandial time to peak enhancement was 4.4 seconds earlier than preprandial (59.6 seconds +/- 9.0 [1 standard deviation] vs 64.0 seconds +/- 9.5; P < .02). No differences in maximum attenuation were found (P > .27). Postprandial maximum slope of hepatic enhancement and temporal and quantitative enhancement characteristics in aorta and spleen did not significantly differ. Postprandial hepatic-to-splenic enhancement ratios increased (P = .04), and aortic-to-hepatic ratios decreased (P = .01). Aortic-to-splenic ratios did not differ (P = .45). CONCLUSION: A liquid meal before intravenous injection of contrast material produces more rapid peak hepatic enhancement, with slightly increased relative hepatic enhancement. A patient's dietary status, however, should not influence the CT protocol.

Authors
Sheafor, DH; Keogan, MT; DeLong, DM; Nelson, RC
MLA Citation
Sheafor, DH, Keogan, MT, DeLong, DM, and Nelson, RC. "Dynamic helical CT of the abdomen: prospective comparison of pre- and postprandial contrast enhancement." Radiology 206.2 (February 1998): 359-363.
PMID
9457186
Source
pubmed
Published In
Radiology
Volume
206
Issue
2
Publish Date
1998
Start Page
359
End Page
363
DOI
10.1148/radiology.206.2.9457186

Superparamagnetic iron oxide particles (SH U 555 A): evaluation of efficacy in three doses for hepatic MR imaging.

PURPOSE: To evaluate the efficacy of SH U 555 A in three doses for magnetic resonance (MR) imaging in the liver and to establish the best postinjection time point for liver MR imaging. MATERIALS AND METHODS: Pre- and postcontrast image sets obtained in 169 patients after injection of SH U 555 A (randomly, 4, 8, or 16 mumol of iron per kilogram of body weight). Three blinded readers evaluated the precontrast and 10- and 40-minute postcontrast MR images of 54, 58, and 57 patients, respectively. RESULTS: Statistically significant differences were observed in diagnostic confidence between images obtained with a dose of 4 or 16 mumol Fe/kg (P = .011) and in good or excellent improvement, respectively, in delineation of lesions on 10-minute postcontrast images (P = .001). No apparent differences in the efficacy evaluation were seen between the 10- and 40-minute postcontrast imaging time points. CONCLUSION: There was a dose-dependent postcontrast improvement in evaluated efficacy parameters (diagnostic confidence, visual evaluations) after injection of SH U 555 A. Accumulation phase imaging could begin as early as 10 minutes after administration.

Authors
Shamsi, K; Balzer, T; Saini, S; Ros, PR; Nelson, RC; Carter, EC; Tollerfield, S; Niendorf, HP
MLA Citation
Shamsi, K, Balzer, T, Saini, S, Ros, PR, Nelson, RC, Carter, EC, Tollerfield, S, and Niendorf, HP. "Superparamagnetic iron oxide particles (SH U 555 A): evaluation of efficacy in three doses for hepatic MR imaging." Radiology 206.2 (February 1998): 365-371.
PMID
9457187
Source
pubmed
Published In
Radiology
Volume
206
Issue
2
Publish Date
1998
Start Page
365
End Page
371
DOI
10.1148/radiology.206.2.9457187

Disseminated thrombosis in primary antiphospholipid syndrome: MR findings.

We report the MR imaging findings in a patient with primary antiphospholipid syndrome, adrenal infarction and widespread thrombosis involving abdominal, pelvic, and pulmonary vessels. This syndrome should be suspected in patients with thromboses and organ infarctions of otherwise undetermined etiology.

Authors
Provenzale, JM; Spritzer, CE; Nelson, RC; Ortel, TL
MLA Citation
Provenzale, JM, Spritzer, CE, Nelson, RC, and Ortel, TL. "Disseminated thrombosis in primary antiphospholipid syndrome: MR findings." Eur J Radiol 26.3 (February 1998): 244-247.
PMID
9587749
Source
pubmed
Published In
European Journal of Radiology
Volume
26
Issue
3
Publish Date
1998
Start Page
244
End Page
247

Carcinoid metastases to the liver: role of triple-phase helical CT.

PURPOSE: To evaluate triple-phase helical computed tomography (CT) of carcinoid liver metastases. MATERIALS AND METHODS: Triple-phase helical CT was performed in 31 patients with proved carcinoid liver metastases. Hepatic arterial-dominant phase (HAP) and portal venous-dominant phase (PVP) images were obtained 20 and 70 seconds after intravenous iopamidol injection. Four independent readers reviewed each phase for lesion number, conspicuity, and attenuation relative to liver. Three readers reviewed each phase to determine which phase best showed the lesions. RESULTS: The lesions detected by readers 1-4 were as follows: noncontrast phase, 164, 177, 204, and 229 lesions; HAP, 178, 177, 214, and 238 lesions; and PVP, 180, 189, 215, and 250 lesions (P > .05). On HAP images, readers found that 80, 73, 96, and 102 lesions were hyperattenuating. Consensus indicated there were 206 focal lesions. Of these 206 lesions, 72, 72, and 62 lesions were best seen on the noncontrast phase, HAP, and PVP images, respectively. Six, 28, and six lesions were seen only on the noncontrast phase, HAP, and PVP images, respectively. Two patients had lesions seen only on the HAP images. CONCLUSION: The HAP and, to a lesser extent, the noncontrast phase provide added value in evaluating carcinoid liver metastasis.

Authors
Paulson, EK; McDermott, VG; Keogan, MT; DeLong, DM; Frederick, MG; Nelson, RC
MLA Citation
Paulson, EK, McDermott, VG, Keogan, MT, DeLong, DM, Frederick, MG, and Nelson, RC. "Carcinoid metastases to the liver: role of triple-phase helical CT." Radiology 206.1 (January 1998): 143-150.
PMID
9423664
Source
pubmed
Published In
Radiology
Volume
206
Issue
1
Publish Date
1998
Start Page
143
End Page
150
DOI
10.1148/radiology.206.1.9423664

Diagnostic and therapeutic ERCP are beneficial in the management of pancreatic necrosis

There is considerable debate regarding the optimal management of pancreatic necrosis (PN). The timing and utility of endoscopic retrograde cholangiopancreatograms (ERCP) in the subset of acute pancreatitis who have PN is unclear. Objectives: It To determine if diagnostic ERCP helps guide further management (endoscopic, surgical) of patients with PN and 2) to evaluate the role of therapeutic ERCP in this patient population. Methods: All patients presenting with acute pancreatitis at our medical center from 1986 to 1996 were reviewed for evidence of PN. To be eligible for inclusion in our study, PN had to be demonstrated by either computerized tomography (CT) showing lack of parenchymal enhancement after intravenous contrast or by histological confirmation of necrosis in surgically resected pancreatic tissue. Data on patients with PN were cross-referenced with the endoscopy database to identify individuals who had ERCP. Results: 34 patients (22M/11F) with an average age of 53 years (SD13) were identified as having PN and ERCP. Alcohol and biliary stones were the most common causes of pancreatitis. CT demonstrated pseudocysts in 20 patients and pancreatic phlegmon alone in 14. Cannulation of the pancreatic duct (PD) failed in 3 patients. The most common pancreatographic findings were communicating pseudocyst ( 17), ductal changes of chronic pancreatitis (9), pancreas divisum (5) and pancreatic stricture (3). Therapeutic endoscopic procedures were performed in 14 (41%) patients, thus: PD stenting (7), pancreatic sphincterotomy (2) and biliary stent or sphincterotomy (5). 24 patients came to surgery; 2 (6%) died of complications of pancreatitis. Conclusions: 1 ) Patients with PN who undergo ERCP are likely to have pancreatic pathology which may be amenable to endoscopic therapy. 2) Endoscopists performing ERCP on patients with PN require therapeutic skills. 3) In this select group of patients with PN, mortality was low despite high morbidity. 4) The majority of patients with PN can be expected to need surgery (68% in our series).

Authors
Enns, R; Vitellas, K; Mergener, K; Nelson, RC; Paulson, EK; Jowell, PS; Branch, MS; Baillie, J
MLA Citation
Enns, R, Vitellas, K, Mergener, K, Nelson, RC, Paulson, EK, Jowell, PS, Branch, MS, and Baillie, J. "Diagnostic and therapeutic ERCP are beneficial in the management of pancreatic necrosis." Gastrointestinal Endoscopy 47.4 (1998): AB135-.
Source
scival
Published In
Gastrointestinal Endoscopy
Volume
47
Issue
4
Publish Date
1998
Start Page
AB135

Impact of endoscopic ultrasound on the need for ERCP in a referral center population

Background: Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) are useful techniques in the evaluation of patients (pts) with biliary and pancreatic diseases. Pts undergoing EUS are commonly undergoing ERCP as well. The utility of performing both procedures has not been studied systematically. We review an 11 month experience of performing sequential EUS/ERCP on pts referred to a tertiary care center. Methods: Pts undergoing same-day EUS and ERCP between 1/97 and 11/97 were identified from a computerized database. Clinic files, endoscopic records, and radiographs were reviewed. Results: Thirty-eight pts were identified (20 females/18 males; age 26-82, mean 53). EUS preceeded ERCP in 27/38 pts and followed ERCP in the remaining 11 pts. Indications for EUS/ERCP and diagnoses made on EUS (EUS Dx) are shown below. The number of cases where ERCP added significant diagnostic information (ERCP/addDx) is indicated. ERCP/Tx denotes the number of pts requiring therapeutic interventions during ERCP. Indication (n) EUS Dx ERCP/addDx ERCP/Tx pancreatic mass (18) normal 8/18 1/81 0/8 (suspected or proven) mass 10/182 0/10 7/103 pancreatitis (8) c/w pancreatitis 8/8 0/8 4/84 pain (8) normal 5/8 1/55 1/55 c/w pancreatitis 3/8 1/36 1/36 ampullary tumor (3) amp, tumor 3/3 0/3 3/3 p.insufficiency (1) normal 1/1 0/1 0/1 1 Pancreatic juice collection revealed adeno-ca in a pt with PD stricture on ERCP and normal EUS (except for small lymph node with negative FNA). 2 FNA was positive for malignancy in 4/10 pts. 3 Stenting of CBD (6) or PD (1). 4 PD sphx (2), PD stenting (1), CBD sphx (1). 5 1 of 2 biliary manometries was abnormal; CBD sphx. 6 One pancreatic manometry was abnormal; PD sphx. Conclusions: 1. ERCP performed in addition to EUS rarely provides additional diagnostic information in pts with the above indications (in only 3/38 pts in this series). 2. The EUS diagnosis of a pancreatic mass or pancreatitis does not always obviate the need for ERCP, as therapeutic interventions are often needed (16/38 pts required therapeutic ERCP in our series). 3. Prospective studies are needed to further define who will benefit most from sequential EUS/ERCP.

Authors
Mergener, K; Jowell, PS; Enns, R; Nelson, RC; Nardi, CB; Branch, MS; Baillie, J
MLA Citation
Mergener, K, Jowell, PS, Enns, R, Nelson, RC, Nardi, CB, Branch, MS, and Baillie, J. "Impact of endoscopic ultrasound on the need for ERCP in a referral center population." Gastrointestinal Endoscopy 47.4 (1998): AB150-.
Source
scival
Published In
Gastrointestinal Endoscopy
Volume
47
Issue
4
Publish Date
1998
Start Page
AB150

Unenhanced helical computerized tomography for the evaluation of patients with acute flank pain

Purpose: We determined the value of unenhanced helical computerized tomography (CT) in the diagnosis of acute flank pain in 105 patients evaluated for suspected stone disease. Materials and Methods: Noncontrasted spiral CT was done in 105 consecutive patients seen in our emergency department to evaluate acute flank pain. All CT studies were reviewed for the presence of ureteral or renal calculi, perinephric or periureteral stranding, presence and degree of pelvicalicectasis or other radiological findings. If necessary, an excretory urogram was performed to confirm the presence or absence of urinary stones. Patients were followed to determine clinical outcome including the need for urological intervention. Results: Of the 49 patients determined to have stones 24 (49%) had spontaneous stone passage, 10 (20%) had improved symptoms without documented stone passage and 14 (29%) required surgical intervention. In 29 of 51 patients (57%) with negative CT readings for stone disease a diagnosis was established by other intra- abdominal findings. In 21 patients (41%) no clinical diagnosis could be established, and i scan in a patient with a distal ureteral calculus was interpreted as falsely positive. These findings yielded a sensitivity of 98%, specificity 98% and overall accuracy 96% for diagnosing ureteral stones. Conclusions: Despite the limitations of helical CT in evaluating renal function and nonobstructing ureteral calculi, noncontrasted CT is a sensitive imaging modality for the detection of urinary tract calculi and obstruction. The majority of our patients required no further imaging to determine the need for urological intervention. At our institution spiral CT has become the standard method to evaluate patients with acute flank pain leading to more rapid turnover in the emergency department at similar or even reduced cost to conventional excretory urography.

Authors
Vieweg, J; Teh, C; Freed, K; Leder, RA; Smith, RHA; Nelson, RH; Preminger, GM
MLA Citation
Vieweg, J, Teh, C, Freed, K, Leder, RA, Smith, RHA, Nelson, RH, and Preminger, GM. "Unenhanced helical computerized tomography for the evaluation of patients with acute flank pain." Journal of Urology 160.3 I (1998): 679-684.
Source
scival
Published In
The Journal of Urology
Volume
160
Issue
3 I
Publish Date
1998
Start Page
679
End Page
684
DOI
10.1016/S0022-5347(01)62754-X

Hepatic contrast-enhanced CT: Statistical design for prospective analysis [2] (multiple letters)

Authors
Tello, R; Seltzer, SE; Sheafor, DH; Keogan, MT; DeLong, DM; Nelson, RC
MLA Citation
Tello, R, Seltzer, SE, Sheafor, DH, Keogan, MT, DeLong, DM, and Nelson, RC. "Hepatic contrast-enhanced CT: Statistical design for prospective analysis [2] (multiple letters)." Radiology 209.3 (1998): 879-881.
PMID
9844692
Source
scival
Published In
Radiology
Volume
209
Issue
3
Publish Date
1998
Start Page
879
End Page
881

Outcome of examinations self-referred as a result of spiral CT of the abdomen.

RATIONALE AND OBJECTIVES: The interpretation of an abdominal computed tomographic (CT) scan is occasionally inconclusive. In many of these cases, the radiologist suggests an additional imaging test for further confirmation or clarification. The purpose of this study was to evaluate the outcome of self-referral by the radiologist after abdominal CT scanning. MATERIALS AND METHODS: Reports from 545 consecutive abdominal CT scans were reviewed to track recommendations for additional imaging. In patients who underwent the additional work-up, a determination of the effect of the study was attempted. In patients who did not, explanations were sought. Wording of the recommendations was also recorded. RESULTS: Recommendations were made for additional imaging studies in 105 (19.3%) patients. Of these, 32 (30.5%) were performed and 31 (96.9%) were helpful by confirming malignancy (n = 5), confirming a benign process (n = 24), or being therapeutic (n = 2). In one, no information was added. There were 63 (60.0%) patients who did not undergo the recommended studies. Reasons included "no clinical indication" (n = 51), alternative study performed (n = 9), or study previously performed (n = 3). In eight (7.6%) patients the chart provided insufficient information about whether the patient underwent the study, and in two (1.9%) the chart was unavailable. Wording of the recommendation had no effect on whether the study was performed (P > .05). CONCLUSION: Although interpretation of abdominal CT scans leads to recommendations for additional imaging in a minority of cases, these recommendations were infrequently followed. When followed, however, the findings from the recommended studies were usually helpful. Better clinical information is perhaps the best way to reduce self-referral by radiologists.

Authors
Baumgarten, DA; Nelson, RC
MLA Citation
Baumgarten, DA, and Nelson, RC. "Outcome of examinations self-referred as a result of spiral CT of the abdomen." Acad Radiol 4.12 (December 1997): 802-805.
PMID
9412692
Source
pubmed
Published In
Academic Radiology
Volume
4
Issue
12
Publish Date
1997
Start Page
802
End Page
805

Contrast-enhanced CT of intrahepatic and hilar cholangiocarcinoma: delay time for optimal imaging.

OBJECTIVE: The purpose of this study was to determine the optimal time for obtaining delayed images with contrast-enhanced CT in patients who have intrahepatic or hilar cholangiocarcinoma. SUBJECTS AND METHODS: CT studies were performed in 25 consecutive patients with proven cholangiocarcinoma, including six patients who had undergone radiotherapy or chemotherapy. Dynamic images of the liver were obtained after 150 ml of IV contrast material was administered at 3 ml/sec. Delayed CT images were then obtained at 10, 20, and 30 min. Tumor-liver attenuation difference was determined quantitatively for each time period. Images were qualitatively evaluated by three observers for attenuation of the tumor (hypoattenuating, isoattenuating, or hyperattenuating) relative to the liver. Observer confidence for tumor detection was graded on a four-point scale. Dynamic and delayed images were compared for tumor conspicuity. RESULTS: On dynamic images, 18 tumors (72%) were hypoattenuating, six (24%) were isoattenuating, and one was heterogeneous. On delayed images, 15 (60%) of these 25 tumors were isoattenuating and nine (36%) were hyperattenuating compared with the liver. Tumor-liver attenuation difference was greatest on dynamic studies (p < .01) and did not differ significantly among the three delay times (p > .20). All tumors seen on delayed images were also seen on dynamic images; however, in three patients (12%), the confidence level for presence of tumor was better on delayed than on dynamic images. Confidence levels for presence of tumor did not vary significantly among the three delay times. Attenuation values on dynamic and delayed images did not differ for the groups of patients who had or had not undergone prior radiotherapy or chemotherapy (p > .05). CONCLUSION: In the evaluation of hilar or intrahepatic cholangiocarcinoma, delayed CT images are helpful for tumor characterization and may improve observer confidence for the presence of tumor. The optimal time for acquisition of delayed images is 10-20 min after contrast media injection.

Authors
Keogan, MT; Seabourn, JT; Paulson, EK; McDermott, VG; Delong, DM; Nelson, RC
MLA Citation
Keogan, MT, Seabourn, JT, Paulson, EK, McDermott, VG, Delong, DM, and Nelson, RC. "Contrast-enhanced CT of intrahepatic and hilar cholangiocarcinoma: delay time for optimal imaging." AJR Am J Roentgenol 169.6 (December 1997): 1493-1499.
PMID
9393152
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
169
Issue
6
Publish Date
1997
Start Page
1493
End Page
1499
DOI
10.2214/ajr.169.6.9393152

Pancreatic malignancy: effect of dual-phase helical CT in tumor detection and vascular opacification.

PURPOSE: To determine the relative value of hepatic arterial and portal venous phase helical computed tomographic (CT) scans for tumor detection and vascular opacification in patients with pancreatic malignancy. MATERIALS AND METHODS: Ninety-five patients who had or were suspected of having pancreatic disease underwent dual-phase helical CT. Arterial phase scans were acquired 20-40 seconds after contrast material administration; venous phase scans, 70-100 seconds after administration. Three readers independently scored images in a blinded fashion for the presence of tumor, for lesion attenuation relative to normal pancreas, and for vascular opacification. RESULTS: The final diagnosis was pancreatic malignancy (n = 60), acute or chronic pancreatitis (n = 22), and normal pancreas (n = 13). The readers identified possible or definite tumors on arterial phase studies in 47-50 patients and on venous phase studies in 48-53 patients (P > .10). There was no statistically significant difference in tumor attenuation between scans from the two phases (P > .05). Agreement between the readers for tumor detection was not affected by the scanning phase (P > .10). Opacification of arteries and of veins was greater on arterial phase scans and on venous phase scans, respectively (P < .001). CONCLUSION: The acquisition of arterial phase scans in addition to venous phase scans does not result in improved detection of pancreatic malignancies.

Authors
Keogan, MT; McDermott, VG; Paulson, EK; Sheafor, DH; Frederick, MG; de Long, DM; Nelson, RC
MLA Citation
Keogan, MT, McDermott, VG, Paulson, EK, Sheafor, DH, Frederick, MG, de Long, DM, and Nelson, RC. "Pancreatic malignancy: effect of dual-phase helical CT in tumor detection and vascular opacification." Radiology 205.2 (November 1997): 513-518.
PMID
9356637
Source
pubmed
Published In
Radiology
Volume
205
Issue
2
Publish Date
1997
Start Page
513
End Page
518
DOI
10.1148/radiology.205.2.9356637

Small lymph nodes of the abdomen, pelvis, and retroperitoneum: usefulness of sonographically guided biopsy.

PURPOSE: To evaluate the usefulness of sonographically guided percutaneous biopsy of small lymph nodes in the abdomen, retroperitoneum, and pelvis. MATERIALS AND METHODS: From May 1995 through January 1997, 35 sonographically guided lymph node biopsies were performed in 34 patients. All biopsies were performed with a 20- (n = 18) or 22-gauge (n = 10) self-aspirating needle alone or in combination (n = 7). To determine the amount of compression achieved with the transducer, the skin-to-lesion distance on reference computed tomographic (CT) scans was compared with that on sonograms. A biopsy was considered successful if a specific benign or malignant diagnosis was rendered by the pathologist. RESULTS: Of 35 sonographically guided biopsies, 30 (86%) were successful. Diagnoses included 26 (74%) cases of carcinoma, three (9%) cases of benign reactive lymphocytosis confirmed at open biopsy, and one (3%) case of a lymph node with a positive acid-fast bacilli stain. The average lymph node diameter was 2.1 cm (range, 0.9-4.3 cm). With sonography, a mean of 2.5 needle passes (range, 1-5) were made per biopsy. Transducer compression reduced the skin-to-lesion distance from an average of 8.8 cm (at CT) to 4.5 cm. CONCLUSION: Sonographic guidance seems to provide a reasonable alternative to CT in biopsy of small abdominal, pelvic and retroperitoneal lymph nodes.

Authors
Fisher, AJ; Paulson, EK; Sheafor, DH; Simmons, CM; Nelson, RC
MLA Citation
Fisher, AJ, Paulson, EK, Sheafor, DH, Simmons, CM, and Nelson, RC. "Small lymph nodes of the abdomen, pelvis, and retroperitoneum: usefulness of sonographically guided biopsy." Radiology 205.1 (October 1997): 185-190.
PMID
9314983
Source
pubmed
Published In
Radiology
Volume
205
Issue
1
Publish Date
1997
Start Page
185
End Page
190
DOI
10.1148/radiology.205.1.9314983

Zebra pattern: a diagnostically challenging hepatic parenchymal enhancement pattern at CT arterial portography.

PURPOSE: To investigate the effect of arterial injection site and splenic volume on the hepatic zebra pattern seen at computed tomographic (CT) arterial portography. MATERIALS AND METHODS: Images from CT arterial portographic examinations, performed via either the splenic artery (SA)(n = 47) or superior mesenteric artery (SMA)(n = 51) in 98 patients, were reviewed. The hepatic parenchymal enhancement pattern was assessed by three blinded reviewers. Splenic volume was determined. RESULTS: Twenty-two of 98 (22%) CT arterial portographic studies showed a zebra pattern: 10 of 47 (21%) with injection via the SA and 12 of 51 (24%) with injection via the SMA. The mean percentage of hepatic parenchyma with nontumorous perfusion defects was 55% with the zebra pattern versus 12% without (P < .001). For SA injections, the mean splenic volume was lower in patients with the zebra patterns (321 vs 409 cm3, P = .09). For SMA injections, it was higher in patients with zebra patterns (372 vs 291 cm3, P = .10). CONCLUSION: The zebra pattern can cause difficulties in interpreting images. It is due to alternating, well-defined regions of portal venous hyper- and hypoperfusion; it likely has a multifactorial cause and is likely due to technical parameters such as the injection site, the volume of the spleen, and the hemodynamic effects of the tumor.

Authors
Lawrance, JA; McDermott, VG; Paulson, EK; Keogan, MT; Delong, DM; Meyers, WC; Nelson, RC
MLA Citation
Lawrance, JA, McDermott, VG, Paulson, EK, Keogan, MT, Delong, DM, Meyers, WC, and Nelson, RC. "Zebra pattern: a diagnostically challenging hepatic parenchymal enhancement pattern at CT arterial portography." Radiology 203.1 (April 1997): 115-119.
PMID
9122377
Source
pubmed
Published In
Radiology
Volume
203
Issue
1
Publish Date
1997
Start Page
115
End Page
119
DOI
10.1148/radiology.203.1.9122377

Fine-needle aspiration of the liver and pancreas: a cytology primer for radiologists.

Fine-needle aspiration (FNA) is increasing in popularity as a means of diagnosing mass lesions in intraabdominal organs. With use of radiologic guidance for needle placement, this technique is an effective way to obtain diagnostic material. In selected instances, FNA is superior to core-needle or open biopsy in terms of cost, procedure-associated morbidity, and timeliness of diagnosis. This article summarizes the cytologic features of hepatic and pancreatic lesions most likely to be seen in an active interventional radiologic practice. The specific cytopathologic findings of the more common lesions are emphasized. The authors also discuss some of the limitations of FNA and how to optimize the procurement and utilization of specimen material to obtain the best possible diagnostic outcome.

Authors
Dodd, LG; Mooney, EE; Layfield, LJ; Nelson, RC
MLA Citation
Dodd, LG, Mooney, EE, Layfield, LJ, and Nelson, RC. "Fine-needle aspiration of the liver and pancreas: a cytology primer for radiologists." Radiology 203.1 (April 1997): 1-9. (Review)
PMID
9122373
Source
pubmed
Published In
Radiology
Volume
203
Issue
1
Publish Date
1997
Start Page
1
End Page
9
DOI
10.1148/radiology.203.1.9122373

Helical CT for detecting focal liver lesions in patients with breast carcinoma: comparison of noncontrast phase, hepatic arterial phase, and portal venous phase.

PURPOSE: Our goal was to compare noncontrast phase (NCP), hepatic arterial phase (HAP), and portal venous phase (PVP) helical CT for the detection of focal liver lesions in patients at risk for having metastases from breast carcinoma. METHOD: Eighty-four consecutive CT scans in 80 women with known or suspected liver metastases from breast carcinoma were prospectively evaluated with triple phase helical CT. After NCP, Isovue 300 was administered at 3 ml/s for 40 s, then 2 ml/s for 30 s, with scan delays of 25 s (HAP) and 76 s (PVP), slice thickness of 7 mm, and pitch of 1:1. Two reviewers evaluated each phase for focal liver lesions in a blinded and random fashion followed by side-by-side review for consensus. RESULTS: By consensus, 40 CT scans were normal and 44 CT scans had a total of 105 lesions (46 lesions were graded malignant). PVP detected 39 (85%), HAP 27 (59%), and NCP 28 (61%) malignant lesions. Two malignant lesions were seen only on HAP, 3 only on NCP, and 10 only on PVP. The remainder of lesions were seen on more than one phase. PVP was graded best for detecting lesions in 27 (61%), HAP best in 7 (16%), NCP best in 4 (9%), and PVP equivalent to HAP in 6 (14%) of the 44 cases with lesions. CONCLUSION: In our breast cancer patient population, PVP was superior to NCP and HAP for liver lesion detection. Because no CT scan was converted from negative to positive due to the addition of NCP or HAP, the routine use of these two phases cannot be justified when the clinical concern is the presence or absence of metastases.

Authors
Frederick, MG; Paulson, EK; Nelson, RC
MLA Citation
Frederick, MG, Paulson, EK, and Nelson, RC. "Helical CT for detecting focal liver lesions in patients with breast carcinoma: comparison of noncontrast phase, hepatic arterial phase, and portal venous phase." J Comput Assist Tomogr 21.2 (March 1997): 229-235.
PMID
9071291
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
21
Issue
2
Publish Date
1997
Start Page
229
End Page
235

Doppler US measurement of portal venous flow: variability in healthy fasting volunteers.

PURPOSE: To describe the intrinsic sampling variability of measurements of portal venous flow in healthy volunteers and to estimate the variability attributable to the sonographer, the subject, and the measurement. MATERIALS AND METHODS: In a randomized controlled fashion, nine sonographers measured portal venous flow in five subjects. Each sonographer measured portal venous flow in each volunteer during three separate sessions with three measurements per session. Analysis of variance was used to estimate the contribution of several factors to the observed variability. RESULTS: Overall mean portal venous flow was 390 mL/min +/- 234 (range, 18-1,511 mL/min). The estimated variance components were 1.1 (3%), 2.5 (7%), 7.2 (21%), and 24.0 (69%) for the subject, the sonographer, the interaction between subject and sonographer, and the measurement or intrinsic variability. Similar results were obtained when the analysis of variance was fit by using the rank and median of the measurements. CONCLUSION: Substantial variability exists in measurement of portal venous flow. Variability attributed to inherent differences in repeat measurements contributes more to overall variability than that attributed to either sonographers or subjects.

Authors
Paulson, EK; Kliewer, MA; Frederick, MG; Keogan, MT; DeLong, DM; Nelson, RC
MLA Citation
Paulson, EK, Kliewer, MA, Frederick, MG, Keogan, MT, DeLong, DM, and Nelson, RC. "Doppler US measurement of portal venous flow: variability in healthy fasting volunteers." Radiology 202.3 (March 1997): 721-724.
PMID
9051024
Source
pubmed
Published In
Radiology
Volume
202
Issue
3
Publish Date
1997
Start Page
721
End Page
724
DOI
10.1148/radiology.202.3.9051024

Liver metastases: Improved detection with dynamic gadolinium-enhanced MR imaging?

PURPOSE: To compare dynamic gadolinium-enhanced with unenhanced magnetic resonance (MR) imaging in detection of liver metastases. MATERIALS AND METHODS: Two groups of patients were prospectively examined with unenhanced and dynamic gadolinium-enhanced MR imaging. The first group (n = 48) had proved liver metastases; the second group (n = 49) did not. One set of unenhanced and one set of gadolinium-enhanced MR images were selected per patient. Three independent, blinded readers assessed the images for presence, number, location, and conspicuity of lesions. Data were analyzed with receiver operating characteristic curves, and contrast-to-noise ratios were calculated for the images. RESULTS: There was no statistically significant difference between the use of unenhanced and gadolinium-enhanced MR images in the differentiation of patients with from patients without metastases. The numbers of false-positive and false-negative diagnoses of individual lesions were higher (not statistically significant) with dynamic MR images than with unenhanced MR images. At dynamic MR imaging, contrast- to-noise ratio was highest in the early phase (30 seconds after injection of the contrast agent) but was not significantly different from the contrast- to noise ratio of the T2-weighted images. CONCLUSION: Dynamic gadolin-ium- enhanced MR imaging showed no improvement over unenhanced MR imaging in detectability of liver metastases.

Authors
Hamm, B; Mahfouz, A-E; Taupitz, M; Mitchell, DG; Nelson, R; Halpern, E; Speidel, A; Wolf, K-J; Saini, S
MLA Citation
Hamm, B, Mahfouz, A-E, Taupitz, M, Mitchell, DG, Nelson, R, Halpern, E, Speidel, A, Wolf, K-J, and Saini, S. "Liver metastases: Improved detection with dynamic gadolinium-enhanced MR imaging?." Radiology 202.3 (1997): 677-682.
PMID
9051015
Source
scival
Published In
Radiology
Volume
202
Issue
3
Publish Date
1997
Start Page
677
End Page
682

Pancreatic malignancy: Effect of dual-phase helical ct in tumor detection and vascular opacification

PURPOSE: To determine the relative value of hepatic arterial and portal venous phase helical computed tomographic (CT) scans for tumor detection and vascular opacification in patients with pancreatic malignancy. MATERIALS AND METHODS: Ninety-five patients who had or were suspected of having pancreatic disease underwent dual-phase helical CT. Arterial phase scans were acquired 20-40 seconds after contrast material administration; venous phase scans, 70-100 seconds after administration. Three readers independently scored images in a blinded fashion for the presence of tumor, for lesion attenuation relative to normal pancreas, and for vascular opacification. RESULTS: The final diagnosis was pancreatic malignancy (n = 60), acute or chronic pancreatitis (n = 22), and normal pancreas (n = 13). The readers identified possible or definite tumors on arterial phase studies in 47-50 patients and on venous phase studies in 48-53 patients (P > .10). There was no statistically significant difference in tumor attenuation between scans from the two phases (P > .05). Agreement between the readers for tumor detection was not affected by the scanning phase (P > .10). Opacification of arteries and of veins was greater on arterial phase scans and on venous phase scans, respectively (P < .001). CONCLUSION: The acquisition of arterial phase scans in addition to venous phase scans does not result in improved detection of pancreatic malignancies. © RSNA, 1997.

Authors
Keogan, MT; McDermott, VG; Paulson, EK; Sheafor, DH; Frederick, MG; Delong, DM; Nelson, RC
MLA Citation
Keogan, MT, McDermott, VG, Paulson, EK, Sheafor, DH, Frederick, MG, Delong, DM, and Nelson, RC. "Pancreatic malignancy: Effect of dual-phase helical ct in tumor detection and vascular opacification." Radiology 205.2 (1997): 503-512.
Source
scival
Published In
Radiology
Volume
205
Issue
2
Publish Date
1997
Start Page
503
End Page
512

Sonography: the undiscovered jewel of interventional radiology.

Because most radiologists in the United States have been taught that fluoroscopy and computed tomography (CT) are the best guidance techniques for nonvascular interventional procedures, sonography has been greatly underused in this regard. Recently, sonography has been gaining recognition as a highly useful and versatile guidance technique. It has many advantages over CT and fluoroscopic guidance, including real-time imaging with vessel visualization, decreased procedure time and cost, portability, and lack of ionizing radiation. Sonography should be the primary guidance technique for many nonvascular interventional procedures, and use of sonography as an adjunct guidance technique increases the ease and speed with which many other interventional procedures are performed. Sonography should generally be used instead of CT for guidance of abdominal and pelvic biopsy and drainage. Sonographic guidance should replace CT and fluoroscopic guidance for biopsy and drainage of accessible peripheral thoracic and mediastinal masses. Use of sonographic guidance should be integrated into all interventional radiology suites to reduce radiation exposure and facilitate the performance of many nonvascular and some vascular interventional procedures that have traditionally been performed under fluoroscopic guidance.

Authors
Dodd, GD; Esola, CC; Memel, DS; Ghiatas, AA; Chintapalli, KN; Paulson, EK; Nelson, RC; Ferris, JV; Baron, RL
MLA Citation
Dodd, GD, Esola, CC, Memel, DS, Ghiatas, AA, Chintapalli, KN, Paulson, EK, Nelson, RC, Ferris, JV, and Baron, RL. "Sonography: the undiscovered jewel of interventional radiology." Radiographics 16.6 (November 1996): 1271-1288.
PMID
8946535
Source
pubmed
Published In
Radiographics : a review publication of the Radiological Society of North America, Inc
Volume
16
Issue
6
Publish Date
1996
Start Page
1271
End Page
1288
DOI
10.1148/radiographics.16.6.8946535

Hepatic artery: variability in measurement of resistive index and systolic acceleration time in healthy volunteers.

PURPOSE: To determine the intrinsic sampling variability of measurements of hepatic artery resistive index and systolic acceleration time in healthy subjects and to estimate the components of variability attributable to the sonographer, individual measurement, and subject. MATERIALS AND METHODS: In a randomized, controlled (blinded) fashion, nine sonographers measured hepatic artery resistive index and systolic acceleration time in five healthy subjects by using Doppler ultrasound (US). Analysis of variance was used to estimate the contribution of several factors to the observed variability in measurements. RESULTS: The standard deviation for a single measurement was 0.08 for resistive index and 39 msec for systolic acceleration time. For resistive index, the estimated variance components were 0.0012 (18%), 0.0004 (6%), and 0.0050 (76%) for the subject, sonographer, and intrinsic variability, respectively. For systolic acceleration time, the estimated variance components were 59 msec (4%), 264 msec (17%), and 1,250 msec (79%) for the subject, sonographer, and intrinsic variability, respectively. CONCLUSION: Because of substantial variability in hepatic arterial measures, caution is indicated when interpreting small changes in the measurement of these Doppler US indexes.

Authors
Paulson, EK; Kliewer, MA; Frederick, MG; Keogan, MT; Delong, DM; Nelson, RC
MLA Citation
Paulson, EK, Kliewer, MA, Frederick, MG, Keogan, MT, Delong, DM, and Nelson, RC. "Hepatic artery: variability in measurement of resistive index and systolic acceleration time in healthy volunteers." Radiology 200.3 (September 1996): 725-729.
PMID
8756922
Source
pubmed
Published In
Radiology
Volume
200
Issue
3
Publish Date
1996
Start Page
725
End Page
729
DOI
10.1148/radiology.200.3.8756922

MR of focal liver lesions: comparison of breath-hold and non-breath-hold hybrid RARE and conventional spin-echo T2-weighted pulse sequences.

To compare liver lesion detection rates, tissue signal and noise data, and qualitative parameters for breath-hold (BH) and non-breath-hold (NBH) hybrid rapid acquisition with relaxation enhancement (RARE) and conventional spin-echo (CSE) T2-weighted (CSE-T2) MR sequences, 20 patients were imaged using all three sequences. Lesion detection rates were 73.5% for the CSE-T2 sequence and 81.1% and 88.6% for the BH-RARE and NBH-RARE sequences, respectively (P = .027). Mean lesion-to-liver signal-difference-to-noise ratio for the NBH-RARE sequence was 14.0 +/- 11.5, significantly greater than 9.8 +/- 7.8 obtained for the BH-RARE sequence (P = .050) and 9.0 +/- 6.2 obtained for the CSE-T2 sequence (P = .015). The NBH-RARE sequence demonstrated fewer artifacts and greater overall image quality compared to the CSE-T2 sequence. The NBH-RARE sequence is a useful alternative to the liver signal-difference-to-noise ratio and lesion detection rate and better overall image quality.

Authors
Carpenter, KD; Macaulay, SE; Schulte, SJ; Obregon, RG; Nelson, RC; Simon, HE; Schmiedl, UP
MLA Citation
Carpenter, KD, Macaulay, SE, Schulte, SJ, Obregon, RG, Nelson, RC, Simon, HE, and Schmiedl, UP. "MR of focal liver lesions: comparison of breath-hold and non-breath-hold hybrid RARE and conventional spin-echo T2-weighted pulse sequences." J Magn Reson Imaging 6.4 (July 1996): 596-602.
PMID
8835952
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
6
Issue
4
Publish Date
1996
Start Page
596
End Page
602

Timing of parenchymal enhancement on dual-phase dynamic helical CT of the liver: how long does the hepatic arterial phase predominate?

OBJECTIVE: Dual-phase dynamic helical CT is now being used to detect and characterize benign and malignant hypervascular lesions in the liver. The purpose of this study is to define the timing and degree of parenchymal enhancement of normal liver during the hepatic arterial phase. SUBJECTS AND METHODS: This prospective study included 102 patients with known or suspected hypervascular hepatic lesions who underwent dual-phase helical CT. After unenhanced CT scanning, we injected iopamidol (Isovue 300; Bracco Diagnostics, Princeton, NJ) at 3 ml/sec for 120 ml, then at 2 ml/sec for 55-60 ml. Scan delay for the hepatic arterial phase was 25 sec and for the portal venous phase was 76 sec. Section thickness was 7 mm and pitch was 1:1. Operator-defined regions of interest were obtained from all three phases. RESULTS: Mean unenhanced attenuation of the liver was 51 +/- 12 H. The liver revealed progressive enhancement during the hepatic arterial phase as follows: an increase of 10 H occurred at a mean time of 33 +/- 4 sec, 20 H at 39 +/- 6 sec, 30 H at 44 +/- 8 sec, 40 H at 46 +/- 6 sec, and 50 H at 48 +/- 5 sec. At 20 H and 30 H of enhancement, we found a statistically significant difference (p < .01) for the mean times of men and women. Mean peak enhancement during the portal venous phase was 89 +/- 23 H. CONCLUSIONS: Because the hepatic arterial contribution to liver perfusion is approximately 30%, parenchymal enhancement greater than approximately 30% of peak might indicate portal venous predominance. In our study, this percentage corresponded to an increase of approximately 30 H. Therefore, detection of hypervascular lesions in the hepatic arterial phase may be compromised when imaging lasts longer than approximately 44 sec after the initiation of contrast material injection because 44 sec was the mean time for 30 H of enhancement in our series. However, variability between patients was marked, particularly between men and women. Furthermore, the data suggests that the hepatic arterial phase may be relatively brief and that it may be difficult to image properly using current helical CT technology.

Authors
Frederick, MG; McElaney, BL; Singer, A; Park, KS; Paulson, EK; McGee, SG; Nelson, RC
MLA Citation
Frederick, MG, McElaney, BL, Singer, A, Park, KS, Paulson, EK, McGee, SG, and Nelson, RC. "Timing of parenchymal enhancement on dual-phase dynamic helical CT of the liver: how long does the hepatic arterial phase predominate?." AJR Am J Roentgenol 166.6 (June 1996): 1305-1310.
PMID
8633437
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
166
Issue
6
Publish Date
1996
Start Page
1305
End Page
1310
DOI
10.2214/ajr.166.6.8633437

CT during arterial portography: comparison of injection into the splenic versus superior mesenteric artery.

PURPOSE: To determine whether the diagnostic quality of computed tomography (CT) during arterial portography (CTAP) performed via the splenic artery (SA) is better than that performed via the superior mesenteric artery (SMA). MATERIALS AND METHODS: The authors evaluated CTAP images obtained in 98 patients from 1991 to 1994; 47 examinations were performed via the SA and 51 were performed via the SMA. Images were reviewed, by consensus, by three radiologists blinded to catheter location. Hepatic enhancement was quantitatively assessed in 53 patients (31 in the SA group, 22 in the SMA group). RESULTS: The numbers of low-attenuation non-tumor-related perfusion defects (19 in the SA group, 17 in the SMA group), high-attenuation non-tumor-related perfusion defects (six in the SA group, six in the SMA group), diffuse mottled perfusion abnormalities (six in the SA group, five in the SMA group), and portal venous flow defects (20 in the SA group, 20 in the SMA group) were similar in both groups (P > .05). Peak hepatic enhancement was similar in both groups (SMA group = 111 HU; SA group = 112 HU) (P > .05). CONCLUSION: There is no difference in quality between CTAP performed via the SA versus CTAP performed via the SMA.

Authors
McDermott, VG; Lawrance, JA; Paulson, EK; Keogan, MT; Suhocki, PV; DeLong, DM; Nelson, RC
MLA Citation
McDermott, VG, Lawrance, JA, Paulson, EK, Keogan, MT, Suhocki, PV, DeLong, DM, and Nelson, RC. "CT during arterial portography: comparison of injection into the splenic versus superior mesenteric artery." Radiology 199.3 (June 1996): 627-631.
PMID
8637977
Source
pubmed
Published In
Radiology
Volume
199
Issue
3
Publish Date
1996
Start Page
627
End Page
631
DOI
10.1148/radiology.199.3.8637977

The concentric-ring sign revisited - Reply

Authors
Provenzale, JM; Ortel, TL; Nelson, RC
MLA Citation
Provenzale, JM, Ortel, TL, and Nelson, RC. "The concentric-ring sign revisited - Reply." AMERICAN JOURNAL OF ROENTGENOLOGY 166.6 (June 1996): 1493-1493.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
166
Issue
6
Publish Date
1996
Start Page
1493
End Page
1493

Use of time during body computed tomography scanning in a tertiary care teaching hospital: focus on patient throughput.

RATIONALE AND OBJECTIVES: To control costs, it is increasingly important to make efficient use of imaging technology. We sought to determine and analyze the time required to complete each step of a body computed tomography (CT) scan, focusing on factors that influence patient throughput. METHODS: Over 4 weeks, we prospectively monitored the time required for each step of a body CT scan (i.e., image time, check time, and clear time). Covariate data were collected by patient status: outpatient, inpatient, emergency department (ED), and intensive care unit (ICU); work shift; and radiologist training level (junior resident, senior resident, fellow, and attending). Technologists also predicted whether repeat images would be requested by the radiologist. RESULTS: Three hundred eighty CT examinations were studied: 277 for outpatients, 90 for inpatients, 9 for ED patients, and 4 for ICU patients. The mean total examination time was 44.7 min (mean image time = 33.1 min, mean review time = 8.2 min, and mean clear time = 3.4 min), which did not differ significantly with patient status. A second opinion was sought from a consultant radiologist on the scans of 44 patients. Consultation was requested significantly more frequently (1) by junior residents than by senior residents or fellows and (2) for ED and ICU patients (22% and 50%, respectively) than in outpatients and inpatients (10% and 14%, respectively). Repeat images were obtained from 75 patients, and this was not significantly related to patient status, scan type, or radiologist training level. When the technologist predicted that no repeat images were needed, this prediction agreed with the radiologist in 86% of the cases. When the technologist predicted that repeat images were necessary, this prediction agreed with the radiologist in 56% of the cases. CONCLUSION: Reviewing scans before the patient leaves the CT suite adds considerably to the total time required to complete a scan, particularly if junior residents review scans. If technologists obtain repeat images at their discretion, time would be saved.

Authors
Paulson, EK; Leder, RA; Delong, DM; Keogan, MT; Moore, AR; Nelson, RC
MLA Citation
Paulson, EK, Leder, RA, Delong, DM, Keogan, MT, Moore, AR, and Nelson, RC. "Use of time during body computed tomography scanning in a tertiary care teaching hospital: focus on patient throughput." Acad Radiol 3.3 (March 1996): 254-259.
PMID
8796673
Source
pubmed
Published In
Academic Radiology
Volume
3
Issue
3
Publish Date
1996
Start Page
254
End Page
259

Ultrasonography.

Authors
Nelson, RC; Carroll, BA; Charboneau, JW; Cooperberg, PL; Frederic, MG; O'Hara, SM; Paulson, EK; Piccoli, CW; Pretorius, DH; Winter, TC
MLA Citation
Nelson, RC, Carroll, BA, Charboneau, JW, Cooperberg, PL, Frederic, MG, O'Hara, SM, Paulson, EK, Piccoli, CW, Pretorius, DH, and Winter, TC. "Ultrasonography." Radiology 198.2 (February 1996): 598-600.
PMID
8596875
Source
pubmed
Published In
Radiology
Volume
198
Issue
2
Publish Date
1996
Start Page
598
End Page
600
DOI
10.1148/radiology.198.2.8596875

A comparison of Magnetic Resonance Cholangiopancreatography (MRCP) and ERCP in the evaluation of chronic pancreatitis

Introduction: Magnetic Resonance Cholangiopancreatography (MRCP) is a novel application of MRI which may replace diagnostic ERCP in many cases. The indications for and diagnostic yield of MRCP remain to be elucidated. We performed a comparison of MRCP and ERCP in 9 cases of chronic pancreatitis. Methods: Both ERCP and MRCP were performed within a 24 hour period on 9 patients, 5 female, 4 male, median age 57 years. MRCP was performed on a 1.5 Tesla GE scanner using a phased array surface coil and respiratory gating. Axial and coronal T2 weighted flow compensated spin echo sequences with 4mm slices were used to image the pancreas, liver and bile ducts. A T1 weighted axial sequence of the pancreas was also obtained. Maximum intensity projection 3D reconstructions were then made of the pancreatic duct (PD) and biliary tree. No therapeutic procedures were performed at ERCP. The MRCP was read by two radiologists and the results compared with the ERCP films. Results: The MRCP images were of diagnostic quality in all 9 patients. At ERCP a pancreatogram was obtained in all 9 patients and a cholangiogram in 8. In the patient in whom a cholangiogram could not be obtained at ERCP, MRCP demonstrated a dilated biliary tree. In the same patient, ERCP revealed a PD cutoff while MRCP defined a common bile duct stricture and visualized the dilated PD upstream from (proximal to) the stricture. Finally, PD calculi not seen at ERCP were detected in 2 cases by MRCP. Pancreatic duct abnormalities including side branch changes were detected by MRCP in all 9 cases. Conclusion: MRCP compares well with ERCP in assessing the pancreatic duct. In our series, MRCP successfully demonstrated all clinically significant abnormalities seen on ERCP. MRCP may provide complementary information to ERCP such as PD calculi and pancreatic ductal anatomy proximal to the site of an obstruction.

Authors
Andrew, PTM; Maniatis, AG; Jowell, PS; Keogan, M; Nelson, R; Spritzer, C; Branch, MS; Baillie, J
MLA Citation
Andrew, PTM, Maniatis, AG, Jowell, PS, Keogan, M, Nelson, R, Spritzer, C, Branch, MS, and Baillie, J. "A comparison of Magnetic Resonance Cholangiopancreatography (MRCP) and ERCP in the evaluation of chronic pancreatitis." Gastrointestinal Endoscopy 43.4 (1996): 388--.
Source
scival
Published In
Gastrointestinal Endoscopy
Volume
43
Issue
4
Publish Date
1996
Start Page
388-

Technique for MR imaging of the liver.

Authors
Saini, S; Nelson, RC
MLA Citation
Saini, S, and Nelson, RC. "Technique for MR imaging of the liver." Radiology 197.3 (December 1995): 575-577.
PMID
7480718
Source
pubmed
Published In
Radiology
Volume
197
Issue
3
Publish Date
1995
Start Page
575
End Page
577
DOI
10.1148/radiology.197.3.7480718

Aberrant venous drainage to the liver: imaging implications.

Authors
Nelson, RC; McDermott, VG; Paulson, EK
MLA Citation
Nelson, RC, McDermott, VG, and Paulson, EK. "Aberrant venous drainage to the liver: imaging implications." Radiology 197.2 (November 1995): 338-340.
PMID
7480673
Source
pubmed
Published In
Radiology
Volume
197
Issue
2
Publish Date
1995
Start Page
338
End Page
340
DOI
10.1148/radiology.197.2.7480673

95TH ANNUAL-MEETING OF THE ARRS - CASE OF THE DAY WINNERS

Authors
NELSON, RC
MLA Citation
NELSON, RC. "95TH ANNUAL-MEETING OF THE ARRS - CASE OF THE DAY WINNERS." AMERICAN JOURNAL OF ROENTGENOLOGY 165.3 (September 1995): 710-710.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
165
Issue
3
Publish Date
1995
Start Page
710
End Page
710

MR cholangiopancreatography: efficacy of three-dimensional turbo spin-echo technique.

Authors
McDermott, VG; Nelson, RC
MLA Citation
McDermott, VG, and Nelson, RC. "MR cholangiopancreatography: efficacy of three-dimensional turbo spin-echo technique." AJR Am J Roentgenol 165.2 (August 1995): 301-302.
PMID
7618544
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
165
Issue
2
Publish Date
1995
Start Page
301
End Page
302
DOI
10.2214/ajr.165.2.7618544

Adrenal hemorrhage in patients with primary antiphospholipid syndrome: imaging findings.

OBJECTIVE: The primary antiphospholipid syndrome consists of recurrent thromboses, early stroke, recurrent fetal loss, and livedo reticularis in patients with antiphospholipid antibodies and without systemic lupus erythematosus. The purpose of this study was to analyze the imaging findings in patients who had this syndrome as well as adrenal hemorrhage. MATERIALS AND METHODS: The medical records and reports of radiologic examinations of 228 patients with elevated titers of lupus anticoagulant or anticardiolipin antibodies from January 1992 to April 1994 were examined for indications of adrenal hemorrhage. Four patients (two men and two women 38-78 years old) were identified as having adrenal hemorrhage. The abdominal CT and MR imaging findings for three patients and autopsy data for the fourth patient were analyzed. RESULTS: Adrenal hemorrhage was seen in all three patients who underwent abdominal CT and in one patient who underwent MR imaging. Adrenal hemorrhage was bilateral in three patients. Extension of hemorrhage into the perinephric space was present in two patients. Associated clinical findings probably attributable to the presence of antiphospholipid antibodies included amaurosis fugax (two patients), deep venous thrombosis (three patients), and transient ischemic attacks or stroke (two patients). CONCLUSION: Antiphospholipid antibodies appear to be a risk factor for adrenal hemorrhage. The presence of these antibodies should be suspected in patients who have adrenal hemorrhage as well as recurrent thromboses and early stroke.

Authors
Provenzale, JM; Ortel, TL; Nelson, RC
MLA Citation
Provenzale, JM, Ortel, TL, and Nelson, RC. "Adrenal hemorrhage in patients with primary antiphospholipid syndrome: imaging findings." AJR Am J Roentgenol 165.2 (August 1995): 361-364.
PMID
7618557
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
165
Issue
2
Publish Date
1995
Start Page
361
End Page
364
DOI
10.2214/ajr.165.2.7618557

RE - MR-CHOLANGIOPANCREATOGRAPHY - EFFICACY OF 3-DIMENSIONAL TURBO SPIN-ECHO TECHNIQUE

Authors
MCDERMOTT, VG; NELSON, RC
MLA Citation
MCDERMOTT, VG, and NELSON, RC. "RE - MR-CHOLANGIOPANCREATOGRAPHY - EFFICACY OF 3-DIMENSIONAL TURBO SPIN-ECHO TECHNIQUE." AMERICAN JOURNAL OF ROENTGENOLOGY 165.2 (August 1995): 301-302.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
165
Issue
2
Publish Date
1995
Start Page
301
End Page
302

Musculoskeletal case of the day. Giant cell tumor of the sacrum.

Authors
Nguyen, TP; Burk, DL
MLA Citation
Nguyen, TP, and Burk, DL. "Musculoskeletal case of the day. Giant cell tumor of the sacrum." AJR. American journal of roentgenology 165.1 (July 1995): 201-202.
PMID
7785596
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
165
Issue
1
Publish Date
1995
Start Page
201
End Page
202
DOI
10.2214/ajr.165.1.7785596

ARRS 1995 CASE OF THE DAY

Authors
NELSON, RC
MLA Citation
NELSON, RC. "ARRS 1995 CASE OF THE DAY." AMERICAN JOURNAL OF ROENTGENOLOGY 165.1 (July 1995): 185-185.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
165
Issue
1
Publish Date
1995
Start Page
185
End Page
185

DONT UPSET MY EQUILIBRIUM AGAIN - REPLY

Authors
SMALL, WC; BERNARDINO, ME; NELSON, RC
MLA Citation
SMALL, WC, BERNARDINO, ME, and NELSON, RC. "DONT UPSET MY EQUILIBRIUM AGAIN - REPLY." AMERICAN JOURNAL OF ROENTGENOLOGY 164.4 (April 1995): 1023-1024.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
164
Issue
4
Publish Date
1995
Start Page
1023
End Page
1024

Imaging in the preoperative evaluation of adult liver-transplant candidates: goals, merits of various procedures, and recommendations.

Advances in organ procurement and surgical techniques have made orthotopic liver transplantation (OLT) an accepted treatment for many adult patients with end-stage hepatic disease. At present, OLT is being performed in patients with a variety of diseases, and 5-year survival is estimated at 65-78% [1]. Over 80% of hepatic transplants are performed in patients with cirrhosis or primary cholestatic liver disease, and only 5% of transplants are performed for malignant hepatic neoplasms (Table 1) [2]. Because the supply of donor organs is limited, preoperative clinical and radiologic evaluation of the transplant candidate is critical for appropriate patient selection. The main objective of preoperative imaging is to provide the surgeon with the pertinent information needed to plan and perform OLT and to exclude patients for whom surgery either is not feasible or will be of no benefit.

Authors
Redvanly, RD; Nelson, RC; Stieber, AC; Dodd, GD
MLA Citation
Redvanly, RD, Nelson, RC, Stieber, AC, and Dodd, GD. "Imaging in the preoperative evaluation of adult liver-transplant candidates: goals, merits of various procedures, and recommendations." AJR Am J Roentgenol 164.3 (March 1995): 611-617.
PMID
7863881
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
164
Issue
3
Publish Date
1995
Start Page
611
End Page
617
DOI
10.2214/ajr.164.3.7863881

Ultrasonography.

Authors
Nelson, RC; Carroll, BA; Cooperberg, PL; Gordon, PB; Mack, LA; Madrazo, BL; Paulson, EK; Pretorius, DH
MLA Citation
Nelson, RC, Carroll, BA, Cooperberg, PL, Gordon, PB, Mack, LA, Madrazo, BL, Paulson, EK, and Pretorius, DH. "Ultrasonography." Radiology 194.2 (February 1995): 619-626.
PMID
7824754
Source
pubmed
Published In
Radiology
Volume
194
Issue
2
Publish Date
1995
Start Page
619
End Page
626
DOI
10.1148/radiology.194.2.7824754

Sterilization with Methyl Cyanoacrylate-induced Fallopian Tube Occlusion from a Nonsurgical Transvaginal Approach in Rabbits

Purpose: To evaluate a nonsurgical, nonhormonal sterilization procedure performed with use of transvaginal microcatheterization techniques and methyl cyanoacrylate (MCA) as a sclerosing agent. Materials and Methods: Seventeen adult virgin female rabbits underwent bilateral fallopian tube cannulation through a nonsurgical transvaginal approach with use of a coaxial catheter system with fluoroscopic guidance. Fourteen of the rabbits underwent bilateral fallopian tube occlusion with direct MCA injection; the remaining three rabbits were separated as controls. Three of the rabbits with occlusions were killed as temporal histologic controls. The remaining 11 rabbits with occlusions and the initial three controls underwent 6 months of mating trials. All 17 rabbits were killed. Gross inspection was performed and histologic specimens of their fallopian tubes were obtained. Results: None of the 11 rabbits with occlusions that underwent mating became pregnant. All three control rabbits became pregnant. Histologic examination of the occluded fallopian tubes demonstrated long-segment tubal wall fibrosis with varying degrees of occlusion. No peritoneal abnormalities were identified. Histologic findings for the three control animals were normal. Conclusion: With use of a nonsurgical transcervical coaxial catheter system, MCA can be placed directly into fallopian tubes without difficulty. MCA administration leads to fallopian tube fibrosis and occlusion. A 100% nonpregnancy rate was demonstrated. Further investigation may lead to a safer, more convenient, and less expensive form of permanent sterilization. © 1995 Society of Interventional Radiology.

Authors
Berkey, GS; Nelson, R; Zuckerman, AM; Dillehay, D; Cope, C
MLA Citation
Berkey, GS, Nelson, R, Zuckerman, AM, Dillehay, D, and Cope, C. "Sterilization with Methyl Cyanoacrylate-induced Fallopian Tube Occlusion from a Nonsurgical Transvaginal Approach in Rabbits." Journal of Vascular and Interventional Radiology 6.5 (1995): 669-674.
PMID
8541665
Source
scival
Published In
JVIR: Journal of Vascular and Interventional Radiology
Volume
6
Issue
5
Publish Date
1995
Start Page
669
End Page
674
DOI
10.1016/S1051-0443(95)71161-7

Neuroradiology case of the day

Authors
Nelson, RC; Enterline, DS; Davey, NC; Tien, RD; Garabedian, V
MLA Citation
Nelson, RC, Enterline, DS, Davey, NC, Tien, RD, and Garabedian, V. "Neuroradiology case of the day." American Journal of Roentgenology 165.1 (1995): 212-215.
Source
scival
Published In
American Journal of Roentgenology
Volume
165
Issue
1
Publish Date
1995
Start Page
212
End Page
215

Pediatric radiology case of the day

Authors
Nelson, RC; Dentino, CM; Frush, DP; III, GSB
MLA Citation
Nelson, RC, Dentino, CM, Frush, DP, and III, GSB. "Pediatric radiology case of the day." American Journal of Roentgenology 165.1 (1995): 207-211.
Source
scival
Published In
American Journal of Roentgenology
Volume
165
Issue
1
Publish Date
1995
Start Page
207
End Page
211

Genitourinary case of the day

Authors
Nelson, RC; Leder, RA; Frederick, MG; Hall, BP; Elenberger, CD
MLA Citation
Nelson, RC, Leder, RA, Frederick, MG, Hall, BP, and Elenberger, CD. "Genitourinary case of the day." American Journal of Roentgenology 165.1 (1995): 197-200.
Source
scival
Published In
American Journal of Roentgenology
Volume
165
Issue
1
Publish Date
1995
Start Page
197
End Page
200

Chest case of the day

Authors
Nelson, RC; McAdams, HP; McElaney, B; Erasmus, J
MLA Citation
Nelson, RC, McAdams, HP, McElaney, B, and Erasmus, J. "Chest case of the day." American Journal of Roentgenology 165.1 (1995): 186-191.
Source
scival
Published In
American Journal of Roentgenology
Volume
165
Issue
1
Publish Date
1995
Start Page
186
End Page
191

MR cholangiopancreatography: Efficacy of three-dimensional turbo spin- echo technique

OBJECTIVE. The purpose of this study was to correlate a new three- dimensional turbo spin-echo MR cholangiopancreatography technique with endoscopic cholangiopancreatography or percutaneous cholangiography to determine the efficacy of the new technique for visualizing and diagnosing diseases of the pancreatic and biliary ducts. It was hypothesized that the new technique would provide diagnostic images without prolonged breath holding or a surface coil as required by previous MR techniques. SUBJECTS AND METHODS. We describe a respiratory-triggered, heavily T2-weighted, three- dimensional, multislab turbo spin-echo sequence for MR cholangiopancreatography. Thirty patients with suspected biliary or pancreatic disease were randomly selected from referrals for endoscopic retrograde cholangiopancreatography. All patients were imaged with the optimized MR technique prior to attempted endoscopic or percutaneous cholangiopancreatography. The MR images were evaluated without additional clinical or radiographic information by consensus opinion of two of the authors for visualization and caliber of the ducts. When the ducts were abnormal, the level and probable cause were categorized as follows: normal, periampullary stricture, localized duct stenosis, multifocal strictures, calculous disease, duct anomalies, and cystic disease. The images obtained by conventional percutaneous or endoscopic cholangiopancreatography were evaluated in the same manner with the exception that additional clinical and radiologic information was provided. The diagnostic categories determined by MR and direct cholangiopancreatography were compared. Patients were included in the analysis only if endoscopic or percutaneous opacification of the biliary or pancreatic ducts was successful. RESULTS. Diagnostic MR images were obtained in 29 (97%) of 30 patients. Endoscopic or percutaneous cholangiopancreatography was successful in 21 of the 29 patients for the common bile duct and in 17 of the 29 patients for the pancreatic duct. The diagnosis for the common bile duct by the MR technique agreed with the diagnosis by endoscopic or percutaneous cholangiopancreatography in 19 (90%) of 21 patients. For diagnosis of diseases of the pancreatic duct, there was agreement in 15 (88%) of 17 patients. CONCLUSION. Respiratory-triggered, multislab, three-dimensional turbo spin-echo MR cholangiopancreatography is a noninvasive technique for visualization of the pancreatic and biliary ductal systems. It is capable of providing diagnostic information equivalent to invasive techniques in a large percentage of patients and should be the technique of choice when invasive techniques are incomplete, unsuccessful, or technically difficult.

Authors
Barish, MA; Yuce, EK; Soto, JA; Chuttani, R; Ferrucci, JT; McDermott, VG; Nelson, RC
MLA Citation
Barish, MA, Yuce, EK, Soto, JA, Chuttani, R, Ferrucci, JT, McDermott, VG, and Nelson, RC. "MR cholangiopancreatography: Efficacy of three-dimensional turbo spin- echo technique." American Journal of Roentgenology 165.2 (1995): 295-302.
PMID
7618543
Source
scival
Published In
American Journal of Roentgenology
Volume
165
Issue
2
Publish Date
1995
Start Page
295
End Page
302

Gastrointestinal case of the day

Authors
Paulson, EK; Keogan, MT; Folz, EK; McGee, SG; Low, VHS; Nelson, RC
MLA Citation
Paulson, EK, Keogan, MT, Folz, EK, McGee, SG, Low, VHS, and Nelson, RC. "Gastrointestinal case of the day." American Journal of Roentgenology 165.1 (1995): 192-196.
Source
scival
Published In
American Journal of Roentgenology
Volume
165
Issue
1
Publish Date
1995
Start Page
192
End Page
196

Induced pneumoperitoneum in CT evaluation of peritoneal carcinomatosis

Background: Imaging of peritoneal carcinomatosis is a well-known problem even for technologies as recent as computed tomography (CT). The purpose of this study was to evaluate whether CT performed after induced pneumoperitoneum (CT-PP) could have a higher sensitivity in the detection of peritoneal implants over conventional CT. Methods: Five patients with known ovarian malignancies underwent standard CT and CT-PP. Exploratory laparotomy was performed with a maximum interval of 7 days from the last imaging procedure. Results were prospectively compared with surgical findings on a compartment to compartment basis. Results: CT-PP was well-tolerated with no serious adverse reactions registered. The anterior and visceral peritoneum, the paracolic gutters and subphrenic areas were particularly well depicted but not the pelvis which was poorly evaluated in all cases. CT-PP detected all the three cases where peritoneal carcinomatosis was present even when metastatic nodules were smaller than 2 mm; it also showed intraabdominal adhesions in two patients, an important finding that precludes the use of intraperitoneal chemotherapy. Conclusions: With CT-PP there seems to be a reduction in the threshold of detectability of peritoneal implants. The direct demonstration of intraperitoneal adhesions is an important secondary finding. Disadvantages of CT-PP are (1) it is a time-consuming method and (2) it does not evaluate all the peritoneal recesses potentially involved in peritoneal carcinomatosis.

Authors
Caseiro-Alves, F; Goncalo, M; Abraul, E; Pinto, E; Oliveira, C; Ramos, V; Nelson, RC; Frederick, MG
MLA Citation
Caseiro-Alves, F, Goncalo, M, Abraul, E, Pinto, E, Oliveira, C, Ramos, V, Nelson, RC, and Frederick, MG. "Induced pneumoperitoneum in CT evaluation of peritoneal carcinomatosis." Abdominal Imaging 20.1 (1995): 52-55.
Source
scival
Published In
Abdominal Imaging
Volume
20
Issue
1
Publish Date
1995
Start Page
52
End Page
55
DOI
10.1007/BF00199645

Peritoneal carcinomatosis

Authors
Nelson, RC; Frederick, MG
MLA Citation
Nelson, RC, and Frederick, MG. "Peritoneal carcinomatosis." Abdominal Imaging 20.1 (1995): 56-57.
Source
scival
Published In
Abdominal Imaging
Volume
20
Issue
1
Publish Date
1995
Start Page
56
End Page
57
DOI
10.1007/BF00199646

Practical CT of the liver.

Authors
Nelson, RC; Small, WC
MLA Citation
Nelson, RC, and Small, WC. "Practical CT of the liver." AJR Am J Roentgenol 163.4 (October 1994): 988-.
PMID
8092049
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
163
Issue
4
Publish Date
1994
Start Page
988
DOI
10.2214/ajr.163.4.8092049

WHAT IS THE MOST PRACTICAL STRATEGY TO PERFORM CT SCANNING OF THE LIVER

Authors
NELSON, RC; SMALL, WC
MLA Citation
NELSON, RC, and SMALL, WC. "WHAT IS THE MOST PRACTICAL STRATEGY TO PERFORM CT SCANNING OF THE LIVER." AMERICAN JOURNAL OF ROENTGENOLOGY 163.4 (October 1994): 988-988.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
163
Issue
4
Publish Date
1994
Start Page
988
End Page
988

Recurrent tumor after resection of hepatic metastases from colorectal carcinoma: location and time of discovery as determined by CT.

OBJECTIVE: Despite studies showing increased survival rates for patients after surgical resection of hepatic metastases, recurrences occur in 75% of treated patients. The purpose of this study was to determine the location and time of discovery of recurrent tumor on CT scans after resection of hepatic metastases from colorectal carcinoma. MATERIALS AND METHODS: In a 6-year period, 32 patients (16 men and 16 women) who had undergone partial hepatic resection for colorectal metastases had follow-up CT at our institution. A total of 125 CT examinations of the chest and abdomen were retrospectively reviewed for the presence and location of recurrent disease. Recurrence was either confirmed by biopsy (n = 12) or presumed on the basis of growth of new lesions (n = 17). RESULTS: With a mean follow-up of 22 months (range, 1-60 months), recurrence was found at 29 sites in 25 patients. Thirteen sites were hepatic, and 16 were extrahepatic. Three patients had both hepatic and pulmonary disease. Recurrence within the liver was away from surgical margins in 11 (85%) of 13 patients at 14 +/- 7 months and adjacent to a surgical margin in the remaining two patients (15%) at 17 +/- 1 months. Extrahepatic recurrences were discovered in the lung in 11 (69%) of 16 patients at 21 +/- 12 months; in an adrenal gland in two patients (13%) at 19 +/- 5 months; in lymph nodes of the porta hepatis in one patient (6%) at 11 months; at the primary colonic anastomosis in one patient (6%) at 3 months; and in a retroperitoneal lymph node in the remaining patient (6%) at 12 months. CONCLUSION: Surgery was effective in treating the preoperatively detected hepatic metastases. Only two of 25 patients had recurrence related to a hepatic surgical margin. Most recurrences occur more than 1 year after surgery, most often in lung or liver away from surgical margins, and they probably represent small metastases undetectable with current preoperative or intraoperative techniques.

Authors
Harned, RK; Chezmar, JL; Nelson, RC
MLA Citation
Harned, RK, Chezmar, JL, and Nelson, RC. "Recurrent tumor after resection of hepatic metastases from colorectal carcinoma: location and time of discovery as determined by CT." AJR Am J Roentgenol 163.1 (July 1994): 93-97.
PMID
8010256
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
163
Issue
1
Publish Date
1994
Start Page
93
End Page
97
DOI
10.2214/ajr.163.1.8010256

MR detection of leakage from silicone breast implants: value of a silicone-selective pulse sequence.

OBJECTIVE: The purpose of this study was to determine the value of MR imaging with a silicone-selective pulse sequence for detecting leakage from silicone breast implants. SUBJECTS AND METHODS: Women with silicone breast implants were referred for this study on the basis of clinical or imaging findings suggestive of implant rupture. Twenty-eight patients with 38 implants were examined with silicone-selective MR imaging and also underwent surgical removal of the studied implant. All but four also had mammography before MR imaging. Results of silicone-selective MR imaging for the detection of silicone leakage were compared with mammographic and surgical findings. Surgical proof was considered the gold standard. RESULTS: Silicone-selective MR imaging showed an apparently intact implant in 21 cases; 20 of these were found to be intact at surgery. Silicone-selective MR imaging showed evidence of leakage in 17 implants, all of which showed leakage at surgery. The sensitivity for detection of leakage was 94%; the specificity was 100%. The findings of silicone-selective MR imaging and mammography were in agreement in 30 of 34 cases in which both studies were performed. In the four cases of disagreement, surgical findings agreed with MR findings in three and with mammographic findings in one. When the findings of mammography and silicone-selective MR imaging were combined, the correct status (leakage or no leakage) of all implants examined was determinable. CONCLUSION: Silicone-selective MR imaging is highly effective for detecting leakage from silicone breast implants. Accuracy is improved when mammographic and MR findings are considered together.

Authors
Monticciolo, DL; Nelson, RC; Dixon, WT; Bostwick, J; Mukundan, S; Hester, TR
MLA Citation
Monticciolo, DL, Nelson, RC, Dixon, WT, Bostwick, J, Mukundan, S, and Hester, TR. "MR detection of leakage from silicone breast implants: value of a silicone-selective pulse sequence." AJR Am J Roentgenol 163.1 (July 1994): 51-56.
PMID
8010247
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
163
Issue
1
Publish Date
1994
Start Page
51
End Page
56
DOI
10.2214/ajr.163.1.8010247

Contrast-enhanced spiral CT of the liver: effect of different amounts and injection rates of contrast material on early contrast enhancement.

OBJECTIVE: Spiral CT allows rapid hepatic imaging during a single breath-hold. The increase in imaging speed potentially allows contrast material to be used more efficaciously than with conventional dynamic CT, perhaps allowing a decrease in the volume of required contrast agent. To determine how this can be accomplished, we studied the effect of different bolus IV injection rates and amounts of contrast material on early hepatic enhancement during dynamic bolus spiral CT. SUBJECTS AND METHODS: A group of 20 healthy male volunteers were divided into four groups of five each. The groups received 75, 100, 125, or 150 ml of contrast material (Omnipaque 300, 300 mg l/ml). Each person within each group was scanned as contrast material was injected at rates of 3, 4, and 5 ml/sec. Hepatic enhancement was evaluated by comparing quantitative regions of interest before and after bolus injection of contrast material. Variations in enhancement produced by changes in volume and injection rate of contrast material were evaluated on early, middle, and late sections of the spiral, corresponding to 32-34, 41-43, and 51-53 sec, respectively, after the injection of contrast material was begun. RESULTS: Hepatic enhancement increased more rapidly when the bolus of contrast material was given at a rate of 5 ml/sec than at the slower rates of 3 or 4 ml/sec. Enhancement of the liver was greatest at the late portion of the spiral (51-53 sec after start of the bolus injection), averaging 73 and 79 H for volumes of 125 and 150 ml, respectively, at 5 ml/sec, and the enhancement was still increasing at that time. Enhancement curves predict 50- and 70-H mean increases in hepatic attenuation on initial slices with scan delays of approximately 40 and 50 sec, respectively, for these two protocols. CONCLUSION: Our results demonstrate that there is a marked dependence on early hepatic enhancement produced by variations in volume and injection rate of contrast material. We found no difference in the results produced by 125- and 150-ml volumes. These results are important for maximizing the effectiveness of IV contrast material during rapid hepatic spiral CT scanning.

Authors
Small, WC; Nelson, RC; Bernardino, ME; Brummer, LT
MLA Citation
Small, WC, Nelson, RC, Bernardino, ME, and Brummer, LT. "Contrast-enhanced spiral CT of the liver: effect of different amounts and injection rates of contrast material on early contrast enhancement." AJR Am J Roentgenol 163.1 (July 1994): 87-92.
PMID
8010255
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
163
Issue
1
Publish Date
1994
Start Page
87
End Page
92
DOI
10.2214/ajr.163.1.8010255

Splenic magnetic resonance imaging using particulate agents.

Authors
Small, WC; Nelson, RC; Sherbourne, GM; Bernardino, ME
MLA Citation
Small, WC, Nelson, RC, Sherbourne, GM, and Bernardino, ME. "Splenic magnetic resonance imaging using particulate agents." Invest Radiol 29 Suppl 2 (June 1994): S12-S14.
PMID
7928204
Source
pubmed
Published In
Investigative Radiology
Volume
29 Suppl 2
Publish Date
1994
Start Page
S12
End Page
S14

Enhancement effects of a hepatocyte receptor-specific MR contrast agent in an animal model.

The enhancement characteristics of the liver and spleen produced by a hepatocyte-specific magnetic resonance imaging agent, an arabinogalactan-coated ultrasmall superparamagnetic iron oxide derivative, BMS 180550, were evaluated. Both heavily T1- and T2-weighted sequences were used. Imaging was performed in the farm pig model, as a function of contrast agent concentration (5, 10, and 20 mumol of iron per kilogram) and delay (immediate, 0.5, 2.5, 5.0, 7.5, and 9.0 hours) after bolus injection of BMS 180550. BMS 180550 provided excellent contrast enhancement characteristics by producing marked positive enhancement with T1-weighted sequences and marked negative enhancement with T2-weighted sequences. The T1-weighted enhancement immediately after contrast agent injection was of greater magnitude in the spleen (329% +/- 83) than in the liver (66% +/- 16). Postcontrast negative enhancement with T2-weighted sequences was largely hepatocyte specific at 5 and 10 mumol/kg but was also seen within the spleen at 20 mumol/kg. The authors discuss the possible mechanisms that produce these changes and conclude that 10 mumol/kg BMS 180550 is near the optimum dose for maximizing the enhancement properties of this agent with all sequences in the farm pig.

Authors
Small, WC; Nelson, RC; Sherbourne, GM; Bernardino, ME
MLA Citation
Small, WC, Nelson, RC, Sherbourne, GM, and Bernardino, ME. "Enhancement effects of a hepatocyte receptor-specific MR contrast agent in an animal model." J Magn Reson Imaging 4.3 (May 1994): 325-330.
PMID
8061429
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
4
Issue
3
Publish Date
1994
Start Page
325
End Page
330

Abdominal-gastrointestinal radiology.

Authors
Balfe, DM; Baker, ME; Chezmar, JL; de Lange, EE; Lichtenstein, JE; Nelson, RC; Ros, PR
MLA Citation
Balfe, DM, Baker, ME, Chezmar, JL, de Lange, EE, Lichtenstein, JE, Nelson, RC, and Ros, PR. "Abdominal-gastrointestinal radiology." Radiology 190.2 (February 1994): 597-598.
PMID
8284425
Source
pubmed
Published In
Radiology
Volume
190
Issue
2
Publish Date
1994
Start Page
597
End Page
598
DOI
10.1148/radiology.190.2.8284425

Radiological evaluation of metastases to the liver: The Emory experience.

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Radiological evaluation of metastases to the liver: The Emory experience." Cancer Treat Res 69 (1994): 129-146. (Review)
PMID
8031646
Source
pubmed
Published In
Cancer Treatment and Research
Volume
69
Publish Date
1994
Start Page
129
End Page
146

Combined CT arterial portography and CT hepatic angiography for evaluation of the hepatic resection candidate. Work in progress.

PURPOSE: To determine whether the addition of computed tomographic (CT) angiography to CT arterial portography would improve lesion detection and heighten confidence in interpreting perfusion abnormalities. MATERIALS AND METHODS: The two examinations were performed sequentially in 10 candidates for surgical resection of hepatic tumors. Arterial vascular access was obtained with bilateral punctures of the common femoral artery and selective placement of angiographic catheters in the hepatic artery and superior mesenteric artery (SMA). CT scans were obtained first during injection of contrast material into the SMA, followed by repeated imaging of the liver during injection of contrast material into the hepatic artery. RESULTS: The procedure demonstrated, among other results, three additional lesions in two patients, a possibly nontumorous abnormality as tumorous in one, and a suspected tumorous abnormality as nontumorous in one. Suspected nontumorous abnormalities in four patients were confirmed at CT angiography. CONCLUSION: These preliminary data support a trial of this technique in a larger population.

Authors
Chezmar, JL; Bernardino, ME; Kaufman, SH; Nelson, RC
MLA Citation
Chezmar, JL, Bernardino, ME, Kaufman, SH, and Nelson, RC. "Combined CT arterial portography and CT hepatic angiography for evaluation of the hepatic resection candidate. Work in progress." Radiology 189.2 (November 1993): 407-410.
PMID
8210367
Source
pubmed
Published In
Radiology
Volume
189
Issue
2
Publish Date
1993
Start Page
407
End Page
410
DOI
10.1148/radiology.189.2.8210367

MR imaging of silicone gel-filled breast implants in vivo with a method that visualizes silicone selectively.

The lack of an adequately sensitive method for detecting silicone leakage and reported serious complications due to silicone leakage were cited as justification by the U.S. Food and Drug Administration for imposing the current restrictions on silicone gel-filled breast prostheses. The authors report a new magnetic resonance imaging method for visualizing silicone leakage: the silicone-only sequence (SOS). The method uses the conventional STIR (short-inversion-time inversion-recovery) technique combined with a 1331 radio-frequency pulse train widely used for water suppression in spectroscopy. With the SOS, silicone can be imaged while signals from fat and water are suppressed. The authors used the SOS to image phantoms and normal and ruptured silicone gel-filled breast prostheses.

Authors
Mukundan, S; Dixon, WT; Kruse, BD; Monticciolo, DL; Nelson, RC
MLA Citation
Mukundan, S, Dixon, WT, Kruse, BD, Monticciolo, DL, and Nelson, RC. "MR imaging of silicone gel-filled breast implants in vivo with a method that visualizes silicone selectively." J Magn Reson Imaging 3.5 (September 1993): 713-717.
PMID
8400556
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
3
Issue
5
Publish Date
1993
Start Page
713
End Page
717

Splenic venous flow exceeding portal venous flow at Doppler sonography: relationship to portosystemic varices.

OBJECTIVE: The purpose of this study was to determine if the Doppler sonographic finding of hepatopetal flow in the splenic vein that exceeds hepatopetal flow in the portal vein is associated with portosystemic varices. MATERIALS AND METHODS: Sixty-four patients with chronic liver disease were studied retrospectively. In 32 patients, splenic venous flow exceeded portal venous flow (S > P group); in 32 patients, portal venous flow exceeded splenic venous flow (P > S group). All patients were evaluated with Doppler sonography and CT of the upper part of the abdomen. Upper endoscopy was performed within 3 months of sonography in 44 of the 64 patients. RESULTS: In the S > P group, mean splenic volume was significantly larger (p = .02) than in the other group. The prevalence of varices as determined by CT in the esophageal, coronary, and peripancreatic regions was also higher in this group (p < or = .01). When esophageal varices were present, they were judged on the basis of their CT appearance to be massive in 50% of the S > P group and in 0% of the P > S group. Upper endoscopy revealed esophageal varices in 92% of the S > P group and in 55% of the P > S group (p < .005). Bleeding esophageal varices were noted in 75% of the S > P group and in 30% of the P > S group (p < .01). CONCLUSION: Patients with chronic liver disease and the Doppler sonographic finding of splenic venous flow that exceeds portal venous flow have an increased prevalence of portosystemic varices, which tend to be larger and more likely to bleed.

Authors
Nelson, RC; Sherbourne, GM; Spencer, HB; Chezmar, JL
MLA Citation
Nelson, RC, Sherbourne, GM, Spencer, HB, and Chezmar, JL. "Splenic venous flow exceeding portal venous flow at Doppler sonography: relationship to portosystemic varices." AJR Am J Roentgenol 161.3 (September 1993): 563-567.
PMID
8352105
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
161
Issue
3
Publish Date
1993
Start Page
563
End Page
567
DOI
10.2214/ajr.161.3.8352105

"Keyhole" method for accelerating imaging of contrast agent uptake.

Magnetic resonance (MR) imaging methods with good spatial and contrast resolution are often too slow to follow the uptake of contrast agents with the desired temporal resolution. Imaging can be accelerated by skipping the acquisition of data normally taken with strong phase-encoding gradients, restricting acquisition to weak-gradient data only. If the usual procedure of substituting zeroes for the missing data is followed, blurring results. Substituting instead reference data taken before or well after contrast agent injection reduces this problem. Volunteer and patient images obtained by using such reference data show that imaging can be usefully accelerated severalfold. Cortical and medullary regions of interest and whole kidney regions were studied, and both gradient- and spin-echo images are shown. The method is believed to be compatible with other acceleration methods such as half-Fourier reconstruction and reading of more than one line of k space per excitation.

Authors
van Vaals, JJ; Brummer, ME; Dixon, WT; Tuithof, HH; Engels, H; Nelson, RC; Gerety, BM; Chezmar, JL; den Boer, JA
MLA Citation
van Vaals, JJ, Brummer, ME, Dixon, WT, Tuithof, HH, Engels, H, Nelson, RC, Gerety, BM, Chezmar, JL, and den Boer, JA. ""Keyhole" method for accelerating imaging of contrast agent uptake." J Magn Reson Imaging 3.4 (July 1993): 671-675.
PMID
8347963
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
3
Issue
4
Publish Date
1993
Start Page
671
End Page
675

Pathology and imaging of hepatocellular neoplasms: are findings from Asian populations applicable to non-Asian groups?

Authors
Nelson, RC; Chezmar, JL
MLA Citation
Nelson, RC, and Chezmar, JL. "Pathology and imaging of hepatocellular neoplasms: are findings from Asian populations applicable to non-Asian groups?." AJR Am J Roentgenol 160.6 (June 1993): 1188-1190.
PMID
8388619
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
160
Issue
6
Publish Date
1993
Start Page
1188
End Page
1190
DOI
10.2214/ajr.160.6.8388619

Magnetic resonance imaging after arterial portography with manganese dipyridoxal diphosphate.

RATIONALE AND OBJECTIVES: The authors assess performing hepatic magnetic resonance imaging (MRI) after arterial portography with manganese dipyridoxal diphosphate (MnD-PDP), a hepatobiliary contrast agent, as an invasive but potentially highly sensitive means of focal lesion detection. METHODS: Eight pigs underwent superior mesenteric artery catheterization and injection of 10 mumol/kg MnDPDP. Magnetic resonance imaging at 1.5 T (SE-140/10) was performed before, then at 15 and 30 minutes after injection. Seven or more days later, the same MRI protocol was performed after intravenous injection of 10 mumol/kg MnDPDP. RESULTS: Fifteen minutes after intra-arterial injection, enhancement of the liver predominated (86 +/- 13%), followed by the renal cortex (44 +/- 14%), pancreas (26 +/- 9%), and spleen (14 +/- 9%). At 30 minutes, enhancement of renal cortex significantly increased (50 +/- 14%). There was no significant difference in enhancement of the liver, spleen, pancreas, or renal cortex when we compared intra-arterial and intravenous administration. CONCLUSION: After the injection of 10 mumol/kg MnDPDP into the superior mesenteric artery of pigs there is no significant difference in visceral organ enhancement compared to intravenous administration. The data suggests that the hepatocyte binding sites may be overwhelmed by this dose and/or injection rate of MnDPDP.

Authors
Nelson, RC; Chezmar, JL; Thompson, GH; Webber, JB; Garrison, MH; Spencer, HB; Dillehay, DL
MLA Citation
Nelson, RC, Chezmar, JL, Thompson, GH, Webber, JB, Garrison, MH, Spencer, HB, and Dillehay, DL. "Magnetic resonance imaging after arterial portography with manganese dipyridoxal diphosphate." Invest Radiol 28.4 (April 1993): 335-340.
PMID
8478175
Source
pubmed
Published In
Investigative Radiology
Volume
28
Issue
4
Publish Date
1993
Start Page
335
End Page
340

Hepatic arterial resistive indices: correlation with the severity of cirrhosis.

Forty-three patients who were scheduled to undergo a percutaneous liver biopsy were evaluated with Doppler sonography to determine the hepatic arterial resistive index (RI). The histologic specimens were graded by a pathologist regarding cirrhosis and inflammation. The specimens demonstrated no cirrhosis in 12 of 43 (28%) patients, early cirrhosis in 10 of 43 (23%), and established cirrhosis in 21 of 43 (49%). Analysis also revealed that inflammation was absent in three of 43 (7%) patients, minimal in seven of 43 (16%), mild in 17 of 43 (40%), moderate in 13 of 43 (30%), and severe in three of 43 (7%). Hepatic artery RIs (without correction for heart rate) ranged from 0.64 +/- 0.06 in patients with early cirrhosis to 0.68 +/- 0.09 in patients with severe inflammation. There was no significant correlation between the degree of cirrhosis and/or inflammation and hepatic artery RI (with or without correction for heart rate). We conclude that Doppler determination of hepatic artery RIs is not a reliable method of predicting the severity of hepatic cirrhosis and/or inflammation.

Authors
Vassiliades, VG; Ostrow, TD; Chezmar, JL; Hertzler, GL; Nelson, RC
MLA Citation
Vassiliades, VG, Ostrow, TD, Chezmar, JL, Hertzler, GL, and Nelson, RC. "Hepatic arterial resistive indices: correlation with the severity of cirrhosis." Abdom Imaging 18.1 (1993): 61-65.
PMID
8431696
Source
pubmed
Published In
Abdominal Imaging
Volume
18
Issue
1
Publish Date
1993
Start Page
61
End Page
65

Dual contrast enhancement of both T1- and T2-weighted sequences using ultrasmall superparamagnetic iron oxide.

BMS 180549 (previously AMI-227), an ultrasmall superparamagnetic iron particulate agent, was investigated to determine its utility as a contrast agent on T1-weighted, as well as T2-weighted sequences, as a function of route of administration, (intravenous versus selective arterial) and concentration. Twelve farm pigs were divided into three groups of four each by route of administration (intravenous, selective superior mesenteric, or selective hepatic arterial injection). 10 mumol/kg and 20 mumol/kg dosages were given and evaluated both immediately after and 20-24 hr after contrast infusion, using both spin-echo and gradient-echo T1 and T2-weighted sequences. Significant postcontrast liver and spleen enhancement was noted at both concentrations, regardless of route of administration on both T1- and T2-weighted sequences. The earliest postcontrast T1-weighted sequence obtained during the 1-3 min interval following IV administration of high dose (20 mumol/kg) contrast demonstrated an average of +42.8% liver and +249.0% spleen enhancement; 24 hr later this decreased to 0 and 7.2%, respectively. The earliest postcontrast T2-weighted sequence obtained during the 8-17 min interval post high-dose IV contrast showed an average of -75.8% decrease in liver and -28.7% decrease in spleen signal intensity; 24 hr later the magnitude of these changes diminished to -33.1% and +2.5%, respectively. No significant difference was noted in liver or spleen enhancement, regardless of route of contrast administration (intravenous versus intraarterial).

Authors
Small, WC; Nelson, RC; Bernardino, ME
MLA Citation
Small, WC, Nelson, RC, and Bernardino, ME. "Dual contrast enhancement of both T1- and T2-weighted sequences using ultrasmall superparamagnetic iron oxide." Magn Reson Imaging 11.5 (1993): 645-654.
PMID
8345779
Source
pubmed
Published In
Magnetic Resonance Imaging
Volume
11
Issue
5
Publish Date
1993
Start Page
645
End Page
654

Imaging of patients with potentially resectable hepatic neoplasms.

Authors
Harned, RK; Chezmar, JL; Nelson, RC
MLA Citation
Harned, RK, Chezmar, JL, and Nelson, RC. "Imaging of patients with potentially resectable hepatic neoplasms." AJR Am J Roentgenol 159.6 (December 1992): 1191-1194.
PMID
1442380
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
159
Issue
6
Publish Date
1992
Start Page
1191
End Page
1194
DOI
10.2214/ajr.159.6.1442380

Persistence of portosystemic collaterals and splenomegaly on CT after orthotopic liver transplantation.

OBJECTIVE: The appearances of portosystemic collaterals and splenomegaly on CT before and after liver transplantation were evaluated. MATERIALS AND METHODS: The records of 54 patients undergoing liver transplantation during a 2.5-year period were reviewed retrospectively. Twenty-five of these patients, in whom both a preoperative abdominal CT scan and a follow-up CT scan at least 1 year after transplantation had been obtained, were clinically well and had had no significant episodes of rejection, severe recurrent hepatitis, or other complication at the time of study. A total of 94 abdominal CT scans in these patients were reviewed to assess changes in portosystemic collaterals and splenic volume. RESULTS: At 6 months after transplantation, portosystemic collaterals at one or more sites were seen in 14 (74%) of the 19 patients scanned at this time in whom collaterals had been seen on CT preoperatively. At 1 year after transplantation, splenic hilar collaterals persisted in 64% of patients, splenocolic ligament collaterals in 50%, retroperitoneal collaterals in 38%, and peripancreatic collaterals in 38% of patients with preoperative varices at these sites who were examined with CT at this interval. Splenic hilar, coronary, and retroperitoneal collaterals were found to persist for up to 4 years after transplantation in the single patient examined at that time. Splenic volume decreased in 94% of patients examined after transplantation, with a mean reduction of 60 +/- 19%. However, the spleen remained significantly enlarged in 56% of patients. CONCLUSION: We conclude that portosystemic collaterals and splenomegaly frequently persist after liver transplantation, but that this finding need not indicate recurrence of hepatic disease or other posttransplantation complications.

Authors
Chezmar, JL; Redvanly, RD; Nelson, RC; Henderson, JM
MLA Citation
Chezmar, JL, Redvanly, RD, Nelson, RC, and Henderson, JM. "Persistence of portosystemic collaterals and splenomegaly on CT after orthotopic liver transplantation." AJR Am J Roentgenol 159.2 (August 1992): 317-320.
PMID
1632346
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
159
Issue
2
Publish Date
1992
Start Page
317
End Page
320
DOI
10.2214/ajr.159.2.1632346

CT during arterial portography: diagnostic pitfalls.

Computed tomography (CT) during arterial portography (CTAP) is an important technique for evaluating the liver before hepatic tumor resection. With this technique, most tumors are of low attenuation compared with that of enhancing parenchyma. At times, low-attenuation lesions are encountered that represent perfusion abnormalities rather than tumor deposits. These perfusion abnormalities can be categorized as (a) those resulting from improper technique; (b) those extending from hilum to capsule (straight-line sign), with or without an obstructing mass; (c) perihilar and periligamentous abnormalities; (d) subcapsular defects (linear or wedge shaped); and (e) those seen with cirrhosis or regenerating nodules. Adjuvant use of delayed CT, magnetic resonance imaging, and intraoperative ultrasound aids in characterization of these nontumorous defects, thereby improving specificity. The authors conclude that when potential candidates are evaluated for hepatic tumor resection, knowledge of the existence of the various diagnostic pitfalls of CTAP and their imaging characteristics is imperative to avoid inadvertent false results.

Authors
Nelson, RC; Thompson, GH; Chezmar, JL; Harned, RK; Fernandez, MP
MLA Citation
Nelson, RC, Thompson, GH, Chezmar, JL, Harned, RK, and Fernandez, MP. "CT during arterial portography: diagnostic pitfalls." Radiographics 12.4 (July 1992): 705-718.
PMID
1321980
Source
pubmed
Published In
Radiographics : a review publication of the Radiological Society of North America, Inc
Volume
12
Issue
4
Publish Date
1992
Start Page
705
End Page
718
DOI
10.1148/radiographics.12.4.1321980

The frequency and significance of small (less than or equal to 15 mm) hepatic lesions detected by CT.

The purpose of our study was to determine the frequency of detection of small hepatic lesions (less than or equal to 15 mm) in outpatients who had abdominal CT and to assess the significance of these lesions in the presence or absence of known malignant tumors. Contrast-enhanced abdominal CT scans in 1454 patients were reviewed. In 254 patients (17%), hepatic lesions 15 mm or smaller were detected. In 51% of these patients, lesions were judged benign on the basis of other imaging studies, biopsy results, or stability for at least 6 months as shown by CT. Lesions were judged malignant on the basis of progression seen on radiologic studies or biopsy in 22%. The other 27% of the patients had lesions that could not be classified. The majority of patients with small hepatic lesions (82%) were known to have a malignant tumor; in 51% of these patients, lesions were diagnosed as benign. No patient without a known malignant tumor had a small hepatic lesion that was determined to be malignant. Multiple small lesions were more likely to represent malignant disease than were single small lesions. We conclude that small hepatic lesions are common (seen in 17% of our patients), and that there is a high probability that hepatic lesions smaller than 15 mm are benign, even in patients known to have an extrahepatic malignant tumor.

Authors
Jones, EC; Chezmar, JL; Nelson, RC; Bernardino, ME
MLA Citation
Jones, EC, Chezmar, JL, Nelson, RC, and Bernardino, ME. "The frequency and significance of small (less than or equal to 15 mm) hepatic lesions detected by CT." AJR Am J Roentgenol 158.3 (March 1992): 535-539.
PMID
1738990
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
158
Issue
3
Publish Date
1992
Start Page
535
End Page
539
DOI
10.2214/ajr.158.3.1738990

Peritoneal carcinomatosis: preoperative CT with intraperitoneal contrast material.

Thirty-five abdominal computed tomographic (CT) scans of 27 patients with peritoneal metastases from a mucin-producing tumor of the appendix, colon, small bowel, or ovary were retrospectively reviewed. Fifteen scans were obtained of 15 patients after CT with intraperitoneal infusion of contrast material (IP), and 20 scans were obtained of 16 patients with CT without IP. Subsequent exploratory laparotomy revealed that all 27 patients had multi-focal spread of peritoneal metastases. The sensitivity of CTIP and CT without IP for detection of peritoneal metastases at all sites of involvement was 61% and 59%, respectively. For CTIP, the highest sensitivity was in the right subphrenic space (88%), splenic hilum (86%), and left subphrenic space (83%). For CT without IP, the highest sensitivity was noted in the splenic hilum (100%), left subphrenic space (75%), and left paracolic gutter (75%). CTIP and CT without IP had low sensitivity for detection of disease in the greater omentum (50% each) and small-bowel mesentery (38% and 59%, respectively), two areas that had the highest frequency of metastases.

Authors
Nelson, RC; Chezmar, JL; Hoel, MJ; Buck, DR; Sugarbaker, PH
MLA Citation
Nelson, RC, Chezmar, JL, Hoel, MJ, Buck, DR, and Sugarbaker, PH. "Peritoneal carcinomatosis: preoperative CT with intraperitoneal contrast material." Radiology 182.1 (January 1992): 133-138.
PMID
1727276
Source
pubmed
Published In
Radiology
Volume
182
Issue
1
Publish Date
1992
Start Page
133
End Page
138
DOI
10.1148/radiology.182.1.1727276

The use of transcutaneous electrical nerve stimulation during the biliary lithotripsy procedure.

Transcutaneous electrical nerve stimulation (TENS) has been suggested as a means to reduce the amount of intravenous analgesia/sedation in patients undergoing extracorporeal shock wave lithotripsy (ESWL). A retrospective analysis of 79 ESWL procedures on 73 consecutive unselected patients was done in an attempt to determine the effectiveness of TENS in reducing the amount of intravenous fentanyl citrate and/or midazolam HCl needed to control pain and anxiety during the ESWL procedure. The study was divided into two parts: (1) all patients receiving TENS (n = 44) versus a non-TENS group (n = 35), and (2) comparison of the early (n = 22) and late non-TENS (n = 22) groups against each other; separately the late non-TENS group was compared to the entire TENS group. In the study, TENS reduce the amount of fentanyl citrate needed to control anxiety by 22.9% (P less than 0.025). No difference was noted when the early and late non-TENS group of patients were compared to each other. A gender difference was noted with a significant reduction in the dose of fentanyl citrate only in female patients receiving TENS (45.4%). Likewise, there was a significant reduction in the dose of midazolam HCl only in males who had TENS (38.9%). The data suggests that TENS may be a useful addition to reduce the amount of sedation and analgesia during ESWL.

Authors
Torres, WE; Fraser, NP; Baumgartner, BR; Nelson, RC; Evans, GR; Jones, V; Peterson, J
MLA Citation
Torres, WE, Fraser, NP, Baumgartner, BR, Nelson, RC, Evans, GR, Jones, V, and Peterson, J. "The use of transcutaneous electrical nerve stimulation during the biliary lithotripsy procedure." J Stone Dis 4.1 (January 1992): 41-45.
PMID
10149174
Source
pubmed
Published In
The Journal of stone disease
Volume
4
Issue
1
Publish Date
1992
Start Page
41
End Page
45

Fast spin-echo imaging of the abdomen during breath-holding: an alternative to RASE and other fast imaging techniques.

We have developed a rapidly acquired T1-weighted spin-echo pulse sequence that uses gradient echo-like parameters of TR 70 ms, TE 10 ms, NEX-1 (SE 70/10/1) with large pulse angles, and presaturation. This sequence yields two images of the abdomen during a comfortable breath-hold of 9 s. Preliminary phantom studies with this sequence demonstrated that peak signal-to-noise ratios occurred at pulse angles of 120 degrees and 135 degrees. Compared to this rapidly acquired sequence, a conventional T1-weighted spin-echo sequence of TR 140 ms, TE 10 ms, NEX-4 demonstrated 2.8 times the signal-to-noise ratio, 2.6 times the liver-spleen contrast-to-noise ratio but only 1.6 times the contrast-to-artifact ratio. When normalized for the imaging time, however, there was little difference in the signal-to-noise and contrast-to-noise ratios, although the SE 70/10/1 demonstrated 2.0 times the contrast-to-artifact ratio. We conclude that for abdominal imaging the SE 70/10/1 is an excellent alternative to RASE and other fast imaging techniques, and, although there are inherently low signal-to-noise ratios, it may be particularly useful when coupled with a paramagnetic contrast agent.

Authors
Nelson, RC; Chezmar, JL
MLA Citation
Nelson, RC, and Chezmar, JL. "Fast spin-echo imaging of the abdomen during breath-holding: an alternative to RASE and other fast imaging techniques." Gastrointest Radiol 17.4 (1992): 295-299.
PMID
1426843
Source
pubmed
Published In
Abdominal Imaging
Volume
17
Issue
4
Publish Date
1992
Start Page
295
End Page
299

Surgical pros and cons

Authors
Makuuchi, M; Machi, J; Sugarbaker, PH; Nelson, RC
MLA Citation
Makuuchi, M, Machi, J, Sugarbaker, PH, and Nelson, RC. "Surgical pros and cons." Surgery Gynecology and Obstetrics 174.6 (1992): 519-521.
Source
scival
Published In
Surgery Gynecology and Obstetrics
Volume
174
Issue
6
Publish Date
1992
Start Page
519
End Page
521

The frequency and significance of small (≤15 mm) hepatic lesions detected by CT

The purpose of our study was to determine the frequency of detection of small hepatic lesions (≤15 mm) in outpatients who had abdominal CT and to assess the significance of these lesions in the presence or absence of known malignant tumors. Contrast-enhanced abdominal CT scans in 1454 patients were reviewed. In 254 patients (17%), hepatic lesions 15 mm or smaller were detected. In 51% of these patients, lesions were judged benign on the basis of other imaging studies, biopsy results, or stability for at least 6 months as shown by CT. Lesions were judged malignant on the basis of progression seen on radiologic studies or biopsy in 22%. The other 27% of the patients had lesions that could not be classified. The majority of patients with small hepatic lesions (82%) were known to have a malignant tumor; in 51% of these patients, lesions were diagnosed as benign. No patient without a known malignant tumor had a small hepatic lesion that was determined to be malignant. Multiple small lesions were more likely to represent malignant disease than were single small lesions. We conclude that small hepatic lesions are common (seen in 17% of our patients), and that there is a high probability that hepatic lesions smaller than 15 mm are benign, even in patients known to have an extrahepatic malignant tumor.

Authors
Jones, EC; Chezmar, JL; Nelson, RC; Bernardino, ME
MLA Citation
Jones, EC, Chezmar, JL, Nelson, RC, and Bernardino, ME. "The frequency and significance of small (≤15 mm) hepatic lesions detected by CT." American Journal of Roentgenology 158.3 (1992): 535-539.
Source
scival
Published In
American Journal of Roentgenology
Volume
158
Issue
3
Publish Date
1992
Start Page
535
End Page
539

Techniques for computed tomography of the liver.

We recommend that the CT technique of choice for routine screening of the liver, especially when there is potential for neoplasia, is dynamic CT using a single monophasic bolus of not less than 150 mL of a 60% iodinated contrast agent and a dynamic incremental package yielding at least 7 sections/minute. Routine use of noncontrast CT prior to dynamic CT is not indicated unless there is suspicion of a hypervascular tumor. We prefer to examine these particular patients with delayed CT 4 to 6 hours after receiving at least 60 g of iodine, as lesion to liver contrast is superior to noncontrast CT. Other indications for delayed CT include indeterminate lesions on dynamic CT or CTAP and perfusion defects on CTAP. In patients who are possible candidates for hepatic tumor resection, more invasive techniques such as CTAP are indicated as they yield the highest sensitivity to focal hepatic lesions, especially small lesions. A combination of CTAP and MR, however, demonstrates a superior lesion detection rate than either modality alone. CT-Lipiodol is a useful technique for detecting and palliating hepatocellular carcinomas, especially in patients with concomitant cirrhosis.

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Techniques for computed tomography of the liver." Radiol Clin North Am 29.6 (November 1991): 1199-1212. (Review)
PMID
1947041
Source
pubmed
Published In
Radiologic Clinics of North America
Volume
29
Issue
6
Publish Date
1991
Start Page
1199
End Page
1212

Comparison of ultrasonography and oral cholecystography in lithotripsy. II. Determining retreatment.

Both ultrasonography (US) and oral cholecystography (OCG) are being used to evaluate patients after extracorporeal shock wave lithotripsy (ESWL) for gallstones. Criteria for retreatment after the initial ESWL are usually related to the size of the residual fragments. This study examines the efficacy of ultrasound and OCG for determining both the size and number of stone fragments in the gallbladder in an in vitro model and in patients. Ultrasonography and OCG examinations using an in vitro ESWL phantom with ten groups of stones, and on 39 patients, were reviewed independently by three radiologists to determine both the size and number of stone fragments. For the in vitro study, the three readers estimated the correct number of fragments, or the next closest range, in 87% of observations by OCG and in 43% by US. The size of the largest fragment was measured within 1 mm of its actual size in 87% of observations by OCG and 20% by US. Correlation coefficients for the mean measurements of the three readers versus the actual fragment size and number were greater for OCG than for US. For the in vivo study, the three readers agreed in 47% of the OCG versus 32% of US examinations with respect to the number of fragments, and in 65% of OCG compared to 40% of US studies with respect to size of the largest fragment. Multiple statistical analyses demonstrate that these differences are statistically significant. A discrepancy among the readers concerning whether a patient was eligible for retreatment occurred in 15% of OCG as compared to 45% of US studies. Both the in vivo and in vitro studies indicate that there is more interobserver reproducibility for OCG than for US, and that OCG is more reliable in making the decision concerning patient eligibility for retreatment following lithotripsy.

Authors
Baumgartner, BR; Jones, MT; Torres, WE; Nelson, RC; Peterson, JE
MLA Citation
Baumgartner, BR, Jones, MT, Torres, WE, Nelson, RC, and Peterson, JE. "Comparison of ultrasonography and oral cholecystography in lithotripsy. II. Determining retreatment." Invest Radiol 26.7 (July 1991): 636-639.
PMID
1885269
Source
pubmed
Published In
Investigative Radiology
Volume
26
Issue
7
Publish Date
1991
Start Page
636
End Page
639

Manganese dipyridoxyl diphosphate. Effect of dose, time, and pulse sequence on hepatic enhancement in rats.

We used an animal model to investigate the hepatic enhancement characteristics of manganese dipyridoxyl diphosphate (MnDPDP) related to time, dose, and pulse sequence. The contrast doses selected were in the human tolerance range. Using an SE 300/15 pulse sequence, maximum mean hepatic enhancement of 45% (8 mumols/kg) and 58% (12 mumols/kg) over baseline was seen during a plateau maintained between 5 and 50 minutes postinjection in the 8 mumols/kg group, and between 10 and 90 minutes in the 12 mumols/kg group. This plateau was followed by a very gradual decline in hepatic enhancement. Using either 4 or 8 mumols/kg, there was a significant increase in postcontrast hepatic intensity on all relatively T1-weighted pulse sequences (spin echo [SE] 300/15, inversion recovery [IR] 1400/20/400, gradient echo [GE] 47/13/80 degrees, and GE 60/20/30 degrees) except GE 47/13/80 degrees at 4 mumols/kg. At 8 mumols/kg there was superior enhancement, with IR 1400/20/400 and SE 300/15, but at 4 mumols/kg there was no consistently superior sequence. None of the relatively T2-weighted pulse sequences (SE 2000/50, SE 2000/100, or GE 100/30/20 degrees) demonstrated a significant change in hepatic intensity using either dose of contrast. The data suggest that the best combination of dose, pulse sequence, and time for hepatic imaging with MnDPDP is 8 mumols/kg using heavily T1-weighted sequences 5 to 60 minutes following contrast administration.

Authors
Nelson, RC; Chezmar, JL; Newberry, LB; Malko, JA; Gedgaudas-McClees, RK; Bernardino, ME
MLA Citation
Nelson, RC, Chezmar, JL, Newberry, LB, Malko, JA, Gedgaudas-McClees, RK, and Bernardino, ME. "Manganese dipyridoxyl diphosphate. Effect of dose, time, and pulse sequence on hepatic enhancement in rats." Invest Radiol 26.6 (June 1991): 569-573.
PMID
1907259
Source
pubmed
Published In
Investigative Radiology
Volume
26
Issue
6
Publish Date
1991
Start Page
569
End Page
573

Shock wave lithotripsy of gallstones: results and 12-month follow-up in 174 patients.

At the authors' institution, as part of the on-going Dornier National Biliary Lithotripsy Study, 174 patients with gallstones were randomly assigned to receive either ursodeoxycholic acid (UDCA) or placebo for 6 months after undergoing extracorporeal shock wave lithotripsy (ESWL). Six weeks after ESWL, 40 (23%) patients were re-treated for gallstone fragments larger than 5 mm in diameter. No significant difference in the UDCA- and placebo-treated patients was noted. The overall 6- and 12-month stone-free rates for all patients with initially noncalcified stones were as follows: UDCA patients, 31% and 36%, respectively, and placebo patients, 21% and 23%, respectively (P less than .05). In patients with a single, noncalcified gallstone that was at most 20 mm in diameter, the 12-month stone-free rates were as follows: UDCA patients, 60%, and placebo patients, 33% (P less than .01). Patients with noncalcified stones that were 11-20 mm in diameter who were treated with UDCA had a higher rate of stone clearance than placebo patients. At 6 months, the authors' previous study demonstrated no significant difference in the two groups of patients. However, the stone-free rate at 12 months was noted to be significantly higher for patients with a single, noncalcified stone that was at most 20 mm in diameter begun on UDCA than for all other groups of patients.

Authors
Torres, WE; Baumgartner, BR; Nelson, RC; Morris, SJ
MLA Citation
Torres, WE, Baumgartner, BR, Nelson, RC, and Morris, SJ. "Shock wave lithotripsy of gallstones: results and 12-month follow-up in 174 patients." Radiology 179.3 (June 1991): 699-701.
PMID
2027977
Source
pubmed
Published In
Radiology
Volume
179
Issue
3
Publish Date
1991
Start Page
699
End Page
701
DOI
10.1148/radiology.179.3.2027977

Liver transplant biopsies with a biopsy gun.

The authors evaluated the safety and efficacy of a biopsy gun for performance of image-guided percutaneous biopsy of hepatic allografts in liver transplant recipients. Two hundred fifty-two liver biopsies were performed in 58 transplant recipients over a 27-month period by using this instrument with an 18-gauge needle. Major complications occurred in two of the 252 biopsies (0.8%): One hemopneumothorax necessitated drainage with a chest tube, and one hemorrhage necessitated transfusion. No patient required surgical exploration because of a complication of the biopsy. Specimens were adequate for accurate histopathologic diagnosis in 248 of 252 procedures (98.4%). The authors conclude that image-guided percutaneous biopsy of hepatic allografts with use of the biopsy gun is a safe and accurate method of obtaining hepatic tissue from liver transplant recipients for histopathologic analysis.

Authors
Chezmar, JL; Keith, LL; Nelson, RC; Plaire, JC; Hertzler, GL; Bernardino, ME
MLA Citation
Chezmar, JL, Keith, LL, Nelson, RC, Plaire, JC, Hertzler, GL, and Bernardino, ME. "Liver transplant biopsies with a biopsy gun." Radiology 179.2 (May 1991): 447-448.
PMID
2014290
Source
pubmed
Published In
Radiology
Volume
179
Issue
2
Publish Date
1991
Start Page
447
End Page
448
DOI
10.1148/radiology.179.2.2014290

Forty-four-year-old woman with flank pain.

Authors
Alexander, JA; Nelson, RC; McDonald, DN; Baumgartner, BR
MLA Citation
Alexander, JA, Nelson, RC, McDonald, DN, and Baumgartner, BR. "Forty-four-year-old woman with flank pain." Urology 37.4 (April 1991): 350-352.
PMID
2014601
Source
pubmed
Published In
Urology
Volume
37
Issue
4
Publish Date
1991
Start Page
350
End Page
352

Hepatic dynamic sequential CT: section enhancement profiles with a bolus of ionic and nonionic contrast agents.

The enhancement characteristics in different portions of the liver during dynamic sequential bolus computed tomography (CT) with iodinated contrast material (DSBCT) were prospectively evaluated in 75 patients by using iothalamate meglumine, iopamidol, and iohexol (25 patients received each agent). After baseline noncontrast CT was performed, DSBCT was performed with a 180-mL intravenous bolus administered at 2 mL/sec. Scanning was started 25 seconds after the bolus was initiated, by using a 3-second scan time and rapid cephalocaudal table incrementation, yielding contiguous 8-mm-thick sections at a rate of nine sections per minute. On postcontrast images, peak enhancement was 115% for iopamidol and 117% for iohexol, both of which were superior to iothalamate meglumine at 95% (P less than .05). After peaking, enhancement then decreased for all three contrast agents, although the decline was more precipitous for iothalamate meglumine. Enhancement on the more caudal sections with both iopamidol and iohexol was superior to that with iothalamate meglumine (P less than .05). The data suggest that the enhancement characteristics for the two nonionic agents may be more optimal for detection of focal hepatic lesions than the ionic agent.

Authors
Nelson, RC; Moyers, JH; Chezmar, JL; Hoel, MJ; Jones, EC; Peterson, JE; Cork, RD; Bernardino, ME
MLA Citation
Nelson, RC, Moyers, JH, Chezmar, JL, Hoel, MJ, Jones, EC, Peterson, JE, Cork, RD, and Bernardino, ME. "Hepatic dynamic sequential CT: section enhancement profiles with a bolus of ionic and nonionic contrast agents." Radiology 178.2 (February 1991): 499-502.
PMID
1987614
Source
pubmed
Published In
Radiology
Volume
178
Issue
2
Publish Date
1991
Start Page
499
End Page
502
DOI
10.1148/radiology.178.2.1987614

Extracorporeal shock wave lithotripsy of gallstones: results and 6-month follow-up in 141 patients.

A study of biliary shock wave lithotripsy of gallstones sponsored by Dornier Medical Systems, Munich, began in the United States in May 1988 to evaluate the efficacy and safety of extracorporeal shock wave lithotripsy (ESWL) and the need for adjunctive therapy with ursodeoxycholic acid (UDCA). One hundred forty-one symptomatic patients with one to three gallstones 5-30 mm in diameter were randomized to treatment. One week before ESWL, patients were given either UDCA or placebo. This treatment was continued for 6 months. All patients underwent follow-up at predetermined intervals. According to the protocol, re-treatment for fragments larger than 5 mm in diameter could be performed only at 6 weeks; 26 (18%) of the 141 patients were retreated. At 6 months, the stone-free rates for single stones were as follows: patients with noncalcified stones receiving UDCA, 29%; patients with noncalcified stones receiving placebo, 24%; and patients with partially calcified stones receiving either UDCA or placebo, 6%. No significant difference was noted between the UDCA and placebo groups. At 6 months, the stone-free rates in patients with single, noncalcified stones 20 mm or less in diameter were 40% (UDCA) and 32% (placebo), which is superior to rates for those with solitary, noncalcified gallstones 21-30 mm in diameter and those with two or three stones.

Authors
Torres, WE; Steinberg, HV; Davis, RC; Baumgartner, BR; Nelson, RC; Casarella, WJ
MLA Citation
Torres, WE, Steinberg, HV, Davis, RC, Baumgartner, BR, Nelson, RC, and Casarella, WJ. "Extracorporeal shock wave lithotripsy of gallstones: results and 6-month follow-up in 141 patients." Radiology 178.2 (February 1991): 509-512.
PMID
1987616
Source
pubmed
Published In
Radiology
Volume
178
Issue
2
Publish Date
1991
Start Page
509
End Page
512
DOI
10.1148/radiology.178.2.1987616

Magnetic resonance imaging of the pancreas with gadolinium-DTPA.

Gadolinium (Gd)-DTPA was evaluated as a contrast agent for magnetic resonance (MR) imaging of the pancreas at 1.5T. Twenty-five patients were imaged with identical gradient-echo (GE) (TR 47, TE 13, 80 degree pulse angle) and spin-echo (SE) (TR 300, TE 15) MR sequences prior to and following an intravenous bolus of 0.1 mmol/kg Gd-DTPA. Marked pancreatic enhancement was demonstrated on dynamic sequential breath-hold GE images obtained immediately following the Gd-DTPA bolus (116% mean enhancement over pre-Gd-DTPA images). Enhancement decreased but persisted on the SE images obtained approximately 5 and 15 min following the Gd-DTPA bolus (65 and 60% mean enhancement, respectively). Five of the patients had a pancreatic mass. In these five patients, the enhancement of pancreatic tissue resulted in improved conspicuity of the mass. These initial results suggest that pancreatic enhancement occurs following an intravenous bolus of Gd-DTPA and has the potential to improve MR visualization of pancreatic masses.

Authors
Chezmar, JL; Nelson, RC; Small, WC; Bernardino, ME
MLA Citation
Chezmar, JL, Nelson, RC, Small, WC, and Bernardino, ME. "Magnetic resonance imaging of the pancreas with gadolinium-DTPA." Gastrointest Radiol 16.2 (1991): 139-142.
PMID
2016027
Source
pubmed
Published In
Abdominal Imaging
Volume
16
Issue
2
Publish Date
1991
Start Page
139
End Page
142

Abdominal-gastrointestinal radiology.

Authors
Balfe, DM; Chezmar, J; Koehler, RE; Lichtenstein, JE; Nelson, R
MLA Citation
Balfe, DM, Chezmar, J, Koehler, RE, Lichtenstein, JE, and Nelson, R. "Abdominal-gastrointestinal radiology." Radiology 178.3 (1991): 911-913.
PMID
1994450
Source
scival
Published In
Radiology
Volume
178
Issue
3
Publish Date
1991
Start Page
911
End Page
913

Duplex sonography in the evaluation of pancreas transplants

Multiple allograft duplex sonographic examinations were performed on six patients who underwent pancreas transplantation to determine the role of this imaging modality. Poor correlation was found between gland size, parenchymal echogenicity or resistive index, and either rejection and/or cyclosporine toxicity. The pancreatic duct was not dilated on any of the examinations. Seven peripancreatic fluid collections were noted but were generally small. In one patient, no Doppler frequency shifts were found in spite of extensive interrogation of the parenchyma and subsequent biopsy confirmed allograft infarction. Duplex sonography appears most useful for excluding ductal dilatation, for detecting peripancreatic fluid collections, and for identifying infarction.

Authors
Newberry, LB; Nelson, RC
MLA Citation
Newberry, LB, and Nelson, RC. "Duplex sonography in the evaluation of pancreas transplants." Journal of Diagnostic Medical Sonography 7.2 (1991): 74-80.
Source
scival
Published In
Journal of Diagnostic Medical Sonography
Volume
7
Issue
2
Publish Date
1991
Start Page
74
End Page
80

Segmental liver anatomy [4]

Authors
Marti-Bonmati, L; Nelson, RC; Chezmar, JL; Murray, DR; Bernardino, ME; Sugarbaker, PH
MLA Citation
Marti-Bonmati, L, Nelson, RC, Chezmar, JL, Murray, DR, Bernardino, ME, and Sugarbaker, PH. "Segmental liver anatomy [4]." Radiology 179.2 (1991): 585-586.
PMID
2014318
Source
scival
Published In
Radiology
Volume
179
Issue
2
Publish Date
1991
Start Page
585
End Page
586

Surgical pros and cons

Authors
Makuuchi, M; Machi, J; Sugarbaker, PH; Nelson, RC
MLA Citation
Makuuchi, M, Machi, J, Sugarbaker, PH, and Nelson, RC. "Surgical pros and cons." Surgery Gynecology and Obstetrics 173.6 (1991): 487-490.
Source
scival
Published In
Surgery Gynecology and Obstetrics
Volume
173
Issue
6
Publish Date
1991
Start Page
487
End Page
490

Biliary lithotripsy: in vitro analysis of gallstone fragmentation for equivalent stone volumes.

The relationship between gallstone fragmentation during extracorporeal shock wave lithotripsy (ESWL) and gallstone volume is poorly understood. Clinical results of ESWL show that the highest stone-free rate at 6 months occurs with radiolucent single gallstones 20 mm or less in diameter. In an in vitro study, individual gallstones from cholecystectomy specimens were divided by size and composition into nine single- and nine multiple-stone groups; the stones were then paired on the basis of similar volume. ESWL was performed in a phantom and the size of the largest fragment was measured at 500, 1,000, and 1,500 shock waves. At 1,500 shock waves, sandlike particles were present in six of nine single stones versus two of nine multiple stone groups; the mean size of the largest fragment at 1,500 shock waves was 2.1 mm (single) and 4.4 mm (multiple) in diameter. When corrected for volume, the authors' data suggest that single stones are more easily broken into fragments smaller than 5 mm in diameter than multiple gallstones. The implication, especially when spark-gap technology is used, is that more shock wave energy (ie, an increased number of shock waves at a higher kilovoltage) will be necessary to achieve the same results when treating patients with multiple stones versus a single gallstone with a similar stone volume.

Authors
Torres, WE; Baumgartner, BR; Jones, MT; Nelson, RC
MLA Citation
Torres, WE, Baumgartner, BR, Jones, MT, and Nelson, RC. "Biliary lithotripsy: in vitro analysis of gallstone fragmentation for equivalent stone volumes." Radiology 177.2 (November 1990): 507-509.
PMID
2217793
Source
pubmed
Published In
Radiology
Volume
177
Issue
2
Publish Date
1990
Start Page
507
End Page
509
DOI
10.1148/radiology.177.2.2217793

A segmental approach to computerized tomographic portography for hepatic resection.

Surgical treatment has proved to be of benefit to patients with primary and metastatic tumors of the liver. However, the ability to localize tumors preoperatively to particular segments within the liver has not been emphasized. The large size of this organ and its complex vascular structure have not allowed the surgeon either to determine accurately the hepatic segment occupied by the tumor or to identify major vascular structures adjacent to the tumor. We have expanded the use of a new roentgenologic technique to determine preoperatively with more clear definition the segmental anatomy of the liver. Computerized tomographic portography (CT-P) images hepatic veins and the segmental branches of portal vein and identifies the anatomic location of tumor nodules. To read the roentgenograms, one first identifies the middle CT-P slice that will cut the transverse scissura. Slices cephalad to the transverse scissura are through segments 7, 8, 4a and 2 in a clockwise order; slices caudad to the transverse scissura are through 6, 5, 4b and 3. Selected CT-P cuts from a series of patients show the typical CT-P configuration of the hepatic vasculature anatomy and the structures that can be identified roentgenologically. The CT-P provides valuable information not previously available preoperatively to the surgeon operating upon the liver.

Authors
Sugarbaker, PH; Nelson, RC; Murray, DR; Chezmar, JL; Bernardino, ME
MLA Citation
Sugarbaker, PH, Nelson, RC, Murray, DR, Chezmar, JL, and Bernardino, ME. "A segmental approach to computerized tomographic portography for hepatic resection." Surg Gynecol Obstet 171.3 (September 1990): 189-195.
PMID
2385811
Source
pubmed
Published In
Surgery Gynecology and Obstetrics
Volume
171
Issue
3
Publish Date
1990
Start Page
189
End Page
195

Diagnostic approach to hepatic hemangiomas.

Authors
Nelson, RC; Chezmar, JL
MLA Citation
Nelson, RC, and Chezmar, JL. "Diagnostic approach to hepatic hemangiomas." Radiology 176.1 (July 1990): 11-13.
PMID
2191359
Source
pubmed
Published In
Radiology
Volume
176
Issue
1
Publish Date
1990
Start Page
11
End Page
13
DOI
10.1148/radiology.176.1.2191359

Preoperative localization of focal liver lesions to specific liver segments: utility of CT during arterial portography.

The authors retrospectively studied 36 hepatic masses in 20 patients who underwent computed tomography during arterial portography (CTAP) and subsequent hepatic tumor resection. The authors used the right main and left main portal veins as landmarks for the transverse scissura, along with the hepatic veins, the gallbladder fossa, and the umbilical fissure to blindly predict the segmental location of each tumor confirmed at surgery. The right main and left main portal veins were found to be consistently near the middle sections through the liver. CTAP findings and surgical descriptions agreed on the primary segmental location of 33 of 36 focal lesions (92%) but disagreed on the extent of 11 of 36 lesions (31%). Further review of the CTAP scans of the 11 lesions revealed that the extent of the lesion was more correctly described at surgery in six masses and at CTAP in four masses; in one lesion, opposite margins of the same mass were correctly described at both surgery and CTAP. Since it may be difficult or impossible to localize deep hepatic lesions intraoperatively by means of palpation or inspection, CTAP is a helpful preoperative tool for determining the segmental location of lesions and for planning the surgical approach.

Authors
Nelson, RC; Chezmar, JL; Sugarbaker, PH; Murray, DR; Bernardino, ME
MLA Citation
Nelson, RC, Chezmar, JL, Sugarbaker, PH, Murray, DR, and Bernardino, ME. "Preoperative localization of focal liver lesions to specific liver segments: utility of CT during arterial portography." Radiology 176.1 (July 1990): 89-94.
PMID
2353115
Source
pubmed
Published In
Radiology
Volume
176
Issue
1
Publish Date
1990
Start Page
89
End Page
94
DOI
10.1148/radiology.176.1.2353115

Gallstone extracorporeal shock-wave lithotripsy: time and treatment considerations.

We evaluated 30 gallstone lithotripsy procedures performed on 27 patients with the Dornier MPL-9000 Lithotripter to determine how time was spent in the lithotripsy suite and to evaluate the various technical reasons for interrupting the administration of shock waves during the treatment. The procedure averaged 98 +/- 32 min total time in the lithotripsy suite. This included an average of 22 +/- 6 min before the treatment, 70 +/- 28 min for administration of shock waves, and 6 +/- 2 min after the treatment. The time required to deliver the shock waves did not correlate with patient age, sex, or weight; the number of gallstones; or the number or date of the treatment. However, a trend was seen toward an association between shorter treatment times and larger stone volumes. On the average, the administration of shock waves was interrupted every 48 shock waves for various reasons. Electronically changing the imaging plane of the in-line sonographic transducer to retarget the stone in the focal zone was by far the most frequent reason for interrupting shock-wave delivery, averaging 56 shock waves between changes. We conclude that extracorporeal shock-wave lithotripsy of gallstones is a time consuming and technically demanding procedure that requires continuous monitoring and frequent interruption in order to optimize targeting and fragmentation of the stone(s) while maintaining the patient's comfort.

Authors
Nelson, RC; Rowland, GA; Torres, WE; Baumgartner, BR
MLA Citation
Nelson, RC, Rowland, GA, Torres, WE, and Baumgartner, BR. "Gallstone extracorporeal shock-wave lithotripsy: time and treatment considerations." AJR Am J Roentgenol 154.2 (February 1990): 291-294.
PMID
2105016
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
154
Issue
2
Publish Date
1990
Start Page
291
End Page
294
DOI
10.2214/ajr.154.2.2105016

Hepatic iron overload: diagnosis and quantification by noninvasive imaging.

The diagnostic efficacy of magnetic resonance (MR) and computed tomography (CT) for detection and quantification of hepatic iron was assessed in a series of patients under investigation for clinical or biochemical evidence of hepatic iron overload. Thirty patients underwent MR imaging (SE 30,60/1000 or SE 30,60/2000) at 0.5 Tesla with calculation of hepatic T2 and liver to paraspinous muscle signal intensity ratios. Twenty-nine patients also had measurement of hepatic attenuation on noncontrast CT images. Results of these imaging studies were correlated in all patients with quantitative iron determination from liver biopsy specimens. The best predictor of liver iron among parameters studied was the ratio of the signal intensities of liver and paraspinous muscle (L/M) on a SE 60/1000 sequence. Both MR using L/M ratios and CT were sensitive methods for detection of severe degrees of hepatic iron overload with 100% of patients with hepatic iron on biopsy greater than 600 micrograms/100 mg liver dry weight detected on the basis of L/M less than 0.6 or CT attenuation greater than 70 Hounsfield units (HU). The MR parameter, however, was more specific than CT (100 vs 50%) and showed a higher degree of correlation with quantitated hepatic iron from biopsy. T2 measurements showed poor correlation with hepatic iron, due to difficulty in obtaining precise T2 measurements in vivo when the signal intensity is low. None of the parameters utilized was sensitive for detecting mild or moderate degrees of hepatic iron overload. We conclude that MR and CT are sensitive techniques for noninvasive detection of severe hepatic iron overload, with MR providing greater specificity than CT.(ABSTRACT TRUNCATED AT 250 WORDS)

Authors
Chezmar, JL; Nelson, RC; Malko, JA; Bernardino, ME
MLA Citation
Chezmar, JL, Nelson, RC, Malko, JA, and Bernardino, ME. "Hepatic iron overload: diagnosis and quantification by noninvasive imaging." Gastrointest Radiol 15.1 (1990): 27-31.
PMID
2298350
Source
pubmed
Published In
Abdominal Imaging
Volume
15
Issue
1
Publish Date
1990
Start Page
27
End Page
31
DOI
10.1007/BF01888728

Portal venous gas after hepatic transplantation: sonographic detection and clinical significance.

In seven (18%) of 39 liver transplantation patients, serial Doppler sonographic examinations performed in the first 2 weeks after the transplantation showed transient, highly echogenic nonshadowing particles moving within the portal vein, believed to be portal venous air. This finding was associated with sepsis in one patient, a positive stool culture for Clostridium difficile in another, and postoperative ileus in a third patient. A fourth patient had primary graft failure and required a second transplant. No potential cause was found in the other three patients. None of the patients had bowel infarction or necrosis. The finding was not associated with transplant rejection or graft infection. We conclude that the sonographic finding of portal venous gas is common in the first 2 weeks after hepatic transplantation and may not have grave prognostic significance.

Authors
Chezmar, JL; Nelson, RC; Bernardino, ME
MLA Citation
Chezmar, JL, Nelson, RC, and Bernardino, ME. "Portal venous gas after hepatic transplantation: sonographic detection and clinical significance." AJR Am J Roentgenol 153.6 (December 1989): 1203-1205.
PMID
2683676
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
153
Issue
6
Publish Date
1989
Start Page
1203
End Page
1205
DOI
10.2214/ajr.153.6.1203

Contrast-enhanced CT of the liver and spleen: comparison of ionic and nonionic contrast agents.

We conducted a randomized, blinded, prospective study evaluating hepatic parenchymal density changes during dynamic bolus CT (180 ml of contrast material given IV) and delayed CT (5 hr after 60 g of iodine) in order to compare the enhancement characteristics of an ionic contrast agent (iothalamate-60) and two nonionic agents (iohexol-300 and iopamidol-300). A total of 75 patients with known or suspected cancer were studied (25 patients per contrast agent). After a baseline unenhanced CT scan was obtained, dynamic bolus and delayed CT scans were obtained for all patients with one of the three contrast agents. The density of the liver and spleen was measured in Hounsfield units (H) for unenhanced CT, dynamic bolus CT, and delayed CT. The average percentage of enhancement was calculated as follows: postcontrast density minus precontrast density was divided by precontrast density and then multiplied by 100. For dynamic bolus CT, the average percentage of enhancement of the liver was 105% when iohexol-300 was used, 98% when iopamidol-300 was used, and 83% when iothalamate-60 was used. No significant difference was seen between the postcontrast enhancement of the three contrast agents on dynamic bolus CT scans (p greater than .05). For delayed CT, the average percentage of enhancement of the liver was 34% when iothalamate-60 was used, 28% when iopamidol-300 was used, and 16% when iohexol-300 was used. Both iothalamate-60 and iopamidol-300 showed superior enhancement on delayed CT, compared with iohexol-300 (p = .0001). We conclude that for dynamic bolus CT, all three contrast agents are similar, with no statistically significant differences in postcontrast enhancement of the liver. For delayed CT, however, hepatic enhancement with iothalamate-60 and iopamidol-300 is statistically superior to that with iohexol-300.

Authors
Nelson, RC; Chezmar, JL; Peterson, JE; Bernardino, ME
MLA Citation
Nelson, RC, Chezmar, JL, Peterson, JE, and Bernardino, ME. "Contrast-enhanced CT of the liver and spleen: comparison of ionic and nonionic contrast agents." AJR Am J Roentgenol 153.5 (November 1989): 973-976.
PMID
2801447
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
153
Issue
5
Publish Date
1989
Start Page
973
End Page
976
DOI
10.2214/ajr.153.5.973

Nutrition and aging.

Aging is multifactorial and is dependent on genetic, life-style, and environmental factors. Successful aging relies upon a nutritionally complete diet and adequate exercise to counteract some of the physiologic changes related to age. A nutritionally sound diet for wellness in normal elderly is outlined which usually does not require additional vitamin supplements. Protein-calorie malnutrition is very prevalent in older patients with chronic disease, living alone, and receiving low income. Nutritional assessment and early intervention in the hospitalized elderly patient is extremely important to reduce the morbidity associated with this disease.

Authors
Nelson, RC; Franzi, LR
MLA Citation
Nelson, RC, and Franzi, LR. "Nutrition and aging." Med Clin North Am 73.6 (November 1989): 1531-1550. (Review)
PMID
2509831
Source
pubmed
Published In
Medical Clinics of North America
Volume
73
Issue
6
Publish Date
1989
Start Page
1531
End Page
1550

Renal corticomedullary junction. Performance of T1-weighted MR pulse sequences.

Inability to demonstrate the renal corticomedullary junction (CMJ) on magnetic resonance (MR) images has been reported in connection with several medical renal diseases. T1-weighted spin echo pulse sequences have been advocated to demonstrate a signal intensity difference between cortex and medulla. This study was undertaken to determine which of several T1-weighted spin echo (SE) and gradient echo (GE) sequences are better for delineation of the CMJ. The MR studies were performed at 0.5 Tesla on 27 normal volunteers. Multi-slice axial images of both kidneys were obtained in all subjects at each of the following five pulse sequences: SE 250/20, SE 500/30, SE 900/30, and GE 300/15 with 80 degrees and 64 degrees flip angles. Contrast/noise ratios were calculated for the signal intensity differences between cortex and medulla; the average standardized contrast/noise ratios ranked as follows: GE 300/15/80 degrees = 3.01 +/- 0.74, GE 300/15/64 degrees = 2.72 +/- 0.74, SE 250/20 = 2.02 +/- 0.33, SE 500/30 = 1.96 +/- 0.51, and SE 900/30 = 1.71 +/- 0.39. In addition, the five sequences for each patient were randomized and the images were independently ranked for delineation of CMJ by three MR radiologists. The cumulative subjective ranking for all observers from best to worst is as follows: SE 500/30, GE 300/15/80 degrees, GE 300/15/64 degrees, SE 900/30, SE 250/20. Although better contrast/noise ratios are achieved with the GE sequences and the more T1-weighted SE sequences, as a practical matter this does not seem to be the only significant factor when compared with the visual image evaluation by independent observers.(ABSTRACT TRUNCATED AT 250 WORDS)

Authors
Baumgartner, BR; Nelson, RC; Torres, WE; Malko, JA; Peterson, JE; Bernardino, ME
MLA Citation
Baumgartner, BR, Nelson, RC, Torres, WE, Malko, JA, Peterson, JE, and Bernardino, ME. "Renal corticomedullary junction. Performance of T1-weighted MR pulse sequences." Invest Radiol 24.11 (November 1989): 884-887.
PMID
2807803
Source
pubmed
Published In
Investigative Radiology
Volume
24
Issue
11
Publish Date
1989
Start Page
884
End Page
887

Hand-held electronic teaching-aid for demonstrating MRI concepts.

We describe a hand-held electronic teaching-aid for magnetic resonance imaging (MRI), which can be used to demonstrate the dependence of signal intensity on changing pulse sequence parameters (TR and TE), the dependence of intensity on changing tissue parameters (T1 and T2), and the ideas of "T1-weighting" and "T2-weighting" as they relate to image contrast. The device was specifically designed to be easy to use and readily accessible to residents-in-training and MR neophytes.

Authors
Malko, JA; Nelson, RC
MLA Citation
Malko, JA, and Nelson, RC. "Hand-held electronic teaching-aid for demonstrating MRI concepts." Invest Radiol 24.11 (November 1989): 927-931.
PMID
2807811
Source
pubmed
Published In
Investigative Radiology
Volume
24
Issue
11
Publish Date
1989
Start Page
927
End Page
931

Hepatic tumors: comparison of CT during arterial portography, delayed CT, and MR imaging for preoperative evaluation.

Forty-three patients with known primary or secondary neoplastic involvement of the liver underwent evaluation to determine the number, size, and location of focal lesions before possible tumor resection. Imaging studies included computed tomography (CT) during arterial portography (CTAP), delayed CT, and magnetic resonance (MR) imaging at various pulse sequences. Results of radiologic studies were compared with surgical and pathologic findings. In the combined group of surgical and nonsurgical patients, CTAP was significantly more sensitive (85%) than all other techniques except 1.5-T T2-weighted spin-echo imaging (64%). Combining the information from all MR pulse sequences yielded a cumulative sensitivity of 68%. Combining the information from two modalities yielded sensitivity of 96% for CTAP plus MR imaging, 85% for CTAP plus delayed CT, and 77% for delayed CT plus MR imaging. The authors conclude that when it is vital to know the precise number, size, and location of focal hepatic lesions before tumor resection, CTAP has the highest sensitivity, but MR imaging is an important adjuvant.

Authors
Nelson, RC; Chezmar, JL; Sugarbaker, PH; Bernardino, ME
MLA Citation
Nelson, RC, Chezmar, JL, Sugarbaker, PH, and Bernardino, ME. "Hepatic tumors: comparison of CT during arterial portography, delayed CT, and MR imaging for preoperative evaluation." Radiology 172.1 (July 1989): 27-34.
PMID
2662254
Source
pubmed
Published In
Radiology
Volume
172
Issue
1
Publish Date
1989
Start Page
27
End Page
34
DOI
10.1148/radiology.172.1.2662254

Gallbladder lithotripsy.

Authors
Steinberg, HV; Torres, WE; Nelson, RC
MLA Citation
Steinberg, HV, Torres, WE, and Nelson, RC. "Gallbladder lithotripsy." Radiology 172.1 (July 1989): 7-11.
PMID
2662257
Source
pubmed
Published In
Radiology
Volume
172
Issue
1
Publish Date
1989
Start Page
7
End Page
11
DOI
10.1148/radiology.172.1.2662257

Are hepatic and muscle T2 values different at 0.5 and 1.5 Tesla?

In an effort to determine whether T2 values of liver and muscle change with increasing field strength, 144 abdominal MR examinations were retrospectively evaluated. These patients were evaluated with a dual echo T2-weighted spin-echo sequence. Eighty-two of the examinations were performed at 0.5 Tesla and 72 at 1.5 Tesla (T). Eleven of the patients were evaluated with both MR systems with the same sequences. T2 values were also obtained from a Fe NH4(SO4)2 12H2O phantom. The T2 values of liver decreased from 57.8 +/- 11.3 at 0.5 T to 43.7 +/- 8.3 at 1.5 T. The T2 values of muscle decreased from 44.2 +/- 9 at 0.5 T to 35.4 +/- 7.2 at 1.5 T. Patients who were examined on both systems also demonstrated a decrease in both liver and muscle T2 values. For concentrations in the range of hepatic T2's, the phantom demonstrated a decrease in T2 values from 0.5 to 1.5 T ranging from 20.3 to 23.4%. All the T2 changes were statistically significant (p less than .05). The findings suggest that T2 values may depend on field strength, or may vary due to other hardware-related differences.

Authors
Bernardino, ME; Chaloupka, JC; Malko, JA; Chezmar, JL; Nelson, RC
MLA Citation
Bernardino, ME, Chaloupka, JC, Malko, JA, Chezmar, JL, and Nelson, RC. "Are hepatic and muscle T2 values different at 0.5 and 1.5 Tesla?." Magn Reson Imaging 7.4 (July 1989): 363-367.
PMID
2811617
Source
pubmed
Published In
Magnetic Resonance Imaging
Volume
7
Issue
4
Publish Date
1989
Start Page
363
End Page
367

Magnetic resonance imaging in hemochromatosis: extrahepatic iron deposition.

The magnetic resonance (MR) appearance of the liver in hemochromatosis has been previously described. We report a case in which iron deposition in the pancreas, spleen, and lymph nodes is demonstrated by MR.

Authors
Housman, JF; Chezmar, JL; Nelson, RC
MLA Citation
Housman, JF, Chezmar, JL, and Nelson, RC. "Magnetic resonance imaging in hemochromatosis: extrahepatic iron deposition." Gastrointest Radiol 14.1 (1989): 59-60.
PMID
2910746
Source
pubmed
Published In
Abdominal Imaging
Volume
14
Issue
1
Publish Date
1989
Start Page
59
End Page
60
DOI
10.1007/BF01889156

Delayed magnetic resonance hepatic imaging with gadolinium-DTPA.

Magnetic resonance imaging of the liver was performed on 11 rabbits (3-5 kg) before and at 4, 5 and 6 hours after the intravenous administration of 0.3 mM/kg Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) to determine if hepatocytes exhibit delayed excretion of Gd-DTPA, similar to the delayed hepatic excretion of iodinated contrast agents. Imaging was performed at 0.5 Tesla in the axial plane using a spin echo sequence of TR/TE, 250/20 milliseconds. Precontrast and postcontrast intensity changes for liver and muscle were standardized and compared over time. The average percent of postcontrast enhancement for liver and muscle, respectively was: 30.6 +/- 9.5% and 17.3 +/- 17.0% immediately postcontrast; 9.7 +/- 13.6% and 1.6 +/- 13.8% at 4 hours; 9.6 +/- 7.8% and 4.3 +/- 13.2% at 5 hours; and 11.0 +/- 7.8% and 4.1 +/- 11.7% at 6 hours. We conclude that there is not significant hepatocyte excretion of Gd-DTPA at 4 to 6 hours postcontrast injection in rabbits and that this may not be an advantageous paramagnetic contrast strategy for focal hepatic lesion detection.

Authors
Nelson, RC; Umpierrez, ME; Chezmar, JL; Bernardino, ME
MLA Citation
Nelson, RC, Umpierrez, ME, Chezmar, JL, and Bernardino, ME. "Delayed magnetic resonance hepatic imaging with gadolinium-DTPA." Invest Radiol 23.7 (July 1988): 509-511.
PMID
3170138
Source
pubmed
Published In
Investigative Radiology
Volume
23
Issue
7
Publish Date
1988
Start Page
509
End Page
511

Liver and abdominal screening in patients with cancer: CT versus MR imaging.

A prospective multiinstitutional study was performed to compare the ability of dynamic sequential contrast material-enhanced computed tomography (CT), delayed contrast material-enhanced CT, and two T1-weighted magnetic resonance (MR) sequences (spin echo and inversion recovery) to demonstrate metastatic disease in the liver and abdomen in patients with cancer. All four techniques had comparable rates of hepatic lesion detection when compared individually or when the combined CT techniques were compared with the combined MR techniques. The sensitivity to hepatic disease was 96% (27 of 28 patients) for the combined MR techniques versus 93% (26 of 28 patients) for the combined CT techniques. However, CT was statistically superior in the detection of extrahepatic disease, with significant extrahepatic findings demonstrated by CT in only 12 of 59 patients (20%). For this reason, the authors continue to recommend CT in the initial screening of patients with cancer for upper abdominal metastatic disease.

Authors
Chezmar, JL; Rumancik, WM; Megibow, AJ; Hulnick, DH; Nelson, RC; Bernardino, ME
MLA Citation
Chezmar, JL, Rumancik, WM, Megibow, AJ, Hulnick, DH, Nelson, RC, and Bernardino, ME. "Liver and abdominal screening in patients with cancer: CT versus MR imaging." Radiology 168.1 (July 1988): 43-47.
PMID
3380982
Source
pubmed
Published In
Radiology
Volume
168
Issue
1
Publish Date
1988
Start Page
43
End Page
47
DOI
10.1148/radiology.168.1.3380982

Adrenal masses: characterization with T1-weighted MR imaging.

The ability of a T1-weighted spin-echo magnetic resonance (MR) sequence to allow differentiation of benign from malignant adrenal masses at 0.5 T was investigated in 28 patients with 35 adrenal masses. All nine lesions with an adrenal mass-liver signal intensity ratio of 0.71 or less were metastases, and all 15 with a ratio of 0.78 or more were adenomas. Eleven masses (31%)--including six adenomas, three metastases, a pheochromocytoma, and a neuroblastoma--had ratios between these values. Nine of ten masses with adrenal mass-fat intensity ratios of 0.35 or less were metastases, and all 12 with ratios of 0.42 or more were benign. Eleven masses (31%), four malignant and one benign, had ratios between these values. The ratios for two masses could not be calculated due to lack of fat. The specificity of T1-weighted MR imaging in differentiating benign from malignant adrenal masses appears similar to that reported for T2-weighted imaging. However, significant overlap occurred, as has also been reported for T2-weighted imaging. While both imaging sequences may help distinguish benign from malignant adrenal masses in some cases, biopsy is still necessary when an accurate histologic diagnosis is essential.

Authors
Chezmar, JL; Robbins, SM; Nelson, RC; Steinberg, HV; Torres, WE; Bernardino, ME
MLA Citation
Chezmar, JL, Robbins, SM, Nelson, RC, Steinberg, HV, Torres, WE, and Bernardino, ME. "Adrenal masses: characterization with T1-weighted MR imaging." Radiology 166.2 (February 1988): 357-359.
PMID
3336711
Source
pubmed
Published In
Radiology
Volume
166
Issue
2
Publish Date
1988
Start Page
357
End Page
359
DOI
10.1148/radiology.166.2.3336711

Focal hepatic lesions: detection by dynamic and delayed computed tomography versus short TE/TR spin echo and fast field echo magnetic resonance imaging.

Eighteen patients with focal hepatic lesions were evaluated with two computed tomographic (CT) techniques including dynamic sequential bolus contrast CT and delayed contrast CT, and 3 magnetic resonance (MR) techniques including a spin echo pulse sequence with TE/TR of 21/310 msec and 2 fast field echo sequences using a TE/TR of 15/300 msec and 80 degrees flip angle (T1-weighted) and TE/TR of 15/500 msec and 10-20 degrees flip angle (T2-weighted). We concluded that CT, using delayed contrast and dynamic sequential bolus contrast techniques, was consistently superior to the 3 MR pulse sequences used on our imagers in terms of number of lesions detected, lesion-to-liver contrast, and quality of scan.

Authors
Nelson, RC; Chezmar, JL; Steinberg, HV; Torres, WE; Baumgartner, BR; Gedgaudas-McClees, RK; Bernardino, ME
MLA Citation
Nelson, RC, Chezmar, JL, Steinberg, HV, Torres, WE, Baumgartner, BR, Gedgaudas-McClees, RK, and Bernardino, ME. "Focal hepatic lesions: detection by dynamic and delayed computed tomography versus short TE/TR spin echo and fast field echo magnetic resonance imaging." Gastrointest Radiol 13.2 (1988): 115-122.
PMID
3360245
Source
pubmed
Published In
Abdominal Imaging
Volume
13
Issue
2
Publish Date
1988
Start Page
115
End Page
122

Finding motion parameters from spherical motion fields (or the advantages of having eyes in the back of your head).

A theory is developed for determining the motion of an observer given the motion field over a full 360 degree image sphere. The method is based on the fact that for an observer translating without rotation, the projected circular motion field about any equator can be divided into disjoint semicircles of clockwise and counterclockwise flow, and on the observation that the effects of rotation decouple around the three equators defining the three principal axes of rotation. Since the effect of rotation is geometrical, the three rotational parameters can be determined independently by searching, in each case, for a rotational value for which the derotated equatorial motion field can be partitioned into 180 degree arcs of clockwise and counterclockwise flow. The direction of translation is also obtained from this analysis. This search is two dimensional in the motion parameters, and can be performed relatively efficiently. Because information is correlated over large distances, the method can be considered a pattern recognition rather than a numerical algorithm. The algorithm is shown to be robust and relatively insensitive to noise and to missing data. Both theoretical and empirical studies of the error sensitivity are presented. The theoretical analysis shows that for white noise of bounded magnitude M, the expected errors is at worst linearly proportional to M. Empirical tests demonstrate negligible error for perturbations of up to 20% in the input, and errors of less than 20% for perturbations of up to 200%.

Authors
Nelson, RC; Aloimonos, J
MLA Citation
Nelson, RC, and Aloimonos, J. "Finding motion parameters from spherical motion fields (or the advantages of having eyes in the back of your head)." Biol Cybern 58.4 (1988): 261-273.
PMID
3358957
Source
pubmed
Published In
Biological Cybernetics
Volume
58
Issue
4
Publish Date
1988
Start Page
261
End Page
273

Role of computed tomography in screening for hepatocellular carcinoma in patients with cirrhosis.

One hundred patients with cirrhosis underwent abdominal computed tomography (CT) using a delayed contrast technique to determine liver and spleen volume. These scans were reviewed to screen this "at risk" population for hepatocellular carcinoma (HCC). Fifteen of the 100 screened patients had focal abnormalities suspicious for HCC. On biopsy, only 1 patient was shown to have HCC. The other 14 patients had either fatty infiltration or focal regeneration. In the same time interval, a total of 10 patients had histologically proven HCC. All presented with symptoms and died within 4 months of diagnosis. The results show that focal hepatic lesions can be detected by CT but in this population the lesions may not be due to HCC. The incidence of HCC was approximately 1%, probably reflecting a truly low incidence in this population.

Authors
Henderson, JM; Campbell, JD; Olson, R; Nelson, RC
MLA Citation
Henderson, JM, Campbell, JD, Olson, R, and Nelson, RC. "Role of computed tomography in screening for hepatocellular carcinoma in patients with cirrhosis." Gastrointest Radiol 13.2 (1988): 129-134.
PMID
2834256
Source
pubmed
Published In
Abdominal Imaging
Volume
13
Issue
2
Publish Date
1988
Start Page
129
End Page
134

Magnetic resonance imaging for detection of arterial and venous occlusion in canine muscle flaps and bowel segments

Magnetic resonance imaging (MRI) was performed on 16 muscle flaps and eight jejunal segments in dogs to assess its usefulness in detecting vascular occlusion. Arterial or venous occlusion was carried out in 11 muscles and six bowel segments, with the remaining sham flaps serving as controls. Imaging was performed over 2 hours using a spin echo pulse sequence with T2 weighting. Arterial occlusions in muscles resulted in T2 values 15-30% higher than controls, while venous occlusion produced T2 values 55-75% higher than controls. Differences became significant (p < 0.05) at 10 minutes after venous occlusion and at 35 minutes after arterial occlusion. Differences between occluded and control bowel segments, although demonstrating a similar trend, failed to reach statistical significance in this preliminary study. The authors conclude that magnetic resonance imaging may be a valuable method for early detection of venous and arterial occlusion in muscle flaps. Further study may also demonstrate this technique to be useful in the diagnosis of ischemic bowel.

Authors
Elias, DL; Nelson, RC; Herbst, MD; Zubowicz, VN
MLA Citation
Elias, DL, Nelson, RC, Herbst, MD, and Zubowicz, VN. "Magnetic resonance imaging for detection of arterial and venous occlusion in canine muscle flaps and bowel segments." Annals of Surgery 206.5 (December 1, 1987): 624-627.
Source
scopus
Published In
Annals of Surgery
Volume
206
Issue
5
Publish Date
1987
Start Page
624
End Page
627

Magnetic resonance imaging for detection of arterial and venous occlusion in canine muscle flaps and bowel segments.

Magnetic resonance imaging (MRI) was performed on 16 muscle flaps and eight jejunal segments in dogs to assess its usefulness in detecting vascular occlusion. Arterial or venous occlusion was carried out in 11 muscles and six bowel segments, with the remaining sham flaps serving as controls. Imaging was performed over 2 hours using a spin echo pulse sequence with T2 weighting. Arterial occlusions in muscles resulted in T2 values 15-30% higher than controls, while venous occlusion produced T2 values 55-75% higher than controls. Differences became significant (p less than 0.05) at 10 minutes after venous occlusion and at 35 minutes after arterial occlusion. Differences between occluded and control bowel segments, although demonstrating a similar trend, failed to reach statistical significance in this preliminary study. The authors conclude that magnetic resonance imaging may be a valuable method for early detection of venous and arterial occlusion in muscle flaps. Further study may also demonstrate this technique to be useful in the diagnosis of ischemic bowel.

Authors
Elias, DL; Nelson, RC; Herbst, MD; Zubowicz, VN
MLA Citation
Elias, DL, Nelson, RC, Herbst, MD, and Zubowicz, VN. "Magnetic resonance imaging for detection of arterial and venous occlusion in canine muscle flaps and bowel segments." Ann Surg 206.5 (November 1987): 624-627.
PMID
3675023
Source
pubmed
Published In
Annals of Surgery
Volume
206
Issue
5
Publish Date
1987
Start Page
624
End Page
627

Controlled eddy currents: applications to MR imaging.

We describe how the artifact caused by eddy currents generated in free standing copper coils may be controlled and used to advantage in magnetic resonance (MR) imaging. The eddy currents distort the excitation field of the MR imager in the vicinity of the coil; the coils may then be used to reduce the signal intensity of tissues adjacent to them. Two examples of how this signal reduction may be used to advantage are given. In one example a coil was used to eliminate an aliasing artifact by removing the signal from an unwanted object. In another example a coil was placed on the anterior abdominal wall of a subject, thereby reducing the high-intensity signal from subcutaneous fat and the resulting ghosting from respiratory motion.

Authors
Malko, JA; Nelson, RC
MLA Citation
Malko, JA, and Nelson, RC. "Controlled eddy currents: applications to MR imaging." J Comput Assist Tomogr 11.6 (November 1987): 1044-1049.
PMID
2960704
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
11
Issue
6
Publish Date
1987
Start Page
1044
End Page
1049

Evaluation of temazepam and diphenhydramine as hypnotics in a nursing-home population.

Seventeen nursing home residents with sleeping problems were enrolled in a randomized, double-blind, crossover trial of temazepam 15 mg, diphenhydramine (DPH) 50 mg, and placebo. Each drug was given for five consecutive nights with a 72-hour washout period between drugs. Subjects were assessed three times weekly with tests of psychomotor and cognitive function and four times weekly with observer sleep diaries and morning sleep questionnaires. Three subjects failed to complete the study. By report of the subjects, DPH resulted in shorter sleep latency than did placebo (t = 2.77, p less than 0.05). On the fifth night, use of DPH was associated with longer duration of sleep than temazepam (t = 2.88, p less than 0.05). No significant difference in tests of neurologic function was noted although, compared with placebo, subjects performed more poorly on seven of eight tests while taking temazepam and five of eight tests while taking DPH. Several instances of daytime hypersomnolence were noted in subjects taking temazepam and DPH, but none in subjects given placebo.

Authors
Meuleman, JR; Nelson, RC; Clark, RL
MLA Citation
Meuleman, JR, Nelson, RC, and Clark, RL. "Evaluation of temazepam and diphenhydramine as hypnotics in a nursing-home population." Drug Intell Clin Pharm 21.9 (September 1987): 716-720.
PMID
2888637
Source
pubmed
Published In
Drug Intelligence and Clinical Pharmacy
Volume
21
Issue
9
Publish Date
1987
Start Page
716
End Page
720

The impact of the addition of naloxone on the use and abuse of pentazocine.

An epidemic of abuse with "T's and blues" began in the late 1970's in which pentazocine-Talwin tablets ("T")--and the antihistamine tripelennamine (known as blues) were crushed, dissolved together, filtered, and injected intravenously. The resulting high was reported to be similar to that of heroin. In 1981, the manufacturer and the Food and Drug Administration met to discuss a possible solution. As a result, 0.5 mg of naloxone hydrochloride, a narcotic antagonist that is pharmacologically inactive at that dose orally but active if administered parenterally, was added to the tablet formulation. The reformulated product, Talwin Nx, was approved for marketing in late 1982 and introduced in the second quarter of 1983. Distribution of Talwin tablets in the United States was discontinued. The Drug Abuse Warning Network (DAWN) of the National Institute of Drug Abuse and IMS America's National Prescription Audit were used to review the use and abuse patterns of pentazocine before and after the naloxone intervention. The number of prescriptions dispensed quarterly for pentazocine products remained fairly stable from 1981 through the first quarter of 1983 and increased after the introduction of Talwin Nx. In contrast, DAWN emergency room and medical examiner mentions decreased after the product reformulation. The rates of both emergency room and medical examiner mentions per million prescriptions were substantially lower in the 2 years following the introduction of Talwin Nx (decreases of 70 percent by emergency rooms and 71 percent by medical examiners), indicating that the product reformulation successfully reduced pentazocine abuse.

Authors
Baum, C; Hsu, JP; Nelson, RC
MLA Citation
Baum, C, Hsu, JP, and Nelson, RC. "The impact of the addition of naloxone on the use and abuse of pentazocine." Public Health Rep 102.4 (July 1987): 426-429.
PMID
3112855
Source
pubmed
Published In
Public health reports (Washington, D.C. : 1974)
Volume
102
Issue
4
Publish Date
1987
Start Page
426
End Page
429

Comparison of pulsed Doppler sonography and angiography in patients with portal hypertension.

Pulsed Doppler sonography and liver panangiography were performed in 43 patients with cirrhosis. Fourteen patients were evaluated preoperatively, and 28 patients were evaluated after a variceal decompressive shunt. One patient was studied before and after undergoing a shunt. The direction of portal blood flow by Doppler sonography was compared with both the grading pattern and direction of flow by angiography. When portal blood flow was determined to be antegrade by Doppler sonography, angiography showed antegrade flow in 84% (grade I, II, or III portal venous pattern). Six percent had retrograde flow (grade IV), and 10% had portal vein thrombosis. When the portal blood flow was determined to be retrograde by Doppler sonography, angiography showed retrograde flow (grade IV portal venous pattern) in 80% and antegrade flow (grade I, II, or III) in 20%. When an inadequate Doppler tracing was obtained from the portal vein, angiography showed either grade I, II, or III in 38%; grade IV in 50%, and portal vein thrombosis in 13%. There was poor correlation between the calculated mean flow rates, as determined by Doppler sonography, and the angiographic grade. We conclude that pulsed Doppler sonography is accurate in determining the direction of portal flow when an adequate tracing is obtained (36 of 44 studies). When an inadequate tracing is obtained, retrograde portal flow or portal vein thrombosis is likely.

Authors
Nelson, RC; Lovett, KE; Chezmar, JL; Moyers, JH; Torres, WE; Murphy, FB; Bernardino, ME
MLA Citation
Nelson, RC, Lovett, KE, Chezmar, JL, Moyers, JH, Torres, WE, Murphy, FB, and Bernardino, ME. "Comparison of pulsed Doppler sonography and angiography in patients with portal hypertension." AJR Am J Roentgenol 149.1 (July 1987): 77-81.
PMID
3296714
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
149
Issue
1
Publish Date
1987
Start Page
77
End Page
81
DOI
10.2214/ajr.149.1.77

Kidney changes after extracorporeal shock wave lithotripsy: appearance on MR imaging.

The occurrence of changes in the kidneys after extracorporeal shock wave lithotripsy (ESWL) was evaluated with magnetic resonance (MR) imaging in 34 patients, utilizing T1-weighted spin-echo pulse sequences. Five of the 34 patients underwent bilateral ESWL therapy before MR imaging. Of the 39 kidneys studied, 29 (74%) showed one or more changes on MR imaging: subcapsular or perinephric fluid (n = 10), focal (n = 16) or diffuse (n = 8) loss of the corticomedullary junction (CMJ), and focal areas of increased (n = 7) or decreased (n = 3) signal intensity. The CMJ changes were more prominent with increasing numbers of shock waves administered during the procedure. These relatively subtle changes detected on MR imaging may not be apparent with other imaging techniques. The long-term clinical significance of these findings is not yet known, although no apparent serious renal pathologic condition was detected.

Authors
Baumgartner, BR; Dickey, KW; Ambrose, SS; Walton, KN; Nelson, RC; Bernardino, ME
MLA Citation
Baumgartner, BR, Dickey, KW, Ambrose, SS, Walton, KN, Nelson, RC, and Bernardino, ME. "Kidney changes after extracorporeal shock wave lithotripsy: appearance on MR imaging." Radiology 163.2 (May 1987): 531-534.
PMID
3562837
Source
pubmed
Published In
Radiology
Volume
163
Issue
2
Publish Date
1987
Start Page
531
End Page
534
DOI
10.1148/radiology.163.2.3562837

Renal allograft rejection: evaluation by Doppler US and MR imaging.

A prospective study compared the efficacy of Doppler ultrasonography (US) and magnetic resonance (MR) imaging in evaluating 38 renal allografts, with specific attention to transplant rejection. Forty-three Doppler US and 42 MR examinations were performed and interpreted. Histologic correlation was obtained from 22 biopsy or nephrectomy specimens. Clinical correlation or a response to instituted therapy was used as confirmation in the remaining allografts. Accuracy in identifying cyclosporine toxicity or acute tubular necrosis could not be evaluated because there were few such cases, with concomitant rejection in most. The ability to predict and identify presence or absence of rejection was not affected by different serum creatinine values. Doppler US was significantly superior to MR imaging in identifying allograft rejection, demonstrating a higher sensitivity (95% vs. 70%), specificity (95% vs. 73%), and accuracy (95% vs. 71%). Because of its low cost and accessibility, Doppler US should become the primary modality for renal transplant screening.

Authors
Steinberg, HV; Nelson, RC; Murphy, FB; Chezmar, JL; Baumgartner, BR; Delaney, VB; Whelchel, JD; Bernardino, ME
MLA Citation
Steinberg, HV, Nelson, RC, Murphy, FB, Chezmar, JL, Baumgartner, BR, Delaney, VB, Whelchel, JD, and Bernardino, ME. "Renal allograft rejection: evaluation by Doppler US and MR imaging." Radiology 162.2 (February 1987): 337-342.
PMID
3541027
Source
pubmed
Published In
Radiology
Volume
162
Issue
2
Publish Date
1987
Start Page
337
End Page
342
DOI
10.1148/radiology.162.2.3541027

MR imaging of renal transplants.

Fifty-six MR studies were obtained in 32 renal transplant patients, by using T1-weighted, spin-echo, and inversion-recovery pulse sequences. The findings, particularly the loss of corticomedullary differentiation, and the extent of vascular penetration into the renal parenchyma, were compared with the clinical and histologic diagnosis of transplant rejection. Thirteen MR studies on 11 patients with clinically normal renal transplants demonstrated normal corticomedullary differentiation. Renal vessels extended into the parenchyma in all 11 patients and to the cortex in 38%. In 37 MR studies on 22 patients with a clinical or histologic diagnosis of acute and/or chronic transplant rejection, the corticomedullary differentiation was normal in 8%, faint in 24%, and absent in 68%. Renal parenchymal vessels were visualized in 32%, but extended to the level of the cortex in only 8%. In 68% of the studies with transplant rejection, no parenchymal vessels were seen. When the corticomedullary differentiation was either faint or absent, the vascular pattern was normal in 6%; in 68% of cases no parenchymal vessels could be identified. We conclude the corticomedullary differentiation and the renal vascular pattern are useful parameters in the evaluation of renal transplant rejection.

Authors
Baumgartner, BR; Nelson, RC; Ball, TI; Wyly, JB; Bourke, E; Delaney, V; Bernardino, ME
MLA Citation
Baumgartner, BR, Nelson, RC, Ball, TI, Wyly, JB, Bourke, E, Delaney, V, and Bernardino, ME. "MR imaging of renal transplants." AJR Am J Roentgenol 147.5 (November 1986): 949-953.
PMID
3532735
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
147
Issue
5
Publish Date
1986
Start Page
949
End Page
953
DOI
10.2214/ajr.147.5.949

Acute injuries of the lateral ligaments of the ankle: comparison of stress radiography and arthrography.

Anterior and inversion stress were applied to the lateral ligaments of the ankle and the findings compared with the arthrograms. Fifty-five patients underwent stress radiography of both ankles and arthrography of the injured ankle within 72 hours of acute injury to the lateral ligaments. Ten patients had normal arthrograms and 45 had evidence of ligamentous injury. Anterior stress measurements could not be correlated with arthrography, and no differentiation between single and double ligament tears could be made. Inversion stress testing was very accurate in predicting ligamentous injury when the angle of inversion was 10 degrees or greater but achieved this degree of accuracy in only 38.2% of patients.

Authors
Sauser, DD; Nelson, RC; Lavine, MH; Wu, CW
MLA Citation
Sauser, DD, Nelson, RC, Lavine, MH, and Wu, CW. "Acute injuries of the lateral ligaments of the ankle: comparison of stress radiography and arthrography." Radiology 148.3 (September 1983): 653-657.
PMID
6878679
Source
pubmed
Published In
Radiology
Volume
148
Issue
3
Publish Date
1983
Start Page
653
End Page
657
DOI
10.1148/radiology.148.3.6878679

Inhibition of glycosylation of bovine herpesvirus 1 glycoproteins by the thymidine analog (E)-5-(2 Bromovinyl)-2'-deoxyuridine.

(E)-5-(2-Bromovinyl)-2'-deoxyuridine (BVdU) was phosphorylated by the bovine herpesvirus 1 (BHV-1)-induced thymidine kinase and subsequently incorporated into viral DNA, resulting in DNA that was more dense than DNA from untreated cells. Incorporation of the drug did not result in the termination of replicating BHV-1 DNA molecules since radioactively labeled DNA synthesized in drug-treated and untreated cells sedimented at similar rates in alkaline sucrose gradients. No differences were observed in the electrophoretic mobility of [35S]methionine-labeled viral polypeptides synthesized in treated and untreated cells, although [3H]glucosamine-labeled viral glycoproteins synthesized in treated cells were of a lower molecular weight than those in untreated cells. In BVdU-treated cells, unlike untreated cells, immature neutral and basic precursors of the mature viral glycoproteins accumulated. Although BVdU-treated and untreated cells contained similar amounts of virus, very little virus was released into the culture supernatant from BVdU-treated cells. Our results suggest that BVdU partially inhibits the glycosylation of BHV-1 glycoproteins. BVdU-sensitive glycosylation, however, is not necessary for expression of these glycoproteins on the surface of infected cells since the glycoproteins could be labeled on intact cells with 125I and because BVdU-treated cells remained sensitive to antibody-dependent, cell-mediated cytotoxity mediated by anti-BHV-1 serum. The phosphorylation of BVdU was a prerequisite for its effect on glycosylation since the glycoproteins of a thymidine kinase-deficient mutant of BHV-1 were not affected.

Authors
Misra, V; Nelson, RC; Babiuk, LA
MLA Citation
Misra, V, Nelson, RC, and Babiuk, LA. "Inhibition of glycosylation of bovine herpesvirus 1 glycoproteins by the thymidine analog (E)-5-(2 Bromovinyl)-2'-deoxyuridine." Antimicrob Agents Chemother 23.6 (June 1983): 857-865.
PMID
6614891
Source
pubmed
Published In
Antimicrobial agents and chemotherapy
Volume
23
Issue
6
Publish Date
1983
Start Page
857
End Page
865

The effect of autoclave sterilization on endodontic files.

This study evaluates the effect of cyclic autoclave sterilization and simulated clinical usage on a mechanical property of one brand of stainless steel endodontic files. The angular deflection moments were measured by a torque apparatus approved by the American Dental Association for such purposes. Comparisons of values for sterilized and nonsterilized files were made. 1. A significant decrease in angular deflection values exists for stainless steel endodontic files having undergone ten cycles of autoclave sterilization versus files having undergone only two or five similar cyclings. 2. All file sizes (15, 20, 25, 30, 35, 40) tested in torsion were detrimentally affected by the autoclave sterilization. 3. Of the files investigated, sizes 35 and 40 were the most adversely affected by the steam-under-pressure sterilization. 4. The angular deflection values of those files subjected to repeated autoclavings were not decreased below the minimum value accepted by the American Dental Association for resistance to torquing forces. It can therefore be concluded that repeated sterilization of a stainless steel endodontic file does result in a significant reduction in the torque resistance of that file. This reduction of the metal property is not significant clinically, however.

Authors
Mitchell, BF; James, GA; Nelson, RC
MLA Citation
Mitchell, BF, James, GA, and Nelson, RC. "The effect of autoclave sterilization on endodontic files." Oral Surg Oral Med Oral Pathol 55.2 (February 1983): 204-207.
PMID
6572871
Source
pubmed
Published In
Oral Surgery, Oral Medicine and Oral Pathology
Volume
55
Issue
2
Publish Date
1983
Start Page
204
End Page
207

The clinical scientist concept.

Authors
Rector, TS; Nelson, RC
MLA Citation
Rector, TS, and Nelson, RC. "The clinical scientist concept." Drug Intell Clin Pharm 16.11 (November 1982): 882-883. (Letter)
PMID
7173053
Source
pubmed
Published In
Drug Intelligence and Clinical Pharmacy
Volume
16
Issue
11
Publish Date
1982
Start Page
882
End Page
883

Pharmacy's role in THC distribution.

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Pharmacy's role in THC distribution." Am J Hosp Pharm 38.1 (January 1981): 29-30. (Letter)
PMID
6259938
Source
pubmed
Published In
American Journal of Hospital Pharmacy
Volume
38
Issue
1
Publish Date
1981
Start Page
29
End Page
30

The effect of antibiotic additions on the mechanical properties of acrylic cement.

Early work on hip prosthesis showed that the metal component would loosen in bone even when screws were used. This practice resulted in the death and resorption of the bone; thus cement was used in orthopedic surgery for firm implantation of prostheses. In recent years antibiotics have been added to the cement as a prophylaxis against infection. This research investigates the effects of antibiotics on the diametral tensile and compression strength of the cement. Samples made with 2 g of antibiotic per surgical packet of bone cement containing the antibiotics gentamicin, keflin, and a combination of the two were tested. These samples were aged at ambient temperature for periods of 1 day and 1, 2, 8, 13, and over 30 weeks. A stastical analysis using a two-way analysis of variance with interaction was conducted. It was concluded that the compression strength was affected by the antibiotic, and not by the aging period, but that there is an antibiotic-aging period interaction. The tensile strength is not affected by either the antibiotic or the aging period, and there is an antibiotic-aging period interaction. Current work being conducted will analyze additional factors and interactions.

Authors
Nelson, RC; Hoffman, RO; Burton, TA
MLA Citation
Nelson, RC, Hoffman, RO, and Burton, TA. "The effect of antibiotic additions on the mechanical properties of acrylic cement." J Biomed Mater Res 12.4 (July 1978): 473-490.
PMID
681370
Source
pubmed
Published In
Journal of Biomedical Materials Research
Volume
12
Issue
4
Publish Date
1978
Start Page
473
End Page
490
DOI
10.1002/jbm.820120403

Biomechanical comparison of male and female distance runners.

Authors
Nelson, RC; Brooks, CM; Pike, NL
MLA Citation
Nelson, RC, Brooks, CM, and Pike, NL. "Biomechanical comparison of male and female distance runners." Ann N Y Acad Sci 301 (1977): 793-807.
PMID
270952
Source
pubmed
Published In
Annals of the New York Academy of Sciences
Volume
301
Publish Date
1977
Start Page
793
End Page
807

Biomechanics of distance running: a longitudinal study.

Authors
Nelson, RC; Gregor, RJ
MLA Citation
Nelson, RC, and Gregor, RJ. "Biomechanics of distance running: a longitudinal study." Res Q 47.3 (October 1976): 417-428.
PMID
1069331
Source
pubmed
Published In
Research quarterly
Volume
47
Issue
3
Publish Date
1976
Start Page
417
End Page
428

Body dimensions of Japanese and American gymnasts.

Authors
LeVeau, B; Ward, T; Nelson, RC
MLA Citation
LeVeau, B, Ward, T, and Nelson, RC. "Body dimensions of Japanese and American gymnasts." Med Sci Sports 6.2 (1974): 146-150.
PMID
4461975
Source
pubmed
Published In
Medicine and science in sports
Volume
6
Issue
2
Publish Date
1974
Start Page
146
End Page
150

Biomechanics of overground versus treadmill running.

Authors
Nelson, RC; Dillman, CJ; Lagasse, P; Bickett, P
MLA Citation
Nelson, RC, Dillman, CJ, Lagasse, P, and Bickett, P. "Biomechanics of overground versus treadmill running." Med Sci Sports 4.4 (1972): 233-240.
PMID
4648586
Source
pubmed
Published In
Medicine and science in sports
Volume
4
Issue
4
Publish Date
1972
Start Page
233
End Page
240

The mechanical energy transformations of pole vaulting with a fiberglass pole.

Authors
Dillman, CJ; Nelson, RC
MLA Citation
Dillman, CJ, and Nelson, RC. "The mechanical energy transformations of pole vaulting with a fiberglass pole." J Biomech 1.3 (August 1968): 175-183.
PMID
16329288
Source
pubmed
Published In
Journal of Biomechanics
Volume
1
Issue
3
Publish Date
1968
Start Page
175
End Page
183

Statistical procedures used in multiple-group experiments.

Authors
Nelson, RC; Morehouse, CA
MLA Citation
Nelson, RC, and Morehouse, CA. "Statistical procedures used in multiple-group experiments." Res Q 37.3 (October 1966): 441-445.
PMID
5223101
Source
pubmed
Published In
Research quarterly
Volume
37
Issue
3
Publish Date
1966
Start Page
441
End Page
445

Relationship between strength and speed of elbow flexion.

Authors
Nelson, RC; Fahrney, RA
MLA Citation
Nelson, RC, and Fahrney, RA. "Relationship between strength and speed of elbow flexion." Res Q 36.4 (December 1965): 455-463.
PMID
5215874
Source
pubmed
Published In
Research quarterly
Volume
36
Issue
4
Publish Date
1965
Start Page
455
End Page
463

Effects of high frequency electrical stimulation on the size and strength of skeletal muscle.

Authors
Massey, BH; Nelson, RC; Sharkey, BC; Comden, T; Otott, GC
MLA Citation
Massey, BH, Nelson, RC, Sharkey, BC, Comden, T, and Otott, GC. "Effects of high frequency electrical stimulation on the size and strength of skeletal muscle." J Sports Med Phys Fitness 5.3 (September 1965): 136-144.
PMID
5850780
Source
pubmed
Published In
The Journal of sports medicine and physical fitness
Volume
5
Issue
3
Publish Date
1965
Start Page
136
End Page
144

EFFECT OF OVERLOAD ON SPEED OF ELBOW FLEXION AND THE ASSOCIATED AFTEREFFECTS.

Authors
NELSON, RC; NOFSINGER, MR
MLA Citation
NELSON, RC, and NOFSINGER, MR. "EFFECT OF OVERLOAD ON SPEED OF ELBOW FLEXION AND THE ASSOCIATED AFTEREFFECTS." Res Q 36 (May 1965): 174-181.
PMID
14329703
Source
pubmed
Published In
Research quarterly
Volume
36
Publish Date
1965
Start Page
174
End Page
181

MINORITY CARRIER TRAPPING AND DYE SENSITIZATION.

Authors
NELSON, RC
MLA Citation
NELSON, RC. "MINORITY CARRIER TRAPPING AND DYE SENSITIZATION." J Phys Chem 69 (March 1965): 714-718.
PMID
14296948
Source
pubmed
Published In
Journal of Physical Chemistry
Volume
69
Publish Date
1965
Start Page
714
End Page
718

A CINEMATOGRAPHICAL ANALYSIS OF SPRINT RUNNING.

Authors
DESHON, DE; NELSON, RC
MLA Citation
DESHON, DE, and NELSON, RC. "A CINEMATOGRAPHICAL ANALYSIS OF SPRINT RUNNING." Res Q 35 (December 1964): 451-455.
PMID
14276388
Source
pubmed
Published In
Research quarterly
Volume
35
Publish Date
1964
Start Page
451
End Page
455

AN INVESTIGATION OF VARIOUS MEASURES USED IN IMPACT TESTING OF PROTECTIVE HEADGEAR.

Authors
NELSON, RC; ALEXANDER, JF; MONTOYE, HJ; VANHUSS, WD
MLA Citation
NELSON, RC, ALEXANDER, JF, MONTOYE, HJ, and VANHUSS, WD. "AN INVESTIGATION OF VARIOUS MEASURES USED IN IMPACT TESTING OF PROTECTIVE HEADGEAR." J Sports Med Phys Fitness 4 (June 1964): 94-102.
PMID
14180745
Source
pubmed
Published In
The Journal of sports medicine and physical fitness
Volume
4
Publish Date
1964
Start Page
94
End Page
102

PROLONGED RUPTURE OF FETAL MEMBRANES.

Authors
WILSON, MG; ARMSTRONG, DH; NELSON, RC; BOAK, RA
MLA Citation
WILSON, MG, ARMSTRONG, DH, NELSON, RC, and BOAK, RA. "PROLONGED RUPTURE OF FETAL MEMBRANES." Am J Dis Child 107 (February 1964): 138-146.
PMID
14091819
Source
pubmed
Published In
American Journal of Diseases of Children
Volume
107
Publish Date
1964
Start Page
138
End Page
146

Photoelectric phenomena in hemoglobin and dyed gelatin.

Authors
Nelson, RC
MLA Citation
Nelson, RC. "Photoelectric phenomena in hemoglobin and dyed gelatin." J Chem Phys 39.1 (July 1, 1963): 112-115.
PMID
5878661
Source
pubmed
Published In
Journal of Chemical Physics
Volume
39
Issue
1
Publish Date
1963
Start Page
112
End Page
115

New source of Pseudomonas aeruginosa in a nursery.

Authors
WILSON, MG; NELSON, RC; PHILLIPS, LH; BOAK, RA
MLA Citation
WILSON, MG, NELSON, RC, PHILLIPS, LH, and BOAK, RA. "New source of Pseudomonas aeruginosa in a nursery." JAMA 175 (April 1, 1961): 1146-1148.
PMID
13785696
Source
pubmed
Published In
JAMA : the journal of the American Medical Association
Volume
175
Publish Date
1961
Start Page
1146
End Page
1148
Show More