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MacFall, James R.

Overview:


My research centers on application and/or development of image processing and magnetic resonance imaging (MRI) techniques for a variety of biomedical focus areas in Psychiatry, Oncology, Lung Disorders and Pediatric Neurological Disorders:
Psychiatry: Research is focused on improving automated methods of brain tissue identification and volume measurement using magnetic resonance images in the context of a study of depression in aging. Similar work is ongoing in bipolar disorder. We are also developing ways to use diffusion tensor imaging to assess the damage caused by vascular lesions to white matter tracts.
Oncology: Research efforts center on how to best quantitate MRI-based diffusion and perfusion parameters and apply them to predicting the course and outcome of cancer therapy. Current efforts involve developing robust algorithms for removing distortion from echo-planar MR diffusion images and producing high resolution MR diffusion images on our research 3 Tesla MR imaging system (Center for Advanced MR Development, CAMRD). I am also collaborating with Radiologists and Oncologists to develop rapid quantitation of tumor vascular permeability and relate changes in the permeability to a variety of vascular targeted therapies in clinical trials. A second effort centers on using MRI to monitor temperature and other tissue parameters during hyperthermia therapy.
Pediatric Neurology/Psychiatry: I am collaborating with researchers at Duke to use MRI methods to evaluate childhood epilepsy, addictions, trauma and abuse. Some of these involve multi-site studies. We are developing ways to use new technology available for advanced analysis and data mining  for such multi-site research.
All of this work is very collaborative between technology oriented and disease oriented researchers. There are continuing opportunities in my group for student research with subsets of data currently under analysis.
Lung Disorders: The lung is particularly challenging to image with MRI. I am collaborating with colleagues to develop MRI methods to image the lungs to provide non-invasive biomarkers for Chronic Obstructive Lung Disease (COPD).

Positions:

Adjunct Professor in the Department of Radiology

Radiology
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Affiliate of the Center for Brain Imaging and Analysis

Duke-UNC Center for Brain Imaging and Analysis
School of Medicine

Education:

B.A. 1967

B.A. — Northwestern University

M.S. 1971

M.S. — University of Maryland, College Park

Ph.D. 1976

Ph.D. — University of Maryland, College Park

Grants:

Training in Medical Imaging

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
July 15, 2003
End Date
August 31, 2019

Consequences of prolonged febrile seizures in childhood

Administered By
Pediatrics, Neurology
AwardedBy
Albert Einstein College of Medicine
Role
Co Investigator
Start Date
May 01, 2013
End Date
April 30, 2017

ACRIN MR Physics Center of Excellence

Administered By
Radiology
AwardedBy
American College of Radiology Imaging Network
Role
Principal Investigator
Start Date
April 29, 2014
End Date
February 28, 2015

Simultaneous Emission and Transmission Mammotomography

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
September 19, 2002
End Date
July 31, 2014

ACRIN MR Physics Center of Excellence

Administered By
Radiology
AwardedBy
American College of Radiology Imaging Network
Role
Principal Investigator
Start Date
October 01, 2013
End Date
February 28, 2014

Cross-disciplinary Training in Medical Physics

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
July 01, 2007
End Date
June 30, 2013

Genes and Alterations in Brain Structure and Function in Depression

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
February 01, 2008
End Date
July 31, 2012

Vascular Depression: Longitudinal Changes

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Investigator
Start Date
April 01, 2007
End Date
September 30, 2011

Bipolar Disorder in Late Life

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
January 01, 2005
End Date
December 31, 2010

A Linux Cluster Computational Facility for Neuroimaging Research

Administered By
Duke-UNC Center for Brain Imaging and Analysis
AwardedBy
National Institutes of Health
Role
Major User
Start Date
April 01, 2009
End Date
March 31, 2010

PTSD & Childhood Sexual Abuse: Psychobiology

Administered By
Psychiatry, Child & Family Mental Health and Developmental Neuroscience
AwardedBy
National Institutes of Health
Role
Consultant
Start Date
September 09, 2002
End Date
August 31, 2009

PTSD & Childhood Sexual Abuse: Psychobiology

Administered By
Psychiatry, Child & Family Mental Health and Developmental Neuroscience
AwardedBy
National Institutes of Health
Role
Consultant
Start Date
September 09, 2002
End Date
August 31, 2008

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

Treatment Outcomes of Vascular Depression

Administered By
Psychiatry & Behavioral Sciences, Translational Neuroscience
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
April 01, 2001
End Date
March 31, 2007

MRI Diffusion Correlates of Neuronal Activity

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
February 15, 2004
End Date
January 31, 2007

Bipolar Disorder in Late Life

Administered By
Psychiatry & Behavioral Sciences, Translational Neuroscience
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
December 01, 1997
End Date
February 28, 2004

Depression in Late Life

Administered By
Psychiatry & Behavioral Sciences, Translational Neuroscience
AwardedBy
National Institutes of Health
Role
Administrative Assistant
Start Date
April 01, 1996
End Date
March 31, 2003

Unified Approach to Hyperthermia Modeling and Planning

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
March 01, 2000
End Date
November 30, 2002

Geriatric Depression: Risk Factors For Adverse Outcomes

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
July 01, 1995
End Date
June 30, 2002

Tolerance To Aluminum In Soil By Mycorrhizal And Non-Mycor

Administered By
Radiology
AwardedBy
Department of Agriculture
Role
Principal Investigator
Start Date
September 01, 1995
End Date
August 31, 2000

Study Of Depression

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
September 30, 1994
End Date
July 01, 2000

Depression In Late Life

Administered By
Psychiatry & Behavioral Sciences
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
December 01, 1995
End Date
November 30, 1999

A Unfied Approach To Hyperthermia Modeling And Planning

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
September 01, 1996
End Date
August 31, 1999

Hyperthermia And Perfusion Effects In Cancer Therapy

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
August 01, 1997
End Date
July 31, 1999

Hyperthermia And Perfusion Effects In Cancer Therapy

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
September 29, 1995
End Date
July 31, 1999

Hyperthermia And Perfusion Effects In Cancer Therapy

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
June 01, 1987
End Date
July 31, 1999

Crc/Pe For The Study Of Depression

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
September 30, 1984
End Date
July 31, 1999

Geratric Depression: Risk Factors For Adverse Outcome

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
July 01, 1995
End Date
June 30, 1999

Geriatric Depression: Risk Factors For Adverse Outcome

Administered By
Psychiatry & Behavioral Sciences, Geriatric Behavioral Health
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
July 01, 1995
End Date
June 30, 1999

Depression In Late Life

Administered By
Psychiatry & Behavioral Sciences
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
April 01, 1997
End Date
March 31, 1999

Magnetic Resonance Monitoring Of Hyperthermia

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
March 01, 1994
End Date
February 28, 1998

Cortisol Cognition Brain Atrophy And Depression

Administered By
Psychiatry & Behavioral Sciences
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
September 01, 1989
End Date
August 30, 1997

Magnetic Resonance Monitoring Of Hypethermia

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
March 01, 1994
End Date
February 28, 1997

An Integrated Center For In Vivo Microscopy

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
September 01, 1990
End Date
September 29, 1996

Magnetic Resonance Studies In Venous Thromboembolism

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
July 01, 1993
End Date
June 30, 1996

Magnetic Resonance Studies In Venous Thromboembolism

Administered By
Radiology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
July 01, 1992
End Date
June 30, 1996

Hyperthermia And Perfusion Effects In Cancer Therapy

Administered By
Radiation Oncology
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
June 01, 1993
End Date
May 31, 1995
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Publications:

Risk factors for subsequent febrile seizures in the FEBSTAT study.

To identify risk and risk factors for developing a subsequent febrile seizure (FS) in children with a first febrile status epilepticus (FSE) compared to a first simple febrile seizure (SFS). To identify home use of rescue medications for subsequent FS.Cases included a first FS that was FSE drawn from FEBSTAT and Columbia cohorts. Controls were a first SFS. Cases and controls were classified according to established FEBSTAT protocols. Cumulative risk for subsequent FS over a 5-year period was compared in FSE versus SFS, and Cox proportional hazards regression was conducted. Separate analysis examined subsequent FS within FSE. The use of rescue medications at home was assessed for subsequent FS.Risk for a subsequent FSE was significantly increased in FSE versus SFS. Any magnetic resonance imaging (MRI) abnormality increased the risk 3.4-fold (p < 0.05), adjusting for age at first FS and FSE and in analyses restricted to children whose first FS was FSE (any MRI abnormality hazard ratio [HR] 2.9, p < 0.05). The risk for a second FS of any type or of subsequent FS lasting >10 min over the 5-year follow-up did not differ in FSE versus SFS. Rectal diazepam was administered at home to 5 (23.8%) of 21 children with subsequent FS lasting ≥10 min.Compared to controls, FSE was associated with an increased risk for subsequent FSE, suggesting the propensity of children with an initial prolonged seizure to experience a prolonged recurrence. Any baseline MRI abnormality increased the recurrence risk when FSE was compared to SFS and when FSE was studied alone. A minority of children with a subsequent FS lasting 10 min or longer were treated with rectal diazepam at home, despite receiving prescriptions after the first FSE. This indicates the need to further improve the education of clinicians and parents in order to prevent subsequent FSE.

Authors
Hesdorffer, DC; Shinnar, S; Lax, DN; Pellock, JM; Nordli, DR; Seinfeld, S; Gallentine, W; Frank, LM; Lewis, DV; Shinnar, RC; Bello, JA; Chan, S; Epstein, LG; Moshé, SL; Liu, B; Sun, S
MLA Citation
Hesdorffer, DC, Shinnar, S, Lax, DN, Pellock, JM, Nordli, DR, Seinfeld, S, Gallentine, W, Frank, LM, Lewis, DV, Shinnar, RC, Bello, JA, Chan, S, Epstein, LG, Moshé, SL, Liu, B, and Sun, S. "Risk factors for subsequent febrile seizures in the FEBSTAT study." Epilepsia 57.7 (July 2016): 1042-1047.
PMID
27265870
Source
epmc
Published In
Epilepsia
Volume
57
Issue
7
Publish Date
2016
Start Page
1042
End Page
1047
DOI
10.1111/epi.13418

APOE ε4 associated with preserved executive function performance and maintenance of temporal and cingulate brain volumes in younger adults.

The APOE ε4 allele is associated with cognitive deficits and brain atrophy in older adults, but studies in younger adults are mixed. We examined APOE genotype effects on cognition and brain structure in younger adults and whether genotype effects differed by age and with presence of depression. 157 adults (32 % ε4 carriers, 46 % depressed) between 20 and 50 years of age completed neuropsychological testing, 131 of which also completed 3 T cranial MRI. We did not observe a direct effect of APOE genotype on cognitive performance or structural MRI measures. A significant genotype by age interaction was observed for executive function, where age had less of an effect on executive function in ε4 carriers. Similar interactions were observed for the entorhinal cortex, rostral and caudal anterior cingulate cortex and parahippocampal gyrus, where the effect of age on regional volumes was reduced in ε4 carriers. There were no significant interactions between APOE genotype and depression diagnosis. The ε4 allele benefits younger adults by allowing them to maintain executive function performance and volumes of cingulate and temporal cortex regions with aging, at least through age fifty years.

Authors
Taylor, WD; Boyd, B; Turner, R; McQuoid, DR; Ashley-Koch, A; MacFall, JR; Saleh, A; Potter, GG
MLA Citation
Taylor, WD, Boyd, B, Turner, R, McQuoid, DR, Ashley-Koch, A, MacFall, JR, Saleh, A, and Potter, GG. "APOE ε4 associated with preserved executive function performance and maintenance of temporal and cingulate brain volumes in younger adults." Brain imaging and behavior (February 3, 2016).
PMID
26843007
Source
epmc
Published In
Brain Imaging and Behavior
Publish Date
2016

Hippocampal Malrotation Is Associated With Prolonged Febrile Seizures: Results of the FEBSTAT Study.

Hippocampal malrotation is characterized by incomplete hippocampal inversion with a rounded shape and blurred internal architecture. There is still debate about whether hippocampal malrotation has pathologic significance. We present findings from the Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study on the frequency of and risk factors for hippocampal malrotation.FEBSTAT is a prospective multicenter study investigating the consequences of febrile status epilepticus in childhood. MRI studies of 226 patients with febrile status epilepticus were analyzed visually by two board-certified neuroradiologists blinded to clinical details and were compared with MRI studies of 96 subjects with first simple febrile seizure. Quantitative analysis of hippocampal volume was performed by two independent observers.Hippocampal malrotation was present in 20 of 226 (8.8%) patients with febrile status epilepticus compared with two of 96 (2.1%) control subjects (odds ratio [OR], 4.56; 95% CI, 1.05-19.92). Hippocampal malrotation was exclusively left-sided in 18 of 22 (81.8%) patients and bilateral in the remaining four patients (18.2%). There was no case of exclusively right-sided hippocampal malrotation. Hippocampal malrotation was more common in boys than in girls (OR, 6.1; 95% CI, 1.7-21.5). On quantitative volumetric MRI analysis, the left hippocampal volume was smaller in patients with hippocampal malrotation than in control subjects with simple febrile seizure (p = 0.004), and the right-to-left hippocampal volume ratio was higher in the hippocampal malrotation group than in the simple febrile seizure group (p < 0.001).Hippocampal malrotation is a developmental malformation that predominantly affects the left hippocampus in male patients and is more frequently found in children with prolonged febrile status epilepticus than in control subjects. These data provide further evidence that hippocampal malrotation represents a pathologic error in brain development rather than a normal variant.

Authors
Chan, S; Bello, JA; Shinnar, S; Hesdorffer, DC; Lewis, DV; MacFall, J; Shinnar, RC; Gomes, W; Litherland, C; Xu, Y; Nordli, DR; Pellock, JM; Frank, LM; Moshé, SL; Sun, S
MLA Citation
Chan, S, Bello, JA, Shinnar, S, Hesdorffer, DC, Lewis, DV, MacFall, J, Shinnar, RC, Gomes, W, Litherland, C, Xu, Y, Nordli, DR, Pellock, JM, Frank, LM, Moshé, SL, and Sun, S. "Hippocampal Malrotation Is Associated With Prolonged Febrile Seizures: Results of the FEBSTAT Study." AJR. American journal of roentgenology 205.5 (November 2015): 1068-1074.
PMID
26496555
Source
epmc
Published In
AJR. American journal of roentgenology
Volume
205
Issue
5
Publish Date
2015
Start Page
1068
End Page
1074
DOI
10.2214/ajr.14.13330

Posterior structural brain volumes differ in maltreated youth with and without chronic posttraumatic stress disorder.

Magnetic resonance imaging studies of maltreated children with posttraumatic stress disorder (PTSD) suggest that maltreatment-related PTSD is associated with adverse brain development. Maltreated youth resilient to chronic PTSD were not previously investigated and may elucidate neuromechanisms of the stress diathesis that leads to resilience to chronic PTSD. In this cross-sectional study, anatomical volumetric and corpus callosum diffusion tensor imaging measures were examined using magnetic resonance imaging in maltreated youth with chronic PTSD (N = 38), without PTSD (N = 35), and nonmaltreated participants (n = 59). Groups were sociodemographically similar. Participants underwent assessments for strict inclusion/exclusion criteria and psychopathology. Maltreated youth with PTSD were psychobiologically different from maltreated youth without PTSD and nonmaltreated controls. Maltreated youth with PTSD had smaller posterior cerebral and cerebellar gray matter volumes than did maltreated youth without PTSD and nonmaltreated participants. Cerebral and cerebellar gray matter volumes inversely correlated with PTSD symptoms. Posterior corpus callosum microstructure in pediatric maltreatment-related PTSD differed compared to maltreated youth without PTSD and controls. The group differences remained significant when controlling for psychopathology, numbers of Axis I disorders, and trauma load. Alterations of these posterior brain structures may result from a shared trauma-related mechanism or an inherent vulnerability that mediates the pathway from chronic PTSD to comorbidity.

Authors
De Bellis, MD; Hooper, SR; Chen, SD; Provenzale, JM; Boyd, BD; Glessner, CE; MacFall, JR; Payne, ME; Rybczynski, R; Woolley, DP
MLA Citation
De Bellis, MD, Hooper, SR, Chen, SD, Provenzale, JM, Boyd, BD, Glessner, CE, MacFall, JR, Payne, ME, Rybczynski, R, and Woolley, DP. "Posterior structural brain volumes differ in maltreated youth with and without chronic posttraumatic stress disorder." Development and psychopathology 27.4 Pt 2 (November 2015): 1555-1576.
PMID
26535944
Source
epmc
Published In
Development and Psychopathology
Volume
27
Issue
4 Pt 2
Publish Date
2015
Start Page
1555
End Page
1576
DOI
10.1017/s0954579415000942

Widespread white matter but focal gray matter alterations in depressed individuals with thoughts of death.

Past work demonstrates that depressed individuals with suicidal thoughts or behaviors exhibit specific neuroanatomical alterations. This may represent a distinct phenotype characterized by specific findings on neuroimaging, but it is unclear if these findings extend to individuals with milder thoughts of death. We examined this question in outpatients with recurrent Major Depressive Disorder not receiving antidepressant treatment.We examined 165 subjects: 53 depressed without thoughts of death, 21 depressed with thoughts of death, and 91 healthy comparison subjects. Participants completed 3T cranial MRI, including anatomical and diffusion tensor imaging acquisitions. Automated methods measured regional gray matter volumes in addition to cortical thickness. White matter analyses examined diffusion measures within specific fiber tracts and included voxelwise comparisons.After adjustment for multiple comparisons, the depressed group with thoughts of death did not exhibit differences in regional gray matter volume, but did exhibit reduced cortical thickness in frontoparietal regions and the insula. This depressed group with thoughts of death also exhibited widespread white matter differences in fractional anisotropy and radial diffusivity. These differences were observed primarily in posterior parietal white matter regions and central white matter tracts adjacent to the basal ganglia and thalamus.Mild thoughts of death are associated with structural alterations in regions of the salience network, default mode network, and thalamocortical circuits. Further work is needed to understand the pathological basis of these findings.

Authors
Taylor, WD; Boyd, B; McQuoid, DR; Kudra, K; Saleh, A; MacFall, JR
MLA Citation
Taylor, WD, Boyd, B, McQuoid, DR, Kudra, K, Saleh, A, and MacFall, JR. "Widespread white matter but focal gray matter alterations in depressed individuals with thoughts of death." Progress in neuro-psychopharmacology & biological psychiatry 62 (October 2015): 22-28.
PMID
25963377
Source
epmc
Published In
Progress in Neuro-Psychopharmacology & Biological Psychiatry
Volume
62
Publish Date
2015
Start Page
22
End Page
28
DOI
10.1016/j.pnpbp.2015.05.001

Hippocampus atrophy and the longitudinal course of late-life depression.

OBJECTIVES: Smaller hippocampal volumes are observed in depression but it remains unclear how antidepressant response and persistent depression relate to changes in hippocampal volume. We examined the longitudinal relationship between hippocampal atrophy and course of late-life depression. SETTING: Academic medical center. PARTICIPANTS: Depressed and never-depressed cognitively intact subjects age 60 years or older. MEASUREMENTS: Depression severity was measured every three months with the Montgomery-Asberg Depression Rating Scale (MADRS). Participants also completed cranial 1.5-T magnetic resonance imaging every 2 years. We compared 2-year change in hippocampal volume based on remission status, then in expanded analyses examined how hippocampal volumes predicted MADRS score. RESULTS: In analyses of 92 depressed and 70 never-depressed subjects, over 2 years the cohort whose depression never remitted exhibited greater hippocampal atrophy than the never-depressed cohort. In expanded analyses of a broader sample of 152 depressed elders, depression severity was significantly predicted by a hippocampus × time interaction where smaller hippocampus volumes over time were associated with greater depression severity. CONCLUSIONS: Hippocampal atrophy is associated with greater and persistent depression severity. Neuropathological studies are needed to determine if this atrophy is related to the toxic effects of persistent depression or related to underlying Alzheimer disease.

Authors
Taylor, WD; McQuoid, DR; Payne, ME; Zannas, AS; MacFall, JR; Steffens, DC
MLA Citation
Taylor, WD, McQuoid, DR, Payne, ME, Zannas, AS, MacFall, JR, and Steffens, DC. "Hippocampus atrophy and the longitudinal course of late-life depression." Am J Geriatr Psychiatry 22.12 (December 2014): 1504-1512.
PMID
24378256
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
22
Issue
12
Publish Date
2014
Start Page
1504
End Page
1512
DOI
10.1016/j.jagp.2013.11.004

Association of gene variants of the renin-angiotensin system with accelerated hippocampal volume loss and cognitive decline in old age.

Genetic factors confer risk for neuropsychiatric phenotypes, but the polygenic etiology of these phenotypes makes identification of genetic culprits challenging. An approach to this challenge is to examine the effects of genetic variation on relevant endophenotypes, such as hippocampal volume loss. A smaller hippocampus is associated with gene variants of the renin-angiotensin system (RAS), a system implicated in vascular disease. However, no studies to date have investigated longitudinally the effects of genetic variation of RAS on the hippocampus.The authors examined the effects of polymorphisms of AGTR1, the gene encoding angiotensin-II type 1 receptor of RAS, on longitudinal hippocampal volumes of older adults. In all, 138 older adults (age ≥60 years) were followed for an average of about 4 years. The participants underwent repeated structural MRI and comprehensive neurocognitive testing, and they were genotyped for four AGTR1 single-nucleotide polymorphisms (SNPs) with low pairwise linkage disequilibrium values and apolipoprotein E (APOE) genotype.Genetic variants at three AGTR1 SNPs (rs2638363, rs1492103, and rs2675511) were independently associated with accelerated hippocampal volume loss over the 4-year follow-up period in the right but not left hemisphere. Intriguingly, these AGTR1 risk alleles also predicted worse episodic memory performance but were not related to other cognitive measures. Two risk variants (rs2638363 and rs12721331) interacted with the APOE4 allele to accelerate right hippocampal volume loss.Risk genetic variants of the RAS may accelerate memory decline in older adults, an effect that may be conferred by accelerated hippocampal volume loss. Molecules involved in this system may hold promise as early therapeutic targets for late-life neuropsychiatric disorders.

Authors
Zannas, AS; McQuoid, DR; Payne, ME; MacFall, JR; Ashley-Koch, A; Steffens, DC; Potter, GG; Taylor, WD
MLA Citation
Zannas, AS, McQuoid, DR, Payne, ME, MacFall, JR, Ashley-Koch, A, Steffens, DC, Potter, GG, and Taylor, WD. "Association of gene variants of the renin-angiotensin system with accelerated hippocampal volume loss and cognitive decline in old age." The American journal of psychiatry 171.11 (November 2014): 1214-1221.
PMID
25124854
Source
epmc
Published In
American Journal of Psychiatry
Volume
171
Issue
11
Publish Date
2014
Start Page
1214
End Page
1221
DOI
10.1176/appi.ajp.2014.13111543

Medical imaging safety in the developing worldMedical imaging safety in the developing world

© 2014 Springer Science+Business Media New York. All rights are reserved.Attention to matters of safety is important in any imaging facility. In the context of the developing world, limited resources may complicate the attempt to set up and operate an imaging facility with the highest standards of safety, but it is nonetheless important to see that all applicable safety measures are carried out. Imaging safety involves several general principles, including the need to minimize radiation exposure consistent with answering the clinical question at hand. Safety considerations relevant to patients, staff, and the general public must be addressed. Safety considerations specific to individual modalities include appropriate limitations on exposure in X-ray and CT imaging, attention to hazards from the magnetic field in magnetic resonance imaging, proper preparation and control of radionuclides in nuclear medicine, and avoidance of excessive prenatal imaging procedures with ultrasound. An important general safety consideration for all imaging modalities is assuring proper clinical utilization; proper utilization includes factors such as not performing imaging procedures without medical referral and supervision, attention to image quality to ensure that procedures do not need to be repeated unnecessarily, and carefully considering the clinical appropriateness of any requested imaging procedure. Training and credentialing of staff is also of utmost importance and includes staff who design, prepare, and evaluate a new imaging facility as well as medical staff who acquire, order, or review images. Ensuring imaging safety requires the input of a team of experts, including trained and qualified medical physicists, health physicists, radiation safety officers, clinical safety personnel, installation and service personnel, radiologic technologists, and radiologists. With appropriate attention to safety, diagnostic imaging can provide a very useful component of healthcare services in resource-limited regions.

Authors
Dobbins, JT; Frush, DP; Kigongo, CJN; MacFall, JR; Reiman, RE; Trahey, GE; Dobbins, JT; Frush, DP; Kigongo, CJN; MacFall, JR; Reiman, RE; Trahey, GE
MLA Citation
Dobbins, JT, Frush, DP, Kigongo, CJN, MacFall, JR, Reiman, RE, Trahey, GE, Dobbins, JT, Frush, DP, Kigongo, CJN, MacFall, JR, Reiman, RE, and Trahey, GE. "Medical imaging safety in the developing worldMedical imaging safety in the developing world (PublishedPublished)." Radiology in Global Health: Strategies, Implementation, and Applications. October 1, 2014. 41-60.
Source
scopus
Volume
9781461406044
Publish Date
2014
Start Page
41
End Page
60
DOI
10.1007/978-1-4614-0604-4_7

Comprehensive population-averaged arterial input function for dynamic contrast-enhanced vmagnetic resonance imaging of head and neck cancer.

PURPOSE: To generate a population-averaged arterial input function (PA-AIF) for quantitative analysis of dynamic contrast-enhanced MRI data in head and neck cancer patients. METHODS AND MATERIALS: Twenty patients underwent dynamic contrast-enhanced MRI during concurrent chemoradiation therapy. Imaging consisted of 2 baseline scans 1 week apart (B1/B2) and 1 scan after 1 week of chemoradiation therapy (Wk1). Regions of interest (ROIs) in the right and left carotid arteries were drawn on coronal images. Plasma concentration curves of all ROIs were averaged and fit to a biexponential decay function to obtain the final PA-AIF (AvgAll). Right-sided and left-sided ROI plasma concentration curves were averaged separately to obtain side-specific AIFs (AvgRight/AvgLeft). Regions of interest were divided by time point to obtain time-point-specific AIFs (AvgB1/AvgB2/AvgWk1). The vascular transfer constant (Ktrans) and the fractional extravascular, extracellular space volume (Ve) for primaries and nodes were calculated using the AvgAll AIF, the appropriate side-specific AIF, and the appropriate time-point-specific AIF. Median Ktrans and Ve values derived from AvgAll were compared with those obtained from the side-specific and time-point-specific AIFs. The effect of using individual AIFs was also investigated. RESULTS: The plasma parameters for AvgAll were a1,2 = 27.11/17.65 kg/L, m1,2 = 11.75/0.21 min(-1). The coefficients of repeatability (CRs) for AvgAll versus AvgLeft were 0.04 min(-1) for Ktrans and 0.02 for Ve. For AvgAll versus AvgRight, the CRs were 0.08 min(-1) for Ktrans and 0.02 for Ve. When AvgAll was compared with AvgB1/AvgB2/AvgWk1, the CRs were slightly higher: 0.32/0.19/0.78 min(-1), respectively, for Ktrans; and 0.07/0.08/0.09 for Ve. Use of a PA-AIF was not significantly different from use of individual AIFs. CONCLUSION: A PA-AIF for head and neck cancer was generated that accounts for differences in right carotid artery versus left carotid artery, day-to-day fluctuations, and early treatment-induced changes. The small CRs obtained for Ktrans and Ve indicate that side-specific AIFs are not necessary. However, a time-point-specific AIF may improve pharmacokinetic accuracy.

Authors
Onxley, JD; Yoo, DS; Muradyan, N; MacFall, JR; Brizel, DM; Craciunescu, OI
MLA Citation
Onxley, JD, Yoo, DS, Muradyan, N, MacFall, JR, Brizel, DM, and Craciunescu, OI. "Comprehensive population-averaged arterial input function for dynamic contrast-enhanced vmagnetic resonance imaging of head and neck cancer." International journal of radiation oncology, biology, physics 89.3 (July 2014): 658-665.
PMID
24929169
Source
epmc
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
89
Issue
3
Publish Date
2014
Start Page
658
End Page
665
DOI
10.1016/j.ijrobp.2014.03.006

Cingulum bundle white matter lesions influence antidepressant response in late-life depression: a pilot study.

Late-life depression is associated with white matter hyperintense lesions (WMLs) occurring in specific fiber tracts. In this study, we sought to determine if greater WML severity in the cingulum bundle or uncinate fasciculus was associated with poor short-term antidepressant response.Eleven depressed elders completed a baseline cranial 3T MRI and received antidepressant treatment following a medication algorithm. MRIs were analyzed to measure the fraction of each fiber tract׳s volume occupied by WMLs. Statistical analyses examined the effect of dichotomized fiber tract WML severity on three- and six-month depression severity after controlling for age and baseline depression severity.Greater WML severity in the left hemispheric cingulum bundle adjacent to the hippocampus was associated with greater post-treatment depression severity at three- (F1,7=6.42, p=0.0390) and six-month assessments (F1,5=9.62, p=0.0268). Other fiber tract WML measures were not significantly associated with outcomes.The study had a small sample size and analyses were limited to only a priori fiber tracts.This pilot study supports the hypothesis that focal damage to the cingulum bundle may contribute to poor short-term antidepressant response. These findings warrant further investigation with a larger, more definitive study.

Authors
Taylor, WD; Kudra, K; Zhao, Z; Steffens, DC; MacFall, JR
MLA Citation
Taylor, WD, Kudra, K, Zhao, Z, Steffens, DC, and MacFall, JR. "Cingulum bundle white matter lesions influence antidepressant response in late-life depression: a pilot study." Journal of affective disorders 162 (June 2014): 8-11.
PMID
24766997
Source
epmc
Published In
Journal of Affective Disorders
Volume
162
Publish Date
2014
Start Page
8
End Page
11
DOI
10.1016/j.jad.2014.03.031

Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images.

INTRODUCTION: White matter hyperintensities (WMHs) are regions of abnormally high intensity on T2-weighted or fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Accurate and reproducible automatic segmentation of WMHs is important since WMHs are often seen in the elderly and are associated with various geriatric and psychiatric disorders. METHODS: We developed a fully automated monospectral segmentation method for WMHs using FLAIR MRIs. Through this method, we introduce an optimal threshold intensity (I O ) for segmenting WMHs, which varies with WMHs volume (V WMH), and we establish the I O -V WMH relationship. RESULTS: Our method showed accurate validations in volumetric and spatial agreements of automatically segmented WMHs compared with manually segmented WMHs for 32 confirmatory images. Bland-Altman values of volumetric agreement were 0.96 ± 8.311 ml (bias and 95 % confidence interval), and the similarity index of spatial agreement was 0.762 ± 0.127 (mean ± standard deviation). Furthermore, similar validation accuracies were obtained in the images acquired from different scanners. CONCLUSIONS: The proposed segmentation method uses only FLAIR MRIs, has the potential to be accurate with images obtained from different scanners, and can be implemented with a fully automated procedure. In our study, validation results were obtained with FLAIR MRIs from only two scanner types. The design of the method may allow its use in large multicenter studies with correct efficiency.

Authors
Yoo, BI; Lee, JJ; Han, JW; Oh, SY; Lee, EY; MacFall, JR; Payne, ME; Kim, TH; Kim, JH; Kim, KW
MLA Citation
Yoo, BI, Lee, JJ, Han, JW, Oh, SY, Lee, EY, MacFall, JR, Payne, ME, Kim, TH, Kim, JH, and Kim, KW. "Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images." Neuroradiology 56.4 (April 2014): 265-281.
PMID
24493377
Source
epmc
Published In
Neuroradiology
Volume
56
Issue
4
Publish Date
2014
Start Page
265
End Page
281
DOI
10.1007/s00234-014-1322-6

Hippocampal sclerosis after febrile status epilepticus: the FEBSTAT study.

OBJECTIVE: Whether febrile status epilepticus (FSE) produces hippocampal sclerosis (HS) and temporal lobe epilepsy (TLE) has long been debated. Our objective is to determine whether FSE produces acute hippocampal injury that evolves to HS. METHODS: FEBSTAT and 2 affiliated studies prospectively recruited 226 children aged 1 month to 6 years with FSE and controls with simple febrile seizures. All had acute magnetic resonance imaging (MRI), and follow-up MRI was obtained approximately 1 year later in the majority. Visual interpretation by 2 neuroradiologists informed only of subject age was augmented by hippocampal volumetrics, analysis of the intrahippocampal distribution of T2 signal, and apparent diffusion coefficients. RESULTS: Hippocampal T2 hyperintensity, maximum in Sommer's sector, occurred acutely after FSE in 22 of 226 children in association with increased volume. Follow-up MRI obtained on 14 of the 22 with acute T2 hyperintensity showed HS in 10 and reduced hippocampal volume in 12. In contrast, follow-up of 116 children without acute hyperintensity showed abnormal T2 signal in only 1 (following another episode of FSE). Furthermore, compared to controls with simple febrile seizures, FSE subjects with normal acute MRI had abnormally low right to left hippocampal volume ratios, smaller hippocampi initially, and reduced hippocampal growth. INTERPRETATION: Hippocampal T2 hyperintensity after FSE represents acute injury often evolving to a radiological appearance of HS after 1 year. Furthermore, impaired growth of normal-appearing hippocampi after FSE suggests subtle injury even in the absence of T2 hyperintensity. Longer follow-up is needed to determine the relationship of these findings to TLE.

Authors
Lewis, DV; Shinnar, S; Hesdorffer, DC; Bagiella, E; Bello, JA; Chan, S; Xu, Y; MacFall, J; Gomes, WA; Moshé, SL; Mathern, GW; Pellock, JM; Nordli, DR; Frank, LM; Provenzale, J; Shinnar, RC; Epstein, LG; Masur, D; Litherland, C; Sun, S; FEBSTAT Study Team,
MLA Citation
Lewis, DV, Shinnar, S, Hesdorffer, DC, Bagiella, E, Bello, JA, Chan, S, Xu, Y, MacFall, J, Gomes, WA, Moshé, SL, Mathern, GW, Pellock, JM, Nordli, DR, Frank, LM, Provenzale, J, Shinnar, RC, Epstein, LG, Masur, D, Litherland, C, Sun, S, and FEBSTAT Study Team, . "Hippocampal sclerosis after febrile status epilepticus: the FEBSTAT study." Ann Neurol 75.2 (February 2014): 178-185.
PMID
24318290
Source
pubmed
Published In
Annals of Neurology
Volume
75
Issue
2
Publish Date
2014
Start Page
178
End Page
185
DOI
10.1002/ana.24081

Hippocampal sclerosis after febrile status epilepticus: The FEBSTAT study

Objective Whether febrile status epilepticus (FSE) produces hippocampal sclerosis (HS) and temporal lobe epilepsy (TLE) has long been debated. Our objective is to determine whether FSE produces acute hippocampal injury that evolves to HS. Methods FEBSTAT and 2 affiliated studies prospectively recruited 226 children aged 1 month to 6 years with FSE and controls with simple febrile seizures. All had acute magnetic resonance imaging (MRI), and follow-up MRI was obtained approximately 1 year later in the majority. Visual interpretation by 2 neuroradiologists informed only of subject age was augmented by hippocampal volumetrics, analysis of the intrahippocampal distribution of T2 signal, and apparent diffusion coefficients. Results Hippocampal T2 hyperintensity, maximum in Sommer's sector, occurred acutely after FSE in 22 of 226 children in association with increased volume. Follow-up MRI obtained on 14 of the 22 with acute T2 hyperintensity showed HS in 10 and reduced hippocampal volume in 12. In contrast, follow-up of 116 children without acute hyperintensity showed abnormal T2 signal in only 1 (following another episode of FSE). Furthermore, compared to controls with simple febrile seizures, FSE subjects with normal acute MRI had abnormally low right to left hippocampal volume ratios, smaller hippocampi initially, and reduced hippocampal growth. Interpretation Hippocampal T2 hyperintensity after FSE represents acute injury often evolving to a radiological appearance of HS after 1 year. Furthermore, impaired growth of normal-appearing hippocampi after FSE suggests subtle injury even in the absence of T2 hyperintensity. Longer follow-up is needed to determine the relationship of these findings to TLE. © 2014 American Neurological Association.

Authors
Lewis, DV; Shinnar, S; Hesdorffer, DC; Bagiella, E; Bello, JA; Chan, S; Xu, Y; MacFall, J; Gomes, WA; Moshé, SL; Mathern, GW; Pellock, JM; Nordli, DR; Frank, LM; Provenzale, J; Shinnar, RC; Epstein, LG; Masur, D; Litherland, C; Sun, S
MLA Citation
Lewis, DV, Shinnar, S, Hesdorffer, DC, Bagiella, E, Bello, JA, Chan, S, Xu, Y, MacFall, J, Gomes, WA, Moshé, SL, Mathern, GW, Pellock, JM, Nordli, DR, Frank, LM, Provenzale, J, Shinnar, RC, Epstein, LG, Masur, D, Litherland, C, and Sun, S. "Hippocampal sclerosis after febrile status epilepticus: The FEBSTAT study." Annals of Neurology 75.2 (January 1, 2014): 178-185.
Source
scopus
Published In
Annals of Neurology
Volume
75
Issue
2
Publish Date
2014
Start Page
178
End Page
185
DOI
10.1002/ana.24081

Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images

Introduction: White matter hyperintensities (WMHs) are regions of abnormally high intensity on T2-weighted or fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Accurate and reproducible automatic segmentation of WMHs is important since WMHs are often seen in the elderly and are associated with various geriatric and psychiatric disorders. Methods: We developed a fully automated monospectral segmentation method for WMHs using FLAIR MRIs. Through this method, we introduce an optimal threshold intensity (I O ) for segmenting WMHs, which varies with WMHs volume (V WMH), and we establish the I O -V WMH relationship. Results: Our method showed accurate validations in volumetric and spatial agreements of automatically segmented WMHs compared with manually segmented WMHs for 32 confirmatory images. Bland-Altman values of volumetric agreement were 0.96 ± 8.311 ml (bias and 95 % confidence interval), and the similarity index of spatial agreement was 0.762 ± 0.127 (mean ± standard deviation). Furthermore, similar validation accuracies were obtained in the images acquired from different scanners. Conclusions: The proposed segmentation method uses only FLAIR MRIs, has the potential to be accurate with images obtained from different scanners, and can be implemented with a fully automated procedure. In our study, validation results were obtained with FLAIR MRIs from only two scanner types. The design of the method may allow its use in large multicenter studies with correct efficiency. © 2014 Springer-Verlag.

Authors
Yoo, BI; Lee, JJ; Han, JW; Oh, SYW; Lee, EY; MacFall, JR; Payne, ME; Kim, TH; Kim, JH; Kim, KW
MLA Citation
Yoo, BI, Lee, JJ, Han, JW, Oh, SYW, Lee, EY, MacFall, JR, Payne, ME, Kim, TH, Kim, JH, and Kim, KW. "Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images." Neuroradiology 56.4 (January 1, 2014): 265-281.
Source
scopus
Published In
Neuroradiology
Volume
56
Issue
4
Publish Date
2014
Start Page
265
End Page
281
DOI
10.1007/s00234-014-1322-6

Hippocampus atrophy and the longitudinal course of late-life depression

© 2014 American Association for Geriatric Psychiatry.Objectives Smaller hippocampal volumes are observed in depression but it remains unclear how antidepressant response and persistent depression relate to changes in hippocampal volume. We examined the longitudinal relationship between hippocampal atrophy and course of late-life depression. Setting Academic medical center. Participants Depressed and never-depressed cognitively intact subjects age 60 years or older. Measurements Depression severity was measured every three months with the Montgomery-Asberg Depression Rating Scale (MADRS). Participants also completed cranial 1.5-T magnetic resonance imaging every 2 years. We compared 2-year change in hippocampal volume based on remission status, then in expanded analyses examined how hippocampal volumes predicted MADRS score. Results In analyses of 92 depressed and 70 never-depressed subjects, over 2 years the cohort whose depression never remitted exhibited greater hippocampal atrophy than the never-depressed cohort. In expanded analyses of a broader sample of 152 depressed elders, depression severity was significantly predicted by a hippocampus × time interaction where smaller hippocampus volumes over time were associated with greater depression severity. Conclusions Hippocampal atrophy is associated with greater and persistent depression severity. Neuropathological studies are needed to determine if this atrophy is related to the toxic effects of persistent depression or related to underlying Alzheimer disease.

Authors
Taylor, WD; McQuoid, DR; Payne, ME; Zannas, AS; MacFall, JR; Steffens, DC
MLA Citation
Taylor, WD, McQuoid, DR, Payne, ME, Zannas, AS, MacFall, JR, and Steffens, DC. "Hippocampus atrophy and the longitudinal course of late-life depression." American Journal of Geriatric Psychiatry 22.12 (2014): 1504-1512.
Source
scival
Published In
American Journal of Geriatric Psychiatry
Volume
22
Issue
12
Publish Date
2014
Start Page
1504
End Page
1512
DOI
10.1016/j.jagp.2013.11.004

Perfluoropropane gas as a magnetic resonance lung imaging contrast agent in humans.

BACKGROUND: Fluorine-enhanced MRI is a relatively inexpensive and straightforward technique that facilitates regional assessments of pulmonary ventilation. In this report, we assess its suitability through the use of perfluoropropane (PFP) in a cohort of human subjects with normal lungs and subjects with lung disease. METHODS: Twenty-eight subjects between the ages of 18 and 71 years were recruited for imaging and were classified based on spirometry findings and medical history. Imaging was carried out on a Siemens TIM Trio 3T MRI scanner using two-dimensional, gradient echo, fast low-angle shot and three-dimensional gradient echo, volumetric, interpolated, breath-hold examination sequences for proton localizers and PFP functional scans, respectively. Respiratory waveforms and physiologic signals of interest were monitored throughout the imaging sessions. A region-growing algorithm was applied to the proton localizers to define the lung field of view for analysis of the PFP scans. RESULTS: All subjects tolerated the gas mixture well with no adverse side effects. Images of healthy lungs demonstrated a homogeneous distribution of the gas with sufficient signal-to-noise ratios, while lung images from asthmatic and emphysematous lungs demonstrated increased heterogeneity and ventilation defects. CONCLUSIONS: Fluorine-enhanced MRI using a normoxic PFP gas mixture is a well-tolerated, radiation-free technique for regionally assessing pulmonary ventilation. The inherent physical characteristics and applicability of the gaseous agent within a magnetic resonance setting facilitated a clear differentiation between normal and diseased lungs.

Authors
Halaweish, AF; Moon, RE; Foster, WM; Soher, BJ; McAdams, HP; MacFall, JR; Ainslie, MD; MacIntyre, NR; Charles, HC
MLA Citation
Halaweish, AF, Moon, RE, Foster, WM, Soher, BJ, McAdams, HP, MacFall, JR, Ainslie, MD, MacIntyre, NR, and Charles, HC. "Perfluoropropane gas as a magnetic resonance lung imaging contrast agent in humans." Chest 144.4 (October 2013): 1300-1310.
PMID
23722696
Source
pubmed
Published In
Chest
Volume
144
Issue
4
Publish Date
2013
Start Page
1300
End Page
1310
DOI
10.1378/chest.12-2597

Negative life stress and longitudinal hippocampal volume changes in older adults with and without depression.

Major depressive disorder is associated with smaller hippocampal volumes but the mechanisms underlying this relationship are unclear. To examine the effect of environmental influences, we examined the relationship between self-reported stressors and two-year change in hippocampal volume. Seventy elderly nondepressed subjects and eighty-nine elderly depressed subjects were followed for two years. The number of negative stressful life events (nSLE), perceived stress levels, and cranial MRI were obtained at baseline and at the two-year assessment. For secondary analyses, subjects provided blood for 5-HTTLPR polymorphism genotyping. After controlling for covariates including presence or absence of depression, greater numbers of baseline nSLEs were significantly associated with greater baseline hippocampal volumes bilaterally. Greater numbers of baseline nSLEs were also associated with reduction in hippocampal volume over two years in the right but not the left hemisphere. Neither perceived stress levels nor changes in stress measures were significantly associated with hippocampal volume measures. However, in secondary analyses, we found that increases in perceived stress over time was associated with volume reduction of the left hippocampus, but only in 5-HTTLPR L/L homozygotes. Our findings suggest different short- and long-term effects of negative life stressors on hippocampal volumes in older adults. These effects appear independent on the presence or absence of depression. Furthermore, these effects may be moderated by genetic polymorphisms in key neurotransmitter systems. These novel findings have important implications for understanding environmental influences on brain aging.

Authors
Zannas, AS; McQuoid, DR; Payne, ME; Steffens, DC; MacFall, JR; Ashley-Koch, A; Taylor, WD
MLA Citation
Zannas, AS, McQuoid, DR, Payne, ME, Steffens, DC, MacFall, JR, Ashley-Koch, A, and Taylor, WD. "Negative life stress and longitudinal hippocampal volume changes in older adults with and without depression." J Psychiatr Res 47.6 (June 2013): 829-834.
PMID
23478048
Source
pubmed
Published In
Journal of Psychiatric Research
Volume
47
Issue
6
Publish Date
2013
Start Page
829
End Page
834
DOI
10.1016/j.jpsychires.2013.02.008

Change in Hippocampus Volume and Longitudinal Course of Late-Life Depression

Authors
Taylor, WD; McQuoid, DR; Payne, ME; Zannas, AS; MacFall, JR; Steffens, DC
MLA Citation
Taylor, WD, McQuoid, DR, Payne, ME, Zannas, AS, MacFall, JR, and Steffens, DC. "Change in Hippocampus Volume and Longitudinal Course of Late-Life Depression." May 1, 2013.
Source
wos-lite
Published In
Biological Psychiatry
Volume
73
Issue
9
Publish Date
2013
Start Page
195S
End Page
195S

Fiber tract-specific white matter lesion severity Findings in late-life depression and by AGTR1 A1166C genotype.

Past work demonstrated that late-life depression is associated with greater severity of ischemic cerebral hyperintense white matter lesions, particularly frontal lesions. However, these lesions are also associated with other neuropsychiatric deficits, so these clinical relationships may depend on which fiber tracts are damaged. We examined the ratio of lesion to nonlesioned white matter tissue within multiple fiber tracts between depressed and nondepressed elders. We also sought to determine if the AGTR1 A1166C and BDNF Val66Met polymorphisms contributed to vulnerability to lesion development in discrete tracts. The 3T structural MR images and blood samples for genetic analyses were acquired on 54 depressed and 37 nondepressed elders. Lesion maps were created through an automated tissue segmentation process and applied to a probabilistic white matter fiber tract atlas allowing for identification of the fraction of the tract occupied by lesion. The depressed cohort exhibited a significantly greater lesion ratio only in the left upper cingulum near the cingulate gyrus (F((1,86)) = 4.62, P = 0.0344), supporting past work implicating cingulate dysfunction in the pathogenesis of depression. In the 62 Caucasian subjects with genetic data, AGTR1 C1166 carriers exhibited greater lesion ratios across multiple tracts including the anterior thalamic radiation and inferior fronto-occipital fasciculus. In contrast, BDNF Met allele carriers exhibited greater lesion ratios only in the frontal corpus callosum. Although these findings did not survive correction for multiple comparisons, this study supports our hypothesis and provides preliminary evidence that genetic differences related to vascular disease may increase lesion vulnerability differentially across fiber tracts.

Authors
Taylor, WD; Zhao, Z; Ashley-Koch, A; Payne, ME; Steffens, DC; Krishnan, RR; Hauser, E; MacFall, JR
MLA Citation
Taylor, WD, Zhao, Z, Ashley-Koch, A, Payne, ME, Steffens, DC, Krishnan, RR, Hauser, E, and MacFall, JR. "Fiber tract-specific white matter lesion severity Findings in late-life depression and by AGTR1 A1166C genotype." Hum Brain Mapp 34.2 (February 2013): 295-303.
PMID
22021115
Source
pubmed
Published In
Human Brain Mapping
Volume
34
Issue
2
Publish Date
2013
Start Page
295
End Page
303
DOI
10.1002/hbm.21445

A comparison of radial keyhole strategies for high spatial and temporal resolution 4D contrast-enhanced MRI in small animal tumor models.

PURPOSE: Dynamic contrast-enhanced (DCE) MRI has been widely used as a quantitative imaging method for monitoring tumor response to therapy. The simultaneous challenges of increasing temporal and spatial resolution in a setting where the signal from the much smaller voxel is weaker have made this MR technique difficult to implement in small-animal imaging. Existing protocols employed in preclinical DCE-MRI acquire a limited number of slices resulting in potentially lost information in the third dimension. This study describes and compares a family of four-dimensional (3D spatial + time), projection acquisition, radial keyhole-sampling strategies that support high spatial and temporal resolution. METHODS: The 4D method is based on a RF-spoiled, steady-state, gradient-recalled sequence with minimal echo time. An interleaved 3D radial trajectory with a quasi-uniform distribution of points in k-space was used for sampling temporally resolved datasets. These volumes were reconstructed with three different k-space filters encompassing a range of possible radial keyhole strategies. The effect of k-space filtering on spatial and temporal resolution was studied in a 5 mM CuSO(4) phantom consisting of a meshgrid with 350-μm spacing and in 12 tumors from three cell lines (HT-29, LoVo, MX-1) and a primary mouse sarcoma model (three tumors∕group). The time-to-peak signal intensity was used to assess the effect of the reconstruction filters on temporal resolution. As a measure of heterogeneity in the third dimension, the authors analyzed the spatial distribution of the rate of transport (K(trans)) of the contrast agent across the endothelium barrier for several different types of tumors. RESULTS: Four-dimensional radial keyhole imaging does not degrade the system spatial resolution. Phantom studies indicate there is a maximum 40% decrease in signal-to-noise ratio as compared to a fully sampled dataset. T1 measurements obtained with the interleaved radial technique do not differ significantly from those made with a conventional Cartesian spin-echo sequence. A bin-by-bin comparison of the distribution of the time-to-peak parameter shows that 4D radial keyhole reconstruction does not cause significant temporal blurring when a temporal resolution of 9.9 s is used for the subsamples of the keyhole data. In vivo studies reveal substantial tumor heterogeneity in the third spatial dimension that may be missed with lower resolution imaging protocols. CONCLUSIONS: Volumetric keyhole imaging with projection acquisition provides a means to increase spatiotemporal resolution and coverage over that provided by existing 2D Cartesian protocols. Furthermore, there is no difference in temporal resolution between the higher spatial resolution keyhole reconstruction and the undersampled projection data. The technique allows one to measure complex heterogeneity of kinetic parameters with isotropic, microscopic spatial resolution.

Authors
Subashi, E; Moding, EJ; Cofer, GP; MacFall, JR; Kirsch, DG; Qi, Y; Johnson, GA
MLA Citation
Subashi, E, Moding, EJ, Cofer, GP, MacFall, JR, Kirsch, DG, Qi, Y, and Johnson, GA. "A comparison of radial keyhole strategies for high spatial and temporal resolution 4D contrast-enhanced MRI in small animal tumor models." Med Phys 40.2 (February 2013): 022304-.
PMID
23387766
Source
pubmed
Published In
Medical physics
Volume
40
Issue
2
Publish Date
2013
Start Page
022304
DOI
10.1118/1.4774050

Fiber tract-specific white matter lesion severity Findings in late-life depression and by AGTR1 A1166C genotype

Past work demonstrated that late-life depression is associated with greater severity of ischemic cerebral hyperintense white matter lesions, particularly frontal lesions. However, these lesions are also associated with other neuropsychiatric deficits, so these clinical relationships may depend on which fiber tracts are damaged. We examined the ratio of lesion to nonlesioned white matter tissue within multiple fiber tracts between depressed and nondepressed elders. We also sought to determine if the AGTR1 A1166C and BDNF Val66Met polymorphisms contributed to vulnerability to lesion development in discrete tracts. The 3T structural MR images and blood samples for genetic analyses were acquired on 54 depressed and 37 nondepressed elders. Lesion maps were created through an automated tissue segmentation process and applied to a probabilistic white matter fiber tract atlas allowing for identification of the fraction of the tract occupied by lesion. The depressed cohort exhibited a significantly greater lesion ratio only in the left upper cingulum near the cingulate gyrus (F(1,86) = 4.62, P = 0.0344), supporting past work implicating cingulate dysfunction in the pathogenesis of depression. In the 62 Caucasian subjects with genetic data, AGTR1 C1166 carriers exhibited greater lesion ratios across multiple tracts including the anterior thalamic radiation and inferior fronto-occipital fasciculus. In contrast, BDNF Met allele carriers exhibited greater lesion ratios only in the frontal corpus callosum. Although these findings did not survive correction for multiple comparisons, this study supports our hypothesis and provides preliminary evidence that genetic differences related to vascular disease may increase lesion vulnerability differentially across fiber tracts. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.

Authors
Taylor, WD; Zhao, Z; Ashley-Koch, A; Payne, ME; Steffens, DC; Krishnan, RR; Hauser, E; Macfall, JR
MLA Citation
Taylor, WD, Zhao, Z, Ashley-Koch, A, Payne, ME, Steffens, DC, Krishnan, RR, Hauser, E, and Macfall, JR. "Fiber tract-specific white matter lesion severity Findings in late-life depression and by AGTR1 A1166C genotype." Human Brain Mapping 34.2 (2013): 295-303.
Source
scival
Published In
Human Brain Mapping
Volume
34
Issue
2
Publish Date
2013
Start Page
295
End Page
303
DOI
10.1002/hbm.21445

Negative life stress and longitudinal hippocampal volume changes in older adults with and without depression

Major depressive disorder is associated with smaller hippocampal volumes but the mechanisms underlying this relationship are unclear. To examine the effect of environmental influences, we examined the relationship between self-reported stressors and two-year change in hippocampal volume. Seventy elderly nondepressed subjects and eighty-nine elderly depressed subjects were followed for two years. The number of negative stressful life events (nSLE), perceived stress levels, and cranial MRI were obtained at baseline and at the two-year assessment. For secondary analyses, subjects provided blood for 5-HTTLPR polymorphism genotyping. After controlling for covariates including presence or absence of depression, greater numbers of baseline nSLEs were significantly associated with greater baseline hippocampal volumes bilaterally. Greater numbers of baseline nSLEs were also associated with reduction in hippocampal volume over two years in the right but not the left hemisphere. Neither perceived stress levels nor changes in stress measures were significantly associated with hippocampal volume measures. However, in secondary analyses, we found that increases in perceived stress over time was associated with volume reduction of the left hippocampus, but only in 5-HTTLPR L/L homozygotes. Our findings suggest different short- and long-term effects of negative life stressors on hippocampal volumes in older adults. These effects appear independent on the presence or absence of depression. Furthermore, these effects may be moderated by genetic polymorphisms in key neurotransmitter systems. These novel findings have important implications for understanding environmental influences on brain aging. © 2013 Elsevier Ltd.

Authors
Zannas, AS; McQuoid, DR; Payne, ME; Steffens, DC; MacFall, JR; Ashley-Koch, A; Taylor, WD
MLA Citation
Zannas, AS, McQuoid, DR, Payne, ME, Steffens, DC, MacFall, JR, Ashley-Koch, A, and Taylor, WD. "Negative life stress and longitudinal hippocampal volume changes in older adults with and without depression." Journal of Psychiatric Research 47.6 (2013): 829-834.
Source
scival
Published In
Journal of Psychiatric Research
Volume
47
Issue
6
Publish Date
2013
Start Page
829
End Page
834
DOI
10.1016/j.jpsychires.2013.02.008

Risk Factors for Febrile Status Epilepticus: A Case-Control Study

Objective: To identify risk factors for developing a first febrile status epilepticus (FSE) among children with a first febrile seizure (FS). Study design: Cases were children with a first FS that was FSE drawn from the Consequences of Prolonged Febrile Seizures in Childhood and Columbia cohorts. Controls were children with a first simple FS and separately, children with a first complex FS that was not FSE. Identical questionnaires were administered to family members of the 3 cohorts. Magnetic resonance imaging protocol and readings were consistent across cohorts, and seizure phenomenology was assessed by the same physicians. Risk factors were analyzed using logistic regression. Results: Compared with children with simple FS, FSE was associated with younger age, lower temperature, longer duration (1-24 hours) of recognized temperature before FS, female sex, structural temporal lobe abnormalities, and first-degree family history of FS. Compared with children with other complex FS, FSE was associated with low temperature and longer duration (1-24 hours) of temperature recognition before FS. Risk factors for complex FS that was not FSE were similar in magnitude to those for FSE but only younger age was significant. Conclusions: Among children with a first FS, FSE appears to be due to a combination of lower seizure threshold (younger age and lower temperatures) and impaired regulation of seizure duration. Clinicians evaluating FS should be aware of these factors as many episodes of FSE go unnoticed. Further work is needed to develop strategies to prevent FSE. © 2013 Mosby, Inc. All rights reserved.

Authors
Hesdorffer, DC; Shinnar, S; Lewis, DV; Jr, DRN; Pellock, JM; Moshé, SL; Shinnar, RC; Litherland, C; Bagiella, E; Frank, LM; al, E
MLA Citation
Hesdorffer, DC, Shinnar, S, Lewis, DV, Jr, DRN, Pellock, JM, Moshé, SL, Shinnar, RC, Litherland, C, Bagiella, E, Frank, LM, and al, E. "Risk Factors for Febrile Status Epilepticus: A Case-Control Study." Journal of Pediatrics (2013).
PMID
23809042
Source
scival
Published In
The Journal of Pediatrics
Publish Date
2013
DOI
10.1016/j.jpeds.2013.05.038

Risk factors for febrile status epilepticus: A case-control study

Objective To identify risk factors for developing a first febrile status epilepticus (FSE) among children with a first febrile seizure (FS). Study design Cases were children with a first FS that was FSE drawn from the Consequences of Prolonged Febrile Seizures in Childhood and Columbia cohorts. Controls were children with a first simple FS and separately, children with a first complex FS that was not FSE. Identical questionnaires were administered to family members of the 3 cohorts. Magnetic resonance imaging protocol and readings were consistent across cohorts, and seizure phenomenology was assessed by the same physicians. Risk factors were analyzed using logistic regression. Results Compared with children with simple FS, FSE was associated with younger age, lower temperature, longer duration (1-24 hours) of recognized temperature before FS, female sex, structural temporal lobe abnormalities, and first-degree family history of FS. Compared with children with other complex FS, FSE was associated with low temperature and longer duration (1-24 hours) of temperature recognition before FS. Risk factors for complex FS that was not FSE were similar in magnitude to those for FSE but only younger age was significant. Conclusions Among children with a first FS, FSE appears to be due to a combination of lower seizure threshold (younger age and lower temperatures) and impaired regulation of seizure duration. Clinicians evaluating FS should be aware of these factors as many episodes of FSE go unnoticed. Further work is needed to develop strategies to prevent FSE. Copyright © 2013 Mosby Inc. All rights reserved.

Authors
Hesdorffer, DC; Shinnar, S; Lewis, DV; Jr, DRN; Pellock, JM; Moshé, SL; Shinnar, RC; Litherland, C; Bagiella, E; Frank, LM; Bello, JA; Chan, S; Masur, D; Macfall, J; Sun, S
MLA Citation
Hesdorffer, DC, Shinnar, S, Lewis, DV, Jr, DRN, Pellock, JM, Moshé, SL, Shinnar, RC, Litherland, C, Bagiella, E, Frank, LM, Bello, JA, Chan, S, Masur, D, Macfall, J, and Sun, S. "Risk factors for febrile status epilepticus: A case-control study." Journal of Pediatrics 163.4 (2013): 1147-1151.e1.
Source
scival
Published In
The Journal of Pediatrics
Volume
163
Issue
4
Publish Date
2013
Start Page
1147
End Page
1151.e1
DOI
10.1016/j.jpeds.2013.05.038

Treatment Course With Antidepressant Therapy in Late-Life Depression.

OBJECTIVE In order to assess the effect of gray matter volumes and cortical thickness on antidepressant treatment response in late-life depression, the authors examined the relationship between brain regions identified a priori and Montgomery-Åsberg Depression Rating Scale (MADRS) scores over the course of an antidepressant treatment trial. METHOD In a nonrandomized prospective trial, 168 patients who were at least 60 years of age and met DSM-IV criteria for major depression underwent MRI and were enrolled in a 12-week treatment study. Exclusion criteria included cognitive impairment or severe medical disorders. The volumes or cortical thicknesses of regions of interest that differed between the depressed group and a comparison group (N=50) were determined. These regions of interest were used in analyses of the depressed group to predict antidepressant treatment outcome. Mixed-model analyses adjusting for age, education, age at depression onset, race, baseline MADRS score, scanner, and interaction with time examined predictors of MADRS scores over time. RESULTS Smaller hippocampal volumes predicted a slower response to treatment. With the inclusion of white matter hyperintensity severity and neuropsychological factor scores, the best model included hippocampal volume and cognitive processing speed to predict rate of response over time. A secondary analysis showed that hippocampal volume and frontal pole thickness differed between patients who achieved remission and those who did not. CONCLUSIONS These data expand our understanding of the prediction of treatment course in late-life depression. The authors propose that the primary variables of hippocampal volume and cognitive processing speed, subsuming other contributing variables (episodic memory, executive function, language processing) predict antidepressant response.

Authors
Sheline, YI; Disabato, BM; Hranilovich, J; Morris, C; D'Angelo, G; Pieper, C; Toffanin, T; Taylor, WD; Macfall, JR; Wilkins, C; Barch, DM; Welsh-Bohmer, KA; Steffens, DC; Krishnan, RR; Doraiswamy, PM
MLA Citation
Sheline, YI, Disabato, BM, Hranilovich, J, Morris, C, D'Angelo, G, Pieper, C, Toffanin, T, Taylor, WD, Macfall, JR, Wilkins, C, Barch, DM, Welsh-Bohmer, KA, Steffens, DC, Krishnan, RR, and Doraiswamy, PM. "Treatment Course With Antidepressant Therapy in Late-Life Depression." Am J Psychiatry 169.11 (November 1, 2012): 1185-1193.
PMID
23034601
Source
pubmed
Published In
American Journal of Psychiatry
Volume
169
Issue
11
Publish Date
2012
Start Page
1185
End Page
1193
DOI
10.1176/appi.ajp.2012.12010122

Treatment course with antidepressant therapy in late-life depression.

OBJECTIVE: In order to assess the effect of gray matter volumes and cortical thickness on antidepressant treatment response in late-life depression, the authors examined the relationship between brain regions identified a priori and Montgomery-Åsberg Depression Rating Scale (MADRS) scores over the course of an antidepressant treatment trial. METHOD: In a nonrandomized prospective trial, 168 patients who were at least 60 years of age and met DSM-IV criteria for major depression underwent MRI and were enrolled in a 12-week treatment study. Exclusion criteria included cognitive impairment or severe medical disorders. The volumes or cortical thicknesses of regions of interest that differed between the depressed group and a comparison group (N=50) were determined. These regions of interest were used in analyses of the depressed group to predict antidepressant treatment outcome. Mixed-model analyses adjusting for age, education, age at depression onset, race, baseline MADRS score, scanner, and interaction with time examined predictors of MADRS scores over time. RESULTS: Smaller hippocampal volumes predicted a slower response to treatment. With the inclusion of white matter hyper-intensity severity and neuropsychological factor scores, the best model included hippocampal volume and cognitive processing speed to predict rate of response over time. A secondary analysis showed that hippocampal volume and frontal pole thickness differed between patients who achieved remission and those who did not. CONCLUSIONS: These data expand our understanding of the prediction of treatment course in late-life depression. The authors propose that the primary variables of hippocampal volume and cognitive processing speed, subsuming other contributing variables (episodic memory, executive function, language processing) predict antidepressant response.

Authors
Sheline, YI; Disabato, BM; Hranilovich, J; Morris, C; D'Angelo, G; Pieper, C; Toffanin, T; Taylor, WD; MacFall, JR; Wilkins, C; Barch, DM; Welsh-Bohmer, KA; Steffens, DC; Krishnan, RR; Doraiswamy, PM
MLA Citation
Sheline, YI, Disabato, BM, Hranilovich, J, Morris, C, D'Angelo, G, Pieper, C, Toffanin, T, Taylor, WD, MacFall, JR, Wilkins, C, Barch, DM, Welsh-Bohmer, KA, Steffens, DC, Krishnan, RR, and Doraiswamy, PM. "Treatment course with antidepressant therapy in late-life depression." Am J Psychiatry 169.11 (November 2012): 1185-1193.
PMID
23534057
Source
pubmed
Published In
American Journal of Psychiatry
Volume
169
Issue
11
Publish Date
2012
Start Page
1185
End Page
1193
DOI
10.1176/appi.ajp.2012.12010122

Trajectories of early brain volume development in fragile X syndrome and autism.

OBJECTIVE: To examine patterns of early brain growth in young children with fragile X syndrome (FXS) compared with a comparison group (controls) and a group with idiopathic autism. METHOD: The study included 53 boys 18 to 42 months of age with FXS, 68 boys with idiopathic autism (autism spectrum disorder), and a comparison group of 50 typically developing and developmentally delayed controls. Structural brain volumes were examined using magnetic resonance imaging across two time points, at 2 to 3 and again at 4 to 5 years of age, and total brain volumes and regional (lobar) tissue volumes were examined. In addition, a selected group of subcortical structures implicated in the behavioral features of FXS (e.g., basal ganglia, hippocampus, amygdala) was studied. RESULTS: Children with FXS had larger global brain volumes compared with controls but were not different than children with idiopathic autism, and the rate of brain growth from 2 to 5 years of age paralleled that seen in controls. In contrast to children with idiopathic autism who had generalized cortical lobe enlargement, children with FXS showed specific enlargement in the temporal lobe white matter, cerebellar gray matter, and caudate nucleus, but a significantly smaller amygdala. CONCLUSIONS: This structural longitudinal magnetic resonance imaging study of preschoolers with FXS observed generalized brain overgrowth in children with FXS compared with controls, evident at age 2 and maintained across ages 4 to 5. In addition, different patterns of brain growth that distinguished boys with FXS from boys with idiopathic autism were found.

Authors
Hazlett, HC; Poe, MD; Lightbody, AA; Styner, M; MacFall, JR; Reiss, AL; Piven, J
MLA Citation
Hazlett, HC, Poe, MD, Lightbody, AA, Styner, M, MacFall, JR, Reiss, AL, and Piven, J. "Trajectories of early brain volume development in fragile X syndrome and autism." J Am Acad Child Adolesc Psychiatry 51.9 (September 2012): 921-933.
PMID
22917205
Source
pubmed
Published In
Journal of the American Academy of Child and Adolescent Psychiatry
Volume
51
Issue
9
Publish Date
2012
Start Page
921
End Page
933
DOI
10.1016/j.jaac.2012.07.003

AGTR1 gene variation: association with depression and frontotemporal morphology.

The renin-angiotensin system (RAS) is implicated in the response to physiological and psychosocial stressors, but its role in stress-related psychiatric disorders is poorly understood. We examined if variation in AGTR1, the gene coding for the type 1 angiotensin II receptor (AT(1)R), is associated with a diagnosis of depression and differences in white matter hyperintensities and frontotemporal brain volumes. Participants comprised 257 depressed and 116 nondepressed elderly Caucasian subjects who completed clinical assessments and provided blood samples for genotyping. We used a haplotype-tagging single nucleotide polymorphism (htSNP) analysis to test for variation in AGTR1. For measurement of hyperintense lesions, 1.5 Tesla magnetic resonance imaging (MRI) data were available on 33 subjects. For measurements of the hippocampus and dorsolateral prefrontal cortex (dlPFC), 3 Tesla MRI data were available on 70 subjects. Two htSNPs exhibited statistically significant frequency differences between diagnostic cohorts: rs10935724 and rs12721331. Although hyperintense lesion volume did not significantly differ by any htSNP, dlPFC and hippocampus volume differed significantly for several htSNPs. Intriguingly, for those htSNPs differing significantly for both dlPFC and hippocampus volume, the variant associated with smaller dlPFC volume was associated with larger hippocampal volume. This supports the idea that genetic variation in AGTR1 is associated with depression and differences in frontotemporal morphology.

Authors
Taylor, WD; Benjamin, S; McQuoid, DR; Payne, ME; Krishnan, RR; MacFall, JR; Ashley-Koch, A
MLA Citation
Taylor, WD, Benjamin, S, McQuoid, DR, Payne, ME, Krishnan, RR, MacFall, JR, and Ashley-Koch, A. "AGTR1 gene variation: association with depression and frontotemporal morphology." Psychiatry Res 202.2 (May 31, 2012): 104-109.
PMID
22703619
Source
pubmed
Published In
Psychiatry Research
Volume
202
Issue
2
Publish Date
2012
Start Page
104
End Page
109
DOI
10.1016/j.pscychresns.2012.03.007

A heterogeneous human tissue mimicking phantom for RF heating and MRI thermal monitoring verification.

This paper describes a heterogeneous phantom that mimics a human thigh with a deep-seated tumor, for the purpose of studying the performance of radiofrequency (RF) heating equipment and non-invasive temperature monitoring with magnetic resonance imaging (MRI). The heterogeneous cylindrical phantom was constructed with an outer fat layer surrounding an inner core of phantom material mimicking muscle, tumor and marrow-filled bone. The component materials were formulated to have dielectric and thermal properties similar to human tissues. The dielectric properties of the tissue mimicking phantom materials were measured with a microwave vector network analyzer and impedance probe over the frequency range of 80-500 MHz and at temperatures of 24, 37 and 45 °C. The specific heat values of the component materials were measured using a differential scanning calorimeter over the temperature range of 15-55 °C. The thermal conductivity value was obtained from fitting the curves obtained from one-dimensional heat transfer measurement. The phantom was used to verify the operation of a cylindrical four-antenna annular phased array extremity applicator (140 MHz) by examining the proton resonance frequency shift (PRFS) thermal imaging patterns for various magnitude/phase settings (including settings to focus heating in tumors). For muscle and tumor materials, MRI was also used to measure T1/T2* values (1.5 T) and to obtain the slope of the PRFS phase change versus temperature change curve. The dielectric and thermal properties of the phantom materials were in close agreement to well-accepted published results for human tissues. The phantom was able to successfully demonstrate satisfactory operation of the tested heating equipment. The MRI-measured thermal distributions matched the expected patterns for various magnitude/phase settings of the applicator, allowing the phantom to be used as a quality assurance tool. Importantly, the material formulations for the various tissue types may be used to construct customized phantoms that are tailored for different anatomical sites.

Authors
Yuan, Y; Wyatt, C; Maccarini, P; Stauffer, P; Craciunescu, O; Macfall, J; Dewhirst, M; Das, SK
MLA Citation
Yuan, Y, Wyatt, C, Maccarini, P, Stauffer, P, Craciunescu, O, Macfall, J, Dewhirst, M, and Das, SK. "A heterogeneous human tissue mimicking phantom for RF heating and MRI thermal monitoring verification." Phys Med Biol 57.7 (April 7, 2012): 2021-2037.
PMID
22430012
Source
pubmed
Published In
Physics in Medicine and Biology
Volume
57
Issue
7
Publish Date
2012
Start Page
2021
End Page
2037
DOI
10.1088/0031-9155/57/7/2021

Prospective trial of synchronous bevacizumab, erlotinib, and concurrent chemoradiation in locally advanced head and neck cancer.

PURPOSE: We assessed the safety and efficacy of synchronous VEGF and epidermal growth factor receptor (EGFR) blockade with concurrent chemoradiation (CRT) in locally advanced head and neck cancer (HNC). EXPERIMENTAL DESIGN: Newly diagnosed patients with stage III/IV HNC received a 2-week lead-in of bevacizumab and/or erlotinib, followed by both agents with concurrent cisplatin and twice daily radiotherapy. Safety was assessed using Common Toxicity Criteria version 3.0. The primary efficacy endpoint was clinical complete response (CR) rate after CRT. RESULTS: Twenty-nine patients enrolled on study, with 27 completing therapy. Common grade III toxicities were mucositis (n = 14), dysphagia (n = 8), dehydration (n = 7), osteoradionecrosis (n = 3), and soft tissue necrosis (n = 2). Feeding tube placement was required in 79% but no patient remained dependent at 12-month posttreatment. Clinical CR after CRT was 96% [95% confidence interval (CI), 82%-100%]. Median follow-up was 46 months in survivors, with 3-year locoregional control and distant metastasis-free survival rates of 85% and 93%. Three-year estimated progression-free survival, disease-specific survival, and overall survival rates were 82%, 89%, and 86%, respectively. Dynamic contrast enhanced MRI (DCE-MRI) analysis showed that patients who had failed had lower baseline pretreatment median K(trans) values, with subsequent increases after lead-in therapy and 1 week of CRT. Patients who did not fail had higher median K(trans) values that decreased during therapy. CONCLUSIONS: Dual VEGF/EGFR inhibition can be integrated with CRT in locally advanced HNC, with efficacy that compares favorably with historical controls albeit with an increased risk of osteoradionecrosis. Pretreatment and early DCE-MRI may prospectively identify patients at high risk of failure.

Authors
Yoo, DS; Kirkpatrick, JP; Craciunescu, O; Broadwater, G; Peterson, BL; Carroll, MD; Clough, R; MacFall, JR; Hoang, J; Scher, RL; Esclamado, RM; Dunphy, FR; Ready, NE; Brizel, DM
MLA Citation
Yoo, DS, Kirkpatrick, JP, Craciunescu, O, Broadwater, G, Peterson, BL, Carroll, MD, Clough, R, MacFall, JR, Hoang, J, Scher, RL, Esclamado, RM, Dunphy, FR, Ready, NE, and Brizel, DM. "Prospective trial of synchronous bevacizumab, erlotinib, and concurrent chemoradiation in locally advanced head and neck cancer." Clin Cancer Res 18.5 (March 1, 2012): 1404-1414.
PMID
22253412
Source
pubmed
Published In
Clinical cancer research : an official journal of the American Association for Cancer Research
Volume
18
Issue
5
Publish Date
2012
Start Page
1404
End Page
1414
DOI
10.1158/1078-0432.CCR-11-1982

Dynamic contrast-enhanced MRI in head-and-neck cancer: the impact of region of interest selection on the intra- and interpatient variability of pharmacokinetic parameters.

PURPOSE: Dynamic contrast-enhanced (DCE) MRI-extracted parameters measure tumor microvascular physiology and are usually calculated from an intratumor region of interest (ROI). Optimal ROI delineation is not established. The valid clinical use of DCE-MRI requires that the variation for any given parameter measured within a tumor be less than that observed between tumors in different patients. This work evaluates the impact of tumor ROI selection on the assessment of intra- and interpatient variability. METHOD AND MATERIALS: Head and neck cancer patients received initial targeted therapy (TT) treatment with erlotinib and/or bevacizumab, followed by radiotherapy and concurrent cisplatin with synchronous TT. DCE-MRI data from Baseline and the end of the TT regimen (Lead-In) were analyzed to generate the vascular transfer function (K(trans)), the extracellular volume fraction (v(e)), and the initial area under the concentration time curve (iAUC(1 min)). Four ROI sampling strategies were used: whole tumor or lymph node (Whole), the slice containing the most enhancing voxels (SliceMax), three slices centered in SliceMax (Partial), and the 5% most enhancing contiguous voxels within SliceMax (95Max). The average coefficient of variation (aCV) was calculated to establish intrapatient variability among ROI sets and interpatient variability for each ROI type. The average ratio between each intrapatient CV and the interpatient CV was calculated (aRCV). RESULTS: Baseline primary/nodes aRCVs for different ROIs not including 95Max were, for all three MR parameters, in the range of 0.14-0.24, with Lead-In values between 0.09 and 0.2, meaning a low intrapatient vs. interpatient variation. For 95Max, intrapatient CVs approximated interpatient CVs, meaning similar data dispersion and higher aRCVs (0.6-1.27 for baseline) and 0.54-0.95 for Lead-In. CONCLUSION: Distinction between different patient's primary tumors and/or nodes cannot be made using 95Max ROIs. The other three strategies are viable and equivalent for using DCE-MRI to measure head and neck cancer physiology.

Authors
Craciunescu, OI; Yoo, DS; Cleland, E; Muradyan, N; Carroll, MD; MacFall, JR; Barboriak, DP; Brizel, DM
MLA Citation
Craciunescu, OI, Yoo, DS, Cleland, E, Muradyan, N, Carroll, MD, MacFall, JR, Barboriak, DP, and Brizel, DM. "Dynamic contrast-enhanced MRI in head-and-neck cancer: the impact of region of interest selection on the intra- and interpatient variability of pharmacokinetic parameters." Int J Radiat Oncol Biol Phys 82.3 (March 1, 2012): e345-e350.
PMID
21985945
Source
pubmed
Published In
International Journal of Radiation: Oncology - Biology - Physics
Volume
82
Issue
3
Publish Date
2012
Start Page
e345
End Page
e350
DOI
10.1016/j.ijrobp.2011.05.059

Comprehensive analysis of the Cramer-Rao bounds for magnetic resonance temperature change measurement in fat-water voxels using multi-echo imaging.

OBJECT: The aim of this paper is to characterize the noise propagation for MRI temperature change measurement with emphasis on finding the best echo time combinations that yield the lowest temperature noise. MATERIALS AND METHODS: A Cramer-Rao lower-bound (CRLB) calculation was used to estimate the temperature noise for a model of the MR signal in fat-water voxels. The temperature noise CRLB was then used to find a set of echo times that gave the lowest temperature change noise for a range of fat-water frequency differences, temperature changes, fat/water signal ratios, and T2* values. CRLB estimates were verified by Monte Carlo simulation and in phantoms using images acquired in a 1.5 T magnet. RESULTS: Results show that regions exist where the CRLB predicts minimal temperature variation as a function of the other variables. The results also indicate that the CRLB values calculated in this paper provide excellent guidance for predicting the variation of temperature measurements due to changes in the signal parameters. For three echo scans, the best noise characteristics are seen for TE values of 20.71, 23.71, and 26.71 ms. Results for five and seven echo scans are also presented in the text. CONCLUSION: The results present a comprehensive analysis of the effects of different scan parameters on temperature noise, potentially benefiting the selection of scan parameters for clinical MRI thermometry.

Authors
Wyatt, C; Soher, BJ; Arunachalam, K; MacFall, J
MLA Citation
Wyatt, C, Soher, BJ, Arunachalam, K, and MacFall, J. "Comprehensive analysis of the Cramer-Rao bounds for magnetic resonance temperature change measurement in fat-water voxels using multi-echo imaging." MAGMA 25.1 (February 2012): 49-61.
PMID
21442434
Source
pubmed
Published In
Magnetic Resonance Materials in Physics, Biology and Medicine
Volume
25
Issue
1
Publish Date
2012
Start Page
49
End Page
61
DOI
10.1007/s10334-011-0247-x

Thermal dose fractionation affects tumour physiological response.

PURPOSE: It is unknown whether a thermal dose should be administered using a few large fractions with higher temperatures or a larger number of fractions with lower temperatures. To evaluate this we assessed the effect of administering the same total thermal dose, approximately 30 CEM43T(90), in one versus three to four fractions per week, over 5 weeks. MATERIALS AND METHODS: Canine sarcomas were randomised to receive one of the hyperthermia fractionation schemes along with fractionated radiotherapy. Tumour response was based on changes in tumour volume, oxygenation, water diffusion quantified using MRI, and a panel of histological and immunohistochemical end points. RESULTS: There was a greater reduction in tumour volume and water diffusion at the end of therapy in tumours receiving one hyperthermia fraction per week. There was a weak but significant association between improved tumour oxygenation 24 h after the first hyperthermia treatment and extent of volume reduction at the end of therapy. Finally, the direction of change of HIF-1α and CA-IX immunoreactivity after the first hyperthermia fraction was similar and there was an inverse relationship between temperature and the direction of change of CA-IX. There were no significant changes in interstitial fluid pressure, VEGF, vWF, apoptosis or necrosis as a function of treatment group or temperature. CONCLUSIONS: We did not identify an advantage to a three to four per week hyperthermia prescription, and response data pointed to a one per week prescription being superior.

Authors
Thrall, DE; Maccarini, P; Stauffer, P; Macfall, J; Hauck, M; Snyder, S; Case, B; Linder, K; Lan, L; McCall, L; Dewhirst, MW
MLA Citation
Thrall, DE, Maccarini, P, Stauffer, P, Macfall, J, Hauck, M, Snyder, S, Case, B, Linder, K, Lan, L, McCall, L, and Dewhirst, MW. "Thermal dose fractionation affects tumour physiological response." Int J Hyperthermia 28.5 (2012): 431-440.
PMID
22804741
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
28
Issue
5
Publish Date
2012
Start Page
431
End Page
440
DOI
10.3109/02656736.2012.689087

Bipolar disorder, brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and brain morphology.

In this study of the effect of bipolar status and presence of BDNF Val66Met polymorphism on differences in regional brain volumes, we hypothesized based on previous studies that 1) bipolar subjects will have smaller regional brain volumes than healthy controls; 2) BDNF Met66 allele carriers within the same population are likely to have smaller regional brain volumes as compared to Val66 homozygyotes. In our Caucasian sample of 166 bipolar subjects and 64 gender-matched healthy controls, we found significant decreases in total (p = 0.005) and regional gray matter volumes in bipolar patients compared to healthy controls, more pronounced in the inferior and posterior parts of the brain, together with a concomitant increase in total CSF (p = 0.012) particularly in the lateral ventricles (p = 0.023). However, there was no difference in white matter volumes noted by other studies. Furthermore we did not find significant differences in other brain regions that have been reported by other authors. Nor did we find a significant effect of BDNF on these measurements.

Authors
Teh, CA; Lee, TS; Kuchibhatla, M; Ashley-Koch, A; Macfall, J; Krishnan, R; Beyer, J
MLA Citation
Teh, CA, Lee, TS, Kuchibhatla, M, Ashley-Koch, A, Macfall, J, Krishnan, R, and Beyer, J. "Bipolar disorder, brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and brain morphology." PLoS One 7.7 (2012): e38469-.
PMID
22859933
Source
pubmed
Published In
PloS one
Volume
7
Issue
7
Publish Date
2012
Start Page
e38469
DOI
10.1371/journal.pone.0038469

Design and phenomenology of the FEBSTAT study

Purpose: Febrile status epilepticus (FSE) has been associated with hippocampal injury and subsequent hippocampal sclerosis (HS) and temporal lobe epilepsy. The FEBSTAT study was designed to prospectively examine the association between prolonged febrile seizures and development of HS and associated temporal lobe epilepsy, one of the most controversial issues in epilepsy. We report on the baseline phenomenology of the final cohorts as well as detailed aims and methodology. Methods: The "Consequences of Prolonged Febrile Seizures in Childhood" (FEBSTAT) study is a prospective, multicenter study. Enrolled are children, aged 1 month to 6 years of age, presenting with a febrile seizure lasting 30 min or longer based on ambulance, emergency department, and hospital records, and parental interview. At baseline, procedures included a magnetic resonance imaging (MRI) study and electroencephalography (EEG) recording done within 72 h of FSE, and a detailed history and neurologic examination. Baseline development and behavior are assessed at 1 month. The baseline assessment is repeated, with age-appropriate developmental testing at 1 and 5 years after enrollment as well as at the development of epilepsy and 1 year after that. Telephone calls every 3 months document additional seizures. Two other groups of children are included: a "control" group consisting of children with a first febrile seizure ascertained at Columbia University and with almost identical baseline and 1-year follow-up examinations and a pilot cohort of FSE from Duke University. Key Findings: The FEBSTAT cohort consists of 199 children with a median age at baseline of 16.0 months (interquartile range [IQR] 12.0-24.0) and a median duration of FSE of 70.0 min (IQR 47.0-110.0). Seizures were continuous in 57.3% and behaviorally intermittent (without recovery in between) in 31.2%; most were partial (2.0%) or secondary generalized (65.8%), and almost all (98.0%) culminated in a generalized tonic-clonic seizure. Of the 199 children, 86.4% had normal development and 20% had prior febrile seizures. In one third of cases, FSE was unrecognized in the emergency department. The Duke existing cohort consists of 23 children with a median age of FSE onset of 18.0 months (IQR 14.0-28.0) and median duration of FSE of 90.0 min (IQR 50.0-170.0). The Columbia control cohort consists of 159 children with a first febrile seizure who received almost the same workup as the FEBSTAT cohort at baseline and at 1 year. They were followed by telephone every 4 months for a median of 42 months. Among the control cohort, 64.2% had a first simple FS, 26.4% had a first complex FS that was not FSE, and 9.4% had FSE. Among the 15 with FSE, the median age at onset was 14.0 months (IQR 12.0-20.0) and the median duration of FSE was 43.0 min (IQR 35.0-75.0). Significance: The FEBSTAT study presents an opportunity to prospectively study the relationship between FSE and acute hippocampal damage, the development of mesial temporal sclerosis, epilepsy (particularly temporal lobe epilepsy), and impaired hippocampal function in a large cohort. It is hoped that this study may illuminate a major mystery in clinical epilepsy today, and permit the development of interventions designed to prevent the sequelae of FSE. © 2012 International League Against Epilepsy.

Authors
Hesdorffer, DC; Shinnar, S; Lewis, DV; Moshé, SL; Jr, DRN; Pellock, JM; MacFall, J; Shinnar, RC; Masur, D; Frank, LM; Epstein, LG; Litherland, C; Seinfeld, S; Bello, JA; Chan, S; Bagiella, E; Sun, S
MLA Citation
Hesdorffer, DC, Shinnar, S, Lewis, DV, Moshé, SL, Jr, DRN, Pellock, JM, MacFall, J, Shinnar, RC, Masur, D, Frank, LM, Epstein, LG, Litherland, C, Seinfeld, S, Bello, JA, Chan, S, Bagiella, E, and Sun, S. "Design and phenomenology of the FEBSTAT study." Epilepsia 53.9 (2012): 1471-1480.
PMID
22742587
Source
scival
Published In
Epilepsia
Volume
53
Issue
9
Publish Date
2012
Start Page
1471
End Page
1480
DOI
10.1111/j.1528-1167.2012.03567.x

MRI abnormalities following febrile status epilepticus in children: The FEBSTAT study

Objective: The FEBSTAT study is a prospective study that seeks to determine the acute and long-term consequences of febrile status epilepticus (FSE) in childhood. Methods: From 2003 to 2010, 199 children age 1 month to 5 years presenting with FSE (>30 minutes) were enrolled in FEBSTAT within 72 hours of the FSE episode. Of these, 191 had imaging with emphasis on the hippocampus. All MRIs were reviewed by 2 neuroradiologists blinded to clinical details. A group of 96 children with first simple FS who were imaged using a similar protocol served as controls. Results: A total of 22 (11.5%) children had definitely abnormal (n = 17) or equivocal (n = 5) increased T2 signal in the hippocampus following FSE compared with none in the control group (p < 0.0001). Developmental abnormalities of the hippocampus were more common in the FSE group (n = 20, 10.5%) than in controls (n = 2, 2.1%) (p < 0.0097) with hippocampal malrotation being the most common (15 cases and 2 controls). Extrahippocampal imaging abnormalities were present in 15.7% of the FSE group and 15.6% of the controls. However, extrahippocampal imaging abnormalities of the temporal lobe were more common in the FSE group (7.9%) than in controls (1.0%) (p = 0.015). Conclusions: This prospective study demonstrates that children with FSE are at risk for acute hippocampal injury and that a substantial number also have abnormalities in hippocampal development. Follow-up studies are in progress to determine the long-term outcomes in these children. Copyright © 2012 by AAN Enterprises, Inc.

Authors
Shinnar, S; Bello, JA; Chan, S; Hesdorffer, DC; Lewis, DV; MacFall, J; Pellock, JM; Nordli, DR; Frank, LM; Moshe, SL; Gomes, W; Shinnar, RC; Sun, S
MLA Citation
Shinnar, S, Bello, JA, Chan, S, Hesdorffer, DC, Lewis, DV, MacFall, J, Pellock, JM, Nordli, DR, Frank, LM, Moshe, SL, Gomes, W, Shinnar, RC, and Sun, S. "MRI abnormalities following febrile status epilepticus in children: The FEBSTAT study." Neurology 79.9 (2012): 871-877.
PMID
22843278
Source
scival
Published In
Neurology
Volume
79
Issue
9
Publish Date
2012
Start Page
871
End Page
877
DOI
10.1212/WNL.0b013e318266fcc5

Reduction of dorsolateral prefrontal cortex gray matter in late-life depression.

Postmortem studies have documented abnormalities in the dorsolateral prefrontal cortex (dlPFC) in depressed subjects. In this study we used magnetic resonance imaging to test for dlPFC volume differences between older depressed and non-depressed individuals. Eighty-eight subjects meeting DSM IV criteria for major depressive disorder and thirty-five control subjects completed clinical evaluations and cranial 3T magnetic resonance imaging. After tissue types were identified using an automated segmentation process, the dlPFC was measured in both hemispheres using manual delineation based on anatomical landmarks. Depressed subjects had significantly lower gray matter in the left and right dorsolateral prefrontal cortex (standardized to cerebral parenchyma) after controlling for age and sex. Our study confirmed the reduction of dorsolateral prefrontal cortex in elderly depressed subjects, especially in the gray matter. These regional abnormalities may be associated with psychopathological changes in late-life depression.

Authors
Chang, CC; Yu, SC; McQuoid, DR; Messer, DF; Taylor, WD; Singh, K; Boyd, BD; Krishnan, KR; MacFall, JR; Steffens, DC; Payne, ME
MLA Citation
Chang, CC, Yu, SC, McQuoid, DR, Messer, DF, Taylor, WD, Singh, K, Boyd, BD, Krishnan, KR, MacFall, JR, Steffens, DC, and Payne, ME. "Reduction of dorsolateral prefrontal cortex gray matter in late-life depression." Psychiatry Res 193.1 (July 30, 2011): 1-6.
PMID
21596532
Source
pubmed
Published In
Psychiatry Research
Volume
193
Issue
1
Publish Date
2011
Start Page
1
End Page
6
DOI
10.1016/j.pscychresns.2011.01.003

Comparison of genomics and functional imaging from canine sarcomas treated with thermoradiotherapy predicts therapeutic response and identifies combination therapeutics.

PURPOSE: While hyperthermia is an effective adjuvant treatment to radiotherapy, we do not completely understand the nature of the response heterogeneity. EXPERIMENTAL DESIGN: We performed gene expression analysis of 22 spontaneous canine sarcomas before and after the first hyperthermia treatment administered as an adjuvant to radiotherapy. In parallel, diffusion-weighted MRI (DWI) was done prior to the treatment course and at the end of therapy. RESULTS: From the integrative analysis of gene expression and DWI, we identified significant correlation between tumor responses with genes involved in VEGF signaling, telomerase, DNA repair, and inflammation. The treatment-induced changes in gene expression identified 2 distinct tumor subtypes with significant differences in their gene expression and treatment response, as defined by changes in DWI. The 2 tumor subtypes could also be readily identified by pretreatment gene expression. The tumor subtypes, with stronger expression response and DWI increase, had higher levels of HSP70, POT1, and centrosomal proteins, and lower levels of CD31, vWF, and transferrin. Such differential gene expression between the 2 subtypes was used to interrogate connectivity map and identify linkages to an HSP90 inhibitor, geldanamycin. We further validated the ability of geldanamycin to enhance cell killing of human tumor cells with hyperthermia and radiotherapy in clonogenic assays. CONCLUSIONS: To our knowledge, this is one of the first successful attempts to link changes in gene expression and functional imaging to understand the response heterogeneity and identify compounds enhancing thermoradiotherapy. This study also demonstrates the value of canine tumors to provide information generalizable to human tumors.

Authors
Chi, JT; Thrall, DE; Jiang, C; Snyder, S; Fels, D; Landon, C; McCall, L; Lan, L; Hauck, M; MacFall, JR; Viglianti, BL; Dewhirst, MW
MLA Citation
Chi, JT, Thrall, DE, Jiang, C, Snyder, S, Fels, D, Landon, C, McCall, L, Lan, L, Hauck, M, MacFall, JR, Viglianti, BL, and Dewhirst, MW. "Comparison of genomics and functional imaging from canine sarcomas treated with thermoradiotherapy predicts therapeutic response and identifies combination therapeutics." Clin Cancer Res 17.8 (April 15, 2011): 2549-2560.
PMID
21292819
Source
pubmed
Published In
Clinical cancer research : an official journal of the American Association for Cancer Research
Volume
17
Issue
8
Publish Date
2011
Start Page
2549
End Page
2560
DOI
10.1158/1078-0432.CCR-10-2583

BDNF Val66Met genotype and 6-month remission rates in late-life depression.

Although not observed in younger adult cohorts, in older individuals the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is associated with major depressive disorder (MDD) risk. It is further associated with subjective social support and magnetic resonance imaging (MRI) hyperintense lesions, clinical features independently related to MDD. We examined the relationship between this polymorphism and antidepressant remission rates in an elderly sample with MDD, while also testing for mediation effects of social support and hyperintensities. A total of 229 elderly Caucasian subjects with MDD completed baseline assessments, 1.5 T MRI, and BDNF genotyping. They received antidepressant medication under a structured treatment algorithm and were evaluated for remission at 3 and 6 months. At the 3-month evaluation, BDNF Val66Met genotype was not associated with remission (Wald's χ²=2.51, P=0.1131). When not controlling for multiple comparisons, Met66 allele carriers were more likely to be remitted at 6 months (χ²=4.32, P=0.0377) with an odds ratio of 1.82 (95% CI: 1.04, 3.22). This effect persisted after controlling for lesion volume and social support, neither of which mediated this relationship. Thus in this exploratory analysis, the Met66 allele may be associated with increased odds of remission in older subjects, but also with increased time to remission as there was no 3-month effect.

Authors
Taylor, WD; McQuoid, DR; Ashley-Koch, A; MacFall, JR; Bridgers, J; Krishnan, RR; Steffens, DC
MLA Citation
Taylor, WD, McQuoid, DR, Ashley-Koch, A, MacFall, JR, Bridgers, J, Krishnan, RR, and Steffens, DC. "BDNF Val66Met genotype and 6-month remission rates in late-life depression." Pharmacogenomics J 11.2 (April 2011): 146-154.
PMID
20195291
Source
pubmed
Published In
The Pharmacogenomics Journal
Volume
11
Issue
2
Publish Date
2011
Start Page
146
End Page
154
DOI
10.1038/tpj.2010.12

One-year change in anterior cingulate cortex white matter microstructure: relationship with late-life depression outcomes.

OBJECTIVE: differences in white matter structure measured with diffusion tensor imaging (DTI) are associated with late-life depression, but results examining how these differences relate to antidepressant remission are mixed. To better describe these relationships, the authors examined how 1-year change in DTI measures are related to 1-year course of depression. DESIGN: one-year cross-sectional follow-up to a 12-week clinical trial of sertraline. SETTING: outpatients at an academic medical center. PARTICIPANTS: twenty-nine depressed and 20 never-depressed elderly subjects. Over the 1-year period, 16 depressed subjects achieved and maintained remission, whereas 13 did not. MEASUREMENTS: one-year change in fractional anisotropy (FA) and diffusivity in frontal white matter, as measured by DTI. RESULTS: contrary to our hypotheses, depressed subjects who did not remit over the study interval exhibited significantly less change in anterior cingulate cortex (ACC) white matter FA than did never-depressed or depressed-remitted subjects. There were no group differences in other frontal or central white matter regions. Moreover, there was a significant positive relationship between change in Montgomery-Asberg Depression Rating Scale (MADRS) and change in ACC FA, wherein greater interval decline in FA was associated with greater interval decline in MADRS. CONCLUSION: older depressed individuals who remit exhibit white matter changes comparable with what is observed in never-depressed individuals, whereas nonremitters exhibit significantly less change in ACC FA. Such a finding may be related to either antidepressant effects on brain structure or the effects of chronic stress on brain structure. Further work is needed to better understand this relationship.

Authors
Taylor, WD; Macfall, JR; Boyd, B; Payne, ME; Sheline, YI; Krishnan, RR; Murali Doraiswamy, P
MLA Citation
Taylor, WD, Macfall, JR, Boyd, B, Payne, ME, Sheline, YI, Krishnan, RR, and Murali Doraiswamy, P. "One-year change in anterior cingulate cortex white matter microstructure: relationship with late-life depression outcomes." Am J Geriatr Psychiatry 19.1 (January 2011): 43-52.
PMID
20808126
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
19
Issue
1
Publish Date
2011
Start Page
43
End Page
52
DOI
10.1097/JGP.0b013e3181e70cec

Correction of breathing-induced errors in magnetic resonance thermometry of hyperthermia using multiecho field fitting techniques.

PURPOSE: Breathing motion can create large errors when performing magnetic resonance (MR) thermometry of the breast. Breath holds can be used to minimize these errors, but not eliminate them. Between breath holds, the referenceless method can be used to further reduce errors by relying on regions of nonheated fatty tissue surrounding the heated region. When the surrounding tissue is heated (i.e., for a hyperthermia treatment), errors can result due to phase changes of the small amounts of water in the tissue. Therefore, an extension of the referenceless method is proposed which fits for the field in fatty tissue independent of temperature change and extrapolates it to the water-rich regions. METHODS: Nonheating experiments were performed with male volunteers performing breath holds on top of a phantom mimicking a breast with a tumor. Heating experiments were also conducted with the same phantom while mechanically simulated breath holds were performed. A nonheating experiment was also performed with a healthy female breast. For each experiment, a nonlinear fitting algorithm was used to fit for temperature change and B0 field inside of the fatty tissue. The field changes were then extrapolated into water-rich (tumor) portions of the image using a least-squares fit to a fifth-order equation, to correct for field changes due to breath hold changes. Similar results were calculated using the image phase, to mimic the use of the referenceless method. RESULTS: Phantom results showed large reduction of mean error and standard deviation. In the non-heating experiments, the traditional referenceless method and our extended method both corrected by similar amounts. However, in the heating experiments, the average deviation of the temperature calculated with the extended method from a fiber optic probe temperature was approximately 50% less than the deviation with the referenceless method. The in vivo breast results demonstrated reduced standard deviation and mean. CONCLUSIONS: In this paper, we have developed an extension of the referenceless method to correct for breathing errors using multiecho fitting methods to fit for the B0 field in the fatty tissue and using measured field changes as references to extrapolate field corrections into a water-only (tumor) region. This technique has been validated in a number of situations, and in all cases, the correction method has been shown to greatly reduce temperature error in water-rich regions. The method has also been shown to be an improvement over similar methods that use image phase changes instead of field changes, particularly when temperature changes are induced.

Authors
Wyatt, CR; Soher, BJ; MacFall, JR
MLA Citation
Wyatt, CR, Soher, BJ, and MacFall, JR. "Correction of breathing-induced errors in magnetic resonance thermometry of hyperthermia using multiecho field fitting techniques." Med Phys 37.12 (December 2010): 6300-6309.
PMID
21302786
Source
pubmed
Published In
Medical physics
Volume
37
Issue
12
Publish Date
2010
Start Page
6300
End Page
6309
DOI
10.1118/1.3515462

Variability in frontotemporal brain structure: the importance of recruitment of African Americans in neuroscience research.

BACKGROUND: Variation in brain structure is both genetically and environmentally influenced. The question about potential differences in brain anatomy across populations of differing race and ethnicity remains a controversial issue. There are few studies specifically examining racial or ethnic differences and also few studies that test for race-related differences in context of other neuropsychiatric research, possibly due to the underrepresentation of ethnic minorities in clinical research. It is within this context that we conducted a secondary data analysis examining volumetric MRI data from healthy participants and compared the volumes of the amygdala, hippocampus, lateral ventricles, caudate nucleus, orbitofrontal cortex (OFC) and total cerebral volume between Caucasian and African-American participants. We discuss the importance of this finding in context of neuroimaging methodology, but also the need for improved recruitment of African Americans in clinical research and its broader implications for a better understanding of the neural basis of neuropsychiatric disorders. METHODOLOGY/PRINCIPAL FINDINGS: This was a case control study in the setting of an academic medical center outpatient service. Participants consisted of 44 Caucasians and 33 ethnic minorities. The following volumetric data were obtained: amygdala, hippocampus, lateral ventricles, caudate nucleus, orbitofrontal cortex (OFC) and total cerebrum. Each participant completed a 1.5 T magnetic resonance imaging (MRI). Our primary finding in analyses of brain subregions was that when compared to Caucasians, African Americans exhibited larger left OFC volumes (F (1,68) = 7.50, p = 0.008). CONCLUSIONS: The biological implications of our findings are unclear as we do not know what factors may be contributing to these observed differences. However, this study raises several questions that have important implications for the future of neuropsychiatric research.

Authors
Isamah, N; Faison, W; Payne, ME; MacFall, J; Steffens, DC; Beyer, JL; Krishnan, KR; Taylor, WD
MLA Citation
Isamah, N, Faison, W, Payne, ME, MacFall, J, Steffens, DC, Beyer, JL, Krishnan, KR, and Taylor, WD. "Variability in frontotemporal brain structure: the importance of recruitment of African Americans in neuroscience research. (Published online)" PLoS One 5.10 (October 26, 2010): e13642-.
Website
http://hdl.handle.net/10161/4581
PMID
21049028
Source
pubmed
Published In
PloS one
Volume
5
Issue
10
Publish Date
2010
Start Page
e13642
DOI
10.1371/journal.pone.0013642

Angiotensin receptor gene polymorphisms and 2-year change in hyperintense lesion volume in men.

This longitudinal study examined the relationship between 2-year change in white matter hyperintense lesion (WML) volume and polymorphisms in genes coding for the angiotensin-II type 1 and type 2 receptors, AGTR1 A1166C and AGTR2 C3123A, respectively. 137 depressed and 94 non-depressed participants aged >or=60 years were enrolled. Standard clinical evaluations were performed on all participants and blood samples obtained for genotyping. 1.5-T MRI (magnetic resonance imaging) data were obtained at baseline and approximately 2 years later. These scans were processed using a semi-automated segmentation process, which allowed for the calculation of WML volume at each time point. Statistical models were tested for the relationship between change in WML volume and genotype, while also controlling for age, sex, diagnostic strata, baseline WML volume and comorbid cerebrovascular risk factors. In men, AGTR1 1166A allele homozygotes exhibited significantly less change in WML volume than 1166C carriers. We also found that men reporting hypertension (HTN) with the AGTR2 3123C allele exhibit less change in WML volume than hypertensive men with the 3123A allele, or men without HTN. There were no significant relationships between these polymorphisms and change in WML volume in women. No significant gene-gene or gene-depression interactions were observed. Our results parallel earlier observed gender differences of the relationship between other renin-angiotensin system polymorphisms and HTN. Further work is needed to determine whether these observed relationships are secondary to polymorphisms affecting response to antihypertensive medication, and whether antihypertensive medications can slow WML progression and lower the risk of morbidity associated with WMLs.

Authors
Taylor, WD; Steffens, DC; Ashley-Koch, A; Payne, ME; MacFall, JR; Potocky, CF; Krishnan, KR
MLA Citation
Taylor, WD, Steffens, DC, Ashley-Koch, A, Payne, ME, MacFall, JR, Potocky, CF, and Krishnan, KR. "Angiotensin receptor gene polymorphisms and 2-year change in hyperintense lesion volume in men." Mol Psychiatry 15.8 (August 2010): 816-822.
PMID
19274051
Source
pubmed
Published In
Molecular Psychiatry
Volume
15
Issue
8
Publish Date
2010
Start Page
816
End Page
822
DOI
10.1038/mp.2009.26

Dynamic contrast enhanced-MRI in head and neck cancer patients: variability of the precontrast longitudinal relaxation time (T10).

PURPOSE: Calculation of the precontrast longitudinal relaxation times (T10) is an integral part of the Tofts-based pharmacokinetic (PK) analysis of dynamic contrast enhanced-magnetic resonance images. The purpose of this study was to investigate the interpatient and over time variability of T10 in head and neck primary tumors and involved nodes and to determine the median T10 for primary and nodes (T10(p,n)). The authors also looked at the implication of using voxel-based T10 values versus region of interest (ROI)-based T10 on the calculated values for vascular permeability (K(trans)) and extracellular volume fraction (v(e)). METHODS: Twenty head and neck cancer patients receiving concurrent chemoradiation and molecularly targeted agents on a prospective trial comprised the study population. Voxel-based T10's were generated using a gradient echo sequence on a 1.5 T MR scanner using the variable flip angle method with two flip angles [J. A. Brookes et al., "Measurement of spin-lattice relaxation times with FLASH for dynamic MRI of the breast," Br. J. Radiol. 69, 206-214 (1996)]. The voxel-based T10, K(trans), and v(e) were calculated using iCAD's (Nashua, NH) software. The mean T10's in muscle and fat ROIs were calculated (T10(m,f)). To assess reliability of ROI drawing, T10(p,n) values from ROIs delineated by 2 users (A and B) were calculated as the average of the T10's for 14 patients. For a subset of three patients, the T10 variability from baseline to end of treatment was also investigated. The K(trans) and v(e) from primary and node ROIs were calculated using voxel-based T10 values and T10(p,n) and differences reported. RESULTS: The calculated T10 values for fat and muscle are within the range of values reported in literature for 1.5 T, i.e., T10(m) = 0.958 s and T10(f) = 0.303 s. The average over 14 patients of the T10's based on drawings by users A and B were T10(pA) = 0.804 s, T10(nA) = 0.760 s, T10(pB) = 0.849 s, and T10(nB) = 0.810 s. The absolute percentage difference between K(trans) and v(e) calculated with voxel-based T10 versus T10(p,n) ranged from 6% to 81% and from 2% to 24%, respectively. CONCLUSIONS: There is a certain amount of variability in the median T10 values between patients, but the differences are not significant. There were also no statistically significant differences between the T10 values for primary and nodes at baseline and the subsequent time points (p = 0.94 Friedman test). Voxel-based T10 calculations are essential when quantitative Tofts-based PK analysis in heterogeneous tumors is needed. In the absence of T10 mapping capability, when a relative, qualitative analysis is deemed sufficient, a value of T10(p,n) = 0.800 s can be used as an estimate for T10 for both the primary tumor and the affected nodes in head and neck cancers at all the time points considered.

Authors
Craciunescu, O; Brizel, D; Cleland, E; Yoo, D; Muradyan, N; Carroll, M; Barboriak, D; MacFall, J
MLA Citation
Craciunescu, O, Brizel, D, Cleland, E, Yoo, D, Muradyan, N, Carroll, M, Barboriak, D, and MacFall, J. "Dynamic contrast enhanced-MRI in head and neck cancer patients: variability of the precontrast longitudinal relaxation time (T10)." Med Phys 37.6 (June 2010): 2683-2692.
PMID
20632579
Source
pubmed
Published In
Medical physics
Volume
37
Issue
6
Publish Date
2010
Start Page
2683
End Page
2692
DOI
10.1118/1.3427487

Noninvasive temperature mapping with MRI using chemical shift water-fat separation.

Tissues containing both water and lipids, e.g., breast, confound standard MR proton reference frequency-shift methods for mapping temperatures due to the lack of temperature-induced frequency shift in lipid protons. Generalized Dixon chemical shift-based water-fat separation methods, such as GE's iterative decomposition of water and fat with echo asymmetry and least-squares estimation method, can result in complex water and fat images. Once separated, the phase change over time of the water signal can be used to map temperature. Phase change of the lipid signal can be used to correct for non-temperature-dependent phase changes, such as amplitude of static field drift. In this work, an image acquisition and postprocessing method, called water and fat thermal MRI, is demonstrated in phantoms containing 30:70, 50:50, and 70:30 water-to-fat by volume. Noninvasive heating was applied in an Off1-On-Off2 pattern over 50 min, using a miniannular phased radiofrequency array. Temperature changes were referenced to the first image acquisition. Four fiber optic temperature probes were placed inside the phantoms for temperature comparison. Region of interest (ROI) temperature values colocated with the probes showed excellent agreement (global mean +/- standard deviation: -0.09 +/- 0.34 degrees C) despite significant amplitude of static field drift during the experiments.

Authors
Soher, BJ; Wyatt, C; Reeder, SB; MacFall, JR
MLA Citation
Soher, BJ, Wyatt, C, Reeder, SB, and MacFall, JR. "Noninvasive temperature mapping with MRI using chemical shift water-fat separation." Magn Reson Med 63.5 (May 2010): 1238-1246.
PMID
20432295
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
63
Issue
5
Publish Date
2010
Start Page
1238
End Page
1246
DOI
10.1002/mrm.22310

The brain-derived neurotrophic factor Val66Met polymorphism, hippocampal volume, and cognitive function in geriatric depression.

OBJECTIVE: The Val66Met polymorphism of the brain-derived neurotrophic factor (BDNF) gene is associated with geriatric depression. In studies of younger adults without depression, met allele carriers exhibit smaller hippocampal volumes and have poorer performance on neuropsychological tests. The authors examined the relationship between the BDNF gene and hippocampal volumes in depressed and nondepressed older individuals and its relationship with memory functions mediated by the hippocampus. DESIGN: One hundred seventy-six elderly depressed white participants and 88 nondepressed participants completed clinical assessments, neuropsychological testing, and provided blood samples for genotyping. One hundred seventy-three participants also underwent brain magnetic resonance imaging. Statistical modeling tested the relationship between genotype and hippocampal volume and function while controlling for diagnosis and other covariates. RESULTS: BDNF genotype was not associated with a difference in performance on tests mediated by the hippocampus, including word list learning, prose recall, nonverbal memory, or digit span. After controlling for covariates, BDNF genotype was not significantly associated with hippocampal volume (F[1, 171] = 1.10, p = 0.30). CONCLUSION: Despite different findings in younger populations, the BDNF Val66Met polymorphism is not significantly associated with hippocampal volume or function in a geriatric population. The authors hypothesize that other factors may have a stronger effect on hippocampal structure in older individuals and that the association between the Val66Met polymorphism and geriatric depression is mediated through other mechanisms.

Authors
Benjamin, S; McQuoid, DR; Potter, GG; Payne, ME; MacFall, JR; Steffens, DC; Taylor, WD
MLA Citation
Benjamin, S, McQuoid, DR, Potter, GG, Payne, ME, MacFall, JR, Steffens, DC, and Taylor, WD. "The brain-derived neurotrophic factor Val66Met polymorphism, hippocampal volume, and cognitive function in geriatric depression." Am J Geriatr Psychiatry 18.4 (April 2010): 323-331.
PMID
20220593
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
18
Issue
4
Publish Date
2010
Start Page
323
End Page
331
DOI
10.1097/JGP.0b013e3181cabd2b

Support for the vascular depression hypothesis in late-life depression: results of a 2-site, prospective, antidepressant treatment trial.

CONTEXT: Research on vascular depression has used 2 approaches to subtype late-life depression, based on executive dysfunction or white matter hyperintensity severity. OBJECTIVE: To evaluate the relationship of neuropsychological performance and white matter hyperintensity with clinical response in late-life depression. DESIGN: Two-site, prospective, nonrandomized controlled trial. SETTING: Outpatient clinics at Washington University and Duke University. PARTICIPANTS: A total of 217 subjects aged 60 years or older met DSM-IV criteria for major depression, scored 20 or more on the Montgomery-Asberg Depression Rating Scale (MADRS), and received vascular risk factor scores, neuropsychological testing, and magnetic resonance imaging; they were excluded for cognitive impairment or severe medical disorders. Fazekas rating was conducted to grade white matter hyperintensity lesions. Intervention Twelve weeks of sertraline treatment, titrated by clinical response. Main Outcome Measure Participants' MADRS scores over time. RESULTS: Baseline neuropsychological factor scores correlated negatively with baseline Fazekas scores. A mixed model examined effects of predictor variables on MADRS scores over time. Baseline episodic memory (P = .002), language (P = .007), working memory (P = .01), processing speed (P < .001), executive function factor scores (P = .002), and categorical Fazekas ratings (P = .05) predicted MADRS scores, controlling for age, education, age of onset, and race. Controlling for baseline MADRS scores, these factors remained significant predictors of decrease in MADRS scores, except for working memory and Fazekas ratings. Thirty-three percent of subjects achieved remission (MADRS < or =7). Remitters differed from nonremitters in baseline cognitive processing speed, executive function, language, episodic memory, and vascular risk factor scores. CONCLUSIONS: Comprehensive neuropsychological function and white matter hyperintensity severity predicted MADRS scores prospectively over a 12-week treatment course with selective serotonin reuptake inhibitors in late-life depression. Baseline neuropsychological function differentiated remitters from nonremitters and predicted time to remission in a proportional hazards model. Predictor variables correlated highly with vascular risk factor severity. These data support the vascular depression hypothesis and highlight the importance of linking subtypes based on neuropsychological function and white matter integrity. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00045773.

Authors
Sheline, YI; Pieper, CF; Barch, DM; Welsh-Bohmer, K; McKinstry, RC; MacFall, JR; D'Angelo, G; Garcia, KS; Gersing, K; Wilkins, C; Taylor, W; Steffens, DC; Krishnan, RR; Doraiswamy, PM
MLA Citation
Sheline, YI, Pieper, CF, Barch, DM, Welsh-Bohmer, K, McKinstry, RC, MacFall, JR, D'Angelo, G, Garcia, KS, Gersing, K, Wilkins, C, Taylor, W, Steffens, DC, Krishnan, RR, and Doraiswamy, PM. "Support for the vascular depression hypothesis in late-life depression: results of a 2-site, prospective, antidepressant treatment trial." Arch Gen Psychiatry 67.3 (March 2010): 277-285.
PMID
20194828
Source
pubmed
Published In
Archives of General Psychiatry
Volume
67
Issue
3
Publish Date
2010
Start Page
277
End Page
285
DOI
10.1001/archgenpsychiatry.2009.204

An Association Study of the Val158Met Polymorphism of the COMT Gene with Orbitofrontal Cortex Volumes in the Elderly

Authors
Benjamin, S; McQuoid, DR; Payne, ME; MacFall, JR; Steffens, DC; Taylor, WD
MLA Citation
Benjamin, S, McQuoid, DR, Payne, ME, MacFall, JR, Steffens, DC, and Taylor, WD. "An Association Study of the Val158Met Polymorphism of the COMT Gene with Orbitofrontal Cortex Volumes in the Elderly." March 2010.
Source
wos-lite
Published In
American Journal of Geriatric Psychiatry
Volume
18
Issue
3
Publish Date
2010
Start Page
S92
End Page
S93

Amygdalar Volume in Late Life Depression

Authors
Burke, J; McQuoid, DR; Payne, ME; MacFall, JR; Steffens, DC; Taylor, W
MLA Citation
Burke, J, McQuoid, DR, Payne, ME, MacFall, JR, Steffens, DC, and Taylor, W. "Amygdalar Volume in Late Life Depression." March 2010.
Source
wos-lite
Published In
American Journal of Geriatric Psychiatry
Volume
18
Issue
3
Publish Date
2010
Start Page
S91
End Page
S91

Utility of functional imaging in prediction or assessment of treatment response and prognosis following thermotherapy.

The purpose of this review is to examine the roles that functional imaging may play in prediction of treatment response and determination of overall prognosis in patients who are enrolled in thermotherapy trials, either in combination with radiotherapy, chemotherapy or both. Most of the historical work that has been done in this field has focused on magnetic resonance imaging/magnetic resonance spectroscopy (MRI/MRS) methods, so the emphasis will be there, although some discussion of the role that positron emission tomography (PET) might play will also be examined. New optical technologies also hold promise for obtaining low cost, yet valuable physiological data from optically accessible sites. The review is organised by traditional outcome parameters: local response, local control and progression-free or overall survival. Included in the review is a discussion of future directions for this type of translational work.

Authors
Dewhirst, MW; Thrall, DE; Palmer, G; Schroeder, T; Vujaskovic, Z; Cecil Charles, H; Macfall, J; Wong, T
MLA Citation
Dewhirst, MW, Thrall, DE, Palmer, G, Schroeder, T, Vujaskovic, Z, Cecil Charles, H, Macfall, J, and Wong, T. "Utility of functional imaging in prediction or assessment of treatment response and prognosis following thermotherapy." Int J Hyperthermia 26.3 (2010): 283-293. (Review)
PMID
20170362
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
26
Issue
3
Publish Date
2010
Start Page
283
End Page
293
DOI
10.3109/02656730903286214

Gray and white matter brain volumes in older adults with bipolar disorder.

OBJECTIVES: Structural magnetic resonance imaging (MRI) studies have been inconsistent in demonstrating volumetric differences in subjects with bipolar disorder. Most studies have not found difference in total gray or white matter in bipolar patients compared with controls, but there have been several studies suggesting that regional abnormalities are present. These have predominately been located in the frontal and temporal lobes. Since age has been inversely correlated with total gray matter in patients, analyses of gray matter changes in older adults or in studies that have included older subjects have been difficult. This study assessed the presence of gray matter volume, and the potential for regional volumetric differences in older adults with bipolar disorder. METHODS: Fifty-six older adults with DSM-IV bipolar disorder (mean age 60.5) and 43 non-psychiatrically ill controls (mean age 58.1) had structured interviews and MRI scanning on a 1.5T GE Scanner. Image parcellation divided the cerebrum into 16 units. Volumetric differences were examined using the multivariate linear regression models with alpha = 0.05. RESULTS: Relative to controls, the older adults with bipolar disorder had significantly smaller gray matter volumes bilaterally in the inferior frontal areas. White matter volume was also reduced in these same areas but did not reach statistical significance when controlled for gender and age. No significant difference was noted in total gray or white matter volumes. CONCLUSIONS: Older adults with bipolar disorder showed gray matter volumetric deficits in inferior frontal lobe regions which include structures identified as contributing to the anterior limbic network.

Authors
Beyer, JL; Kuchibhatla, M; Payne, ME; Macfall, J; Cassidy, F; Krishnan, KR
MLA Citation
Beyer, JL, Kuchibhatla, M, Payne, ME, Macfall, J, Cassidy, F, and Krishnan, KR. "Gray and white matter brain volumes in older adults with bipolar disorder." Int J Geriatr Psychiatry 24.12 (December 2009): 1445-1452.
PMID
19452498
Source
pubmed
Published In
International Journal of Geriatric Psychiatry
Volume
24
Issue
12
Publish Date
2009
Start Page
1445
End Page
1452
DOI
10.1002/gps.2285

Accuracy of real time noninvasive temperature measurements using magnetic resonance thermal imaging in patients treated for high grade extremity soft tissue sarcomas.

PURPOSE: To establish accuracy of real time noninvasive temperature measurements using magnetic resonance thermal imaging in patients treated for high grade extremity soft tissue sarcomas. METHODS: Protocol patients with advanced extremity sarcomas were treated with external beam radiation therapy and hyperthermia. Invasive temperature measures were compared to noninvasive magnetic resonance thermal imaging (MRTI) at 1.5 T performed during hyperthermia. Volumetric temperature rise images were obtained using the proton resonance frequency shift (PRFS) technique during heating in a 140 MHz miniannular phased array applicator. MRTI temperature changes were compared to invasive measurements of temperature with a multisensor fiber optic probe inside a #15 g catheter in the tumor. Since the PRFS technique is sensitive to drifts in the primary imaging magnetic field, temperature change distributions were corrected automatically during treatment using temperature-stable reference materials to characterize field changes in 3D. The authors analyzed MRT images and compared, in evaluable treatments, MR-derived temperatures to invasive temperatures measured in extremity sarcomas. Small regions of interest (ROIs) were specified near each invasive sensor identified on MR images. Temperature changes in the interstitial sensors were compared to the corresponding ROI PRFS-based temperature changes over the entire treatment and over the steady-state period. Nonevaluable treatments (motion/imaging artifacts, noncorrectable drifts) were not included in the analysis. RESULTS: The mean difference between MRTI and interstitial probe measurements was 0.91 degrees C for the entire heating time and 0.85 degrees C for the time at steady state. These values were obtained from both tumor and normal tissue ROIs. When the analysis is done on just the tumor ROIs, the mean difference for the whole power on time was 0.74 degrees C and during the period of steady state was 0.62 degrees C. CONCLUSIONS: The data show that for evaluable treatments, excellent correlation (deltaT < 1 degrees C) of MRTI-ROI and invasive measurements can be achieved, but that motion and other artifacts are still serious challenges that must be overcome in future work.

Authors
Craciunescu, OI; Stauffer, PR; Soher, BJ; Wyatt, CR; Arabe, O; Maccarini, P; Das, SK; Cheng, KS; Wong, TZ; Jones, EL; Dewhirst, MW; Vujaskovic, Z; MacFall, JR
MLA Citation
Craciunescu, OI, Stauffer, PR, Soher, BJ, Wyatt, CR, Arabe, O, Maccarini, P, Das, SK, Cheng, KS, Wong, TZ, Jones, EL, Dewhirst, MW, Vujaskovic, Z, and MacFall, JR. "Accuracy of real time noninvasive temperature measurements using magnetic resonance thermal imaging in patients treated for high grade extremity soft tissue sarcomas." Med Phys 36.11 (November 2009): 4848-4858.
PMID
19994492
Source
pubmed
Published In
Medical physics
Volume
36
Issue
11
Publish Date
2009
Start Page
4848
End Page
4858
DOI
10.1118/1.3227506

Dynamic contrast-enhanced magnetic resonance imaging as a predictor of clinical outcome in canine spontaneous soft tissue sarcomas treated with thermoradiotherapy.

PURPOSE: This study tests whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters obtained from canine patients with soft tissue sarcomas, treated with hyperthermia and radiotherapy, are predictive of therapeutic outcome. EXPERIMENTAL DESIGN: Thirty-seven dogs with soft tissue sarcomas had DCE-MRI done before and following the first hyperthermia. Signal enhancement for tumor and reference muscle were fitted empirically, yielding a washin/washout rate for the contrast agent and tumor area under the signal enhancement curve (AUC) calculated from 0 to 60 seconds, 90 seconds, and the time of maximal enhancement in the reference muscle. These parameters were then compared with local tumor control, metastasis-free survival, and overall survival. RESULTS: Pretherapy rate of contrast agent washout was positively predictive of improved overall and metastasis-free survival with hazard ratio of 0.67 (P = 0.015) and 0.68 (P = 0.012), respectively. After the first hyperthermia washin rate, AUC60, AUC90, and AUCt-max were predictive of improved overall and metastasis-free survival with hazard ratio ranging from 0.46 to 0.53 (P < 0.002) and 0.44 to 0.55 (P < 0.004), respectively. DCE-MRI parameters were compared with extracellular pH and (31)P MR spectroscopy results (previously published) in the same patients showing a correlation. This suggested that an increase in perfusion after therapy was effective in eliminating excess acid from the tumor. CONCLUSIONS: This study shows that DCE-MRI has utility predicting overall and metastasis-free survival in canine patients with soft tissue sarcomas. To our knowledge, this is the first time that DCE-MRI parameters are predictive of clinical outcome for soft tissue sarcomas.

Authors
Viglianti, BL; Lora-Michiels, M; Poulson, JM; Lan, L; Yu, D; Sanders, L; Craciunescu, O; Vujaskovic, Z; Thrall, DE; Macfall, J; Charles, CH; Wong, T; Dewhirst, MW
MLA Citation
Viglianti, BL, Lora-Michiels, M, Poulson, JM, Lan, L, Yu, D, Sanders, L, Craciunescu, O, Vujaskovic, Z, Thrall, DE, Macfall, J, Charles, CH, Wong, T, and Dewhirst, MW. "Dynamic contrast-enhanced magnetic resonance imaging as a predictor of clinical outcome in canine spontaneous soft tissue sarcomas treated with thermoradiotherapy." Clin Cancer Res 15.15 (August 1, 2009): 4993-5001.
PMID
19622579
Source
pubmed
Published In
Clinical cancer research : an official journal of the American Association for Cancer Research
Volume
15
Issue
15
Publish Date
2009
Start Page
4993
End Page
5001
DOI
10.1158/1078-0432.CCR-08-2222

Real-time MRI-guided hyperthermia treatment using a fast adaptive algorithm.

Magnetic resonance (MR) imaging is promising for monitoring and guiding hyperthermia treatments. The goal of this work is to investigate the stability of an algorithm for online MR thermal image guided steering and focusing of heat into the target volume. The control platform comprised a four-antenna mini-annular phased array (MAPA) applicator operating at 140 MHz (used for extremity sarcoma heating) and a GE Signa Excite 1.5 T MR system, both of which were driven by a control workstation. MR proton resonance frequency shift images acquired during heating were used to iteratively update a model of the heated object, starting with an initial finite element computed model estimate. At each iterative step, the current model was used to compute a focusing vector, which was then used to drive the next iteration, until convergence. Perturbation of the driving vector was used to prevent the process from stalling away from the desired focus. Experimental validation of the performance of the automatic treatment platform was conducted with two cylindrical phantom studies, one homogeneous and one muscle equivalent with tumor tissue (conductivity 50% higher) inserted, with initial focal spots being intentionally rotated 90 degrees and 50 degrees away from the desired focus, mimicking initial setup errors in applicator rotation. The integrated MR-HT treatment platform steered the focus of heating into the desired target volume in two quite different phantom tissue loads which model expected patient treatment configurations. For the homogeneous phantom test where the target was intentionally offset by 90 degrees rotation of the applicator, convergence to the proper phase focus in the target occurred after 16 iterations of the algorithm. For the more realistic test with a muscle equivalent phantom with tumor inserted with 50 degrees applicator displacement, only two iterations were necessary to steer the focus into the tumor target. Convergence improved the heating efficacy (the ratio of integral temperature in the tumor to integral temperature in normal tissue) by up to six-fold, compared to the first iteration. The integrated MR-HT treatment algorithm successfully steered the focus of heating into the desired target volume for both the simple homogeneous and the more challenging muscle equivalent phantom with tumor insert models of human extremity sarcomas after 16 and 2 iterations, correspondingly. The adaptive method for MR thermal image guided focal steering shows promise when tested in phantom experiments on a four-antenna phased array applicator.

Authors
Stakhursky, VL; Arabe, O; Cheng, KS; Macfall, J; Maccarini, P; Craciunescu, O; Dewhirst, M; Stauffer, P; Das, SK
MLA Citation
Stakhursky, VL, Arabe, O, Cheng, KS, Macfall, J, Maccarini, P, Craciunescu, O, Dewhirst, M, Stauffer, P, and Das, SK. "Real-time MRI-guided hyperthermia treatment using a fast adaptive algorithm." Phys Med Biol 54.7 (April 7, 2009): 2131-2145.
PMID
19287081
Source
pubmed
Published In
Physics in Medicine and Biology
Volume
54
Issue
7
Publish Date
2009
Start Page
2131
End Page
2145
DOI
10.1088/0031-9155/54/7/019

Temporal lobe volume in bipolar disorder: relationship with diagnosis and antipsychotic medication use.

BACKGROUND: We tested for differences in temporal lobe volume in bipolar disorder and the relationship between these volumes and psychotropic medication use. METHODS: 125 subjects with bipolar disorder and 87 comparison subjects with no psychiatric illness completed clinical interviews and 1.5T MRI brain scans. Temporal lobe volumes were manually traced and segmented into gray matter and white matter volumes using an automated process. General linear models examined the relationship between these volumes and diagnosis as the primary predictor with age, sex, education, and race as copredictors. Secondary analyses incorporated the use of psychotropic medication into the linear models, and parsimonious models developed through backwards regression. RESULTS: In initial models, subjects with bipolar disorder exhibited larger temporal lobe white matter bilaterally (left: F(1,211)=2.86, p=0.0047; right: F(1,211)=3.25, p=0.0014). Current antipsychotic use was significantly associated with larger bilateral temporal lobe white matter volumes (left: F(2,211)=9.45, p=0.0001; right: F(2,211)=10.79, p<0.0001), wherein bipolar subjects taking antipsychotics had larger volumes than bipolar subjects not taking antipsychotics or healthy comparison subjects. Temporal lobe gray matter volume was not significantly associated with diagnosis or medication use. LIMITATIONS: Excluding subjects with substance use disorders may limit the study's generalizability. CONCLUSIONS: These findings indicate that differences in temporal lobe white matter are associated with bipolar disorder and use of antipsychotic medications.

Authors
Jones, LD; Payne, ME; Messer, DF; Beyer, JL; MacFall, JR; Krishnan, KR; Taylor, WD
MLA Citation
Jones, LD, Payne, ME, Messer, DF, Beyer, JL, MacFall, JR, Krishnan, KR, and Taylor, WD. "Temporal lobe volume in bipolar disorder: relationship with diagnosis and antipsychotic medication use." J Affect Disord 114.1-3 (April 2009): 50-57.
PMID
18691766
Source
pubmed
Published In
Journal of Affective Disorders
Volume
114
Issue
1-3
Publish Date
2009
Start Page
50
End Page
57
DOI
10.1016/j.jad.2008.07.003

Teasing apart the heterogeneity of autism: Same behavior, different brains in toddlers with fragile X syndrome and autism.

To examine brain volumes in substructures associated with the behavioral features of children with FXS compared to children with idiopathic autism and controls. A cross-sectional study of brain substructures was conducted at the first time-point as part of an ongoing longitudinal MRI study of brain development in FXS. The study included 52 boys between 18-42 months of age with FXS and 118 comparison children (boys with autism-non FXS, developmental-delay, and typical development). Children with FXS and autistic disorder had substantially enlarged caudate volume and smaller amygdala volume; whereas those children with autistic disorder without FXS (i.e., idiopathic autism) had only modest enlargement in their caudate nucleus volumes but more robust enlargement of their amygdala volumes. Although we observed this double dissociation among selected brain volumes, no significant differences in severity of autistic behavior between these groups were observed. This study offers a unique examination of early brain development in two disorders, FXS and idiopathic autism, with overlapping behavioral features, but two distinct patterns of brain morphology. We observed that despite almost a third of our FXS sample meeting criteria for autism, the profile of brain volume differences for children with FXS and autism differed from those with idiopathic autism. These findings underscore the importance of addressing heterogeneity in studies of autistic behavior.

Authors
Hazlett, HC; Poe, MD; Lightbody, AA; Gerig, G; Macfall, JR; Ross, AK; Provenzale, J; Martin, A; Reiss, AL; Piven, J
MLA Citation
Hazlett, HC, Poe, MD, Lightbody, AA, Gerig, G, Macfall, JR, Ross, AK, Provenzale, J, Martin, A, Reiss, AL, and Piven, J. "Teasing apart the heterogeneity of autism: Same behavior, different brains in toddlers with fragile X syndrome and autism." J Neurodev Disord 1.1 (March 2009): 81-90.
PMID
20700390
Source
pubmed
Published In
Journal of Neurodevelopmental Disorders
Volume
1
Issue
1
Publish Date
2009
Start Page
81
End Page
90
DOI
10.1007/s11689-009-9009-8

Reduction of Dorsolateral Prefrontal Cortex Gray Matter in Late-Life Depression

Authors
Chang, C-C; Yu, S-C; McQuoid, DR; Messer, DF; Taylor, WD; Singh, K; Boyd, BD; Krishnan, KRR; MacFall, JR; Steffens, DC; Payne, ME
MLA Citation
Chang, C-C, Yu, S-C, McQuoid, DR, Messer, DF, Taylor, WD, Singh, K, Boyd, BD, Krishnan, KRR, MacFall, JR, Steffens, DC, and Payne, ME. "Reduction of Dorsolateral Prefrontal Cortex Gray Matter in Late-Life Depression." AMERICAN JOURNAL OF GERIATRIC PSYCHIATRY 17.3 (March 2009): A62-A62.
Source
wos-lite
Published In
American Journal of Geriatric Psychiatry
Volume
17
Issue
3
Publish Date
2009
Start Page
A62
End Page
A62

APOE related hippocampal shape alteration in geriatric depression.

Late-onset depression often precedes the onset of dementia associated with the hippocampal degeneration. Using large deformation diffeomorphic metric mapping (LDDMM), we evaluated apolipoprotein E epsilon-4 allele (apoE E4) effects on hippocampal volume and shape in 38 depressed patients without the apoE E4, 14 depressed patients with one apoE E4, and 31 healthy comparison subjects without the apoE E4. The hippocampal volumes were manually assessed. We applied a diffeomorphic template generation procedure for creating the hippocampal templates based on a subset of the population. The LDDMM mappings were used to generate the hippocampal shape of each subject and characterize the surface deformation of each hippocampus relative to the template. Such deformation was modeled as random field characterized by the Laplace-Beltrami basis functions in the template coordinates. Linear regression was used to examine group differences in the hippocampal volume and shape. We found that there were significant hippocampal shape alternations in both depressed groups while the groups of depressed patients and the group of healthy subjects did not differ in the hippocampal volume. The depressed patients with one apoE E4 show more pronounced shape inward-compression in the anterior CA1 than the depressed patients without the apoE E4 when compared with the healthy controls without the apoE E4. Thus, hippocampal shape abnormalities in late-onset depressed patients with one apoE E4 may indicate future conversion of this group to AD at higher risk than depressed patients without the apoE E4.

Authors
Qiu, A; Taylor, WD; Zhao, Z; MacFall, JR; Miller, MI; Key, CR; Payne, ME; Steffens, DC; Krishnan, KR
MLA Citation
Qiu, A, Taylor, WD, Zhao, Z, MacFall, JR, Miller, MI, Key, CR, Payne, ME, Steffens, DC, and Krishnan, KR. "APOE related hippocampal shape alteration in geriatric depression." Neuroimage 44.3 (February 1, 2009): 620-626.
PMID
19010425
Source
pubmed
Published In
NeuroImage
Volume
44
Issue
3
Publish Date
2009
Start Page
620
End Page
626
DOI
10.1016/j.neuroimage.2008.10.010

DCE-MRI parameters have potential to predict response of locally advanced breast cancer patients to neoadjuvant chemotherapy and hyperthermia: a pilot study.

UNLABELLED: Combined therapies represent a staple of modern medicine. For women treated with neoadjuvant chemotherapy (NA ChT) for locally advanced breast cancer (LABC), early determination of whether the patient will fail to respond can enable the use of alternative, more beneficial therapies. This is even more desirable when the combined therapy includes hyperthermia (HT), an efficient way to improve drug delivery, however, more costly and time consuming. There is data showing that this goal can be achieved using magnetic resonance imaging (MRI) with contrast agent (CA) enhancement. This work for the first time proposes combining the information extracted from pre-treatment MR imaging into a morpho-physiological tumour score (MPTS) with the hypothesis that this score will increase the prognostic efficacy, compared to each of its MR-derived components: morphological (derived from the shape of the tumour enhancement) and physiological (derived from the CA enhancement variance dynamics parameters). The MPTS was correlated with response as determined by both pathologic residual tumour and MRI imaging, and was shown to have potential to predict response. The MPTS was extracted from pre-treatment MRI parameters, so independent of the combined therapy used. PURPOSE: To use a novel morpho-physiological tumour score (MPTS) generated from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to predict response to treatment. MATERIALS AND METHODS: A protocol was designed to acquire DCE-MRI images of 20 locally advanced breast cancer (LABC) patients treated with neoadjuvant chemotherapy (NA ChT) and hyperthermia (HT). Imaging was done over 30 min following bolus injection of gadopentetate-based contrast agent. Parametric maps were generated by fitting the signal intensity to a double exponential curve and were used to derive a morphological characterisation of the lesions. Enhancement-variance dynamics parameters, wash-in and wash-out parameters (WiP, WoP), were extracted. The morphological characterisation and the WiP and WoP were combined into a MPTS with the intent of achieving better prognostic efficacy. The MPTS was correlated with response to NA therapy as determined by pathological residual tumour and MRI imaging. RESULTS: The contrast agent in all tumours typically peaked in the first 1-4 min. The tumours' WiP and WoP varied considerably. The MPTS was highly correlated with whether the patients had a pathological response. This scoring system has a specificity of 78% and a sensitivity of 91% for predicting response to NA chemotherapy. The kappa was 0.69 with a 95% confidence interval of [0.38, 1] and a p-value of 0.002. CONCLUSIONS: This pilot study shows that the MPTS derived using pre-treatment MRI images has the potential to predict response to NA ChT and HT in LABC patients. Further prospective studies are needed to confirm the validity of these results.

Authors
Craciunescu, OI; Blackwell, KL; Jones, EL; Macfall, JR; Yu, D; Vujaskovic, Z; Wong, TZ; Liotcheva, V; Rosen, EL; Prosnitz, LR; Samulski, TV; Dewhirst, MW
MLA Citation
Craciunescu, OI, Blackwell, KL, Jones, EL, Macfall, JR, Yu, D, Vujaskovic, Z, Wong, TZ, Liotcheva, V, Rosen, EL, Prosnitz, LR, Samulski, TV, and Dewhirst, MW. "DCE-MRI parameters have potential to predict response of locally advanced breast cancer patients to neoadjuvant chemotherapy and hyperthermia: a pilot study." Int J Hyperthermia 25.6 (2009): 405-415.
PMID
19657852
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
25
Issue
6
Publish Date
2009
Start Page
405
End Page
415
DOI
10.1080/02656730903022700

Hyperthermia MRI temperature measurement: evaluation of measurement stabilisation strategies for extremity and breast tumours.

PURPOSE: MR thermometry using the proton resonance frequency shift (PRFS) method has been used to measure temperature changes during clinical hyperthermia treatment. However, frequency drift of the MRI system can add large errors to the measured temperature change. These drifts can be measured and corrected using oil references placed around the treatment region. In this study, the number and position of four or more oil references were investigated to obtain a practical approach to correct frequency drift during PRFS thermometry in phantoms and in vivo. MATERIALS AND METHODS: Experiments were performed in a 140 MHz four antenna mini-annular phased array (MAPA) heat applicator (for treatment of extremity tumours) and an applicator for heating of the breast, with symmetric and asymmetric positioning of the oil references, respectively. Temperature change PRFS images were obtained during an hour or more of measurement with no application of heat. Afterwards, errors in calculating temperature change due to system drift were quantified with and without various oil reference correction arrangements. RESULTS: Results showed good temperature correction in phantoms and in a human leg, with average errors of 0.28 degrees C and 0.94 degrees C respectively. There was further improvement in the leg when using eight or more oil references, reducing the average error to 0.44 degrees C, while the phantoms showed no significant improvement. CONCLUSIONS: These results indicate that oil reference correction performs well in vivo, and that eight references can improve the correction by up to 0.5 degrees C compared to four references.

Authors
Wyatt, C; Soher, B; Maccarini, P; Charles, HC; Stauffer, P; Macfall, J
MLA Citation
Wyatt, C, Soher, B, Maccarini, P, Charles, HC, Stauffer, P, and Macfall, J. "Hyperthermia MRI temperature measurement: evaluation of measurement stabilisation strategies for extremity and breast tumours." Int J Hyperthermia 25.6 (2009): 422-433.
PMID
19925322
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
25
Issue
6
Publish Date
2009
Start Page
422
End Page
433
DOI
10.1080/02656730903133762

Clinical utility of magnetic resonance thermal imaging (MRTI) for realtime guidance of deep hyperthermia

A critical need has emerged for volumetric thermometry to visualize 3D temperature distributions in real time during deep hyperthermia treatments used as an adjuvant to radiation or chemotherapy for cancer. For the current effort, magnetic resonance thermal imaging (MRTI) is used to measure 2D temperature rise distributions in four cross sections of large extremity soft tissue sarcomas during hyperthermia treatments. Novel hardware and software techniques aredescribed which improve the signal to noise ratio of MR images, minimize motion artifact from circulating coupling fluids, and provide accurate high resolution volumetric thermal dosimetry. For the first 10 extremity sarcoma patients, the mean difference between MRTI region of interest and adjacent interstitial point measurements during the period of steady state temperature was 0.85°C. With 1min temporal resolution of measurements in four image planes, this noninvasive MRTI approach has demonstrated its utility for accurate monitoring and realtime steering of heat into tumors at depth in the body. © 2009 SPIE.

Authors
Stauffer, PR; Craciunescu, OI; Maccarini, PF; Wyatt, C; Arunachalam, K; Arabe, O; Stakhursky, V; Soher, B; MacFall, JR; Li, Z; Joines, WT; Rangarao, S; Cheng, KS; Das, SK; Martins, CD; Charles, C; Dewhirst, MW; Wong, T; Jones, E; Vujaskovic, Z
MLA Citation
Stauffer, PR, Craciunescu, OI, Maccarini, PF, Wyatt, C, Arunachalam, K, Arabe, O, Stakhursky, V, Soher, B, MacFall, JR, Li, Z, Joines, WT, Rangarao, S, Cheng, KS, Das, SK, Martins, CD, Charles, C, Dewhirst, MW, Wong, T, Jones, E, and Vujaskovic, Z. "Clinical utility of magnetic resonance thermal imaging (MRTI) for realtime guidance of deep hyperthermia." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 7181 (2009).
PMID
24224074
Source
scival
Published In
Proceedings of SPIE
Volume
7181
Publish Date
2009
DOI
10.1117/12.812188

Frontal white matter anisotropy and antidepressant remission in late-life depression.

INTRODUCTION: Neuroanatomic features associated with antidepressant treatment outcomes in older depressed individuals are not well established. This study used diffusion tensor imaging to examine frontal white matter structure in depressed subjects undergoing a 12-week trial of sertraline. We hypothesized that remission would be associated with higher frontal anisotropy measures, and failure to remit with lower anisotropy. METHODS: 74 subjects with Major Depressive Disorder and age 60 years or older were enrolled in a twelve-week open-label trial of sertraline and completed clinical assessments and 1.5T magnetic resonance brain imaging. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in regions of interest placed in the white matter of the dorsolateral prefrontal cortex, anterior cingulate cortex, and corpus callosum. Differences in ADC and FA values between subjects who did and did not remit to treatment over the study period were assessed using generalized estimating equations, controlling for age, sex, medical comorbidity and baseline depression severity. RESULTS: Subjects who did not remit to sertraline exhibited higher FA values in the superior frontal gyri and anterior cingulate cortices bilaterally. There were no statistically significant associations between ADC measures and remission. CONCLUSIONS: Failure to remit to sertraline is associated with higher frontal FA values. Functional imaging studies demonstrate that depression is characterized by functional disconnection between frontal and limbic regions. Those individuals where this disconnection is related to structural changes as detected by DTI may be more likely to respond to antidepressants. TRIAL REGISTRATION: ClinicalTrials.gov NCT00339066.

Authors
Taylor, WD; Kuchibhatla, M; Payne, ME; Macfall, JR; Sheline, YI; Krishnan, KR; Doraiswamy, PM
MLA Citation
Taylor, WD, Kuchibhatla, M, Payne, ME, Macfall, JR, Sheline, YI, Krishnan, KR, and Doraiswamy, PM. "Frontal white matter anisotropy and antidepressant remission in late-life depression. (Published online)" PLoS One 3.9 (September 24, 2008): e3267-.
PMID
18813343
Source
pubmed
Published In
PloS one
Volume
3
Issue
9
Publish Date
2008
Start Page
e3267
DOI
10.1371/journal.pone.0003267

Classification of white matter lesions on magnetic resonance imaging in elderly persons.

White matter lesions, commonly seen on MRIs of elderly people, are related to various geriatric disorders, including cerebrovascular diseases, cardiovascular diseases, dementia, and psychiatric disorders. Currently, white matter lesions are divided into periventricular white matter lesions and deep white matter lesions. Although the meaning of these terms varies by study and this dichotomization itself is still in debate, a possible dissimilarity in pathogenic mechanisms between periventricular white matter lesions and deep white matter lesions are providing some clues for understanding pathophysiology of many geriatric syndromes associated with white matter lesions. We have reviewed the distinctions between periventricular white matter lesions and deep white matter lesions in terms of etiology, histopathology, functional correlates, and imaging methodologies. We suggest a new subclassification of white matter lesions that might have better etiological and functional relevance than the current simple dichotomization. The new categories are juxtaventricular, periventricular, deep white, and juxtacortical. This new classification scheme might contribute to reducing the heterogeneity of white matter lesion findings in future research.

Authors
Kim, KW; MacFall, JR; Payne, ME
MLA Citation
Kim, KW, MacFall, JR, and Payne, ME. "Classification of white matter lesions on magnetic resonance imaging in elderly persons." Biol Psychiatry 64.4 (August 15, 2008): 273-280. (Review)
PMID
18471801
Source
pubmed
Published In
Biological Psychiatry
Volume
64
Issue
4
Publish Date
2008
Start Page
273
End Page
280
DOI
10.1016/j.biopsych.2008.03.024

Hippocampal volumes and depression subtypes.

Studies of depression and hippocampal volume have yielded inconsistent results. This inconsistency could stem from the heterogeneity of depressive disorders. We conducted cross-sectional and longitudinal analyses of hippocampal volumes in atypical depressive, melancholic depressive, and control subjects. We found no effect of depression subtype on hippocampal volume or memory performance.

Authors
Greenberg, DL; Payne, ME; MacFall, JR; Steffens, DC; Krishnan, RR
MLA Citation
Greenberg, DL, Payne, ME, MacFall, JR, Steffens, DC, and Krishnan, RR. "Hippocampal volumes and depression subtypes." Psychiatry Res 163.2 (July 15, 2008): 126-132.
PMID
18508244
Source
pubmed
Published In
Psychiatry Research
Volume
163
Issue
2
Publish Date
2008
Start Page
126
End Page
132
DOI
10.1016/j.pscychresns.2007.12.009

Comparison of three physiologically-based pharmacokinetic models for the prediction of contrast agent distribution measured by dynamic MR imaging.

PURPOSE: To compare the performance of three physiologically-based pharmacokinetic (PBPK) models for predicting gadolinium contrast agent concentration-time curves (Gd-CTCs) obtained in superior sagittal sinus (SSS), cerebral cortex, and psoas muscle. MATERIALS AND METHODS: Three published whole-body PBPK models were modified to predict Gd-CTCs in normal-appearing tissue. The models differed in the number of organs modeled and total number of compartments, and were designated as the "well-mixed," "delay," and "dispersion" models. The suitability of the three models to predict Gd-CTC was studied using data from dynamic contrast-enhanced MR perfusion imaging obtained at 1.5T from 10 patients with glioblastoma multiforme and at 3.0T from five patients with liver metastases. RESULTS: The dispersion model produced better fits than the delay model in the SSS (P < 0.0001) and cerebral cortex (P < 0.0001), and better fits than the well-mixed model in psoas muscle (P < 0.005). No model produced better fits than the dispersion model at any of the three locations. CONCLUSION: In this evaluation, the dispersion model was most robust for prediction of Gd-CTCs derived from dynamic contrast-enhanced (DCE)-MRI. This represents a preliminary step in the development of a PBPK model useful for predicting Gd-CTCs at a time resolution appropriate for dynamic MRI applications.

Authors
Barboriak, DP; MacFall, JR; Viglianti, BL; Dewhirst Dvm, MW
MLA Citation
Barboriak, DP, MacFall, JR, Viglianti, BL, and Dewhirst Dvm, MW. "Comparison of three physiologically-based pharmacokinetic models for the prediction of contrast agent distribution measured by dynamic MR imaging." J Magn Reson Imaging 27.6 (June 2008): 1388-1398.
PMID
18504759
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
27
Issue
6
Publish Date
2008
Start Page
1388
End Page
1398
DOI
10.1002/jmri.21344

Hippocampal MRI signal hyperintensity after febrile status epilepticus is predictive of subsequent mesial temporal sclerosis.

OBJECTIVE: The objective of our study was to test the hypothesis that the finding of hyperintense hippocampal signal intensity on T2-weighted MR images soon after febrile status epilepticus is associated with subsequent hippocampal volume loss and persistent abnormal signal intensity on T2-weighted images (i.e., mesial temporal sclerosis). SUBJECTS AND METHODS: Eleven children (mean age, 25 months) underwent initial MRI that included coronal temporal lobe imaging within 72 hours of febrile status epilepticus and follow-up imaging from 3 to 23 months later (mean, 9 months). A neuroradiologist blinded to clinical history graded initial and follow-up hippocampal signal intensity on a scale from 0 (normal) to 4 (markedly increased). Two blinded observers measured hippocampal volumes on initial and follow-up MR studies using commercially available software and volumes from 30 healthy children (mean age, 6.3 years). Initial signal intensity and hippocampal volume changes were compared using Kendall tau correlation coefficients. RESULTS: On initial imaging, hyperintense signal intensity ranging from 1 (minimally increased) to 4 (markedly increased) was seen in seven children. Four children had at least one hippocampus with moderate or marked signal abnormality, three children had a hippocampus with mild or minimal abnormality, and four children had normal signal intensity. The Kendall tau correlation coefficient between signal intensity increase and volume change was -0.68 (p < 0.01). Five children (two with temporal lobe epilepsy and two with complex partial seizures) had hippocampal volume loss and increased signal intensity on follow-up imaging, meeting the criteria for mesial temporal sclerosis. CONCLUSION: MRI findings of a markedly hyperintense hippocampus in children with febrile status epilepticus was highly associated with subsequent mesial temporal sclerosis.

Authors
Provenzale, JM; Barboriak, DP; VanLandingham, K; MacFall, J; Delong, D; Lewis, DV
MLA Citation
Provenzale, JM, Barboriak, DP, VanLandingham, K, MacFall, J, Delong, D, and Lewis, DV. "Hippocampal MRI signal hyperintensity after febrile status epilepticus is predictive of subsequent mesial temporal sclerosis." AJR Am J Roentgenol 190.4 (April 2008): 976-983.
PMID
18356445
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
190
Issue
4
Publish Date
2008
Start Page
976
End Page
983
DOI
10.2214/AJR.07.2407

The brain-derived neurotrophic factor VAL66MET polymorphism and cerebral white matter hyperintensities in late-life depression.

OBJECTIVE: In animal models, brain-derived neurotrophic factor (BDNF) appears to protect against cerebral ischemia. The authors examined whether the BDNF Val66Met polymorphism, which affects BDNF distribution, was associated with greater volumes of hyperintense lesions as detected on magnetic resonance imaging in a cohort of depressed and nondepressed elders. DESIGN: Subjects completed cross-sectional assessments, including clinical evaluation and a brain magnetic resonance imaging scan, and provided blood samples for Val66Met genotyping. SETTING: The study was conducted at a university-based academic hospital. PARTICIPANTS: Participants included 199 depressed and 113 nondepressed subjects aged 60 years or older. MEASUREMENT: Hyperintensity lesion volumes were measured using a semiautomated segmentation procedure. Statistical models examined the relationship between genotype and lesion volume while controlling for depression, presence of hypertension, age, and sex. RESULTS: After controlling for covariates, Met66 allele carriers exhibited significantly greater white matter hyperintensity volumes (F(1,311) = 4.09, p = 0.0442). This effect was independent of a diagnosis of depression or report of hypertension. Genotype was not significantly related to gray matter hyperintensity volume (F(1,311) = 1.14, p = 0.2871). CONCLUSIONS: The BDNF Met66 allele is associated with greater white matter hyperintensity volumes in older individuals. Further work is needed to determine how this may be associated with other clinically relevant findings in late-life depression.

Authors
Taylor, WD; Züchner, S; McQuoid, DR; Payne, ME; MacFall, JR; Steffens, DC; Speer, MC; Krishnan, KR
MLA Citation
Taylor, WD, Züchner, S, McQuoid, DR, Payne, ME, MacFall, JR, Steffens, DC, Speer, MC, and Krishnan, KR. "The brain-derived neurotrophic factor VAL66MET polymorphism and cerebral white matter hyperintensities in late-life depression." Am J Geriatr Psychiatry 16.4 (April 2008): 263-271.
PMID
18263664
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
16
Issue
4
Publish Date
2008
Start Page
263
End Page
271
DOI
10.1097/JGP.0b013e3181591c30

Hippocampus shape analysis and late-life depression.

Major depression in the elderly is associated with brain structural changes and vascular lesions. Changes in the subcortical regions of the limbic system have also been noted. Studies examining hippocampus volumetric differences in depression have shown variable results, possibly due to any volume differences being secondary to local shape changes rather than differences in the overall volume. Shape analysis offers the potential to detect such changes. The present study applied spherical harmonic (SPHARM) shape analysis to the left and right hippocampi of 61 elderly subjects with major depression and 43 non-depressed elderly subjects. Statistical models controlling for age, sex, and total cerebral volume showed a significant reduction in depressed compared with control subjects in the left hippocampus (F(1,103) = 5.26; p = 0.0240) but not right hippocampus volume (F(1,103) = 0.41; p = 0.5213). Shape analysis showed significant differences in the mid-body of the left (but not the right) hippocampus between depressed and controls. When the depressed group was dichotomized into those whose depression was remitted at time of imaging and those who were unremitted, the shape comparison showed remitted subjects to be indistinguishable from controls (both sides) while the unremitted subjects differed in the midbody and the lateral side near the head. Hippocampal volume showed no difference between controls and remitted subjects but nonremitted subjects had significantly smaller left hippocampal volumes with no significant group differences in the right hippocampus. These findings may provide support to other reports of neurogenic effects of antidepressants and their relation to successful treatment for depressive symptoms.

Authors
Zhao, Z; Taylor, WD; Styner, M; Steffens, DC; Krishnan, KR; MacFall, JR
MLA Citation
Zhao, Z, Taylor, WD, Styner, M, Steffens, DC, Krishnan, KR, and MacFall, JR. "Hippocampus shape analysis and late-life depression. (Published online)" PLoS One 3.3 (March 19, 2008): e1837-.
Website
http://hdl.handle.net/10161/4485
PMID
18350172
Source
pubmed
Published In
PloS one
Volume
3
Issue
3
Publish Date
2008
Start Page
e1837
DOI
10.1371/journal.pone.0001837

Diffusion tensor measures of the corpus callosum in adolescents with adolescent onset alcohol use disorders.

BACKGROUND: In adults, myelination injury is associated with alcoholism. Maturation of the corpus callosum is prominent during adolescence. We hypothesized that subjects with adolescent-onset alcohol use disorders (AUD; defined as Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence or abuse) would have myelination microstructural differences compared to controls. METHODS: Adolescent subjects (25 males, 7 females) with an AUD (16.9 +/- 1.2 years), who were recruited from substance abuse treatment programs and had co-morbid mental disorders, and 28 sociodemographically similar healthy controls (17 males, 11 females; 15.9 +/- 1.1 years) underwent a 3.0 T MRI diffusion tensor imaging scan. RESULTS: Measures of rostral body fractional anisotropy (FA) were higher in the AUD group than in the control group. Compared to controls, mean diffusivity (MD) was lower, while FA was higher, in the AUD group in the isthmus region. Anterior corpus callosum microstructural development differed in adolescents with AUD, as age was positively (not negatively) associated with rostrum MD and age was negatively (not positively) associated with rostrum FA. There were sex by group interactions in that control females had higher posterior midbody FA when compared to female adolescents with AUD. CONCLUSIONS: Lower MD and higher FA values in the AUD group suggest pre-morbid vulnerability for accelerated prefrontal and temporo-parietal myelin maturation that may enhance the risk for adolescent AUD. Significant (and opposite to developmentally expected) correlations were seen between anterior corpus callosum MD and FA measures and age in the AUD group, suggesting neurotoxic effects of alcohol on adolescent corpus callosum microstructure. As seen in adults, female adolescents with AUD may be especially vulnerable to corpus callosum microstructural injury. Further diffusion tensor imaging studies of corpus callosum maturation in children at familial risk for alcoholism, and in those with AUD, need to be done to elucidate these mechanisms.

Authors
De Bellis, MD; Van Voorhees, E; Hooper, SR; Gibler, N; Nelson, L; Hege, SG; Payne, ME; MacFall, J
MLA Citation
De Bellis, MD, Van Voorhees, E, Hooper, SR, Gibler, N, Nelson, L, Hege, SG, Payne, ME, and MacFall, J. "Diffusion tensor measures of the corpus callosum in adolescents with adolescent onset alcohol use disorders." Alcohol Clin Exp Res 32.3 (March 2008): 395-404.
PMID
18241319
Source
pubmed
Published In
Alcoholism: Clinical and Experimental Research
Volume
32
Issue
3
Publish Date
2008
Start Page
395
End Page
404
DOI
10.1111/j.1530-0277.2007.00603.x

Aging, gender, and the elderly adult brain: an examination of analytical strategies.

We sought to examine the relations between age, gender and brain volumes in an elderly population; we also sought to examine ways of measuring these relations. Three sets of analyses were used: correlational analyses, in which correlations between independent variables and brain volumes were calculated without correction for intracranial volume (ICV); covariational analyses, in which ICV was used as a covariate in regression equations; and ratio analyses, in which the dependent variable was the ratio of brain volume to ICV. These analyses yielded similar results, except that (as expected) adjusting for ICV altered estimates of gender differences. Analyses of age showed decreases in left caudate, putamen, and right hippocampus and an increase in CSF, a result generally in accord with previous findings. However, we also found a significant decrease of white-matter volumes and no significant decrease in total gray-matter volumes. Correlational analyses showed that men did not always have larger volumes despite their larger head size; women generally had larger volumes after adjusting for ICV. We found no age-gender interactions.

Authors
Greenberg, DL; Messer, DF; Payne, ME; Macfall, JR; Provenzale, JM; Steffens, DC; Krishnan, RR
MLA Citation
Greenberg, DL, Messer, DF, Payne, ME, Macfall, JR, Provenzale, JM, Steffens, DC, and Krishnan, RR. "Aging, gender, and the elderly adult brain: an examination of analytical strategies." Neurobiol Aging 29.2 (February 2008): 290-302.
PMID
17049410
Source
pubmed
Published In
Neurobiology of Aging
Volume
29
Issue
2
Publish Date
2008
Start Page
290
End Page
302
DOI
10.1016/j.neurobiolaging.2006.09.016

Orbitofrontal cortex volume in late life depression: influence of hyperintense lesions and genetic polymorphisms.

BACKGROUND: Orbitofrontal cortex (OFC) volumetric differences have been reported in depression, but in relatively small samples. Factors associated with these differences are not well described. We examined OFC volumes in a large sample of elderly depressed and non-depressed subjects, exploring the relationship between OFC volume, 5HTTLPR genotype, apolipoprotein E (APOE) genotype and hyperintense lesion volume. We hypothesized that smaller OFC volume would be associated with depression, greater hyperintense lesion volume and severity, and APOE epsilon4 or 5HTTLPR short allele carriers. METHOD: A total of 226 depressed and 144 non-depressed older subjects completed 1.5 T magnetic resonance imaging (MRI) and genotyping. OFC volumes and lesion volumes were measured using standardized methods. Lesion severity was additionally rated using the Coffey rating scale. Differences between groups were compared while controlling for age, sex and total cerebral volume; separate models added lesion measures and genetic polymorphisms. RESULTS: Depressed subjects exhibited smaller OFC volumes. There was a trend for a negative association between white-matter lesion volume and OFC volume; however, rated white-matter lesion severity was significantly negatively associated with OFC volume. There was no association between gray-matter lesion measures or 5HTTLPR genotype and OFC volume. Contrary to our hypothesis, subjects who were APOE epsilon4 allele positive exhibited larger OFC volumes; in secondary analyses, this finding was limited to the non-depressed group. CONCLUSIONS: Reduced OFC volumes are seen in depression and associated with greater severity of white-matter lesions. Healthy subjects who are APOE epsilon4 allele positive exhibited larger OFC volumes. This finding should be examined in other populations.

Authors
Taylor, WD; Macfall, JR; Payne, ME; McQuoid, DR; Steffens, DC; Provenzale, JM; Krishnan, KR
MLA Citation
Taylor, WD, Macfall, JR, Payne, ME, McQuoid, DR, Steffens, DC, Provenzale, JM, and Krishnan, KR. "Orbitofrontal cortex volume in late life depression: influence of hyperintense lesions and genetic polymorphisms." Psychol Med 37.12 (December 2007): 1763-1773.
PMID
17335636
Source
pubmed
Published In
Psychological Medicine
Volume
37
Issue
12
Publish Date
2007
Start Page
1763
End Page
1773
DOI
10.1017/S0033291707000128

Predicting memory decline in normal elderly: genetics, MRI, and cognitive reserve.

Major predictors of Alzheimer's disease (AD) include apolipoprotein E (APOE)-epsilon4, hippocampal atrophy on magnetic resonance imaging (MRI), and memory dysfunction prior to diagnosis. We examined 159 normal elderly subjects with MRI and the California Verbal Learning Test (CVLT); 84 returned for longitudinal follow-up 5 years later. Analyses at baseline revealed significant variance in hippocampal volume accounted for by cerebral volume and age but not by APOE isoform. However, interactions involving APOE isoform and laterality were observed. As hypothesized, an APOE x time interaction was revealed for CVLT long-delay free recall: APOE-epsilon3/4 subjects had significantly poorer performance than APOE-epsilon3/3 subjects at follow-up. Forward stepwise multiple regression analysis predicting follow-up long-delay free recall selected baseline recall, followed by number of APOE-epsilon4 alleles, followed by left-hippocampal volume. Age and sex did not enter into the model. We conclude that APOE-epsilon4 predicts longitudinal memory decline in healthy controls and that MRI morphometry of hippocampus adds slightly to predictive value.

Authors
Tupler, LA; Krishnan, KR; Greenberg, DL; Marcovina, SM; Payne, ME; MacFall, JR; Charles, HC; Doraiswamy, PM
MLA Citation
Tupler, LA, Krishnan, KR, Greenberg, DL, Marcovina, SM, Payne, ME, MacFall, JR, Charles, HC, and Doraiswamy, PM. "Predicting memory decline in normal elderly: genetics, MRI, and cognitive reserve." Neurobiol Aging 28.11 (November 2007): 1644-1656.
PMID
16916565
Source
pubmed
Published In
Neurobiology of Aging
Volume
28
Issue
11
Publish Date
2007
Start Page
1644
End Page
1656
DOI
10.1016/j.neurobiolaging.2006.07.001

From the RSNA refresher courses: MR imaging in hyperthermia.

There is growing clinical evidence that the combination of radiation therapy and hyperthermia, when delivered at moderate temperatures (40 degrees-45 degrees C) for sustained times (30-90 minutes), is of benefit with regard to palliative relief of cancer, tumor response, local control, and survival. Adequate measurement of the temperature distribution achieved with the hyperthermia is a key element in successful therapy. Thermal dosimetry, even invasive dosimetry, is a complex topic when applied to the heterogeneous tissue of a tumor and associated organ systems. Imaging in hyperthermia therapy is performed primarily for estimation and control of temperature. Magnetic resonance (MR) imaging has unique parameter dependences that make it possible to monitor hyperthermia therapy by detection of proton resonant frequency changes or diffusion coefficient changes. In addition, MR imaging can be used to assess vascular parameters that not only allow selection of suitable patients for therapy but may also allow demonstration of response to therapy. Finally, as the use of thermally sensitive liposomes for delivery of chemotherapeutic agents is developed, MR imaging may allow determination of local drug dose.

Authors
MacFall, JR; Soher, BJ
MLA Citation
MacFall, JR, and Soher, BJ. "From the RSNA refresher courses: MR imaging in hyperthermia." Radiographics 27.6 (November 2007): 1809-1818. (Review)
PMID
18025519
Source
pubmed
Published In
Radiographics : a review publication of the Radiological Society of North America, Inc
Volume
27
Issue
6
Publish Date
2007
Start Page
1809
End Page
1818
DOI
10.1148/rg.276075097

Longitudinal magnetic resonance imaging vascular changes, apolipoprotein E genotype, and development of dementia in the neurocognitive outcomes of depression in the elderly study.

OBJECTIVE: Several studies suggest that depression is a risk factor for development of dementia in the elderly. In a study of older depressed individuals, the authors examined both neuroimaging and genetic factors in development of dementia. The authors hypothesized that change in subcortical gray matter and white matter hyperintensity volumes would be associated with development of dementia, as would presence of an apolipoprotein E (APOE) epsilon 4 allele. METHODS: The sample consisted of 161 older depressed subjects without dementia who had magnetic resonance imaging scans at baseline and at two years. Blood samples were also taken to determine APOE genotype. All participants were treated with antidepressants using a guideline-based treatment algorithm. Their cognitive status was evaluated annually. A consensus panel of experts evaluated each case to determine cognitive status and assign a diagnosis. RESULTS: Twenty subjects became demented over the follow-up period (5.4 years on average). Change in white matter hyperintensity volume was significantly associated with development of dementia, especially among non-Alzheimer dementias. There was a trend for change in subcortical gray matter hyperintensity volume to be associated with incident dementia. APOE genotype was not associated with onset of dementia. CONCLUSION: Worsening cerebrovascular disease in older depressed adults is associated with cognitive decline and dementia, particularly of the non-Alzheimer disease type. The association of change in white matter lesion volume and incident dementia among depressed elders extends the vascular depression hypothesis of geriatric depression to include cognitive outcomes of depression in the elderly.

Authors
Steffens, DC; Potter, GG; McQuoid, DR; MacFall, JR; Payne, ME; Burke, JR; Plassman, BL; Welsh-Bohmer, KA
MLA Citation
Steffens, DC, Potter, GG, McQuoid, DR, MacFall, JR, Payne, ME, Burke, JR, Plassman, BL, and Welsh-Bohmer, KA. "Longitudinal magnetic resonance imaging vascular changes, apolipoprotein E genotype, and development of dementia in the neurocognitive outcomes of depression in the elderly study." Am J Geriatr Psychiatry 15.10 (October 2007): 839-849.
PMID
17623814
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
15
Issue
10
Publish Date
2007
Start Page
839
End Page
849
DOI
10.1097/JGP.0b013e318048a1a0

The COMT Val158Met polymorphism and temporal lobe morphometry in healthy adults.

We examined the relationship between COMT Val158Met genotype and temporal lobe volumes, including the caudate as a control region. Thirty-one healthy subjects completed 1.5T brain MRI and genotyping. After controlling for demographics, Val158 allele homozygotes exhibited significantly smaller temporal lobe and hippocampal volumes, with a trend for smaller amygdala volumes.

Authors
Taylor, WD; Züchner, S; Payne, ME; Messer, DF; Doty, TJ; MacFall, JR; Beyer, JL; Krishnan, KR
MLA Citation
Taylor, WD, Züchner, S, Payne, ME, Messer, DF, Doty, TJ, MacFall, JR, Beyer, JL, and Krishnan, KR. "The COMT Val158Met polymorphism and temporal lobe morphometry in healthy adults." Psychiatry Res 155.2 (July 15, 2007): 173-177.
PMID
17521892
Source
pubmed
Published In
Psychiatry Research
Volume
155
Issue
2
Publish Date
2007
Start Page
173
End Page
177
DOI
10.1016/j.pscychresns.2007.01.005

Widespread effects of hyperintense lesions on cerebral white matter structure.

OBJECTIVE: Hyperintense lesions are a common finding on neuroimaging and are associated not only with aging, medical illness, and some invasive medical procedures, but also with neurologic and psychiatric morbidity. We hypothesized that hyperintense lesions are associated with alterations in white matter structure beyond the visible lesion boundaries as assessed with diffusion tensor imaging (DTI). SUBJECTS AND METHODS: Eighty-two neurologically intact older individuals completed brain MRI with DTI. DTI scans were analyzed using regions of interest placed in normal-appearing white matter to measure fractional anisotropy and diffusivity in the white matter of the frontal lobe, the genu of the corpus callosum, and the internal capsule. Hyperintense lesions volumes were measured separately in subcortical gray matter and anterior white matter through a semiautomated segmentation program. The relationship between lesion volumes and DTI measures was examined while controlling for patient age, patient sex, and total cerebral volume. RESULTS: Greater anterior white matter lesion volumes were associated with higher diffusivity and lower anisotropy in the white matter of the dorsolateral prefrontal cortex and with higher diffusivity of the internal capsule and white matter lateral to the anterior cingulate cortex. Gray matter lesion volumes were associated with higher diffusivity in the genu of the corpus callosum and the internal capsule. CONCLUSION: Ischemic hyperintense lesions are associated with widespread effects on the structure of the frontal lobe white matter and central white matter structures. This may reflect effects of lesions on neural circuits or identification of white matter changes that have not yet become visible on conventional MRI.

Authors
Taylor, WD; Bae, JN; MacFall, JR; Payne, ME; Provenzale, JM; Steffens, DC; Krishnan, KR
MLA Citation
Taylor, WD, Bae, JN, MacFall, JR, Payne, ME, Provenzale, JM, Steffens, DC, and Krishnan, KR. "Widespread effects of hyperintense lesions on cerebral white matter structure." AJR Am J Roentgenol 188.6 (June 2007): 1695-1704.
PMID
17515396
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
188
Issue
6
Publish Date
2007
Start Page
1695
End Page
1704
DOI
10.2214/AJR.06.1163

Structural integrity of the uncinate fasciculus in geriatric depression: Relationship with age of onset.

BACKGROUND: The uncinate fasciculus connects limbic structures, such as the hippocampus and amygdala, with frontal regions. This study utilized diffusion tensor imaging to examine the structural integrity of the uncinate fasciculus in late-life depression. METHOD: 18 elderly depressed and 19 elderly nondepressed subjects were matched for age and sex; 8 subjects had mid- to late-onset of depression while 10 subjects had early-onset depression. 3T diffusion tensor imaging-based fiber tract mapping delineated the uncinate fasciculus in each hemisphere, which guided measurement of the fractional anisotropy of the uncinate fasciculus in the temporal stem. After controlling for age and sex, differences between diagnostic groups were assessed. RESULTS: After controlling for age and sex, individuals with early onset depression exhibited lower anisotropy of the left uncinate fasciculus than did mid- and late-onset or nondepressed subjects (F(2,36) = 4.50, p = 0.02). Analyses of the right uncinate fasciculus were not statistically significant. CONCLUSIONS: This provides preliminary evidence that there is a structural connectivity deficit between left frontal and limbic structures in early-onset depression. Further work is needed to determine if this is seen in younger depressed subjects, and if it influences treatment outcomes.

Authors
Taylor, WD; MacFall, JR; Gerig, G; Krishnan, RR
MLA Citation
Taylor, WD, MacFall, JR, Gerig, G, and Krishnan, RR. "Structural integrity of the uncinate fasciculus in geriatric depression: Relationship with age of onset." Neuropsychiatr Dis Treat 3.5 (2007): 669-674.
PMID
19300596
Source
pubmed
Published In
Neuropsychiatric disease and treatment
Volume
3
Issue
5
Publish Date
2007
Start Page
669
End Page
674

Dorsolateral prefrontal cortex and anterior cingulate cortex white matter alterations in late-life depression.

BACKGROUND: The dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) are critical for mood regulation. Alterations in the white matter connections of these regions may impair their role in mood regulation and increase the risk of developing depression. This study used diffusion tensor imaging to examine for white matter microstructural abnormalities of these regions and of central white matter structures in late-life depression. METHODS: One hundred six elderly depressed subjects and eighty-four elderly nondepressed subjects underwent clinical assessment and diffusion tensor imaging. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in regions of interest placed in the white matter of the DLPFC, ACC, corpus callosum, and internal capsule. Differences between groups were assessed, controlling for age, sex, and total cerebral volume. RESULTS: After controlling for covariates, depressed subjects had significantly lower FA values in white matter of the right ACC, bilateral superior frontal gyri, and left middle frontal gyrus. There were no significant differences in ADC values. CONCLUSIONS: Lower FA, representing lower tissue organization, is observed in depressed elders in the DLPFC and right ACC. These findings support the hypothesis that altered connectivity between brain regions contributes to the risk of depression.

Authors
Bae, JN; MacFall, JR; Krishnan, KR; Payne, ME; Steffens, DC; Taylor, WD
MLA Citation
Bae, JN, MacFall, JR, Krishnan, KR, Payne, ME, Steffens, DC, and Taylor, WD. "Dorsolateral prefrontal cortex and anterior cingulate cortex white matter alterations in late-life depression." Biol Psychiatry 60.12 (December 15, 2006): 1356-1363.
PMID
16876144
Source
pubmed
Published In
Biological Psychiatry
Volume
60
Issue
12
Publish Date
2006
Start Page
1356
End Page
1363
DOI
10.1016/j.biopsych.2006.03.052

White matter lesion volumes and caudate volumes in late-life depression.

BACKGROUND: Decreased caudate volumes and increased white matter lesions (WMLs) are associated both with aging and late-life depression, but the relationship between the two is unclear. We examined the association between WML and caudate volume, hypothesizing there would be a negative association, which would be stronger for WMLs located in anterior regions. We additionally hypothesized that this association would be stronger in depressed subjects. METHOD: This MRI study included 182 elderly depressed and 64 elderly control subjects. Our imaging analysis procedures divided the brain into anterior and posterior halves. WML volume in each half was calculated, as were left and right caudate volumes. A statistical model incorporating WML volumes, age, total brain volume, diagnosis, and gender was used to examine caudate volumes. RESULTS: WML volume was negatively associated with total and right caudate volume. This association was stronger for WMLs in the anterior half of the brain. Anterior WML volume was additionally negatively associated with right caudate volume in depressed subjects, but not in controls. CONCLUSIONS: Using unadjusted levels of significance, WML volume is negatively associated with right caudate volume in both older populations, but with left caudate volume only in depressed individuals. When statistical corrections for multiple comparisons are used, the finding is limited to a negative association between WML volume and right caudate volume, primarily in depressed subjects. This study demonstrates one mechanism by which WMLs may disrupt frontostriatal circuits.

Authors
Hannestad, J; Taylor, WD; McQuoid, DR; Payne, ME; Krishnan, KR; Steffens, DC; Macfall, JR
MLA Citation
Hannestad, J, Taylor, WD, McQuoid, DR, Payne, ME, Krishnan, KR, Steffens, DC, and Macfall, JR. "White matter lesion volumes and caudate volumes in late-life depression." Int J Geriatr Psychiatry 21.12 (December 2006): 1193-1198.
PMID
16955447
Source
pubmed
Published In
International Journal of Geriatric Psychiatry
Volume
21
Issue
12
Publish Date
2006
Start Page
1193
End Page
1198
DOI
10.1002/gps.1640

Chemodosimetry of in vivo tumor liposomal drug concentration using MRI.

Effective cancer chemotherapy depends on the delivery of therapeutic drugs to cancer cells at cytotoxic concentrations. However, physiologic barriers, such as variable vessel permeability, high interstitial fluid pressure, and heterogeneous perfusion, make it difficult to achieve that goal. Efforts to improve drug delivery have been limited by the lack of noninvasive tools to evaluate intratumoral drug concentration and distribution. Here we demonstrate that tumor drug concentration can be measured in vivo using T(1)-weighted MRI, following systemic administration of liposomes containing both drug (doxorubicin (DOX)) and contrast agent (manganese (Mn)). Mn and DOX concentrations were calculated using T(1) relaxation times and Mn:DOX loading ratios, as previously described. Two independent validations by high-performance liquid chromatography (HPLC) and histologic fluorescence in a rat fibrosarcoma (FSA) model indicate a concordant linear relationship between DOX concentrations determined using T(1) and those measured invasively. This method of imaging exhibits potential for real-time evaluation of chemotherapeutic protocols and prediction of tumor response on an individual patient basis.

Authors
Viglianti, BL; Ponce, AM; Michelich, CR; Yu, D; Abraham, SA; Sanders, L; Yarmolenko, PS; Schroeder, T; MacFall, JR; Barboriak, DP; Colvin, OM; Bally, MB; Dewhirst, MW
MLA Citation
Viglianti, BL, Ponce, AM, Michelich, CR, Yu, D, Abraham, SA, Sanders, L, Yarmolenko, PS, Schroeder, T, MacFall, JR, Barboriak, DP, Colvin, OM, Bally, MB, and Dewhirst, MW. "Chemodosimetry of in vivo tumor liposomal drug concentration using MRI." Magn Reson Med 56.5 (November 2006): 1011-1018.
PMID
17029236
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
56
Issue
5
Publish Date
2006
Start Page
1011
End Page
1018
DOI
10.1002/mrm.21032

Differences in brain volumes among males and female hormone-therapy users and nonusers.

Numerous studies have shown gender differences in the brain volumes of elderly adults. Some evidence shows that higher estrogen levels may be neuroprotective, suggesting that hormone therapy (HT) may in part be responsible for these gender differences; however, few studies have examined the relation between HT and brain volumes. Brain volumes of caudate, putamen, hippocampus, gray matter, white matter, white-matter lesions, and cerebrospinal fluid were measured on magnetic resonance imaging scans. A comprehensive neuropsychological battery was administered. Women were separated into two groups based on HT use, and we used multiple regression analyses to compare these groups with one another and with men. Results of brain-volume measurements showed that HT users had significantly less gray matter and more cerebrospinal fluid than nonusers. Results of the neuropsychological testing showed that HT users performed better on the Shipley Vocabulary Test than males did.

Authors
Greenberg, DL; Payne, ME; MacFall, JR; Provenzale, JM; Steffens, DC; Krishnan, RR
MLA Citation
Greenberg, DL, Payne, ME, MacFall, JR, Provenzale, JM, Steffens, DC, and Krishnan, RR. "Differences in brain volumes among males and female hormone-therapy users and nonusers." Psychiatry Res 147.2-3 (October 30, 2006): 127-134.
PMID
16935478
Source
pubmed
Published In
Psychiatry Research
Volume
147
Issue
2-3
Publish Date
2006
Start Page
127
End Page
134
DOI
10.1016/j.pscychresns.2006.01.001

Dependence of gradient-echo and spin-echo BOLD fMRI at 4 T on diffusion weighting.

Diffusion weighting and spin-echo (SE) acquisitions can be used to help improve the spatial localization of BOLD fMRI at the cost of reduced acquisition rates and lower signal-to-noise ratio (SNR). To evaluate these costs, SE and gradient-echo (GE) data were acquired at 4 T at five diffusion weightings ranging from b = 0 to 1110 s/mm(2) using a robust visual stimulus. The data showed reduced functional contrast when diffusion weighting was applied. As the amount of diffusion weighting increased, the functional contrast initially dropped sharply, and then remained relatively constant for diffusion weightings above 15 s/mm(2) for SE and 30 s/mm(2) for GE data. GE functional BOLD contrast was attenuated to 94.0 +/- 10.1, 87.6 +/- 12.2, 86.4 +/- 8.8 and 83.3 +/- 20.6% of the non-diffusion-weighted GE contrast for diffusion weightings of 15, 30, 200 and 1,110 s/mm(2). The non-diffusion-weighted SE contrast greatly reduced to 19.3 +/- 3.3% of the non-diffusion-weighted GE contrast, demonstrating the large activation attenuation of a SE acquisition. The SE contrast was further reduced to 10.0 +/- 3.6, 9.0 +/- 2.5 and 8.6 +/- 2.0% of the non-diffusion-weighted GE contrast for the 15, 30 and 200 s/mm(2) diffusion-weighted data. These results suggest that only a small amount of diffusion weighting is necessary to suppress the vascular contribution and spin-echo imaging should only be used if there is adequate statistical power available or accurate localization is critical.

Authors
Michelich, CR; Song, AW; Macfall, JR
MLA Citation
Michelich, CR, Song, AW, and Macfall, JR. "Dependence of gradient-echo and spin-echo BOLD fMRI at 4 T on diffusion weighting." NMR Biomed 19.5 (August 2006): 566-572.
PMID
16598695
Source
pubmed
Published In
Nmr in Biomedicine
Volume
19
Issue
5
Publish Date
2006
Start Page
566
End Page
572
DOI
10.1002/nbm.1035

Lobar distribution of lesion volumes in late-life depression: the Biomedical Informatics Research Network (BIRN).

White matter hyperintense lesions on T2-weighted images are associated with late-life depression. Little work has been carried out examining differences in lesion location between elderly individuals with and without depression. In contrast to previous studies examining total brain white matter lesion volume, this study examined lobar differences in white matter lesion volumes derived from brain magnetic resonance imaging. This study examined 49 subjects with a DSM-IV diagnosis of major depression and 50 comparison subjects without depression. All participants were age 60 years or older. White matter lesion volumes were measured in each hemisphere using a semiautomated segmentation process and localized to lobar regions using a lobar atlas created for this sample using the imaging tools provided by the Biomedical Informatics Research Network (BIRN). The lobar lesion volumes were compared against depression status. After controlling for age and hypertension, subjects with depression exhibited significantly greater total white matter lesion volume in both hemispheres and in both frontal lobes than did control subjects. Although a similar trend was observed in the parietal lobes, the difference did not reach a level of statistical significance. Models of the temporal and occipital lobes were not statistically significant. Older individuals with depression have greater white matter disease than healthy controls, predominantly in the frontal lobes. These changes are thought to disrupt neural circuits involved in mood regulation, thus increasing the risk of developing depression.

Authors
MacFall, JR; Taylor, WD; Rex, DE; Pieper, S; Payne, ME; McQuoid, DR; Steffens, DC; Kikinis, R; Toga, AW; Krishnan, KR
MLA Citation
MacFall, JR, Taylor, WD, Rex, DE, Pieper, S, Payne, ME, McQuoid, DR, Steffens, DC, Kikinis, R, Toga, AW, and Krishnan, KR. "Lobar distribution of lesion volumes in late-life depression: the Biomedical Informatics Research Network (BIRN)." Neuropsychopharmacology 31.7 (July 2006): 1500-1507.
PMID
16341022
Source
pubmed
Published In
Neuropsychopharmacology (Nature)
Volume
31
Issue
7
Publish Date
2006
Start Page
1500
End Page
1507
DOI
10.1038/sj.npp.1300986

Reliability in multi-site structural MRI studies: Effects of gradient non-linearity correction on phantom and human data

Longitudinal and multi-site clinical studies create the imperative to characterize and correct technological sources of variance that limit image reproducibility in high-resolution structural MRI studies, thus facilitating precise, quantitative, platform-independent, multi-site evaluation. In this work, we investigated the effects that imaging gradient non-linearity have on reproducibility of multi-site human MRI. We applied an image distortion correction method based on spherical harmonics description of the gradients and verified the accuracy of the method using phantom data. The correction method was then applied to the brain image data from a group of subjects scanned twice at multiple sites having different 1.5 T platforms. Within-site and across-site variability of the image data was assessed by evaluating voxel-based image intensity reproducibility. The image intensity reproducibility of the human brain data was significantly improved with distortion correction, suggesting that this method may offer improved reproducibility in morphometry studies. We provide the source code for the gradient distortion algorithm together with the phantom data. © 2005 Elsevier Inc. All rights reserved.

Authors
Jovicich, J; Czanner, S; Greve, D; Haley, E; Kouwe, AVD; Gollub, R; Kennedy, D; Schmitt, F; Brown, G; MacFall, J; Fischl, B; Dale, A
MLA Citation
Jovicich, J, Czanner, S, Greve, D, Haley, E, Kouwe, AVD, Gollub, R, Kennedy, D, Schmitt, F, Brown, G, MacFall, J, Fischl, B, and Dale, A. "Reliability in multi-site structural MRI studies: Effects of gradient non-linearity correction on phantom and human data." NeuroImage 30.2 (2006): 436-443.
PMID
16300968
Source
scival
Published In
NeuroImage
Volume
30
Issue
2
Publish Date
2006
Start Page
436
End Page
443
DOI
10.1016/j.neuroimage.2005.09.046

Focal and diffuse T2-weighted hyperintensities in neurofibromatosis type 1 (NF1)

Authors
Greenwood, RS; McPhail, E; Eastwood, JD; Kealey, SM; MacFall, JR; Tupler, LA; Harp, AG; Buu, A; Ranga, K
MLA Citation
Greenwood, RS, McPhail, E, Eastwood, JD, Kealey, SM, MacFall, JR, Tupler, LA, Harp, AG, Buu, A, and Ranga, K. "Focal and diffuse T2-weighted hyperintensities in neurofibromatosis type 1 (NF1)." 2006.
Source
wos-lite
Published In
Annals of Neurology
Volume
60
Publish Date
2006
Start Page
S155
End Page
S156

Brain morphometry, T2-weighted hyperintensities, and IQ in children with neurofibromatosis type 1.

BACKGROUND: Larger gray matter (GM) volume in healthy children is correlated with higher IQ. Children with neurofibromatosis type 1 (NF1) have larger brains, their magnetic resonance images frequently show T2-weighted hyperintensities, and their IQs are lower. OBJECTIVES: To confirm the hypotheses that (1) children with NF1 have larger GM and white matter volumes, (2) the greatest volume differences are in the frontal and parietal regions and in children with NF1 with hyperintensities, and (3) GM volume is inversely related to IQ in children with NF1. DESIGN: Wechsler Intelligence Scale for Children-Third Edition IQ testing and measurement of cerebral volumes and hyperintensities in brain magnetic resonance images were performed on 36 children with NF1 and on 36 matched relatives who served as control subjects. RESULTS: Gray matter and white matter volumes were significantly larger in children with NF1. The greatest difference was observed in cerebral white matter volume, predominantly in the frontal lobes, whereas the greatest difference in GM volume was in the temporal, parietal, and occipital regions. In controls, IQ was significantly related to GM volume, but in children with NF1, IQ was not inversely associated with GM volume, although IQs of children with NF1 were significantly lower. CONCLUSIONS: Children with NF1 do not have the normal relationship between GM volume and IQ. Larger GM volume in the posterior brain regions and larger white matter volumes in the frontal brain regions contribute to the larger brain volume in children with NF1.

Authors
Greenwood, RS; Tupler, LA; Whitt, JK; Buu, A; Dombeck, CB; Harp, AG; Payne, ME; Eastwood, JD; Krishnan, KR; MacFall, JR
MLA Citation
Greenwood, RS, Tupler, LA, Whitt, JK, Buu, A, Dombeck, CB, Harp, AG, Payne, ME, Eastwood, JD, Krishnan, KR, and MacFall, JR. "Brain morphometry, T2-weighted hyperintensities, and IQ in children with neurofibromatosis type 1." Arch Neurol 62.12 (December 2005): 1904-1908.
PMID
16344348
Source
pubmed
Published In
Archives of Neurology
Volume
62
Issue
12
Publish Date
2005
Start Page
1904
End Page
1908
DOI
10.1001/archneur.62.12.1904

Cortical white matter microstructural abnormalities in bipolar disorder.

This article reports on preliminary findings describing microstructural abnormalities in the white matter of cortical areas thought to be associated with bipolar disorder. In all, 14 patients with bipolar disorder and 21 nonpsychiatrically ill control subjects underwent MR imaging including a diffusion tensor imaging (DTI) pulse sequence (six directions, b=1000 mm(2)/s). DTI data were analyzed on a workstation using a program that allowed calculation of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) within the following three white matter fiber tracts bilaterally: the orbital frontal cortex, and the superior and middle frontal gyri. These values were compared across patient groups. The left and right orbital frontal white matter exhibited significantly higher ADC values in bipolar subjects than control subjects on both the left (p=0.028) and right (p=0.011). Microstructural changes in the white matter of the orbital frontal areas as reflected by increased ADC values appear to be associated with bipolar disorder. Further research is needed to better understand the interaction of microstructural changes and bipolar symptoms and whether these changes are specific to bipolar disorder.

Authors
Beyer, JL; Taylor, WD; MacFall, JR; Kuchibhatla, M; Payne, ME; Provenzale, JM; Cassidy, F; Krishnan, KR
MLA Citation
Beyer, JL, Taylor, WD, MacFall, JR, Kuchibhatla, M, Payne, ME, Provenzale, JM, Cassidy, F, and Krishnan, KR. "Cortical white matter microstructural abnormalities in bipolar disorder." Neuropsychopharmacology 30.12 (December 2005): 2225-2229.
PMID
15988474
Source
pubmed
Published In
Neuropsychopharmacology (Nature)
Volume
30
Issue
12
Publish Date
2005
Start Page
2225
End Page
2229
DOI
10.1038/sj.npp.1300802

Improved magnetic resonance thermal imaging by combining proton resonance frequency shift (PRFS) and apparent diffusion coefficient (ADC) data.

Effective thermal therapy for cancer is dependent on adequate tumor heating. Adequate heating, in turn, is dependent on reliable volumetric measurement of temperature to guide heating. Proton resonance frequency shift (PRFS) magnetic resonance imaging is frequently used for the purpose of three-dimensional temperature imaging. However, this method is susceptible to drift in the imaging magnetic field, leading to a corresponding drift in the measured temperature. A new approach to correcting for this drift is presented. It combines PRFS imaging alternated with water apparent diffusion coefficient (ADC) imaging to yield resulting thermal images that are drift corrected and possess the complementary strengths of the two methods. The drift-corrected PRFS images retain the high resolution and relatively noise-free characteristic of PRFS imaging while adding on the drift-free stability of ADC imaging. This technique is successfully demonstrated in a phantom experiment. This technique is also applicable to correcting motion-induced sudden large discontinuities in PRFS imaging, although not explicitly demonstrated in this work.

Authors
Das, SK; Macfall, J; McCauley, R; Craciunescu, O; Dewhirst, MW; Samulski, TV
MLA Citation
Das, SK, Macfall, J, McCauley, R, Craciunescu, O, Dewhirst, MW, and Samulski, TV. "Improved magnetic resonance thermal imaging by combining proton resonance frequency shift (PRFS) and apparent diffusion coefficient (ADC) data." Int J Hyperthermia 21.7 (November 2005): 657-667.
PMID
16278169
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
21
Issue
7
Publish Date
2005
Start Page
657
End Page
667
DOI
10.1080/02656730500186346

Creation of DICOM--aware applications using ImageJ.

The demand for image-processing software for radiology applications has been increasing, fueled by advancements in both image-acquisition and image-analysis techniques. The utility of existing image-processing software is often limited by cost, lack of flexibility, and/or specific hardware requirements. In particular, many existing packages cannot directly utilize images formatted using the specifications in part 10 of the DICOM standard ("DICOM images"). We show how image analyses can be performed directly on DICOM images by using ImageJ, a free, Java-based image-processing package (http://rsb.info.nih.gov/ij/). We demonstrate how plug-ins written in our laboratory can be used along with the ImageJ macro script language to create flexible, low-cost, multiplatform image-processing applications that can be directed by information contained in the DICOM image header.

Authors
Barboriak, DP; Padua, AO; York, GE; Macfall, JR
MLA Citation
Barboriak, DP, Padua, AO, York, GE, and Macfall, JR. "Creation of DICOM--aware applications using ImageJ." J Digit Imaging 18.2 (June 2005): 91-99.
PMID
15827831
Source
pubmed
Published In
Journal of Digital Imaging
Volume
18
Issue
2
Publish Date
2005
Start Page
91
End Page
99
DOI
10.1007/s10278-004-1879-4

Greater MRI lesion volumes in elderly depressed subjects than in control subjects.

Hyperintense lesions in both white matter and gray matter on T2-weighted magnetic resonance imaging (MRI) are associated with late-life depression. This large study examined differences in gray and white matter lesion volumes on brain MRI between 253 elderly depressed and 146 control subjects. White matter and gray matter lesion volumes were measured in each hemisphere using a semi-automated segmentation process and compared against depression status. Depressed subjects exhibited significantly greater total white matter (mean 7.22 ml) and gray matter (mean 0.30 ml) lesion volumes in both hemispheres than did control subjects (mean 4.87 ml in white matter and 0.18 ml in gray matter). This difference remained statistically significant even after controlling for confounders such as age, sex, race and reports of hypertension, diabetes and heart disease. Patients with late-life depression have larger white matter lesion and gray matter lesion volumes than do control subjects. Future research should combine similar volumetric techniques with methods of identifying the location of lesions specific to late-life depression.

Authors
Taylor, WD; MacFall, JR; Payne, ME; McQuoid, DR; Steffens, DC; Provenzale, JM; Krishnan, RR
MLA Citation
Taylor, WD, MacFall, JR, Payne, ME, McQuoid, DR, Steffens, DC, Provenzale, JM, and Krishnan, RR. "Greater MRI lesion volumes in elderly depressed subjects than in control subjects." Psychiatry Res 139.1 (May 30, 2005): 1-7.
PMID
15927454
Source
pubmed
Published In
Psychiatry Research
Volume
139
Issue
1
Publish Date
2005
Start Page
1
End Page
7
DOI
10.1016/j.pscychresns.2004.08.004

Influence of serotonin transporter promoter region polymorphisms on hippocampal volumes in late-life depression.

CONTEXT: Polymorphisms in the promoter region of the serotonin transporter gene (5-HTTLPR) influence transcription and may play a role in the pathogenesis and course of depression. Recent research demonstrates that specific polymorphisms may be associated with differences in hippocampal volumes in subjects with depression. OBJECTIVE: To examine associations between 5-HTTLPR genotype and hippocampal volumes in elderly control subjects and elderly subjects classified as having early or late onset of depression. DESIGN: Cohort study examining baseline characteristics. PARTICIPANTS: Subjects were community dwelling and 60 years or older. Using a definition of early-onset depression as depression first occurring at 50 years or younger, we examined 72 subjects with early-onset depression, 63 subjects with late-onset depression, and 83 healthy control subjects. MAIN OUTCOME MEASURES: All subjects underwent genotyping for the 5-HTTLPR and underwent brain magnetic resonance imaging. Analyses of hippocampal volumes were controlled for total cerebral volume, age, and sex. RESULTS: The interaction between diagnosis and 5-HTTLPR genotype was statistically significant for the right hippocampus (P = .04). Subjects with late-onset depression who were homozygous for the long (L) allele (L /L genotype) had significantly smaller right hippocampal volumes than did L /L subjects with early-onset depression (P = .046) or L /L control subjects (P = .01). Post hoc analyses showed that later age of depression onset was associated with smaller hippocampal volumes in subjects with the L /L genotype, but earlier age of onset was associated with smaller hippocampal volumes in subjects who were homozygous for the short (S) allele (S/S genotype). CONCLUSIONS: Subjects with late-onset depression who were homozygous for the L allele exhibited smaller hippocampal volumes than other groups. Genotype also mediated the effect of age of onset on hippocampal volumes. Our findings differ from previous work; however, we examined an older and larger cohort of subjects than previous studies. Possible explanations for these findings include interactions between the serotonergic system and neurotrophic factors or cortisol response to stresses, each of which may affect hippocampal volumes.

Authors
Taylor, WD; Steffens, DC; Payne, ME; MacFall, JR; Marchuk, DA; Svenson, IK; Krishnan, KR
MLA Citation
Taylor, WD, Steffens, DC, Payne, ME, MacFall, JR, Marchuk, DA, Svenson, IK, and Krishnan, KR. "Influence of serotonin transporter promoter region polymorphisms on hippocampal volumes in late-life depression." Arch Gen Psychiatry 62.5 (May 2005): 537-544.
PMID
15867107
Source
pubmed
Published In
Archives of General Psychiatry
Volume
62
Issue
5
Publish Date
2005
Start Page
537
End Page
544
DOI
10.1001/archpsyc.62.5.537

Biological and social predictors of long-term geriatric depression outcome.

OBJECTIVE: In this study, we examined 204 older depressed individuals for up to 64 months to determine factors related to depression outcome. We hypothesized that both presence of vascular brain lesions seen on baseline magnetic resonance imaging (MRI) scans and lower baseline social support measures would be related to worse depression outcome. METHOD: At study entry, all subjects were at least 59 years old, had a diagnosis of major depression, and were free of other major psychiatric illness and primary neurological illness, including dementia and stroke. Depression was diagnosed via structured interview and clinical assessment by a geriatric psychiatrist who completed a Montgomery Asberg Depression Rating Scale (MADRS) to determine severity of depression. Subjects provided self-report data on social support variables and ability to perform basic and instrumental activities of daily living (ADL, IADL). All subjects agreed to have a baseline standardized MRI brain scan. Ratings of severity of hyperintensities were determined for the periventricular white matter, deep white matter, and subcortical gray matter by two readers who decided by consensus. Treatment was provided by geropsychiatrists following clinical guidelines. Using mixed models to analyze the data, we determined the effect of a variety of demographic, social and imaging variables on the trajectory of MADRS score, the outcome variable of interest. RESULTS: MADRS scores decreased steadily over time. In a final HLM model, in which time since entry, a baseline time indicator, age, gender, education and Mini-mental State Examination score were controlled, subjective social support, instrumental ADL impairment, subcortical gray matter severity, and the interactions of time with social network and with subcortical gray matter lesions remained significantly associated with MADRS score. CONCLUSIONS: Both social and biological factors at baseline are associated with longitudinal depression severity in geriatric depression.

Authors
Steffens, DC; Pieper, CF; Bosworth, HB; MacFall, JR; Provenzale, JM; Payne, ME; Carroll, BJ; George, LK; Krishnan, KR
MLA Citation
Steffens, DC, Pieper, CF, Bosworth, HB, MacFall, JR, Provenzale, JM, Payne, ME, Carroll, BJ, George, LK, and Krishnan, KR. "Biological and social predictors of long-term geriatric depression outcome." Int Psychogeriatr 17.1 (March 2005): 41-56.
PMID
15948303
Source
pubmed
Published In
International psychogeriatrics / IPA
Volume
17
Issue
1
Publish Date
2005
Start Page
41
End Page
56

Characterizing tumor changes during neoadjuvant treatment of locally advanced breast cancer patients (LABC) using dynamicenhanced magnetic resonance imaging (DE-MRI)

At Duke University Medical Center, selective LABC patients were treated on a protocol using neoadjuvant Myocet/Paclitaxel (ChT) and HT. With the purpose of generating perfusion/permeability parametric maps and to use gadolinium (Gd) enhancement curves to score and predict response to neoadjuvant treatment, a study was designed to acquire 3 sets of DE-MRI images along the 4 cycles of combined ChT and HT. A T1-weighted three-dimensional fast gradient echo technique was used over 30 minutes following bolus injection of Gd-based contrast agent. Perfusion/permeability maps were generated by fitting the signal intensity to a double exponential curve that generates washin (WiP) and washout (WoP), parameters that are associated with the tumors vascularity/permeability and cellularity. Based on the values of the WiP, the tumors were divided in lowWI (WiP < 100), mediumWI (100<WiP<200) and highWI (WiP > 200). During the HT treatments temperatures in the breast were measured invasively via a catheter inserted under CT guidance. Although minimum sampled temperatures give a crude indication of the temperature distribution, several thermal dose metrics were calculated for each of the HT fractions (e.g. T90, T50, T10). As expected, tumors that were more vascularized (i.e. higher WiP) heated less than tumors with low WiP, a degree on average. The adjuvant treatment also changed the shape and inhomogeneity of the perfusion/permeability maps, with dramatic changes after the first fraction in responders. The correlation between the thermal metrics and pathological response will be discussed, as well as possible correlation with other tumor physiology parameters. In conclusion, the Gd-enhancement analysis of DE-MRI images is able to generate information related to the tumor vascularity, permeability and cellularity that can correlate with the tumor's response to the neoadjuvant treatment in general, and to HT in particular. Work supported by a grant from the NCI CA42745.

Authors
Craciunescu, OI; Jones, EL; Blackwell, KL; Wong, TZ; Rosen, EL; Vujaskovic, Z; MacFall, JR; Liotcheva, V; Lora-Michels, M; Prosnitz, LR; Samulski, TV; Dewhirst, MW
MLA Citation
Craciunescu, OI, Jones, EL, Blackwell, KL, Wong, TZ, Rosen, EL, Vujaskovic, Z, MacFall, JR, Liotcheva, V, Lora-Michels, M, Prosnitz, LR, Samulski, TV, and Dewhirst, MW. "Characterizing tumor changes during neoadjuvant treatment of locally advanced breast cancer patients (LABC) using dynamicenhanced magnetic resonance imaging (DE-MRI)." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5698 (2005): 116-125.
Source
scival
Published In
Proceedings of SPIE
Volume
5698
Publish Date
2005
Start Page
116
End Page
125
DOI
10.1117/12.591173

Hippocampal volume measurement in older adults with bipolar disorder.

OBJECTIVE: Decreased hippocampal volumes have been noted in unipolar depressed subjects, especially in elderly patients and those with cognitive impairment. Initial studies of mixed-aged bipolar subjects and controls have had conflicting findings, with most noting no difference; however this region has not been examined in older bipolar subjects. METHODS: The authors examined the hippocampal volumes of 36 older bipolar subjects (mean age: 58 years) and 29 older normal-comparison (NC) subjects (mean age: 61), using logistic-regression analyses to control for age and gender. Differences between late- and early-onset (before age 45) bipolar subjects were also examined. RESULTS: The left hippocampus was noted to be enlarged in older bipolar subjects, compared with the older NC group (sex and age controlled). No differences were noted in hippocampal volumes by age at onset nor number of previous episodes. The increase in hippocampal volume may be associated with the use of lithium, but not valproic acid. CONCLUSIONS: Left-hippocampal volume is increased in older bipolar subjects compared with NC subjects. The differences were not explained by age at onset, current mood state, or cognitive status, but may be associated with exposure to lithium. This finding would support previous observations about the neural-plasticity effect of lithium.

Authors
Beyer, JL; Kuchibhatla, M; Payne, ME; Moo-Young, M; Cassidy, F; Macfall, J; Krishnan, KR
MLA Citation
Beyer, JL, Kuchibhatla, M, Payne, ME, Moo-Young, M, Cassidy, F, Macfall, J, and Krishnan, KR. "Hippocampal volume measurement in older adults with bipolar disorder." Am J Geriatr Psychiatry 12.6 (November 2004): 613-620.
PMID
15545329
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
12
Issue
6
Publish Date
2004
Start Page
613
End Page
620
DOI
10.1176/appi.ajgp.12.6.613

Late-life depression and microstructural abnormalities in dorsolateral prefrontal cortex white matter.

OBJECTIVE: The purpose of this study was to determine whether microstructural abnormalities in the white matter of the dorsolateral prefrontal cortex are associated with late-life depression. METHOD: Seventeen elderly depressed subjects were compared with 16 elderly subjects who were not depressed. Diffusion tensor imaging was used to measure the fractional anisotropy of the white matter in the dorsolateral prefrontal cortex's superior and middle frontal gyri bilaterally and in the left occipital lobe as a control region. The authors compared results between groups while controlling for age, sex, and comorbid medical disorders. RESULTS: Even after controlling for age, sex, hypertension, and heart disease, the authors found significantly lower fractional anisotropy values in the right superior frontal gyrus white matter of depressed patients than comparison subjects. CONCLUSIONS: Microstructural changes in the white matter of the right superior frontal gyrus are associated with late-life depression. Further work is needed to determine how these changes contribute to depression outcomes.

Authors
Taylor, WD; MacFall, JR; Payne, ME; McQuoid, DR; Provenzale, JM; Steffens, DC; Krishnan, KR
MLA Citation
Taylor, WD, MacFall, JR, Payne, ME, McQuoid, DR, Provenzale, JM, Steffens, DC, and Krishnan, KR. "Late-life depression and microstructural abnormalities in dorsolateral prefrontal cortex white matter." Am J Psychiatry 161.7 (July 2004): 1293-1296.
PMID
15229065
Source
pubmed
Published In
American Journal of Psychiatry
Volume
161
Issue
7
Publish Date
2004
Start Page
1293
End Page
1296
DOI
10.1176/appi.ajp.161.7.1293

In vivo monitoring of tissue pharmacokinetics of liposome/drug using MRI: illustration of targeted delivery.

The purpose of this study was to determine if MnSO(4)/doxorubicin (DOX) loaded liposomes could be used for in vivo monitoring of liposome concentration distribution and drug release using MRI. In vitro results show that T(1) shortening correlates with MnSO(4) concentration. Using a temperature-sensitive liposome formulation, it was found that MnSO(4) release significantly shortened T(1). This feature, therefore, suggests that content release can also be measured with these MnSO(4)-loaded liposomes. The feasibility of monitoring this drug delivery and release-imaging agent was shown in a murine tumor model. Upon tumor heating, nonthermally sensitive liposomes selectively but heterogeneously accumulated in the tumor region. The thermally sensitive liposomes showed a clear pattern of accumulation at the periphery of the tumor, concordant with the release temperature of this formulation (39-40 degrees C). This liposome contrast agent has potential for use with hyperthermia by providing individualized monitoring of tissue drug concentration distribution during or after treatment. This would allow for: 1) modification of treatment variables to improve the uniformity of drug delivery, and 2) provide a means to select patients most likely to benefit from this liposomal drug treatment. Additionally, the drug-loading method used for this liposome is applicable to a wide range of drugs, thereby broadening its applicability. The method is also applicable to other liposomal formulations with triggered release mechanisms.

Authors
Viglianti, BL; Abraham, SA; Michelich, CR; Yarmolenko, PS; MacFall, JR; Bally, MB; Dewhirst, MW
MLA Citation
Viglianti, BL, Abraham, SA, Michelich, CR, Yarmolenko, PS, MacFall, JR, Bally, MB, and Dewhirst, MW. "In vivo monitoring of tissue pharmacokinetics of liposome/drug using MRI: illustration of targeted delivery." Magn Reson Med 51.6 (June 2004): 1153-1162.
PMID
15170835
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
51
Issue
6
Publish Date
2004
Start Page
1153
End Page
1162
DOI
10.1002/mrm.20074

Diffusion tensor imaging of adult age differences in cerebral white matter: relation to response time.

Diffusion tensor imaging (DTI) measures the displacement of water molecules across tissue components, thus providing information regarding the microstructure of cerebral white matter. Fractional anisotropy (FA), the degree to which diffusion is directionally dependent, is typically higher for compact, homogeneous fiber bundles such as the corpus callosum. Previous DTI studies in adults have demonstrated an age-related decline in white matter FA, but whether the relation between FA and behavioral performance varies as a function of age has not been determined. We investigated adult age differences in FA, and age-related changes in the relation between FA and response time (RT), in a visual target-detection task. The results confirmed that, independently of age, FA is higher in the corpus callosum than in other brain regions. We also observed an age-related decline in FA that did not vary significantly across the brain regions. For both age groups, a lower level of integrity of the cerebral white matter (as indexed by FA), in specific brain regions, was associated with slower responses in the visual task. An age-related change in this relation was evident, however, in that the best predictor of RT for younger adults was FA in the splenium of the corpus callosum, whereas for older adults the best predictor was FA in the anterior limb of the internal capsule. This pattern is consistent with measures of the task-related cortical activation obtained from these same individuals and suggests an age-related increase in the attentional control of responses mediated by corticostriatal or corticothalamic circuits.

Authors
Madden, DJ; Whiting, WL; Huettel, SA; White, LE; MacFall, JR; Provenzale, JM
MLA Citation
Madden, DJ, Whiting, WL, Huettel, SA, White, LE, MacFall, JR, and Provenzale, JM. "Diffusion tensor imaging of adult age differences in cerebral white matter: relation to response time." Neuroimage 21.3 (March 2004): 1174-1181.
PMID
15006684
Source
pubmed
Published In
NeuroImage
Volume
21
Issue
3
Publish Date
2004
Start Page
1174
End Page
1181
DOI
10.1016/j.neuroimage.2003.11.004

Clinical characteristics of magnetic resonance imaging-defined subcortical ischemic depression.

BACKGROUND: There is a substantial body of research supporting the vascular depression hypothesis of late-life depression. To update this hypothesis so it incorporates recent research, we propose that the term subcortical ischemic vascular depression may be a more accurate representation of the disease process. We sought to investigate this diagnosis as a construct by examining differences between depressed subjects with and without magnetic resonance imaging defined subcortical ischemic vascular depression. METHODS: This case-control study examined 139 depressed elderly subjects. Demographic data, psychiatric, medical, and family history, depressive symptomatology, and functional impairment were compared between groups dichotomized based on neuroimaging findings. RESULTS: Seventy-five (54%) of the subjects met neuroimaging criteria for subcortical ischemic vascular depression. Age was most strongly associated with increased prevalence of subcortical ischemic vascular depression. Lassitude and a history of hypertension were also positively associated with the diagnosis; a family history of mental illness and loss of libido were negatively associated with the diagnosis. CONCLUSIONS: These data support that subcortical ischemic vascular depression may be a specific syndrome from other types of late-life depression. Further research is needed to further characterize this disorder, particularly in regards to cognitive function and treatment implications.

Authors
Krishnan, KR; Taylor, WD; McQuoid, DR; MacFall, JR; Payne, ME; Provenzale, JM; Steffens, DC
MLA Citation
Krishnan, KR, Taylor, WD, McQuoid, DR, MacFall, JR, Payne, ME, Provenzale, JM, and Steffens, DC. "Clinical characteristics of magnetic resonance imaging-defined subcortical ischemic depression." Biol Psychiatry 55.4 (February 15, 2004): 390-397.
PMID
14960292
Source
pubmed
Published In
Biological Psychiatry
Volume
55
Issue
4
Publish Date
2004
Start Page
390
End Page
397
DOI
10.1016/j.biopsych.2003.08.014

Diffusion tensor imaging: background, potential, and utility in psychiatric research.

Diffusion tensor imaging is a variation of magnetic resonance imaging that measures the diffusion of water in tissues. This can help measure and quantify a tissue's orientation and structure, making it an ideal tool for examining cerebral white matter and neural fiber tracts. It is only beginning to be utilized in psychiatric research. This article reviews the theory behind diffusion tensor imaging, its potential to map fiber tracts in the brain, and its recent use in psychiatric research.

Authors
Taylor, WD; Hsu, E; Krishnan, KR; MacFall, JR
MLA Citation
Taylor, WD, Hsu, E, Krishnan, KR, and MacFall, JR. "Diffusion tensor imaging: background, potential, and utility in psychiatric research." Biol Psychiatry 55.3 (February 1, 2004): 201-207. (Review)
PMID
14744459
Source
pubmed
Published In
Biological Psychiatry
Volume
55
Issue
3
Publish Date
2004
Start Page
201
End Page
207

Caudate volume measurement in older adults with bipolar disorder.

BACKGROUND: Decreased caudate volumes have been noted in unipolar depressed subjects, especially in the elderly and those with cognitive impairment. No differences have been noted in initial studies of multi-aged bipolar subjects; however, this region has not been examined in older bipolar subjects. METHODS: We examined the caudate nuclei volumes of 36 older bipolar subjects (mean age 58) and 35 older controls (mean age 62) using logistic regression analyses to control for age and gender differences. Differences between late- and early-onset (age-of-onset before age 45) bipolar subjects were also examined, as well as the effect of length of illness. RESULTS: The right caudate was noted to be smaller in older bipolar subjects compared with older controls when controlled for sex and age (p = 0.0448). No differences were noted in overall brain volume nor lateral ventricular volume between the bipolar and control subjects. Late-onset bipolar subjects had a decrease in brain volume (p = 0.035) compared with early-onset bipolar subjects. Late-onset bipolar subjects had a decrease in the right (p = 0.044) and total (p = 0.04) caudate size compared with older controls. CONCLUSIONS: Right caudate volume is decreased in older bipolar subjects compared to controls. Bipolar subjects with late-onset illness have significantly decreased right and total caudate volumes compared to controls. This is affected by neither the length of illness nor the age of onset. Late-onset bipolar subjects have decreased total brain volume compared with early-onset bipolar subjects.

Authors
Beyer, JL; Kuchibhatla, M; Payne, M; Moo-Young, M; Cassidy, F; MacFall, J; Krishnan, KR
MLA Citation
Beyer, JL, Kuchibhatla, M, Payne, M, Moo-Young, M, Cassidy, F, MacFall, J, and Krishnan, KR. "Caudate volume measurement in older adults with bipolar disorder." Int J Geriatr Psychiatry 19.2 (February 2004): 109-114.
PMID
14758576
Source
pubmed
Published In
International Journal of Geriatric Psychiatry
Volume
19
Issue
2
Publish Date
2004
Start Page
109
End Page
114
DOI
10.1002/gps.1030

Contrast-enhanced magnetic resonance imaging (CE-MRI) parameters have predictive value in estimating response of locally advanced breast cancer (LABC) patients to neoadjuvant (NA) chemotherapy (CT) and hyperthermia (HT)

Authors
Craciunescu, OI; Blackwell, KL; Jones, EL; Vujaskovic, Z; Rosen, EL; Wong, TZ; MacFall, JR; Liotcheva, V; Yu, D; Lora-Michels, M; Prosnitz, LL; Samulski, TV; Dewhirst, MW
MLA Citation
Craciunescu, OI, Blackwell, KL, Jones, EL, Vujaskovic, Z, Rosen, EL, Wong, TZ, MacFall, JR, Liotcheva, V, Yu, D, Lora-Michels, M, Prosnitz, LL, Samulski, TV, and Dewhirst, MW. "Contrast-enhanced magnetic resonance imaging (CE-MRI) parameters have predictive value in estimating response of locally advanced breast cancer (LABC) patients to neoadjuvant (NA) chemotherapy (CT) and hyperthermia (HT)." 2004.
Source
wos-lite
Published In
Breast Cancer Research and Treatment
Volume
88
Publish Date
2004
Start Page
S18
End Page
S19

Chemodosimetry of in-vivo tumor liposome/drug concentration using MRI

Authors
Viglianti, BL; Michelich, C; Abraham, S; Colvin, OM; Yarmolenko, P; MacFall, JR; Bally, MB; Dewhirst, MW
MLA Citation
Viglianti, BL, Michelich, C, Abraham, S, Colvin, OM, Yarmolenko, P, MacFall, JR, Bally, MB, and Dewhirst, MW. "Chemodosimetry of in-vivo tumor liposome/drug concentration using MRI." 2004.
Source
wos-lite
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
60
Issue
1
Publish Date
2004
Start Page
S225
End Page
S226

MRI lesion severity and mortality in geriatric depression.

OBJECTIVE: The authors correlated magnetic resonance imaging (MRI) lesion severity and mortality among depressed elderly patients. METHOD: They examined the association of mortality and deep white-matter hyperintensity (DWMH), periventricular hyperintensity (PVH), and subcortical gray-matter hyperintensity (SGH) ratings in 259 subjects. RESULTS: DWMH and PVH were significantly associated with mortality initially, and, in final modeling, DWMH remained significant. CONCLUSION: These findings suggest that there is a relationship between cerebrovascular disease severity and mortality among depressed patients. More studies, with larger sample sizes, comparing depressed patients and control subjects are needed to further elucidate this relationship.

Authors
Levy, RM; Steffens, DC; McQuoid, DR; Provenzale, JM; MacFall, JR; Krishnan, KR
MLA Citation
Levy, RM, Steffens, DC, McQuoid, DR, Provenzale, JM, MacFall, JR, and Krishnan, KR. "MRI lesion severity and mortality in geriatric depression." Am J Geriatr Psychiatry 11.6 (November 2003): 678-682.
PMID
14609809
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
11
Issue
6
Publish Date
2003
Start Page
678
End Page
682

White matter hyperintensity progression and late-life depression outcomes.

CONTEXT: White matter hyperintensities (WMHs) are bright foci seen in the parenchyma of the brain on T2-weighted cranial magnetic resonance imaging (MRI) scans and are associated with geriatric depression. Because they are associated with age, they should increase in number and size over time. To our knowledge, this is the first longitudinal, volumetric MRI study of WMHs in depression. OBJECTIVE: To determine if WMH progression over 2 years influences depression outcomes. DESIGN: Over 2 years, depressed subjects received antidepressant treatment according to a naturalistic somatic treatment algorithm designed to offer the best possible treatment to the individual. After the treatment period, depressed subjects were dichotomized based on whether they had reached and sustained remission during this period. PARTICIPANTS: One hundred thirty-three subjects aged 60 years or older meeting DSM-IV criteria for major depressive disorder. MEASURES: Cranial MRI was obtained at baseline and approximately 2 years later. White matter hyperintensity volume was measured in each hemisphere using a semiautomated segmentation process. OUTCOMES: Subjects were dichotomized based on achieving or not achieving remission of depressive symptoms, defined as a Montgomery-Asberg Depression Rating Scale score of 8 or less. RESULTS: The depressed subgroup that achieved and sustained remission had significantly less increases in WMH volume (11.5%) than did the group that did not achieve or sustain remission (31.6%) (P =.01). In a regression model, greater change in WMH volume was significantly associated with failure to sustain remission (P =.004) even when controlling for baseline depression severity, medical illness severity, age, sex, and race. Education was associated with achieving and sustaining remission (P =.02). CONCLUSIONS: Greater progression of WMH volume is associated with poor outcomes in geriatric depression. Future work is needed to develop means of slowing the rate of WMH progression and to determine whether this will lead to improved depression outcomes in elderly persons.

Authors
Taylor, WD; Steffens, DC; MacFall, JR; McQuoid, DR; Payne, ME; Provenzale, JM; Krishnan, KR
MLA Citation
Taylor, WD, Steffens, DC, MacFall, JR, McQuoid, DR, Payne, ME, Provenzale, JM, and Krishnan, KR. "White matter hyperintensity progression and late-life depression outcomes." Arch Gen Psychiatry 60.11 (November 2003): 1090-1096.
PMID
14609884
Source
pubmed
Published In
Archives of General Psychiatry
Volume
60
Issue
11
Publish Date
2003
Start Page
1090
End Page
1096
DOI
10.1001/archpsyc.60.11.1090

Apolipoprotein E genotype and subcortical vascular lesions in older depressed patients and control subjects.

BACKGROUND: Several studies have linked geriatric depression with cerebrovascular disease. The apolipoprotein E gene (APOE) epsilon 4 allele has been associated with a variety of late-life neuropsychiatric disorders, including Alzheimer's disease, vascular dementia, and depression. METHODS: The sample consisted of 145 elderly depressive individuals and 100 nondepressed elderly control subjects. After a standardized clinical assessment, all subjects underwent a magnetic resonance imaging brain scan. Volumes of subcortical white and gray matter lesions were determined using a semi-automated method. Apolipoprotein E genotype was determined on blood sample using a standard protocol. A series of linear regression models were developed to assess the relationships between APOE genotype and white and gray matter lesion volumes. RESULTS: Older age, lower Mini-Mental State Examination score, and having any APOE epsilon 4 allele were each correlated with gray-matter lesion volume in depressed patients. Apolipoprotein E genotype was not associated with any lesion volume among control subjects. In a subsequent linear regression model, gray matter lesion volume was associated with older age, having at least one APOE epsilon 4 allele, and white matter lesion volume among depressed patients. CONCLUSIONS: These results are consistent with previous reports linking cerebrovascular disease and APOE genotype. Further studies are needed to replicate this finding in elderly depressive individuals and to explain the relationship between the APOE locus and development of central nervous system vascular pathology.

Authors
Steffens, DC; Trost, WT; Payne, ME; Hybels, CF; MacFall, JR
MLA Citation
Steffens, DC, Trost, WT, Payne, ME, Hybels, CF, and MacFall, JR. "Apolipoprotein E genotype and subcortical vascular lesions in older depressed patients and control subjects." Biol Psychiatry 54.7 (October 1, 2003): 674-681.
PMID
14512206
Source
pubmed
Published In
Biological Psychiatry
Volume
54
Issue
7
Publish Date
2003
Start Page
674
End Page
681

Serial MR imaging of volumes of hyperintense white matter lesions in elderly patients: correlation with vascular risk factors.

OBJECTIVE: The purpose of the study was to examine change in volume of hyperintense white matter lesions in a cohort of community-dwelling elderly subjects without neuropsychiatric disease. SUBJECTS AND METHODS. One hundred seventeen volunteers underwent brain MR imaging on a 1.5-T scanner. Demographic data and the presence of specific medical illnesses were recorded at the time of the initial scanning. Hyperintense white matter lesion volume was measured using a supervised semiautomated technique that seeded lesions and then created a segmented lesion image. Subjects underwent repeated MR imaging at a mean of 25 months. Mean change in lesion volume and mean percentage of change were determined between the two time points. Logistic regression models were used to examine the differential effects of age, sex, race, and self-reported medical morbidity. RESULTS: Mean baseline volume of cerebral hyperintense lesions was 4.91 cc, and at 2-year follow-up, it was 6.42 cm(2) (p < 0.0001), for a mean increase of 26.7%. Comparable results were seen in separate analyses of hemispheric hyperintense lesion volumes. Neither sex, race, nor baseline hyperintense lesion volume was significantly associated with an interval increase in lesion volume. Age (p = 0.0117) and presence of diabetes (p = 0.0215) were associated with greater change. CONCLUSION: Elderly subjects exhibited approximately a 27% increase in hyperintense lesion volume over a 2-year period, a finding influenced by both age and medical comorbidity rates. Because hyperintense lesions can be associated with several neuropsychiatric conditions, further research is needed to determine if interventions designed to slow hyperintense lesion disease progression may improve neuropsychiatric outcomes.

Authors
Taylor, WD; MacFall, JR; Provenzale, JM; Payne, ME; McQuoid, DR; Steffens, DC; Krishnan, KR
MLA Citation
Taylor, WD, MacFall, JR, Provenzale, JM, Payne, ME, McQuoid, DR, Steffens, DC, and Krishnan, KR. "Serial MR imaging of volumes of hyperintense white matter lesions in elderly patients: correlation with vascular risk factors." AJR Am J Roentgenol 181.2 (August 2003): 571-576.
PMID
12876050
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
181
Issue
2
Publish Date
2003
Start Page
571
End Page
576
DOI
10.2214/ajr.181.2.1810571

Localization of age-associated white matter hyperintensities in late-life depression.

OBJECTIVE: Deep white matter hyperintense lesions are associated with advanced age and late-life depression. The authors examined where age-related cerebral lesions occurred in elderly depressed and healthy control subjects. METHODS: Eighty-seven depressed subjects and 47 control subjects underwent 1.5 T cranial magnetic resonance imaging (MRI). Utilizing a semiautomated method, a segmented image was created containing only white matter lesions. We created a statistical parametric map (SPM) separately for each subject group that displayed the association between lesions in any voxel and advanced age. RESULTS: The SPM analysis in depressed subjects demonstrates a significant association between age and lesions found in bilateral, frontal, and left parietal regions. The analysis in control subjects found significant associations only in bilateral parieto-temporal regions, not frontal regions. CONCLUSIONS: This study demonstrates a different pattern of age-related lesion location between depressed and control subjects. It further supports the theory that frontostriatal disconnection contributes to late-life depression.

Authors
Taylor, WD; MacFall, JR; Steffens, DC; Payne, ME; Provenzale, JM; Krishnan, KR
MLA Citation
Taylor, WD, MacFall, JR, Steffens, DC, Payne, ME, Provenzale, JM, and Krishnan, KR. "Localization of age-associated white matter hyperintensities in late-life depression." Prog Neuropsychopharmacol Biol Psychiatry 27.3 (May 2003): 539-544.
PMID
12691791
Source
pubmed
Published In
Progress in Neuro-Psychopharmacology & Biological Psychiatry
Volume
27
Issue
3
Publish Date
2003
Start Page
539
End Page
544
DOI
10.1016/S0278-5846(02)00358-5

Quantitative assessment of the time course of infarct signal intensity on diffusion-weighted images.

BACKGROUND AND PURPOSE: Diffusion-weighted (DW) MR imaging is important in evaluating acute stroke, and knowledge of the signal intensity changes associated with acute stroke is valuable. Our purpose was to model the time course of the signal intensity of infarcts and to characterize the apparent diffusion coefficient (ADC) and T2 effects on total signal intensity. METHODS: Ninety-two patients were included in this prospective cross-sectional study. Signal intensity in infarcts (4 hours to 417 days) and control regions were recorded on DW images (b = 0 and 1000 s/mm(2)), ADC maps, and ratio images (image with b = 1000 s/mm(2) divided by image with b = 0 s/mm(2)). Cubic spline functions were used for polynomial fitting. The time courses of log signal intensity with log time were modeled. The independent contributions of T2 and ADC to the total signal intensity were retrospectively compared at 0-63 hours, 3-10 days, 11-57 days, and 57 days onward. RESULTS: Mean signal intensity on DW images was maximal at 40 hours after infarction and normalized at 57 days. At 0-63 hours, the positive effect of ADC on signal intensity was greater than that of T2 (log value,13 +/- 0.04 vs 0.11 +/- 0.05; P =.04). At days 3-10, the positive T2 effect predominated (0.13 +/- 0.08 vs 0.08 +/- 0.04; P =.12). At 10-57 days, the positive T2 effect was greater than the negative ADC effect. After day 57, the negative ADC effect predominated. CONCLUSION: The signal intensity of infarcts on DW images normalizes at 57 days, which is substantially later than previously suggested. T2 (shine-through) effect contributes largely to the total infarct signal intensity.

Authors
Eastwood, JD; Engelter, ST; MacFall, JF; Delong, DM; Provenzale, JM
MLA Citation
Eastwood, JD, Engelter, ST, MacFall, JF, Delong, DM, and Provenzale, JM. "Quantitative assessment of the time course of infarct signal intensity on diffusion-weighted images." AJNR Am J Neuroradiol 24.4 (April 2003): 680-687.
PMID
12695203
Source
pubmed
Published In
American Journal of Neuroradiology
Volume
24
Issue
4
Publish Date
2003
Start Page
680
End Page
687

In vivo monitoring of real time tissue pharmacokinetics of liposome/drug concentration using MRI

Authors
Viglianti, BL; Abraham, SA; MacFall, JR; Bally, MB; Dewhirst, MW
MLA Citation
Viglianti, BL, Abraham, SA, MacFall, JR, Bally, MB, and Dewhirst, MW. "In vivo monitoring of real time tissue pharmacokinetics of liposome/drug concentration using MRI." November 2002.
Source
wos-lite
Published In
Radiology
Volume
225
Publish Date
2002
Start Page
647
End Page
648

Development of a semi-automated method for quantification of MRI gray and white matter lesions in geriatric subjects.

Brain magnetic resonance imaging (MRI) allows for quantitative assessment of hyperintense foci, which are seen with aging and various diseases. These foci, considered to represent lesions, are important in the study of various psychiatric illnesses, including depression. Few quantitative measures have been developed for such research. The goal of the current study was to develop a reliable and efficient method for quantifying the volumes of gray and white matter lesions in MRI scans of the elderly. Interrater reliability was determined by repeat lesion measures on 16 scans. Semi-automated segmentation was performed that identified potential lesions, and then lesions were manually selected based upon detailed anatomic criteria. The lesion quantification procedure took between 25 and 45 min per scan. Reliability intraclass correlation coefficients (ICCs) were 0.99 for both gray and white matter lesions. Volumetric results were found to be moderately correlated with previous lesion ratings (r-values between 0.37 and 0.62, P<0.0001). Among the 700 scans processed with this method, lesion volumes ranged from 0 to 7.3 ml for gray matter, and from 0.4 to 96.8 ml for white matter. Our method proved to be efficient and reliable for quantifying lesions in MRI scans of the elderly.

Authors
Payne, ME; Fetzer, DL; MacFall, JR; Provenzale, JM; Byrum, CE; Krishnan, KR
MLA Citation
Payne, ME, Fetzer, DL, MacFall, JR, Provenzale, JM, Byrum, CE, and Krishnan, KR. "Development of a semi-automated method for quantification of MRI gray and white matter lesions in geriatric subjects." Psychiatry Res 115.1-2 (August 20, 2002): 63-77.
PMID
12165368
Source
pubmed
Published In
Psychiatry Research
Volume
115
Issue
1-2
Publish Date
2002
Start Page
63
End Page
77

MR signal intensity of gray matter/white matter contrast and intracranial fat: effects of age and sex.

Signal intensity (SI) values of gray- and white-matter brain regions of interest (ROIs) were obtained from T(2)- and proton density-weighted magnetic resonance (MR) images of 58 normal subjects aged 22-82 years (31 females, 52.3+/-18.8 years; 27 males, 54.1+/-18.1 years). Sampled ROIs included the caudate, putamen, thalamus, orbitofrontal gyrus, gyrus rectus, uncus, frontal white matter, anterior and posterior corpus callosum, cranial-cervical junction fat, and retroorbital fat. Effects of age and sex on SI were examined using repeated-measures analysis of covariance. For both T(2)- and proton density-weighted acquisitions, a significant inverse relationship between age and SI was observed for the ratio of all summed gray-matter ROIs divided by summed white-matter ROIs. This relationship was additionally observed for ratios of both subcortical gray/white matter and cortical gray/white matter. Females compared with males had significantly lower cortical gray/white matter ratios on T(2)-weighted scans. Differences in SI were observed between cranial-cervical junction fat and retroorbital fat on both acquisitions, with females showing significantly higher values for cranial-cervical junction fat and males showing higher values for retroorbital fat. Implications for brain morphometry, the use of fat as a reference standard, and other issues in neuroimaging are discussed.

Authors
Kim, DM; Xanthakos, SA; Tupler, LA; Barboriak, DP; Charles, HC; MacFall, JR; Krishnan, KR
MLA Citation
Kim, DM, Xanthakos, SA, Tupler, LA, Barboriak, DP, Charles, HC, MacFall, JR, and Krishnan, KR. "MR signal intensity of gray matter/white matter contrast and intracranial fat: effects of age and sex." Psychiatry Res 114.3 (July 1, 2002): 149-161.
PMID
12113897
Source
pubmed
Published In
Psychiatry Research
Volume
114
Issue
3
Publish Date
2002
Start Page
149
End Page
161

Hippocampal volume and antidepressant response in geriatric depression.

BACKGROUND: Biological markers of treatment response may include structural brain changes seen on neuroimaging. While most imaging studies have focused on cerebrovascular disease, evidence is growing that the hippocampus may play a role in depression, particularly geriatric depression. METHOD: We studied 60 depressed elderly patients enrolled in a longitudinal study who were treated with antidepressant medications using a treatment guideline-based approach. Baseline and 12-week Montgomery-Asberg Depression Rating Scale (MADRS) scores were obtained via interview with a geriatric psychiatrist. All subjects had a baseline magnetic resonance imaging (MRI) brain scan. MRI scans were processed using standard protocols to determine total cerebral volume and right and left hippocampal volumes. Hippocampal volumes were standardized for total cerebral volume. MADRS scores less than 10 were used to define remission. RESULTS: When the group with the lowest quartile of standardized hippocampal volumes was compared to those above the first quartile, those with small right and total hippocampal volumes were less likely to achieve remission. In a subsequent logistic regression model controlling for age small standardized right hippocampal volumes remained significantly associated with remission. CONCLUSION: Further studies with larger sample are needed to determine if left-right hippocampal volume differences do exist in depression, and basic neuroscience studies will need to elucidate the role of the hippocampus in geriatric depression.

Authors
Hsieh, MH; McQuoid, DR; Levy, RM; Payne, ME; MacFall, JR; Steffens, DC
MLA Citation
Hsieh, MH, McQuoid, DR, Levy, RM, Payne, ME, MacFall, JR, and Steffens, DC. "Hippocampal volume and antidepressant response in geriatric depression." Int J Geriatr Psychiatry 17.6 (June 2002): 519-525.
PMID
12112175
Source
pubmed
Published In
International Journal of Geriatric Psychiatry
Volume
17
Issue
6
Publish Date
2002
Start Page
519
End Page
525
DOI
10.1002/gps.611

APOE genotype and hippocampal volume change in geriatric depression.

BACKGROUND: Apolipoprotein E has been associated with hippocampal volume loss in Alzheimer's disease and in elderly controls. In this study, we examined the role of apolipoprotein E and hippocampal volume change in 45 older nondemented depressed subjects. All had baseline and 2-year magnetic resonance imaging scans. METHODS: Hippocampal volumes were determined using a semiautomated method. RESULTS: Compared with 36 depressed subjects without an apolipoprotein E epsilon4 allele, 9 subjects with at least one APOE epsilon4 allele showed significant decline in hippocampal volume, particularly in the right hippocampus. In a logistic model, percent change in right hippocampal volume remained associated with presence of an APOE epsilon4 allele after controlling for age, gender, Mini-Mental State Examination score, and baseline total cerebral volume. CONCLUSIONS: Future studies are needed to explain this association and to determine whether the finding for the right hippocampus has a biological basis, or if it is merely a function of small sample size.

Authors
Kim, DH; Payne, ME; Levy, RM; MacFall, JR; Steffens, DC
MLA Citation
Kim, DH, Payne, ME, Levy, RM, MacFall, JR, and Steffens, DC. "APOE genotype and hippocampal volume change in geriatric depression." Biol Psychiatry 51.5 (March 1, 2002): 426-429.
PMID
11904138
Source
pubmed
Published In
Biological Psychiatry
Volume
51
Issue
5
Publish Date
2002
Start Page
426
End Page
429

Multiple sclerosis: diffusion tensor MR imaging for evaluation of normal-appearing white matter.

PURPOSE: To determine whether the normal-appearing white matter (NAWM) regions surrounding and remote from multiple sclerosis (MS) plaques have abnormal diffusional anisotropy and to compare anisotropy maps with apparent diffusion coefficient (ADC) maps for sensitivity in the detection of white matter (WM) abnormalities. MATERIALS AND METHODS: Conventional and diffusion tensor magnetic resonance (MR) imaging examinations were performed in 26 patients with MS and in 26 age-matched control subjects. Fractional anisotropy (FA) and ADC maps were generated and coregistered with T2-weighted MR images. Uniform regions of interest were placed on plaques, periplaque white matter (PWM) regions, NAWM regions in the contralateral side of the brain, and WM regions in control subjects to obtain FA and ADC values, which were compared across the WM regions. RESULTS: The mean FA was 0.280 for plaques, 0.383 for PWM, 0.493 for NAWM, and 0.537 for control subject WM. The mean ADC was 1.025 x 10(-3) mm(2)/sec for plaques, 0.786 x 10(-3) mm(2)/sec for PWM, 0.739 x 10(-3) mm(2)/sec for NAWM, and 0.726 x 10(-3) mm(2)/sec for control subject WM. Significant differences in anisotropy and ADC values were observed among all WM regions (P <.001 for all comparisons, except ADC in NAWM vs control subject WM [P =.018]). CONCLUSION: The anisotropy and ADC values were abnormal in all WM regions in the patients with MS and were worse in the periplaque regions than in the distant regions. Diffusion tensor MR imaging may be more accurate than T2-weighted MR imaging for assessment of disease burden.

Authors
Guo, AC; MacFall, JR; Provenzale, JM
MLA Citation
Guo, AC, MacFall, JR, and Provenzale, JM. "Multiple sclerosis: diffusion tensor MR imaging for evaluation of normal-appearing white matter." Radiology 222.3 (March 2002): 729-736.
PMID
11867792
Source
pubmed
Published In
Radiology
Volume
222
Issue
3
Publish Date
2002
Start Page
729
End Page
736
DOI
10.1148/radiol.2223010311

Hippocampal volume and incident dementia in geriatric depression.

The authors investigated the role of baseline hippocampal volume on later clinical emergence of dementia in a group of older, non-demented depressed individuals. Subjects were 115 depressed, non-demented participants in a mental health clinical research center. All subjects were screened for dementia and agreed to have a magnetic resonance imaging (MRI) brain scan at baseline. Subjects were clinically evaluated by geriatric psychiatrists quarterly for up to 5 years and received annual neuropsychological testing. Bivariate analyses examined age, gender, race, educational level, baseline depression severity, age at depression onset, baseline Mini-Mental State Exam (MMSE), left and right hippocampal volume, and total cerebral volume. Age, baseline MMSE, total cerebral volume, and having a small left hippocampal volume were associated with later dementia and were included in subsequent survival analysis. Small left hippocampal volume was significantly associated with later dementia (hazard ratio=2.762). Small left hippocampal size on neuroimaging may be a marker for dementia in depressed patients who have not yet met criteria for a clinical diagnosis of a dementing disorder.

Authors
Steffens, DC; Payne, ME; Greenberg, DL; Byrum, CE; Welsh-Bohmer, KA; Wagner, HR; MacFall, JR
MLA Citation
Steffens, DC, Payne, ME, Greenberg, DL, Byrum, CE, Welsh-Bohmer, KA, Wagner, HR, and MacFall, JR. "Hippocampal volume and incident dementia in geriatric depression." Am J Geriatr Psychiatry 10.1 (January 2002): 62-71.
PMID
11790636
Source
pubmed
Published In
American Journal of Geriatric Psychiatry
Volume
10
Issue
1
Publish Date
2002
Start Page
62
End Page
71

Do prolonged febrile seizures produce medial temporal sclerosis? Hypotheses, MRI evidence and unanswered questions.

Whether or not severe febrile seizures in infancy cause hippocampal injury and subsequent medial temporal sclerosis is an often debated question in epilepsy. Recent magnetic resonance imaging (MRI) of infants suffering from febrile seizures has provided preliminary evidence that abnormally increased T2 signal intensity can be seen in the hippocampi of infants following prolonged and focal febrile seizures. Follow-up MRIs in a few of these infants have confirmed that medial temporal sclerosis can develop following these acute MRI signal changes. In this article, we review the hypotheses and MRI evidence relating to hippocampal injury during prolonged febrile seizures and the later development of medial temporal sclerosis.

Authors
Lewis, DV; Barboriak, DP; MacFall, JR; Provenzale, JM; Mitchell, TV; VanLandingham, KE
MLA Citation
Lewis, DV, Barboriak, DP, MacFall, JR, Provenzale, JM, Mitchell, TV, and VanLandingham, KE. "Do prolonged febrile seizures produce medial temporal sclerosis? Hypotheses, MRI evidence and unanswered questions." Prog Brain Res 135 (2002): 263-278. (Review)
PMID
12143347
Source
pubmed
Published In
Progress in Brain Research
Volume
135
Publish Date
2002
Start Page
263
End Page
278

Subcortical white matter lesions and functional impairment in geriatric depression.

Geriatric depression is associated with significant functional impairment. There is also growing evidence linking vascular brain changes to depression in late life. We sought to examine the relationship between cerebrovascular disease and impairment in basic activities of daily living (BADL) and instrumental activities of daily living (IADL) in a group of older depressives. The sample consisted of 224 depressed adults aged 60 years and above enrolled in Duke's Mental Health Clinical Research Center. All subjects had unipolar major depression and were free of other major psychiatric and neurological illness, including dementia. In a structured interview, subjects reported their medical history and ability to perform both BADL and IADL. Geriatric psychiatrists assessed cognition using the Mini Mental State Examination (MMSE) and depression severity using the Montgomery Asberg Depression Rating Scale (MADRS). Subjects had a standardized magnetic resonance imaging (MRI) brain scan. MRI scans were processed using a semi-automated method to determine volumes of subcortical white matter lesions (WML) and subcortical gray matter lesions (GML). Logistic regression was used to examine effects of WML and GML controlling for demographic and clinical factors. Greater volume of WML was associated with impairment in both BADL and IADL, while GML was associated with IADL impairment. In logistic models, WML remained significantly associated with IADL after controlling for the effects of age, gender, depression severity, and medical comorbidity. We concluded that white matter lesions are independently associated with functional impairment. Further studies are needed to understand how these lesions affect function, e.g., through effects on cognition or motor skills.

Authors
Steffens, DC; Bosworth, HB; Provenzale, JM; MacFall, JR
MLA Citation
Steffens, DC, Bosworth, HB, Provenzale, JM, and MacFall, JR. "Subcortical white matter lesions and functional impairment in geriatric depression." Depress Anxiety 15.1 (2002): 23-28.
PMID
11816049
Source
pubmed
Published In
Depression and Anxiety
Volume
15
Issue
1
Publish Date
2002
Start Page
23
End Page
28

Structural changes as measured by diffusion tensor imaging in late-life depression.

Authors
Taylor, WD; Krishnan, KR; Payne, ME; Wagner, HR; Provenzale, JM; Steffens, DC; MacFall, JR
MLA Citation
Taylor, WD, Krishnan, KR, Payne, ME, Wagner, HR, Provenzale, JM, Steffens, DC, and MacFall, JR. "Structural changes as measured by diffusion tensor imaging in late-life depression." AMERICAN JOURNAL OF GERIATRIC PSYCHIATRY 10.2 (2002): 77-77.
Source
wos-lite
Published In
American Journal of Geriatric Psychiatry
Volume
10
Issue
2
Publish Date
2002
Start Page
77
End Page
77

Longitudinal MR analysis of white matter volume in normal elderly subjects

Authors
Provenzale, JM; MacFall, JR; Payne, ME; Mcquoid, DR; Krishnan, RR
MLA Citation
Provenzale, JM, MacFall, JR, Payne, ME, Mcquoid, DR, and Krishnan, RR. "Longitudinal MR analysis of white matter volume in normal elderly subjects." RADIOLOGY 221 (November 2001): 615-615.
Source
wos-lite
Published In
Radiology
Volume
221
Publish Date
2001
Start Page
615
End Page
615

Evidence of white matter tract disruption in MRI hyperintensities.

BACKGROUND: Diffusion tensor imaging (DTI) of brain tissue measures the apparent diffusion coefficient (ADC), or isotropic diffusion, and anisotropy, or diffusion as influenced by tissue structure. We hypothesized that hyperintensities, when compared with normal tissue by DTI, would show evidence of damage through an increased ADC and decreased anisotropy. We also hypothesized that DTI changes in hyperintensities would be similar between depressed subjects and control subjects. METHODS: Fourteen depressed geriatric patients and nineteen control subjects received DTI. The ADC and aniso-tropy of normal tissue from standard regions were compared with hyperintensities from these regions. The Students' t test compared individual regions and averaged white matter results. RESULTS: Hyperintensities showed higher ADC and lower anisotropy than normal regions. Gray matter exhibited similar trends. There was no significant difference in diffusion characteristics of hyperintensities between subjects and control subjects. CONCLUSIONS: Hyperintensities damage the structure of brain tissue, and do so comparably in depressed subjects and control subjects.

Authors
Taylor, WD; Payne, ME; Krishnan, KR; Wagner, HR; Provenzale, JM; Steffens, DC; MacFall, JR
MLA Citation
Taylor, WD, Payne, ME, Krishnan, KR, Wagner, HR, Provenzale, JM, Steffens, DC, and MacFall, JR. "Evidence of white matter tract disruption in MRI hyperintensities." Biol Psychiatry 50.3 (August 1, 2001): 179-183.
PMID
11513816
Source
pubmed
Published In
Biological Psychiatry
Volume
50
Issue
3
Publish Date
2001
Start Page
179
End Page
183

Medial orbital frontal lesions in late-onset depression.

BACKGROUND: Early studies using magnetic resonance (MR) imaging suggested that subcortical vascular changes are more prevalent in late-life depression and that they may play a role in the pathophysiology of depression. Studying the location of the lesion relative to the occurrence of depression could be critical in delineating the neuroanatomic substrates of depression. Our purpose was to characterize these lesions in terms of location by development of statistical parametric maps of lesions that differentiate patients from control subjects. METHODS: Magnetic resonance images were acquired on 88 elderly depressed subjects ("patients," unipolar major depression assessed using the Duke Depression Evaluation Schedule, age range 63-80 years) enrolled in the Duke University Clinical Research Center for the Study of Late-Life Depression and 47 age- and gender-matched nondepressed subjects ("control subjects"). The MR protocol includes a volumetric, dual-contrast fast spin-echo pulse sequence. A statistical parametric map was formed from a two-group t test to test for differences in lesion density between patients and control subjects. Additional testing was performed to evaluate whether there were regions that correlated with the severity of depression using the 17-item Hamilton Depression rating. RESULTS: The statistical parametric mapping analysis between groups showed two major regions of increased lesion density in the patients in the medial orbital prefrontal white matter. Severity of depression among depressed patients was correlated with lesions in the medial orbital region. CONCLUSIONS: This study supports recent evidence implicating the medial orbital frontal cortex in depression.

Authors
MacFall, JR; Payne, ME; Provenzale, JE; Krishnan, KR
MLA Citation
MacFall, JR, Payne, ME, Provenzale, JE, and Krishnan, KR. "Medial orbital frontal lesions in late-onset depression." Biol Psychiatry 49.9 (May 1, 2001): 803-806.
PMID
11331089
Source
pubmed
Published In
Biological Psychiatry
Volume
49
Issue
9
Publish Date
2001
Start Page
803
End Page
806

Increased brain apparent diffusion coefficient in children with neurofibromatosis type 1.

PURPOSE: To describe the changes in brain water diffusibility in five anatomic locations in children with neurofibromatosis type 1 (NF 1) compared with these changes in control subjects and to describe the water diffusibility changes associated with hyperintense basal ganglia lesions in children with NF 1. MATERIALS AND METHODS: Twenty highly related pairs of children consisting of one child with NF 1 and one unaffected child were examined. Prospective comparisons of isotropic apparent diffusion coefficient (ADC) values at five anatomic locations were performed, with and without T2-hyperintense lesions included. Retrospective analysis of hyperintense globus pallidus lesions in 16 children and in the paired control subjects also was performed. RESULTS: Significant increases in ADC values were seen in all five anatomic locations in the NF 1 group. The greatest increases were seen in the globus pallidus (14%; P =.002) and brachium pontis (10.8%; P =.003). With exclusion of hyperintense lesions, significant ADC increases were measured in four locations. Significant ADC increases were seen in hyperintense globus pallidus lesions in the NF 1 group compared with ADC values in the normal-appearing contralateral globus pallidus (4.9%; P =.02) and those in the globus pallidus of the paired control subjects (16%; P =.003). CONCLUSION: Significant ADC increases were measured both in the hyperintense lesions and in the normal-appearing areas of the brain in children with NF 1.

Authors
Eastwood, JD; Fiorella, DJ; MacFall, JF; Delong, DM; Provenzale, JM; Greenwood, RS
MLA Citation
Eastwood, JD, Fiorella, DJ, MacFall, JF, Delong, DM, Provenzale, JM, and Greenwood, RS. "Increased brain apparent diffusion coefficient in children with neurofibromatosis type 1." Radiology 219.2 (May 2001): 354-358.
PMID
11323456
Source
pubmed
Published In
Radiology
Volume
219
Issue
2
Publish Date
2001
Start Page
354
End Page
358
DOI
10.1148/radiology.219.2.r01ap25354

3D numerical reconstruction of the hyperthermia induced temperature distribution in human sarcomas using DE-MRI measured tissue perfusion: validation against non-invasive MR temperature measurements.

Essential to the success of optimized thermal treatment during hyperthermia is accurate modelling. Advection of energy due to blood perfusion significantly affects the temperature. Without accurate estimates of the magnitude of the local tissue blood perfusion, accurate estimates of the temperature distribution can not be made. It is shown here that the blood mass flow rate per unit volume of tissue in the Pennes' bio-heat equation can be modelled using a relative perfusion index (RPI) determined with dynamic-enhanced magnetic resonance imaging (DE-MRI). Temperature distributions in two patients treated with hyperthermia at Duke University Medical Center for high-grade leg tissue sarcomas are modelled, and the resultant temperatures are compared to measured temperatures using a non-invasive MR thermometry technique. Significant correlations are found between the DE-MRI perfusion images, the MR temperature images, and the numerical simulation of the temperature field. The correlation between DE-MRI measured values and advective heat loss in tissue is used to scale the perfusion distribution, thereby allowing the continuum model to account for the local thermal impact of vasculature in the tumour. Large vessels in tumour and neighbouring healthy tissue need to be taken into account in order to accurately describe the complete temperature distribution.

Authors
Craciunescu, OI; Das, SK; McCauley, RL; MacFall, JR; Samulski, TV
MLA Citation
Craciunescu, OI, Das, SK, McCauley, RL, MacFall, JR, and Samulski, TV. "3D numerical reconstruction of the hyperthermia induced temperature distribution in human sarcomas using DE-MRI measured tissue perfusion: validation against non-invasive MR temperature measurements." Int J Hyperthermia 17.3 (May 2001): 221-239.
PMID
11347728
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
17
Issue
3
Publish Date
2001
Start Page
221
End Page
239

Use of exponential diffusion imaging to determine the age of ischemic infarcts.

OBJECTIVE: Diffusion-weighted magnetic resonance imaging (DWI) detects acute ischemic infarcts with high lesion conspicuity. Determination of infarct age is difficult on DWI alone because infarct signal intensity (SIinfarct) on DWI is influenced by T2 properties ("T2 shine-through"). Maps of the apparent diffusion coefficient (ADC) reflect pure diffusion characteristics without T2 effects but have low lesion conspicuity. Thus, in clinical practice, combined use of DWI and ADC maps is required. Exponential DWI (eDWI) is an innovative means of MRI-diffusion data analysis that merges the advantages of DWI and ADC maps. The authors hypothesized that SIinfarct on eDWI would correlate with infarct age. The authors studied 114 consecutive patients who had 120 ischemic strokes with clearly determined onset times and who underwent echo-planar DWI. The eDWI were generated by dividing the signal intensity on DWI by that on the corresponding T2 image on a pixel-by-pixel basis. SIinfarct on eDWI was measured in the lesion core and expressed as a percentage of contralateral control tissue. On eDWI, relative SIinfarct changed significantly with infarct age (P < .0001). When patients were sorted in infarct-age groups, no significant differences were found within the first 120 hours. However, for patients studied within 5 days, the mean relative SIinfarct was significantly higher compared with patients studied > or = 8 days after stroke (P < .05). For all infarcts up to 5 days old, the eDWI signal intensity was higher than control tissue (hyperintense appearance). All infarcts > 10 days old had an eDWI signal intensity lower than control tissue (hypointense appearance). The authors concluded that the use of eDWI, as a single set of images, reliably differentiates acute infarcts (< or = 5 days old) from infarcts > 10 days old. This feature would be expected to be helpful when the distinction between acute and nonacute infarction cannot be determined on clinical grounds.

Authors
Engelter, ST; Provenzale, JM; Petrella, JR; Alberts, MJ; DeLong, DM; MacFall, JR
MLA Citation
Engelter, ST, Provenzale, JM, Petrella, JR, Alberts, MJ, DeLong, DM, and MacFall, JR. "Use of exponential diffusion imaging to determine the age of ischemic infarcts." J Neuroimaging 11.2 (April 2001): 141-147.
PMID
11296583
Source
pubmed
Published In
Journal of Neuroimaging
Volume
11
Issue
2
Publish Date
2001
Start Page
141
End Page
147

Grey-matter lesions and dementia.

Authors
Steffens, DC; MacFall, JR; Payne, ME; Welsh-Bohmer, KA; Krishnan, KR
MLA Citation
Steffens, DC, MacFall, JR, Payne, ME, Welsh-Bohmer, KA, and Krishnan, KR. "Grey-matter lesions and dementia." Lancet 356.9242 (November 11, 2000): 1686-1687. (Letter)
PMID
11089848
Source
pubmed
Published In
The Lancet
Volume
356
Issue
9242
Publish Date
2000
Start Page
1686
End Page
1687
DOI
10.1016/S0140-6736(05)70393-7

Hippocampal volume in geriatric depression.

BACKGROUND: There is a growing literature on the importance of hippocampal volume in geriatric depression. METHODS: We examined hippocampal volume in a group of elderly depressed patients and a group of elderly control subjects (N = 66 geriatric depressed patients and 18 elderly nondepressed control subjects) recruited through Duke's Mental Health Clinical Research Center for the Study of Depression in the Elderly. The subjects received a standardized evaluation, including a magnetic resonance imaging scan of the brain. Patients had unipolar major depression and were free of comorbid major psychiatric illness and neurologic illness. Differences were assessed using t tests and linear regression modeling. RESULTS: Accounting for the effects of age, gender, and total brain volume, depressed patients tended to have smaller right hippocampal volume (p =.014) and left hippocampal volume (p =.073). Among depressed patients, age of onset was negatively but not significantly related to right hippocampal volume (p =.052) and to left hippocampal volume (p =.062). We noted that among subjects with either right or left hippocampal volume of 3 mL or less, the vast majority were patients rather than control subjects. CONCLUSIONS: These results support a role for hippocampal dysfunction in depression, particularly in late-age onset depression. Longitudinal studies examining both depressive and cognitive outcomes are needed to clarify the relationships between the hippocampus, depression, and dementia.

Authors
Steffens, DC; Byrum, CE; McQuoid, DR; Greenberg, DL; Payne, ME; Blitchington, TF; MacFall, JR; Krishnan, KR
MLA Citation
Steffens, DC, Byrum, CE, McQuoid, DR, Greenberg, DL, Payne, ME, Blitchington, TF, MacFall, JR, and Krishnan, KR. "Hippocampal volume in geriatric depression." Biol Psychiatry 48.4 (August 15, 2000): 301-309.
PMID
10960161
Source
pubmed
Published In
Biological Psychiatry
Volume
48
Issue
4
Publish Date
2000
Start Page
301
End Page
309

The effect of aging on the apparent diffusion coefficient of normal-appearing white matter.

OBJECTIVE: The purpose of our study was to test the hypothesis that the apparent diffusion coefficient (ADC) of normal-appearing white matter increases with advancing age. SUBJECTS AND METHODS: We selected 38 patients with normal MR imaging findings from 332 patients undergoing clinical MR imaging. Diffusion-weighted MR imaging was performed with diffusion gradients applied in three orthogonal directions. For each patient, the average ADC on trace-weighted diffusion images of white matter at prespecified regions of interest and at the thalamus were compared with the patient's age. RESULTS: For the white matter, ADC sorted by patient age in decades increased with advancing age. Patients at least 60 years old had significantly higher ADC (0.769 +/- 0.019 mm(2)/sec x 10(-3)) than patients less than 60 years old (0.740 +/- 0.013 mm(2)/sec x 10(-3)) (p < 0.001). Comparison of individual white matter ADC and age showed a significant increase with advancing age (p < 0.0001). For the thalamus, the average ADC among patients at least 60 years old (0.766 +/- 0.015 mm(2)/sec x 10(-3)) exceeded the average ADC for patients less than 60 years old (0.745 +/- 0.022 mm(2)/sec x 10(-3)) (p < 0.05). However, comparison of individual thalamic ADC and patient ages, although showing a trend to higher ADC with increasing age, did not reach statistical significance (p = 0.06). CONCLUSION: Advancing age is associated with a small but statistically significant increase of water diffusibility in human white matter. A similar trend was present in the thalamus. These increases may reflect mild structural changes associated with normal aging.

Authors
Engelter, ST; Provenzale, JM; Petrella, JR; DeLong, DM; MacFall, JR
MLA Citation
Engelter, ST, Provenzale, JM, Petrella, JR, DeLong, DM, and MacFall, JR. "The effect of aging on the apparent diffusion coefficient of normal-appearing white matter." AJR Am J Roentgenol 175.2 (August 2000): 425-430.
PMID
10915688
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
175
Issue
2
Publish Date
2000
Start Page
425
End Page
430
DOI
10.2214/ajr.175.2.1750425

Correction of MR kappa-space data corrupted by spike noise.

Magnetic resonance images are reconstructed from digitized raw data, which are collected in the spatial-frequency domain (also called kappa-space). Occasionally, single or multiple data points in the k-space data are corrupted by spike noise, causing striation artifacts in images. Thresholding methods for detecting corrupted data points can fail because of small alterations, especially for data points in the low spatial frequency area where the k-space variation is large. Restoration of corrupted data points using interpolations of neighboring pixels can give incorrect results. We propose a Fourier transform method for detecting and restoring corrupted data points using a window filter derived from the striation-artifact structure in an image or an intermediate domain. The method provides an analytical solution for the alteration at each corrupted data point. It can effectively restore corrupted kappa-space data, removing striation artifacts in images, provided that the following three conditions are satisfied. First, a region of known signal distribution (for example, air background) is visible in either the image or the intermediate domain so that it can be selected using a window filter. Second, multiple spikes are separated by the full-width at half-maximum of the point spread function for the window filter. Third, the magnitude of a spike is larger than the minimum detectable value determined by the window filter and the standard deviation of kappa-space random noise.

Authors
Kao, YH; MacFall, JR
MLA Citation
Kao, YH, and MacFall, JR. "Correction of MR kappa-space data corrupted by spike noise." IEEE Trans Med Imaging 19.7 (July 2000): 671-680.
PMID
11055782
Source
pubmed
Published In
IEEE Transactions on Medical Imaging
Volume
19
Issue
7
Publish Date
2000
Start Page
671
End Page
680

Perturbations in hyperthermia temperature distributions associated with counter-current flow: numerical simulations and empirical verification.

Two numerical techniques are used to calculate the effect of large vessel counter-current flow on hyperthermic temperature distributions. One is based on the Navier-Stokes equation for steady-state flow, and the second employs a convective-type boundary condition at the interface of the vessel walls. Steady-state temperature fields were calculated for two energy absorption rate distributions (ARD) in a cylindrical tissue model having two pairs of counter-current vessels (one pair with equal diameter vessels and another pair with unequal diameters). The first assumed a uniform ARD throughout cylinder; the second ARD was calculated for a tissue cylinder inside an existing four antenna Radiofrequency (RF) array. A tissue equivalent phantom was constructed to verify the numerical calculations. Temperatures induced with the RF array were measured using a noninvasive magnetic resonance imaging technique based on the chemical shift of water. Temperatures calculated using the two numerical techniques are in good agreement with the measured data. The results show: 1) the convective-type boundary condition technique reduces computation time by a factor of ten when compared to the fully conjugated method with little quantitative difference (approximately 0.3 degree C) in the numerical accuracy and 2) the use of noninvasive magnetic resonance imaging (thermal imaging) to quantitatively access the temperature perturbations near large vessels is feasible using the chemical shift technique.

Authors
Craciunescu, OI; Samulski, TV; MacFall, JR; Clegg, ST
MLA Citation
Craciunescu, OI, Samulski, TV, MacFall, JR, and Clegg, ST. "Perturbations in hyperthermia temperature distributions associated with counter-current flow: numerical simulations and empirical verification." IEEE Trans Biomed Eng 47.4 (April 2000): 435-443.
PMID
10763289
Source
pubmed
Published In
IEEE Transactions on Biomedical Engineering
Volume
47
Issue
4
Publish Date
2000
Start Page
435
End Page
443
DOI
10.1109/10.828143

Novel techniques for MR imaging of pulmonary airspaces.

Hyperpolarized gas- and molecular oxygen-enhanced MR imaging are two new techniques for high-resolution MR imaging of pulmonary airspaces. Both techniques produce excellent images in a safe, reproducible, and technically feasible manner. Because morphologic and functional information is obtained, and radiation is not used, these techniques may prove ideal for serially evaluating patients with a variety of lung diseases that affect pulmonary ventilation, such as cystic fibrosis, emphysema, asthma, or bronchiolitis obliterans syndrome in lung transplant recipients. At present, the greatest clinical experience is with hyperpolarized He-3-enhanced MR imaging. This technique is limited, however, by the limited availability of He-3, by its polarization requirements, and by the need to tune the MR system to the resonant frequency of the gas. There is less clinical experience with oxygen-enhanced MR imaging. Although this technique produces images with more inherent noise than hyperpolarized He-3 imaging, this problem can be overcome by signal averaging. Oxygen-enhanced imaging has the major advantages of lower cost and ready availability. For oxygen-enhanced imaging, the MR imaging system does not need to be readjusted; imaging is performed at the conventional hydrogen proton frequency.

Authors
McAdams, HP; Hatabu, H; Donnelly, LF; Chen, Q; Tadamura, E; MacFall, JR
MLA Citation
McAdams, HP, Hatabu, H, Donnelly, LF, Chen, Q, Tadamura, E, and MacFall, JR. "Novel techniques for MR imaging of pulmonary airspaces." Magn Reson Imaging Clin N Am 8.1 (February 2000): 205-219.
PMID
10730243
Source
pubmed
Published In
Magnetic Resonance Imaging Clinics of North America
Volume
8
Issue
1
Publish Date
2000
Start Page
205
End Page
219

Temperature-dependent changes in physiologic parameters of spontaneous canine soft tissue sarcomas after combined radiotherapy and hyperthermia treatment.

PURPOSE: The objectives of this study were to evaluate effects of hyperthermia on tumor oxygenation, extracellular pH (pHe), and blood flow in 13 dogs with spontaneous soft tissue sarcomas prior to and after local hyperthermia. METHODS AND MATERIALS: Tumor pO2 was measured using an Eppendorf polarographic device, pHe using interstitial electrodes, and blood flow using contrast-enhanced magnetic resonance imaging (MRI). RESULTS: There was an overall improvement in tumor oxygenation observed as an increase in median pO2 and decrease in hypoxic fraction (% of pO2 measurements <5 mm Hg) at 24-h post hyperthermia. These changes were most pronounced when the median temperature (T50) during hyperthermia treatment was less than 44 degrees C. Tumors with T50 > 44 degrees C were characterized by a decrease in median PO2 and an increase in hypoxic fraction. Similar thermal dose-related changes were observed in tumor perfusion. Perfusion was significantly higher after hyperthermia. Increases in perfusion were most evident in tumors with T50 < 44 degrees C. With T50 > 44 degrees C, there was no change in perfusion after hyperthermia. On average, pHe values declined in all animals after hyperthermia, with the greatest reduction seen for larger T50 values. CONCLUSION: This study suggests that hyperthermia has biphasic effects on tumor physiologic parameters. Lower temperatures tend to favor improved perfusion and oxygenation, whereas higher temperatures are more likely to cause vascular damage, thus leading to greater hypoxia. While it has long been recognized that such effects occur in rodent tumors, this is the first report to tie such changes to temperatures achieved during hyperthermia in the clinical setting. Furthermore, it suggests that the thermal threshold for vascular damage is higher in spontaneous tumors than in more rapidly growing rodent tumors.

Authors
Vujaskovic, Z; Poulson, JM; Gaskin, AA; Thrall, DE; Page, RL; Charles, HC; MacFall, JR; Brizel, DM; Meyer, RE; Prescott, DM; Samulski, TV; Dewhirst, MW
MLA Citation
Vujaskovic, Z, Poulson, JM, Gaskin, AA, Thrall, DE, Page, RL, Charles, HC, MacFall, JR, Brizel, DM, Meyer, RE, Prescott, DM, Samulski, TV, and Dewhirst, MW. "Temperature-dependent changes in physiologic parameters of spontaneous canine soft tissue sarcomas after combined radiotherapy and hyperthermia treatment." Int J Radiat Oncol Biol Phys 46.1 (January 1, 2000): 179-185.
PMID
10656391
Source
pubmed
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
46
Issue
1
Publish Date
2000
Start Page
179
End Page
185

Measurement of apparent diffusion coefficients in human brain: Comparison of three-direction isotropic and six-direction tensor methods

Authors
Barboriak, DP; Petrella, JR; Wong, J; Ott, KC; Provenzale, JM; MacFall, JR
MLA Citation
Barboriak, DP, Petrella, JR, Wong, J, Ott, KC, Provenzale, JM, and MacFall, JR. "Measurement of apparent diffusion coefficients in human brain: Comparison of three-direction isotropic and six-direction tensor methods." RADIOLOGY 213P (November 1999): 274-274.
Source
wos-lite
Published In
Radiology
Volume
213P
Publish Date
1999
Start Page
274
End Page
274

Increased brain apparent diffusion coefficient (ADC) in children with neurofibromatosis type I: FLAIR-prepared measurements of normal-appearing grey and white matter

Authors
Eastwood, JD; MacFall, JR; Delong, DM; Provenzale, JM; Greenwood, R
MLA Citation
Eastwood, JD, MacFall, JR, Delong, DM, Provenzale, JM, and Greenwood, R. "Increased brain apparent diffusion coefficient (ADC) in children with neurofibromatosis type I: FLAIR-prepared measurements of normal-appearing grey and white matter." RADIOLOGY 213P (November 1999): 313-313.
Source
wos-lite
Published In
Radiology
Volume
213P
Publish Date
1999
Start Page
313
End Page
313

Neuroradiology keynote speaker: Time course of MR diffusion abnormalities in stroke

Authors
Provenzale, JM; Engelter, ST; Delong, DM; Petrella, JR; Smith, J; MacFall, JR
MLA Citation
Provenzale, JM, Engelter, ST, Delong, DM, Petrella, JR, Smith, J, and MacFall, JR. "Neuroradiology keynote speaker: Time course of MR diffusion abnormalities in stroke." RADIOLOGY 213P (November 1999): 441-441.
Source
wos-lite
Published In
Radiology
Volume
213P
Publish Date
1999
Start Page
441
End Page
441

Magnetic resonance assessment of cerebral perfusion in depressed cardiac patients: preliminary findings.

OBJECTIVE: The authors investigated the links between depression, cardiac disease, and microcirculatory cerebral blood flow (CBF). METHOD: A magnetic resonance imaging technique based on arterial spin tagging was used to estimate microcirculatory CBF in depressed (N = 5) and comparison (N = 14) elderly subjects with coronary artery disease. Signal intensity ratios corresponding to relative microcirculatory CBF were calculated for four regions on two axial images through the upper and lower halves of the lateral ventricles. RESULTS: On the superior image, estimates of microcirculatory CBF were statistically significantly lower on the left side in the depressed subjects than in the nondepressed group. When the ratios in the superior and inferior images were averaged, the depressed subjects had lower values for both left periventricular regions of interest and the parietal region. CONCLUSIONS: Despite the small study group and indirect estimates of blood flow, these preliminary findings suggest that a relative cerebral hypoperfusion may underlie depression in elderly cardiac patients.

Authors
Doraiswamy, PM; MacFall, J; Krishnan, KR; O'Connor, C; Wan, X; Benaur, M; Lewandowski, M; Fortner, M
MLA Citation
Doraiswamy, PM, MacFall, J, Krishnan, KR, O'Connor, C, Wan, X, Benaur, M, Lewandowski, M, and Fortner, M. "Magnetic resonance assessment of cerebral perfusion in depressed cardiac patients: preliminary findings." Am J Psychiatry 156.10 (October 1999): 1641-1643.
PMID
10518179
Source
pubmed
Published In
American Journal of Psychiatry
Volume
156
Issue
10
Publish Date
1999
Start Page
1641
End Page
1643
DOI
10.1176/ajp.156.10.1641

White matter lesion contrast in fast spin-echo fluid-attenuated inversion recovery imaging: effect of varying effective echo time and echo train length.

OBJECTIVE: Our aim was to determine whether the contrast between white matter lesions and normal-appearing white matter in fast spin-echo fluid-attenuated inversion recovery (FLAIR) images can be improved by lengthening the effective TE and the echo train length. SUBJECTS AND METHODS: Thirty patients with various white matter lesions were imaged using fast spin-echo FLAIR sequences (TR = 10,002 msec; inversion time = 2200) on a 1.5-T MR imaging system. For 14 patients, fast spin-echo FLAIR sequences with a TE of 165 msec and echo train length of 32 (fast spin-echo FLAIR 165/32) were compared with fast spin-echo FLAIR sequences with a TE of 125 msec and echo train length of 24 (fast spin-echo FLAIR 125/24). For 16 other patients, fast spin-echo FLAIR 165/32 sequences were compared with fast spin-echo FLAIR sequences with a TE of 145 msec and echo train length of 28 (fast spin-echo FLAIR 145/28). Signal difference-to-noise ratios were calculated between the lesions and normal-appearing white matter for a typical lesion in each patient. RESULTS: In both groups, a small but statistically significant increase in the signal difference-to-noise ratio was found on the fast spin-echo FLAIR sequences using the longer TE and echo train length. In the first group, signal difference-to-noise ratio increased from 18.7 +/- 4.7 (mean +/- SD) for fast spin-echo FLAIR 125/24 to 20.1 +/- 4.5 for fast spin-echo FLAIR 165/32 (p < .05). In the second group, the signal difference-to-noise ratio increased from 15.4 +/- 4.0 for fast spin-echo FLAIR 145/28 to 16.8 +/- 4.6 for fast spin-echo FLAIR 165/32 (p <.01). In addition, fast spin-echo FLAIR sequences with a longer TE and echo train length were obtained more rapidly (6 min for fast spin-echo FLAIR 125/24, 5 min 20 sec for fast spin-echo FLAIR 145/28, and 4 min 41 sec for fast spin-echo FLAIR 165/32). CONCLUSION: Lengthening the TE to 165 msec and echo train length to 32 in fast spin-echo FLAIR imaging allows both a mild improvement in the contrast between white matter lesions and normal-appearing white matter and shorter imaging times.

Authors
Barboriak, DP; Provenzale, JM; MacFall, JR
MLA Citation
Barboriak, DP, Provenzale, JM, and MacFall, JR. "White matter lesion contrast in fast spin-echo fluid-attenuated inversion recovery imaging: effect of varying effective echo time and echo train length." AJR Am J Roentgenol 173.4 (October 1999): 1091-1096.
PMID
10511185
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
173
Issue
4
Publish Date
1999
Start Page
1091
End Page
1096
DOI
10.2214/ajr.173.4.10511185

Spatially resolved measurements of hyperpolarized gas properties in the lung in vivo. Part II: T *(2).

The transverse relaxation time, T *(2), of hyperpolarized (HP) gas in the lung in vivo is an important parameter for pulse sequence optimization and image contrast. We obtained T *(2) maps of HP (3)He and (129)Xe in guinea pig lungs (n = 17) and in human lungs. Eight different sets of (3)He guinea pig studies were acquired, with variation of slice selection, tidal volume, and oxygen level. For example, for a (3)He tidal volume of 3 cm(3) and no slice selection, the average T *(2) in the trachea was 14.7 ms and 8.0 ms in the intrapulmonary airspaces. The equivalent (129)Xe experiment yielded an average T *(2) of 40.8 ms in the trachea and 18.5 ms in the intrapulmonary airspaces. The average (3)He T *(2) in the human intrapulmonary airspaces was 9.4 ms. The relaxation behavior was predicted by treating the lung as a porous medium, resulting in good agreement between estimated and measured T *(2) values in the intrapulmonary airspaces. Magn Reson Med 42:729-737, 1999.

Authors
Chen, XJ; Möller, HE; Chawla, MS; Cofer, GP; Driehuys, B; Hedlund, LW; MacFall, JR; Johnson, GA
MLA Citation
Chen, XJ, Möller, HE, Chawla, MS, Cofer, GP, Driehuys, B, Hedlund, LW, MacFall, JR, and Johnson, GA. "Spatially resolved measurements of hyperpolarized gas properties in the lung in vivo. Part II: T *(2)." Magn Reson Med 42.4 (October 1999): 729-737.
PMID
10502762
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
42
Issue
4
Publish Date
1999
Start Page
729
End Page
737

Hyperpolarized 3He-enhanced MR imaging of lung transplant recipients: preliminary results.

OBJECTIVE: Bronchiolitis obliterans syndrome is the major cause of long-term graft failure in lung transplant recipients and may be partially reversible if diagnosed early and treated. Diagnosis is difficult because findings of transbronchial biopsy are often negative in patients with early disease. We are investigating a novel MR ventilation agent, hyperpolarized 3He, for evaluating ventilatory abnormalities in lung transplant recipients with suspected bronchiolitis obliterans syndrome. CONCLUSION: In this preliminary study, the extent of ventilatory defects revealed on 3He-enhanced MR images correlated with severity of bronchiolitis obliterans syndrome using an established clinical grading system. This new technique may hold potential for diagnosing bronchiolitis obliterans syndrome in lung transplant recipients.

Authors
McAdams, HP; Palmer, SM; Donnelly, LF; Charles, HC; Tapson, VF; MacFall, JR
MLA Citation
McAdams, HP, Palmer, SM, Donnelly, LF, Charles, HC, Tapson, VF, and MacFall, JR. "Hyperpolarized 3He-enhanced MR imaging of lung transplant recipients: preliminary results." AJR Am J Roentgenol 173.4 (October 1999): 955-959.
PMID
10511156
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
173
Issue
4
Publish Date
1999
Start Page
955
End Page
959
DOI
10.2214/ajr.173.4.10511156

Pitfalls in myocardial perfusion assessment with dynamic MR imaging after administration of a contrast material bolus in dogs.

RATIONALE AND OBJECTIVES: The authors evaluated the artifacts observed on myocardial perfusion curves derived from an inversion-prepared fast gradient-echo (GRE) imaging sequence in dogs after injection of a gadolinium-based contrast agent. MATERIALS AND METHODS: Six mongrel dogs were divided into three groups. In groups 1 and 2, anesthesia was maintained with pentobarbital. Group 2 also received an intravenous injection of atropine (0.03 mg/kg). In group 3, anesthesia was maintained with isoflurane (1.0%). Imaging was performed on a 1.5-T magnetic resonance (MR) imaging unit (one section per heart beat, a 30 x 15-cm field of view, 10-mm section thickness, and 64-kHz bandwidth). Region-of-interest (ROI) markers were placed on the blood pool of the left intraventricular cavity, anterior wall of the left ventricle, and anterior to the chest wall to track respiratory motion. RESULTS: In group 1, the signal intensity (SI) periodically increased during each inspiration due to respiratory sinus arrhythmia. The relation between the SI increase and the variation of the delay between images was demonstrated in vitro and by computer simulations. No periodic increase of the SI was observed when regular cardiac rhythm was maintained by pharmacologic inhibition of the vagal-mediated chronotropic response with either the addition of atropine to pentobarbital or the use of isoflurane as the anesthetic agent. CONCLUSION: In an inversion-prepared fast GRE sequence, respiratory sinus arrhythmia can induce periodic SI increase by varying the respiratory rate interval and delay between images.

Authors
Vallée, JP; MacFall, JR; Lazeyras, F; Wheeler, T; Hedlund, LW; Spritzer, CE; Coleman, RE; Sostman, HD
MLA Citation
Vallée, JP, MacFall, JR, Lazeyras, F, Wheeler, T, Hedlund, LW, Spritzer, CE, Coleman, RE, and Sostman, HD. "Pitfalls in myocardial perfusion assessment with dynamic MR imaging after administration of a contrast material bolus in dogs." Acad Radiol 6.9 (September 1999): 512-520.
PMID
10894059
Source
pubmed
Published In
Academic Radiology
Volume
6
Issue
9
Publish Date
1999
Start Page
512
End Page
520
DOI
10.1016/S1076-6332(99)80428-0

Cystic fibrosis: combined hyperpolarized 3He-enhanced and conventional proton MR imaging in the lung--preliminary observations.

Four patients with cystic fibrosis (CF) were examined with combined hyperpolarized helium 3-enhanced and conventional proton magnetic resonance (MR) imaging. After inhalation of the polarized 3He gas, single breath-hold, gradient-echo images (resonant frequency of 3He) were obtained to depict lung ventilation. Conventional T2-weighted fast spin-echo (hydrogen) images were also obtained to depict morphologic abnormalities. 3He images were successfully and reproducibly generated that showed both morphologic abnormalities and, often more extensive, ventilation abnormalities. 3He MR imaging may provide a method for evaluating progression of pulmonary disease in patients with CF.

Authors
Donnelly, LF; MacFall, JR; McAdams, HP; Majure, JM; Smith, J; Frush, DP; Bogonad, P; Charles, HC; Ravin, CE
MLA Citation
Donnelly, LF, MacFall, JR, McAdams, HP, Majure, JM, Smith, J, Frush, DP, Bogonad, P, Charles, HC, and Ravin, CE. "Cystic fibrosis: combined hyperpolarized 3He-enhanced and conventional proton MR imaging in the lung--preliminary observations." Radiology 212.3 (September 1999): 885-889.
PMID
10478261
Source
pubmed
Published In
Radiology
Volume
212
Issue
3
Publish Date
1999
Start Page
885
End Page
889
DOI
10.1148/radiology.212.3.r99se20885

Hyperpolarized helium-3 magnetic resonance imaging of bronchiolitis obliterans syndrome in lung transplant recipients.

Authors
Palmer, SM; McAdams, HP; MacFall, JR; Donnelly, L; Davis, RD; Tapson, VF
MLA Citation
Palmer, SM, McAdams, HP, MacFall, JR, Donnelly, L, Davis, RD, and Tapson, VF. "Hyperpolarized helium-3 magnetic resonance imaging of bronchiolitis obliterans syndrome in lung transplant recipients." AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE 159.3 (March 1999): A276-A276.
Source
wos-lite
Published In
American journal of respiratory and critical care medicine
Volume
159
Issue
3
Publish Date
1999
Start Page
A276
End Page
A276

Use of MR exponential diffusion-weighted images to eradicate T2 "shine-through" effect.

Authors
Provenzale, JM; Engelter, ST; Petrella, JR; Smith, JS; MacFall, JR
MLA Citation
Provenzale, JM, Engelter, ST, Petrella, JR, Smith, JS, and MacFall, JR. "Use of MR exponential diffusion-weighted images to eradicate T2 "shine-through" effect." AJR Am J Roentgenol 172.2 (February 1999): 537-539.
PMID
9930819
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
172
Issue
2
Publish Date
1999
Start Page
537
End Page
539
DOI
10.2214/ajr.172.2.9930819

Performance of a high-temperature superconducting probe for in vivo microscopy at 2.0 T.

The use of a high-temperature superconducting probe for in vivo magnetic resonance microscopy at 2 T is described. To evaluate the performance of the probe, a series of SNR comparisons are carried out. The SNR increased by a factor of 3.7 compared with an equivalent copper coil. Quantitative measures of the SNR gain are in good agreement with theoretical predictions. A number of issues that are unique to the application of HTS coils are examined, including the difficulty in obtaining homogenous excitation without degrading the SNR of the probe. The use of the HTS probe in transmit-receive mode is simple to implement but results in nonuniform excitation. The effect of using the probe in this mode of operation on the T1 and T2 contrast is investigated. Methods for improving homogeneity are explored, such as employing a transmit volume coil. It is found that the cost of using an external transmit coil is an increased probe noise temperature and a reduced SNR by approximately 30%. Other important aspects of the probe are considered, including the effect of temperature on probe stability. Three-dimensional in vivo imaging sets are acquired to assess the stability of the probe for long scans. High-resolution images of the rat brain demonstrate the utility of the probe for microscopy applications.

Authors
Miller, JR; Hurlston, SE; Ma, QY; Face, DW; Kountz, DJ; MacFall, JR; Hedlund, LW; Johnson, GA
MLA Citation
Miller, JR, Hurlston, SE, Ma, QY, Face, DW, Kountz, DJ, MacFall, JR, Hedlund, LW, and Johnson, GA. "Performance of a high-temperature superconducting probe for in vivo microscopy at 2.0 T." Magn Reson Med 41.1 (January 1999): 72-79.
PMID
10025613
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
41
Issue
1
Publish Date
1999
Start Page
72
End Page
79

Posterior and frontal activation by auditory targets and novel sounds: An event-related functional magnetic resonance imaging study

Authors
Hinton, SC; MacFall, JR; McCarthy, G
MLA Citation
Hinton, SC, MacFall, JR, and McCarthy, G. "Posterior and frontal activation by auditory targets and novel sounds: An event-related functional magnetic resonance imaging study." NeuroImage 9.6 PART II (1999): S793-.
Source
scival
Published In
NeuroImage
Volume
9
Issue
6 PART II
Publish Date
1999
Start Page
S793

Magnetic resonance image guided thermal therapy with a radiofrequency phased array

Radiofrequency (RF) thermal therapy in malignant target sites in lower extremity was monitored using magnetic resonance (MR) chemical shift imaging. The technique worked extremely well in the phantom setting. In the translation to in vivo applications, the results were degraded relative to phantoms with regard to the signal to noise obtained. Even though the current precision is approximately 1.0 °C and less than desirable, the method was extremely useful with regards to feedback information for steering the absorbed energy pattern during therapy.

Authors
Samulski, TV; Jones, E; Henke, F; Buffalo, T; Clegg, ST; MacFall, JM
MLA Citation
Samulski, TV, Jones, E, Henke, F, Buffalo, T, Clegg, ST, and MacFall, JM. "Magnetic resonance image guided thermal therapy with a radiofrequency phased array." Proceedings of SPIE - The International Society for Optical Engineering 3594 (1999): 124-128.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3594
Publish Date
1999
Start Page
124
End Page
128

Frontal cortex activation by auditory targets and novel sounds: An event-related functional magnetic resonance imaging study.

Authors
Hinton, SC; MacFall, JR; McCarthy, G
MLA Citation
Hinton, SC, MacFall, JR, and McCarthy, G. "Frontal cortex activation by auditory targets and novel sounds: An event-related functional magnetic resonance imaging study." JOURNAL OF COGNITIVE NEUROSCIENCE (1999): 102-103.
Source
wos-lite
Published In
Journal of Cognitive Neuroscience
Publish Date
1999
Start Page
102
End Page
103

Hyperpolarized He-3 enhanced MR pulmonary imaging in cystic fibrosis: Preliminary observations

Authors
Donnelly, LF; MacFall, JR; Majure, JM; Smith, J; Frush, DP; Ravin, CE
MLA Citation
Donnelly, LF, MacFall, JR, Majure, JM, Smith, J, Frush, DP, and Ravin, CE. "Hyperpolarized He-3 enhanced MR pulmonary imaging in cystic fibrosis: Preliminary observations." RADIOLOGY 209P (November 1998): 440-441.
Source
wos-lite
Published In
Radiology
Volume
209P
Publish Date
1998
Start Page
440
End Page
441

Optimization of interscanner reproducibility of apparent diffusion coefficient measurements in the human brain using a phantom derived scaling factor

Authors
Petrella, JR; Engelter, ST; Provenzale, JM; Goldwag, SS; MacFall, JR
MLA Citation
Petrella, JR, Engelter, ST, Provenzale, JM, Goldwag, SS, and MacFall, JR. "Optimization of interscanner reproducibility of apparent diffusion coefficient measurements in the human brain using a phantom derived scaling factor." RADIOLOGY 209P (November 1998): 469-469.
Source
wos-lite
Published In
Radiology
Volume
209P
Publish Date
1998
Start Page
469
End Page
469

Patient age correlates with increasing apparent diffusion coefficient of white matter on diffusion-weighted MR imaging

Authors
Engelter, ST; Provenzale, JM; Farrelly, MK; Petrella, JR; MacFall, JR
MLA Citation
Engelter, ST, Provenzale, JM, Farrelly, MK, Petrella, JR, and MacFall, JR. "Patient age correlates with increasing apparent diffusion coefficient of white matter on diffusion-weighted MR imaging." RADIOLOGY 209P (November 1998): 200-201.
Source
wos-lite
Published In
Radiology
Volume
209P
Publish Date
1998
Start Page
200
End Page
201

Functional MRI of the rat somatosensory cortex: effects of hyperventilation.

Functional mapping of the rat somatosensory cortex was performed with T2*-sensitized MRI using a forepaw electrical stimulation model in alpha-chloralose-anesthetized rats at 7 T under both normocapnia and mild hyperventilation-induced hypocapnia. A highly localized activation area, consistent with the known somatosensory cortical region, was detected in all seven animals studied during hypocapnia and in five of the same animals during normocapnia. Quantitatively, hypocapnia was found to significantly increase both the size of the fMRI activation area (3.4 +/- 0.6 mm2 versus 1.5 +/- 0.6 mm2 in normocapnia, mean +/- standard error, n = 7, P < 0.03) and the average fMRI signal intensity increase (3.4 +/- 0.6% versus 2.7 +/- 0.4%, n = 5, P < 0.05). The increased sensitivity of fMRI to functional activation may reflect a widened arterial-venous oxygenation difference resulting from an increased effective oxygen extraction during hyperventilation. The dependence of the fMRI response on the ventilation state underscores the need to control for physiological parameters in animal fMRI studies.

Authors
Hsu, EW; Hedlund, LW; MacFall, JR
MLA Citation
Hsu, EW, Hedlund, LW, and MacFall, JR. "Functional MRI of the rat somatosensory cortex: effects of hyperventilation." Magn Reson Med 40.3 (September 1998): 421-426.
PMID
9727945
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
40
Issue
3
Publish Date
1998
Start Page
421
End Page
426

Single-shot, variable flip-angle slice-selective excitation with four gradient-modulated adiabatic half-passage segments.

Adiabatic pulses, although useful in generating uniform spin nutation in the presence of inhomogeneous B1 fields, are limited for NMR imaging applications due to the lack of slice-selective excitation capability. Selective excitation techniques using gradient modulation have been introduced; however, present methods require either a minimum of two excitations or eight adiabatic segments. Here, a scheme is presented that allows single-shot, arbitrary flip-angle, and slice-selective excitation with only four adiabatic half-passage segments. The technique is demonstrated via computer simulation and experimental tests on a phantom. Furthermore, issues associated with the implementation of these gradient-modulated adiabatic pulses are discussed.

Authors
Hsu, EW; Reeder, SB; MacFall, JR
MLA Citation
Hsu, EW, Reeder, SB, and MacFall, JR. "Single-shot, variable flip-angle slice-selective excitation with four gradient-modulated adiabatic half-passage segments." Magn Reson Med 40.2 (August 1998): 334-340.
PMID
9702716
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
40
Issue
2
Publish Date
1998
Start Page
334
End Page
340

Quantification of myocardial perfusion by MRI after coronary occlusion.

The objectives of this study were to define the relationship between the first order constant of Gd-DTPA transfer (K1) and the myocardial blood flow (MBF) at rest and to compare it with an equivalent relationship obtained for positron emission tomography (PET). In a canine model of permanent coronary occlusion (n = 4), myocardial and blood time concentration curves obtained by 13N-ammonia PET and Gd-DTPA-enhanced MRI were fitted by a one-compartment model to determine K1. A linear relationship was observed between MRI-derived K1 and MBF measured by microspheres (K1 = 0.88 x flow -0.015, R = 0.95), which compares favorably with the equivalent relationship derived from PET (K1 = 0.74 x flow +0.16, R = 0.88). The results of this preliminary study suggest that, at rest and distal to a permanently occluded coronary artery, myocardial perfusion quantification by MRI is possible and can challenge PET.

Authors
Vallée, JP; Sostman, HD; MacFall, JR; DeGrado, TR; Zhang, J; Sebbag, L; Cobb, FR; Wheeler, T; Hedlund, LW; Turkington, TG; Spritzer, CE; Coleman, RE
MLA Citation
Vallée, JP, Sostman, HD, MacFall, JR, DeGrado, TR, Zhang, J, Sebbag, L, Cobb, FR, Wheeler, T, Hedlund, LW, Turkington, TG, Spritzer, CE, and Coleman, RE. "Quantification of myocardial perfusion by MRI after coronary occlusion." Magn Reson Med 40.2 (August 1998): 287-297.
PMID
9702711
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
40
Issue
2
Publish Date
1998
Start Page
287
End Page
297

Simultaneous multislice acquisition with arterial-flow tagging (SMART) using echo planar imaging (EPI).

Arterial spin tagging techniques have been used to image tissue perfusion in MR without contrast injection or ionizing radiation. Currently, spin tagging studies are performed primarily using single-slice imaging sequences, which are time consuming. This note reports a multislice echo-planar arterial spin tagging technique (Simultaneous Multislice Acquisition with aRterial-flow Tagging, or "SMART"). Multiband RF encoding (Hadamard) is used to provide simultaneous multislice acquisition capability for spin tagging techniques (such as echo planar imaging signal targeting with alternating radio frequency and flow-sensitive alternative inversion recovery). The method is illustrated with a two-slice pulse sequence that was implemented using the FAIR technique to generate two perfusion weighted images simultaneously. Compared with single-slice sequences, this two-slice sequence provided similar image quality, signal-to-noise ratio, and twice the spatial coverage compared with the single-slice technique within the same scan time.

Authors
Kao, YH; Wan, X; MacFall, JR
MLA Citation
Kao, YH, Wan, X, and MacFall, JR. "Simultaneous multislice acquisition with arterial-flow tagging (SMART) using echo planar imaging (EPI)." Magn Reson Med 39.4 (April 1998): 662-665.
PMID
9543431
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
39
Issue
4
Publish Date
1998
Start Page
662
End Page
665

Magnetic resonance thermometry during hyperthermia for human high-grade sarcoma.

PURPOSE: To determine the feasibility of measuring temperature noninvasively with magnetic resonance imaging during hyperthermia treatment of human tumors. METHODS: The proton chemical shift detected using phase-difference magnetic resonance imaging (MRI) was used to measure temperature in phantoms and human tumors during treatment with hyperthermia. Four adult patients having high-grade primary sarcoma tumors of the lower leg received 5 hyperthermia treatments in the MR scanner using an MRI-compatible radiofrequency heating applicator. Prior to each treatment, an average of 3 fiberoptic temperature probes were invasively placed into the tumor (or phantom). Hyperthermia was applied concurrent with MR thermometry. Following completion of the treatment, regions of interest (ROI) were defined on MR phase images at each temperature probe location, in bone marrow, and in gel standards placed outside the heated region. The median phase difference (compared to pretreatment baseline images) was calculated for each ROI. This phase difference was corrected for phase drift observed in standards and bone marrow. The observed phase difference, with and without corrections, was correlated with the fiberoptic temperature measurements. RESULTS: The phase difference observed with MRI was found to correlate with temperature. Phantom measurements demonstrated a linear regression coefficient of 4.70 degrees phase difference per degree Celsius, with an R2 = 0.998. After human images with artifact were excluded, the linear regression demonstrated a correlation coefficient of 5.5 degrees phase difference per degree Celsius, with an R2 = 0.84. In both phantom and human treatments, temperature measured via corrected phase difference closely tracked measurements obtained with fiberoptic probes during the hyperthermia treatments. CONCLUSIONS: Proton chemical shift imaging with current MRI and hyperthermia technology can be used to monitor and control temperature during treatment of large tumors in the distal lower extremity.

Authors
Carter, DL; MacFall, JR; Clegg, ST; Wan, X; Prescott, DM; Charles, HC; Samulski, TV
MLA Citation
Carter, DL, MacFall, JR, Clegg, ST, Wan, X, Prescott, DM, Charles, HC, and Samulski, TV. "Magnetic resonance thermometry during hyperthermia for human high-grade sarcoma." Int J Radiat Oncol Biol Phys 40.4 (March 1, 1998): 815-822.
PMID
9531365
Source
pubmed
Published In
International Journal of Radiation Oncology, Biology, Physics
Volume
40
Issue
4
Publish Date
1998
Start Page
815
End Page
822

Reproducibility of ventilation patterns observed using hyperpolarized 3He MRI in normal volunteers

Authors
MacFall, JR; Charles, HC; Ravin, CE
MLA Citation
MacFall, JR, Charles, HC, and Ravin, CE. "Reproducibility of ventilation patterns observed using hyperpolarized 3He MRI in normal volunteers." RADIOLOGY 206.2 (February 1998): 575-576.
Source
wos-lite
Published In
Radiology
Volume
206
Issue
2
Publish Date
1998
Start Page
575
End Page
576

MR microscopy of lung airways with hyperpolarized 3He.

A technique using hyperpolarized (HP) 3He to image the small airways of the lung by using moderate flip angles and a short scanning period during early inspiration is demonstrated. Flip angles (alpha) ranging from 10-90 degrees were used in guinea pig experiments with scanning during the entire inspiration period. A second series acquired data throughout a short window of the ventilatory cycle with alpha = 45 degrees. The success of the animal studies has motivated implementation of similar imaging techniques in the clinical arena. Human studies involved imaging over the total inspiration period with alpha approximately 10 degrees. The first series of guinea pig experiments demonstrated that larger flip angles (50-90 degrees) destroy the magnetization before it reaches the smaller airways. At moderate flip angles (20-40 degrees), airway branching down to the fourth generation was apparent. Fifth-order branchings were seen in the images of the second series. The trachea down to fourth generation pulmonary airway branching, along with some distal air spaces, was seen in the human lung images.

Authors
Chen, XJ; Chawla, MS; Hedlund, LW; Möller, HE; MacFall, JR; Johnson, GA
MLA Citation
Chen, XJ, Chawla, MS, Hedlund, LW, Möller, HE, MacFall, JR, and Johnson, GA. "MR microscopy of lung airways with hyperpolarized 3He." Magn Reson Med 39.1 (January 1998): 79-84.
PMID
9438440
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
39
Issue
1
Publish Date
1998
Start Page
79
End Page
84

A new window into the lung

Authors
Johnson, GA; Hedlund, L; MacFall, J
MLA Citation
Johnson, GA, Hedlund, L, and MacFall, J. "A new window into the lung." Physics World 11.11 (1998): 35-38.
Source
scival
Published In
Physics World
Volume
11
Issue
11
Publish Date
1998
Start Page
35
End Page
38

Overview of diffusion imaging

Diffusion is a major advance in the continuing evolution of MR imaging. It provides contrast and characterization between tissues at a cellular level that may imply differences in function as well as framework. With the development of echo-planar imaging (EPI) diffusion the quality of the data will be such that clinically relevant information can result, and thus clinical usage of EPI diffusion will increase. Many potential applications of diffusion have not yet been explored.

Authors
Gray, L; MacFall, J
MLA Citation
Gray, L, and MacFall, J. "Overview of diffusion imaging." Magnetic Resonance Imaging Clinics of North America 6.1 (1998): 125-138.
Source
scival
Published In
Magnetic Resonance Imaging Clinics of North America
Volume
6
Issue
1
Publish Date
1998
Start Page
125
End Page
138

Hyperthermic treatment of malignant diseases: current status and a view toward the future.

New studies in hyperthermia at the basic science, engineering, and clinical level have stimulated renewed enthusiasm for re-investigating its potential as an anticancer therapy. This article reviews the salient features of these recent results and points out areas for additional investigation. Highlighting these new results is the publication of several positive phase III trials for thermoradiotherapy compared to radiotherapy alone. Important highlights are the encouraging results using magnetic resonance imaging for noninvasive thermometry. If this technology is successfully implemented with real time power control it will revolutionize the clinical application of hyperthermia.

Authors
Dewhirst, MW; Prosnitz, L; Thrall, D; Prescott, D; Clegg, S; Charles, C; MacFall, J; Rosner, G; Samulski, T; Gillette, E; LaRue, S
MLA Citation
Dewhirst, MW, Prosnitz, L, Thrall, D, Prescott, D, Clegg, S, Charles, C, MacFall, J, Rosner, G, Samulski, T, Gillette, E, and LaRue, S. "Hyperthermic treatment of malignant diseases: current status and a view toward the future." Semin Oncol 24.6 (December 1997): 616-625. (Review)
PMID
9422258
Source
pubmed
Published In
Seminars in Oncology
Volume
24
Issue
6
Publish Date
1997
Start Page
616
End Page
625

MRI quantitative myocardial perfusion with compartmental analysis: a rest and stress study.

K1 (first-order transfer constant from arterial plasma to myocardium for Gd-DTPA) and Vd (distribution volume of Gd-DTPA in myocardium) were measured in vivo in a canine model (n = 5) using MRI-derived myocardial perfusion curves and a compartmental model. Perfusion curves were obtained after a bolus injection of Gd-DTPA (0.04 mM/kg) with an inversion-prepared fast gradient echo sequence. Myocardium and blood signal intensity were converted to a concentration of Gd-DTPA, according to a model appropriate for short (<1 s) interimage intervals characteristic of cardiac-triggered acquisitions. Before dipyridamole-induced stress, K1 and Vd, obtained from the fit of the MRI-derived perfusion curves, were 6.2 +/- 1.4 (mHz) and 17.5 +/- 4.2%, respectively. After dipyridamole infusion, a K1 increase of a factor of 2.82 +/- 0.72 was measured (P = 0.003). No change was observed in Vd (P = 0.98). These results suggest that the K1 increase after dipyridamole reflects a flow-related effect that can be useful to quantify the MRI-derived perfusion curves.

Authors
Vallée, JP; Sostman, HD; MacFall, JR; Wheeler, T; Hedlund, LW; Spritzer, CE; Coleman, RE
MLA Citation
Vallée, JP, Sostman, HD, MacFall, JR, Wheeler, T, Hedlund, LW, Spritzer, CE, and Coleman, RE. "MRI quantitative myocardial perfusion with compartmental analysis: a rest and stress study." Magn Reson Med 38.6 (December 1997): 981-989.
PMID
9402200
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
38
Issue
6
Publish Date
1997
Start Page
981
End Page
989

Age and sex effects on brain morphology.

1. Brain morphology can be assessed readily in vivo using magnetic resonance imaging (MRI). 2. In this study, the effects of age and sex on whole-brain morphology were examined using an operator-controlled computer-segmentation protocol. 3. Results indicated that age was associated with gray-matter volume reduction. 4. Brain-size differences between males and females were primarily attributable to white-matter volume. 5. This study confirms the importance of controlling for age and sex in brain-morphology studies.

Authors
Passe, TJ; Rajagopalan, P; Tupler, LA; Byrum, CE; MacFall, JR; Krishnan, KR
MLA Citation
Passe, TJ, Rajagopalan, P, Tupler, LA, Byrum, CE, MacFall, JR, and Krishnan, KR. "Age and sex effects on brain morphology." Prog Neuropsychopharmacol Biol Psychiatry 21.8 (November 1997): 1231-1237.
PMID
9460088
Source
pubmed
Published In
Progress in Neuro-Psychopharmacology & Biological Psychiatry
Volume
21
Issue
8
Publish Date
1997
Start Page
1231
End Page
1237

Flow quantification using fast cine phase-contrast MR imaging, conventional cine phase-contrast MR imaging, and Doppler sonography: in vitro and in vivo validation.

OBJECTIVE: Our purpose was to assess the accuracy of measurements of flow velocity and volume flow rate in an in vitro phantom and in healthy human volunteers using a cardiac-gated, segmented K-space, fast cine phase-contrast (PC) MR imaging technique with view sharing (fast PC). We compared this method with conventional cine PC MR imaging and Doppler sonography. SUBJECTS AND METHODS: Pulsatile flow was generated in a flow phantom that consisted of a cylindric tube having various degrees of tapered stenosis. Phase-encoded velocity maps were obtained using cine PC and fast PC MR imaging. Doppler sonography was also performed. Measurements of aortic and pulmonary artery peak systolic and minimum diastolic velocity and volume flow rate were then compared in eight healthy volunteers using the three imaging techniques. RESULTS: We found excellent agreement between fast PC and cine PC measurements of peak systolic velocity when regions of interest were drawn to exclude vessel margins (r > .99 for phantom studies, and r = .80 for human studies). Correlation between minimum diastolic velocity measurements by MR imaging was limited by noise that resulted from high encoding velocity settings. However, such correlation improved with signal averaging. When compared with predicted values of volume flow rates, both cine PC (r > .99) and fast PC (r = .97) MR imaging were more accurate than Doppler sonography (r = .78) in vitro. Measurements of cardiac output were adversely affected by low signal to noise, especially during diastole; estimates based on systolic forward flow resulted in better agreement between the two MR imaging methods. CONCLUSION: Fast PC MR flow quantification may prove to be a useful adjunct to routine MR studies for measurements of peak flow velocity. However, estimates of volume flow rate using fast PC MR imaging are limited because of increased noise during low diastolic flow as well as edge artifacts.

Authors
Lee, VS; Spritzer, CE; Carroll, BA; Pool, LG; Bernstein, MA; Heinle, SK; MacFall, JR
MLA Citation
Lee, VS, Spritzer, CE, Carroll, BA, Pool, LG, Bernstein, MA, Heinle, SK, and MacFall, JR. "Flow quantification using fast cine phase-contrast MR imaging, conventional cine phase-contrast MR imaging, and Doppler sonography: in vitro and in vivo validation." AJR Am J Roentgenol 169.4 (October 1997): 1125-1131.
PMID
9308476
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
169
Issue
4
Publish Date
1997
Start Page
1125
End Page
1131
DOI
10.2214/ajr.169.4.9308476

Quantification of myocardial perfusion with MRI and exogenous contrast agents.

This review discusses the applications of MRI to quantification of the myocardial perfusion. The first step of the measurement is to obtain a concentration-time curve from a signal intensity-time (SI) curve. Factors which influence the correlation between SI and the concentration are discussed for relaxivity and susceptibility agents. The second stage of measurement is to extract parameters of myocardial perfusion from the concentration-time curve. Two methods are considered, one for an intravascular agent and the other for an extravascular agent. Key points are illustrated with experimental data.

Authors
Vallée, JP; Sostman, HD; MacFall, JR; Coleman, RE
MLA Citation
Vallée, JP, Sostman, HD, MacFall, JR, and Coleman, RE. "Quantification of myocardial perfusion with MRI and exogenous contrast agents." Cardiology 88.1 (January 1997): 90-105. (Review)
PMID
8960631
Source
pubmed
Published In
Cardiology
Volume
88
Issue
1
Publish Date
1997
Start Page
90
End Page
105

Brain tumor segmentation and display using dual-echo MR images

Dual-echo MR brain images provide good contrast between tumors and normal tissues, and they are routine acquired for brain-tumor patients. Segmentation of brain tumors based on these images is useful for treatment planning and follow-up. We report the segmentation of a brain tumor on dual- echo MR images using a combined vector decomposition and probability method. Three-dimensional displays of tumor and skin surface are presented.

Authors
Kao, YH; Sorenson, JA; MacFall, JR; Wan, X
MLA Citation
Kao, YH, Sorenson, JA, MacFall, JR, and Wan, X. "Brain tumor segmentation and display using dual-echo MR images." Chinese Journal of Radiology 22.3 (1997): 105-109.
Source
scival
Published In
Zhonghua fang she xian yi xue za zhi = Chinese journal of radiology
Volume
22
Issue
3
Publish Date
1997
Start Page
105
End Page
109

Potential of MR imaging with hyperpolarized He-3 in lung air spaces

Authors
MacFall, JR; Charles, HC; Black, RD; Happer, W; Middleton, H; Ravin, CE
MLA Citation
MacFall, JR, Charles, HC, Black, RD, Happer, W, Middleton, H, and Ravin, CE. "Potential of MR imaging with hyperpolarized He-3 in lung air spaces." RADIOLOGY 201 (November 1996): 403-403.
Source
wos-lite
Published In
Radiology
Volume
201
Publish Date
1996
Start Page
403
End Page
403

Accuracy and reproducibility of brain and tissue volumes using a magnetic resonance segmentation method.

Magnetic resonance (MR) imaging now allows the qualitative and quantitative assessment of the human brain in vivo. As MR imaging resolution has improved, precise measurement of small brain structures has become possible. Methods of measuring brain regions from MR images include both manual and semiautomated methods. Despite the development of numerous volumetric methods, there have been only limited attempts so far to evaluate the accuracy and reproducibility of these methods. In this study we used phantoms to assess the accuracy of the segmentation process. Our results with simple and complex phantoms indicate an error of 3-5% using either manual or semiautomated techniques. We subsequently used manual and semiautomated volumetric methodologies to study human brain structures in vivo in five normal subjects. Supervised segmentation is a semiautomated method that accomplishes the division of MR images into several tissue types based on differences in signal intensity. This technique requires the operator to manually identify points on the MR images that characterize each tissue type, a process known as seeding. However, the use of supervised segmentation to assess the volumes of gray and white matter is subject to pitfalls. Inhomogeneities of the radiofrequency or magnetic fields can result in misclassification of tissue points during the tissue seeding process, limiting the accuracy and reliability of the segmentation process. We used a structured seeding protocol that allowed for field inhomogeneity that produced reduced variation in measured tissue volumes. We used repeated segmentations to assess intra- and inter-rater reliability, and were able to measure small and large regions of interest with a small degree of variation. In addition, we demonstrated that measurements are reproducible with repeat MR acquisitions, with minimal interscan variability. Segmentation methods can accurately and reliably measure subtle morphometric changes, and will prove a boon to the study of neuropsychiatric disorders.

Authors
Byrum, CE; MacFall, JR; Charles, HC; Chitilla, VR; Boyko, OB; Upchurch, L; Smith, JS; Rajagopalan, P; Passe, T; Kim, D; Xanthakos, S; Ranga, K; Krishnan, R
MLA Citation
Byrum, CE, MacFall, JR, Charles, HC, Chitilla, VR, Boyko, OB, Upchurch, L, Smith, JS, Rajagopalan, P, Passe, T, Kim, D, Xanthakos, S, Ranga, K, and Krishnan, R. "Accuracy and reproducibility of brain and tissue volumes using a magnetic resonance segmentation method." Psychiatry Res 67.3 (October 7, 1996): 215-234.
PMID
8912960
Source
pubmed
Published In
Psychiatry Research
Volume
67
Issue
3
Publish Date
1996
Start Page
215
End Page
234

1H MRI phase thermometry in vivo in canine brain, muscle, and tumor tissue.

The temperature sensitivity of the chemical shift of water (approximately 0.01 ppm/degree C) provides a potential method to monitor temperature changes in vivo or in vitro through the changes in phase of a gradient-echo magnetic resonance (MR) image. This relation was studied at 1.5 T in gel materials and in vivo in canine brain and muscle tissue, heated with a radio frequency (rf) annular phased array hyperthermia antenna. The rf fields associated with heating (130 MHz) and imaging (64 MHz) were decoupled using bandpass filters providing isolation in excess of 100 dB, thus allowing simultaneous imaging and rf heating without deterioration of the MR image signal-to-noise ratio. In a gel, temperature sensitivity of the MR image phase was observed to be (4.41 +/- 0.02) phase degrees/degree C for Te = 20 ms, which allowed temperature changes of 0.22 degree C to be resolved for a 50-mm3 region in less than 10 s of data acquisition. In vivo, for Te = 20 ms, the temperature sensitivity was (3.2 +/- 0.1) phase degrees/degree C for brain tissue, (3.1 +/- 0.1) phase degrees/degree C for muscle, and (3.0 +/- 0.2) phase degrees/degree C for a muscle tumor (sarcoma), allowing temperature changes of 0.6 degree C to be resolved in a 16-mm3 volume in less than 10 s of data acquisition. We conclude that, while the technique is very sensitive to magnetic field inhomogeneity, stability, and subject motion, it appears to be useful for in vivo temperature change measurement.

Authors
MacFall, JR; Prescott, DM; Charles, HC; Samulski, TV
MLA Citation
MacFall, JR, Prescott, DM, Charles, HC, and Samulski, TV. "1H MRI phase thermometry in vivo in canine brain, muscle, and tumor tissue." Med Phys 23.10 (October 1996): 1775-1782.
PMID
8946373
Source
pubmed
Published In
Medical physics
Volume
23
Issue
10
Publish Date
1996
Start Page
1775
End Page
1782
DOI
10.1118/1.597760

Liver MR imaging: comparison of respiratory triggered fast spin echo with T2-weighted spin-echo and inversion recovery.

BACKGROUND: The purpose of this study was to compare a fast spin-echo sequence combined with a respiratory triggering device (R. trig. FSE) with conventional T2-weighted spin-echo (CSE) and inversion recovery (STIR) sequences for the detection of focal hepatic lesions. METHODS: We performed a prospective study of 33 consecutive patients with known or suspected hepatic tumors. All patients underwent R. trig. FSE, CSE, and STIR imaging at 1.5 T. Acquisition times were 10.7 min for the CSE sequence and ranged from 12 to 15 min for STIR and from 5 to 7 min for R. trig FSE. For each sequence, liver-spleen contrast-to-noise ratio (CNR) and liver-lesion CNR were determined quantitatively. Image artifact and sharpness were graded by using a four-point scale on each sequence by two independent readers. Both readers also independently identified hepatic lesions (up to a maximum of eight per patient). For patients with focal lesions, the total number of lesions detected (on each sequence) and the minimum size of detected lesions were also determined by each reader. RESULTS: No significant difference was detected between R. trig. FSE and CSE or STIR in either liver-spleen CNR or liver-lesion CNR. R. trig. FSE images were equivalent to CSE and superior to STIR in sharpness (p < 0.01) and presence of artifact (p < 0.01). R. trig. FSE detected a higher number of lesions (reader 1: n = 92, reader 2: n = 86) than CSE (reader 1: n = 70, reader 2: n = 69) and a significantly higher number than STIR (reader 1: n = 71, reader 2: n = 76). Lesion structure was significantly better defined with R. trig. FSE than with STIR (p < 0.01) and CSE (p < 0.05). CONCLUSIONS: Compared with CSE and STIR, R. trig. FSE produces hepatic images of comparable resolution and detects an increased number of focal hepatic lesions in a shorter period of time.

Authors
Keogan, MT; Spritzer, CE; Paulson, EK; Paine, SS; Harris, L; Dahlke, JL; MacFall, JR
MLA Citation
Keogan, MT, Spritzer, CE, Paulson, EK, Paine, SS, Harris, L, Dahlke, JL, and MacFall, JR. "Liver MR imaging: comparison of respiratory triggered fast spin echo with T2-weighted spin-echo and inversion recovery." Abdom Imaging 21.5 (September 1996): 433-439.
PMID
8832865
Source
pubmed
Published In
Abdominal Imaging
Volume
21
Issue
5
Publish Date
1996
Start Page
433
End Page
439

Human lung air spaces: potential for MR imaging with hyperpolarized He-3.

Two healthy volunteers who had inhaled approximately 0.75 L of laser-polarized helium-3 gas underwent magnetic resonance imaging at 1.5 T with fast gradient-echo pulse sequences and small flip angles ( < 10 degrees). Thick-section (20 mm) coronal images, time-course data (30 images collected every 1.8 seconds), and thin-section (6 mm) images were acquired. Subjects were able to breathe the gas (12% polarization) without difficulty. Thick-section images were of good quality and had a signal-to-noise ratio (S/N) of 32:1 near the surface coil and 16:1 farther away. The time images showed regional differences, which indicated potential value for quantitation. High-resolution images showed greater detail and a S/N of approximately 6:1.

Authors
MacFall, JR; Charles, HC; Black, RD; Middleton, H; Swartz, JC; Saam, B; Driehuys, B; Erickson, C; Happer, W; Cates, GD; Johnson, GA; Ravin, CE
MLA Citation
MacFall, JR, Charles, HC, Black, RD, Middleton, H, Swartz, JC, Saam, B, Driehuys, B, Erickson, C, Happer, W, Cates, GD, Johnson, GA, and Ravin, CE. "Human lung air spaces: potential for MR imaging with hyperpolarized He-3." Radiology 200.2 (August 1996): 553-558.
PMID
8685356
Source
pubmed
Published In
Radiology
Volume
200
Issue
2
Publish Date
1996
Start Page
553
End Page
558
DOI
10.1148/radiology.200.2.8685356

Prospective comparison of helical CT and MR imaging in clinically suspected acute pulmonary embolism.

The purpose of this study is to compare sensitivity and specificity of helical CT and MR imaging for detecting acute pulmonary embolism(PE). Patients who were suspected clinically of having PE were randomly assigned to undergo either helical contrast-enhanced CT or gradient-echo MR (if one modality was contraindicated, the patient was assigned to the other.) Patients were considered to have PE if they had: 1) high-probability V-Q scan and low clinical probability of PE; 2) pulmonary angiogram positive for PE. Patients were considered not to have PE if they had either:1)normal V-Q scan; 2) low probability V-Q scan and low clinical probability of PE; or 3) pulmonary angiogram negative for PE. The CT and MR images were read randomly and independently by five radiologists with varying levels of CT and MR experience. Twenty eight patients underwent CT and 25 MR. A total of 21 patients underwent pulmonary angiography (6 had PE, 15 did not have PE). Of the other 32 patients, 15 had high probability scan/high clinical probability and 17 had low probability scan/low clinical probability. For the five observers, the average sensitivity of CT was 75% and of MR 46%; the average specificity of CT was 89% and of MR 90%. Experience with vascular MR and enhanced CT influenced diagnostic accuracy. For the two vascular MR experts, average sensitivity and specificity of MR were 71% and 97%, and of CT 73% and 97%. In this pilot study, when CT and MR were interpreted with comparable expertise, they had similar accuracy for detecting pulmonary embolism.

Authors
Sostman, HD; Layish, DT; Tapson, VF; Spritzer, CE; DeLong, DM; Trotter, P; MacFall, JR; Patz, EF; Goodman, PC; Woodard, PK; Foo, TK; Farber, JL
MLA Citation
Sostman, HD, Layish, DT, Tapson, VF, Spritzer, CE, DeLong, DM, Trotter, P, MacFall, JR, Patz, EF, Goodman, PC, Woodard, PK, Foo, TK, and Farber, JL. "Prospective comparison of helical CT and MR imaging in clinically suspected acute pulmonary embolism." J Magn Reson Imaging 6.2 (March 1996): 275-281.
PMID
9132089
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
6
Issue
2
Publish Date
1996
Start Page
275
End Page
281

Optimizing fast spin echo acquisitions for hepatic imaging in normal subjects.

The purpose of this study was to determine which implementations of a T2-weighted fast spin-echo sequence of the liver resulted in observer preference in normal subjects. Five volunteers were scanned with a series of fast spin-echo sequences modified to allow for flow compensation, respiratory triggering (RT), ECG triggering, randomized phase encoding (RPE), breath-holding, and echo train length (ETL). Images were compared with conventional 2500/40/80 msec spin-echo images using flow compensation and spatial presaturation by two observers blinded to the specific sequence parameters. All FSE sequences were completed in less than the 12 minutes necessary to perform a conventional spin-echo sequence. The most preferred fast spin-echo sequence employed flow compensation, RT, and used an 8 ETL. Analysis of image preference, signal to noise, and contrast to noise showed that RT was the single most important variable in determining each image response (P < .01, P < .02, P < .01, respectively). There was some evidence that images obtained with an 8 ETL were preferred over those using a 16 ETL (P = .07). No other variables approached statistical significance although one reader preferred images with flow compensation in the frequency direction to those either not flow compensated or flow compensated in the slice direction. Respiratory triggered fast spin-echo images combined with flow compensation in the frequency direction and using ETL = 8 can provide image quality equal to conventional spin-echo sequences with significant time savings.

Authors
Spritzer, CE; Keogan, MT; DeLong, DM; Dahlke, J; MacFall, JR
MLA Citation
Spritzer, CE, Keogan, MT, DeLong, DM, Dahlke, J, and MacFall, JR. "Optimizing fast spin echo acquisitions for hepatic imaging in normal subjects." J Magn Reson Imaging 6.1 (January 1996): 128-135.
PMID
8851417
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
6
Issue
1
Publish Date
1996
Start Page
128
End Page
135

1H MRI phase thermometry in vivo in canine brain, muscle, and tumor tissue

The temperature sensitivity of the chemical shift of water (approximately 0.01 ppm/°C) provides a potential method to monitor temperature changes in vivo or in vitro through the changes in phase of a gradient-echo magnetic resonance (MR) image. This relation was studied at 1.5 T in gel materials and in vivo in canine brain and muscle tissue, heated with a radio frequency (rf) annular phased array hyperthermia antenna. The rf fields associated with heating (130 MHz) and imaging (64 MHz) were decoupled using bandpass filters providing isolation in excess of 100 dB, thus allowing simultaneous imaging and rf heating without deterioration of the MR image signal-to-noise ratio. In a gel, temperature sensitivity of the MR image phase was observed to be (4.41±0.02) phase degrees/°C for T(e)=20 ms, which allowed temperature changes of 0.22 °C to be resolved for a 50-mm3 region in less than 10 s of data acquisition. In vivo, for T(e)=20 ms, the temperature sensitivity was (3.2 ± 0.1) phase degrees/°C for brain tissue, (3.1 ± 0.1) phase degrees/°C for muscle, and (3.0±0.2) phase degrees/°C for a muscle tumor (sarcoma), allowing temperature changes of 0.6 °C to be resolved in a 16-mm3 volume in less than 10 s of data acquisition. We conclude that, while the technique is very sensitive to magnetic field inhomogeneity, stability, and subject motion, it appears to be useful for in vivo temperature change measurement.

Authors
MacFall, JR; Prescott, DM; Charles, HC; Samulski, TV
MLA Citation
MacFall, JR, Prescott, DM, Charles, HC, and Samulski, TV. "1H MRI phase thermometry in vivo in canine brain, muscle, and tumor tissue." Medical Physics 23.10 (1996): 1775-1782.
Source
scival
Published In
Medical physics
Volume
23
Issue
10
Publish Date
1996
Start Page
1775
End Page
1782
DOI
10.1118/1.597760

MR-IMAGING AND CT FOR DETECTING PULMONARY-EMBOLISM AND VENOUS THROMBOEMBOLISM

Authors
SOSTMAN, H; LAYISH, D; SPRITZER, C; GOODMAN, P; PATZ, E; MACFALL, J
MLA Citation
SOSTMAN, H, LAYISH, D, SPRITZER, C, GOODMAN, P, PATZ, E, and MACFALL, J. "MR-IMAGING AND CT FOR DETECTING PULMONARY-EMBOLISM AND VENOUS THROMBOEMBOLISM." RADIOLOGY 197 (November 1995): 303-303.
Source
wos-lite
Published In
Radiology
Volume
197
Publish Date
1995
Start Page
303
End Page
303

HIGH-DOSE MR CONTRAST AGENT FOR THE DIAGNOSIS OF LEPTOMENINGEAL DISEASE

Authors
GRAY, L; MACFALL, J; PROVENZALE, J; KALLMES, D; POTCHEN, M; GLASS, J
MLA Citation
GRAY, L, MACFALL, J, PROVENZALE, J, KALLMES, D, POTCHEN, M, and GLASS, J. "HIGH-DOSE MR CONTRAST AGENT FOR THE DIAGNOSIS OF LEPTOMENINGEAL DISEASE." RADIOLOGY 197 (November 1995): 410-410.
Source
wos-lite
Published In
Radiology
Volume
197
Publish Date
1995
Start Page
410
End Page
410

Magnetic resonance imaging using deoxyhemoglobin contrast versus positron emission tomography in the assessment of brain function.

1. Function of the brain can be assessed through radiologic imaging to determine physiology of underlying tissue. 2. Until recently, positron emission tomography has been the standard tool with which to study function. 3. In the past few years, several investigators have attempted to use magnetic resonance imaging, which has better resolution and is less expensive, to provide functional information. 4. A noninvasive technique termed BOLD (blood oxygen level dependent) has become a popular area of research to determine physiologic change that occurs in the brain in resting as well as activated states. 5. This article reviews what information PET has given us with regard to function of the brain, followed by a discussion of the principle of functional MRI of the brain with emphasis on what has been done in this field as well as future application of the technique.

Authors
Rajagopalan, P; Krishnan, KR; Passe, TJ; Macfall, JR
MLA Citation
Rajagopalan, P, Krishnan, KR, Passe, TJ, and Macfall, JR. "Magnetic resonance imaging using deoxyhemoglobin contrast versus positron emission tomography in the assessment of brain function." Prog Neuropsychopharmacol Biol Psychiatry 19.3 (May 1995): 351-366. (Review)
PMID
7624487
Source
pubmed
Published In
Progress in Neuro-Psychopharmacology & Biological Psychiatry
Volume
19
Issue
3
Publish Date
1995
Start Page
351
End Page
366

Verification of a hyperthermia model method using MR thermometry.

Simulation of hyperthermia induced power and temperature distributions is becoming generally accepted and finding its way into clinical hyperthermia treatments. Such simulations provide a means for understanding the complete three-dimensional temperature distribution. However, the results of the simulation studies should be regarded with caution since modelling errors will result in differences between the actual and simulated temperature distribution. This study uses a diffusion weighted magnetic resonance (MR) based technique to measure hyperthermia induced temperature distributions in a three-dimensional space in a non-perfused phantom. The measured data are used to verify the accuracy of numerical simulations of the same three-dimensional temperature distributions. The simulation algorithm is a finite element based method that first computes the electromagnetic induced power deposition then the temperature distribution. Two non-perfused phantom studies were performed and qualitatively the MR and simulated distributions agreed for steady-state. However, due to the long MR sampling time (approximately 4 min), poor agreement between the simulations and MR measurements were obtained for thermal transients. Good agreement between the simulations and fibreoptic thermometry measurements were obtained. The fiberoptic measurements differed from the simulations by 0.11 +/- 0.59 degrees C and -0.17 +/- 0.29 degrees C (mean +/- standard deviation for the two studies).

Authors
Clegg, ST; Das, SK; Zhang, Y; Macfall, J; Fullar, E; Samulski, TV
MLA Citation
Clegg, ST, Das, SK, Zhang, Y, Macfall, J, Fullar, E, and Samulski, TV. "Verification of a hyperthermia model method using MR thermometry." Int J Hyperthermia 11.3 (May 1995): 409-424.
PMID
7636327
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
11
Issue
3
Publish Date
1995
Start Page
409
End Page
424

Accuracy of surface fit registration for PET and MR brain images using full and incomplete brain surfaces.

OBJECTIVE: The accuracy of a surface-fitting image registration technique has been investigated for matching [18F]fluorodeoxyglucose (FDG) and [15O]H2O PET brain images with MR images. Use of partial-brain surfaces (a single hemisphere or a limited number of slices) was investigated to simulate cases in which severe brain defects or limited axial field of view would preclude using the entire brain surface. MATERIALS AND METHODS: Three FDG and three H2O scans were performed on five volunteers, in addition to volume MR studies. Fiducial markers were placed on the subjects' scalps to provide references for registration accuracy. The registration procedure was applied to each PET-MR set, using the surfaces defined by locating the brain edge in multiple slices for each set. RESULTS: The surfaces fit well, with only 1% scaling necessary for the best fit. Errors in fiducial marker positions between MRI and transformed PET were < 2 mm in the transverse directions and < 4.5 mm in the axial direction. Fits based on the partial surfaces worked well and gave results very similar to the full-brain fits. CONCLUSION: The surface-fitting technique is accurate for FDG and H2O PET studies, even when part of the brain surface cannot be used.

Authors
Turkington, TG; Hoffman, JM; Jaszczak, RJ; MacFall, JR; Harris, CC; Kilts, CD; Pelizzari, CA; Coleman, RE
MLA Citation
Turkington, TG, Hoffman, JM, Jaszczak, RJ, MacFall, JR, Harris, CC, Kilts, CD, Pelizzari, CA, and Coleman, RE. "Accuracy of surface fit registration for PET and MR brain images using full and incomplete brain surfaces." J Comput Assist Tomogr 19.1 (January 1995): 117-124.
PMID
7822526
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
19
Issue
1
Publish Date
1995
Start Page
117
End Page
124

Detection of pulmonary embolism: comparison of contrast-enhanced spiral CT and time-of-flight MR techniques.

We compared the conspicuity of acute pulmonary emboli with contrast-enhanced spiral computed tomography (CT) and two- and three-dimensional time-of-flight magnetic resonance (MR) techniques. Seven dogs who received experimental pulmonary emboli and one control were imaged with spiral CT and with 2-D (FMPVAS and FASTCARD) and 3-D time-of-flight MR. Blinded, independent, prospective evaluations of the CT and MR images by two MR radiologists and two chest radiologists were then compared to the location of the emboli as determined by subsequent pathologic evaluation of the excised lungs. Embolus/blood contrast-to-noise ratios (CNRs) were calculated on both MR and CT images for pulmonary emboli that could be identified. Fifty emboli ranging from 1.0 to 5.5 mm (mean, 2.7, +/- 0.14 SEM) in diameter and from 3.0 to 60 mm (mean, 28.1 +/- 1.9 SEM) in length were found in the seven embolized dogs on pathologic examination. Three of the four radiologists identified more thrombi on CT images than they did on their best MR pulse sequence (FASTCARD) and with greater confidence. The fourth radiologist identified an equal percentage of clot on CT and FASTCARD images with confidence slightly greater on FASTCARD MR than on spiral CT. Mean CNR for the best MR technique was 43.4 (+/- 3.9 SEM) and for CT was 20.7 (+/- 1.3 SEM). In general, pulmonary emboli were detected more accurately on contrast-enhanced spiral CT than on MR. This occurred although the embolus/blood CNR was higher on MR than on CT. Better pulmonary embolus conspicuity on CT images was attributed to better spatial resolution and fewer artifacts on CT than on MR. One MR radiologist performed equally well with both spiral CT and FASTCARD techniques, suggesting that experience may be a factor in performance.

Authors
Woodard, PK; Sostman, HD; MacFall, JR; DeLong, DM; McDonald, JW; Foo, TK; Patz, EF; Goodman, PC; Spritzer, CE
MLA Citation
Woodard, PK, Sostman, HD, MacFall, JR, DeLong, DM, McDonald, JW, Foo, TK, Patz, EF, Goodman, PC, and Spritzer, CE. "Detection of pulmonary embolism: comparison of contrast-enhanced spiral CT and time-of-flight MR techniques." J Thorac Imaging 10.1 (1995): 59-72.
PMID
7891398
Source
pubmed
Published In
Journal of Thoracic Imaging
Volume
10
Issue
1
Publish Date
1995
Start Page
59
End Page
72

Temperature dependence of canine brain tissue diffusion coefficient measured in vivo with magnetic resonance echo-planar imaging

The intensity of conventional spin-echo diffusion-weighted magnetic resonance (MR) images is approximately linearly dependent on temperature over a restricted range using conventional diffusion-weighted spin-echo magnetic resonance imaging (MRI). However, conventional diffusion-weighted MRI is too motion sensitive for in vivo thermometry. The present work evaluated rapid diffusion-weighted echo-planar imaging (EPI), which is less sensitive to motion, for application to non-invasive thermometry in acrylamide gel materials and in vivo in canine brain tissue for applications in therapeutic hyperthermia. The rapidly switched, strong gradients needed for EPI were achieved using a 'local' z-axis gradient coil. Gel materials were heated with a small (10 cm diameter) spiral surface microwave (MW) applicator at 433 MHz, while in vivo heating was accomplished with whole body RF hyperthermia using an annular phased array (130 MHz). The MW or RF fields associated with heating and imaging (64 MHz) were decoupled using bandpass filters providing isolation in excess of 100 dB. This isolation was sufficient to allow simultaneous imaging and MW or RF heating without deterioration of the image signal-to-noise ratio. Using this system in a gel, temperature sensitivity of the diffusion coefficient was observed to be (3.04 ± 0.03)%/°C which allowed temperature changes of 0.55°C to be resolved for a 1.8 cm3 region in < 10 s of data acquisition. In vivo, cardiac gating of the pulse sequence was necessary to minimize motion artifacts in the brain. The temperature sensitivity of brain tissue was (1.9 ± 0.1)%/°C allowing temperature changes of 0.9°C to be resolved in a 0.9 cm3 volume in < 10 s of data acquisition. We conclude that with further optimization of the data acquisition conditions it will be possible to determine 0.5°C temperature changes in 1 cm3 volumes in < 10 s using this technique.

Authors
MacFall, JM; Prescott, DM; Fullar, E; Samulski, TV
MLA Citation
MacFall, JM, Prescott, DM, Fullar, E, and Samulski, TV. "Temperature dependence of canine brain tissue diffusion coefficient measured in vivo with magnetic resonance echo-planar imaging." International Journal of Hyperthermia 11.1 (1995): 73-86.
Source
scival
Published In
International Journal of Hyperthermia
Volume
11
Issue
1
Publish Date
1995
Start Page
73
End Page
86

Changes in pituitary gland signal intensity and morphology as evaluated by magnetic resonance imaging in aging, depression, and by gender

Magnetic resonance images (MRI) were used to measure anterior (A) and posterior (P) pituitary lobe signal intensity changes with age and by gender in 35 normal controls and 19 depressed patients. Females in the control group had a significant increase in both P/A and P/Pons ratios and trended to an increase in the ratio (P-A)/P when compared with the male control group. Depressed females had both a significantly increase P/A ratio and (P-A)/P ratio along with a trended increase in the P/Pons ratio when compared with depressed males. No significant correlation between age and signal intensity were found in either the control or the depressed groups. Nineteen of the controls were age and gender matched with the 19 depressed patients. A significant increase in the (P-A)/P ratio and a trend towards an increase in both the P/A ratio and P/Pons ratio with depression were noted. Changes in shape of the pituitary gland upper border, presence or absence of a posterior pituitary 'bright spot', and changes in signal intensity were then evaluated comparing the two groups. There was no significant difference in 'bright spot' frequency between the two groups. The only significant morphological finding was an increased flat shape of the pituitary in female depressed vs. male depressed.

Authors
Rajagopalan, P; Passe, TJ; Doraiswamy, PM; Figiel, GS; MacFall, JR; Krishnan, KR
MLA Citation
Rajagopalan, P, Passe, TJ, Doraiswamy, PM, Figiel, GS, MacFall, JR, and Krishnan, KR. "Changes in pituitary gland signal intensity and morphology as evaluated by magnetic resonance imaging in aging, depression, and by gender." Depression 2.6 (1995): 303-307.
Source
scival
Published In
Depression
Volume
2
Issue
6
Publish Date
1995
Start Page
303
End Page
307

Relative accuracy and reproducibility of regional MRI brain volumes for point-counting methods.

Volumetric magnetic resonance imaging (MRI) methods for the measurement of various neuroanatomical regions are of great interest in studies of neuropsychiatric disorders. Both manual and semiautomated methods have been developed. Manual methods include tracing and point counting. Point counting methods are widely used in post-mortem and microscopy studies. Point counting has been well validated for these purposes. In this article, we report in a series of separate studies the accuracy and reproducibility of point-counting methods. Absolute accuracy was evaluated with a spherical phantom. Accuracy and time efficiency were subsequently assessed with an anatomically realistic phantom and various size grids. The point-counting method was also compared to a tracing method. Finally, the reproducibility of the point-counting method for the caudate and putamen was evaluated on four subjects in a test-retest experiment. These studies provide an estimate of the accuracy and time efficiency of point-counting methods. The test-retest reliability was also high for both caudate and putamen. Findings suggest that point counting is a reliable and efficient method for estimating volumes.

Authors
MacFall, JR; Byrum, CE; Parashos, I; Early, B; Charles, HC; Chittilla, V; Boyko, OB; Upchurch, L; Krishnan, KR
MLA Citation
MacFall, JR, Byrum, CE, Parashos, I, Early, B, Charles, HC, Chittilla, V, Boyko, OB, Upchurch, L, and Krishnan, KR. "Relative accuracy and reproducibility of regional MRI brain volumes for point-counting methods." Psychiatry Res 55.3 (September 1994): 167-177.
PMID
7870856
Source
pubmed
Published In
Psychiatry Research
Volume
55
Issue
3
Publish Date
1994
Start Page
167
End Page
177

Asymmetric-echo, short TE, retrospectively gated MR imaging of the heart and pulmonary vessels.

Although retrospectively cardiac-gated (cine) magnetic resonance imaging has shown promise for large-vessel pulmonary vascular imaging, it has not been able to depict the peripheral pulmonary vasculature, where signal is dephased because of susceptibility and/or motion artifacts. The authors developed a cine pulse sequence that uses asymmetric echoes and radio-frequency envelopes to achieve reduced gradient moments and a short TE, thereby reducing signal losses due to disordered flow and susceptibility effects. The effects of TE (2.8-12 msec) and the degree of echo symmetry as measured by the echo symmetry fraction (ESF) (0.6-1.0) are considered in the pulmonary vasculature and the heart. In pulmonary vessels, the signal-to-noise ratio nearly doubled as TE was decreased from 12 to 2.8 msec, but there was only about a 15% difference as the ESF decreased from 1.0 to 0.6, consistent with T2* losses dominating gradient moment dephasing. At a TE of 2.8 msec, the sequence improves visualization of pulmonary vessels and may be helpful for diagnosing pulmonary emboli. In the heart, however, the contrast-to-noise ratio between blood and cardiac tissue decreased by 30% as TE decreased from 12 to 2.8 msec and was not affected by changes in ESF. Flow artifacts in the cardiac blood pool, including those that can aid in diagnosis (eg, signal loss due to "jet" flow), are much less pronounced when a small ESF and short TE are used, making this sequence less attractive for investigation of cardiac flow irregularities. The reduced flow artifacts in this case, however, permit excellent depiction of gross cardiac anatomy.

Authors
Richardson, DB; MacFall, JR; Sostman, HD; Spritzer, CE
MLA Citation
Richardson, DB, MacFall, JR, Sostman, HD, and Spritzer, CE. "Asymmetric-echo, short TE, retrospectively gated MR imaging of the heart and pulmonary vessels." J Magn Reson Imaging 4.2 (March 1994): 131-137.
PMID
8180450
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
4
Issue
2
Publish Date
1994
Start Page
131
End Page
137

MR imaging of high-grade cerebral gliomas: value of diffusion-weighted echoplanar pulse sequences.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of diffusion-weighted echoplanar MR imaging in the examination of high-grade brain gliomas compared with that of conventional spin-echo (SE) or fast spin-echo (FSE) MR imaging. We hypothesize that diffusion-weighted MR imaging may enable us to differentiate various tumor components on the basis of differences in the diffusion of water. SUBJECTS AND METHODS: Conventional SE and FSE MR images were obtained in 10 patients with high-grade brain glioma. Diffusion-weighted echoplanar MR images were obtained with a head gradient coil capable of providing diffusion-weighted imaging along the cephalocaudal axis. Using SE and FSE MR images as a baseline, we evaluated the diffusion-weighted MR images for usefulness in distinguishing tumor components on the basis of differences in diffusion. RESULTS: Areas of tumor that showed significant enhancement on T1-weighted SE MR images obtained after injection of contrast material were markedly hyperintense on diffusion-weighted images and had a lower apparent diffusion coefficient (ADC) than the ADCs for nonenhancing tumor and peritumoral edema. Cystic or necrotic portions of tumor showed the most signal suppression on diffusion-weighted images and were associated with the highest ADCs. On T2-weighted FSE MR images, areas of hyperintensity observed in white matter oriented parallel to the direction of the diffusion gradient could be differentiated into two patterns on the basis of findings on diffusion-weighted images: areas that showed marked signal suppression with a higher ADC, most likely representing areas of predominantly peritumoral edema, and areas that showed a lesser degree of signal suppression with similar but slightly lower ADCs than those of edema, most likely representing areas of predominantly nonenhancing tumor. CONCLUSION: Diffusion-weighted echoplanar MR imaging is a useful technique for examining high-grade cerebral gliomas. It enabled us to differentiate various components of the tumor (e.g., enhancing, nonenhancing, cystic, or necrotic) and to distinguish areas of predominantly nonenhancing tumor from areas of predominantly peritumoral edema when the abnormality was located in the white matter aligned in the direction of the diffusion-weighted gradient. Diffusion-weighted echoplanar MR imaging appears to be a powerful tool in the characterization of brain neoplasms.

Authors
Tien, RD; Felsberg, GJ; Friedman, H; Brown, M; MacFall, J
MLA Citation
Tien, RD, Felsberg, GJ, Friedman, H, Brown, M, and MacFall, J. "MR imaging of high-grade cerebral gliomas: value of diffusion-weighted echoplanar pulse sequences." AJR Am J Roentgenol 162.3 (March 1994): 671-677.
PMID
8109520
Source
pubmed
Published In
AJR. American journal of roentgenology
Volume
162
Issue
3
Publish Date
1994
Start Page
671
End Page
677
DOI
10.2214/ajr.162.3.8109520

Parameter estimation and tissue segmentation from multispectral MR images.

A statistical method is developed to classify tissue types and to segment the corresponding tissue regions from relaxation time T(1 ), T(2), and proton density P(D) weighted magnetic resonance images. The method assumes that the distribution of image intensities associated with each tissue type can be expressed as a multivariate likelihood function of three weighted signal intensity values (T(1), T(2), P(D)) at each location within that tissue regions. The method further assumes that the underlying tissue regions are piecewise contiguous and can be characterized by a Markov random field prior. In classifying the tissue types, the method models the likelihood of realizing the images as a finite multivariate-mixture function. The class parameters associated with the tissue types (i.e. the weighted intensity means, variances and correlation coefficients of the multivariate function, as well as the number of voxels within regions of the tissue types of are estimated by maximum likelihood. The estimation fits the class parameters to the image data via the expectation-maximization algorithm. The number of classes associated with the tissue types is determined by the information criterion of minimum description length. The method segments the tissue regions, given the estimated class parameters, by maximum a posteriori probability. The prior is constructed by the tissue-region membership of the first- and second-order neighborhood. The method is tested by a few sets of T(1), T(2), and P(D) weighted images of the brain acquired with a 1.5 Tesla whole body scanner. The number of classes and the associated class parameters are automatically estimated. The regions of different brain tissues are satisfactorily segmented.

Authors
Liang, Z; Macfall, JR; Harrington, DP
MLA Citation
Liang, Z, Macfall, JR, and Harrington, DP. "Parameter estimation and tissue segmentation from multispectral MR images." IEEE Trans Med Imaging 13.3 (1994): 441-449.
PMID
18218519
Source
pubmed
Published In
IEEE Transactions on Medical Imaging
Volume
13
Issue
3
Publish Date
1994
Start Page
441
End Page
449
DOI
10.1109/42.310875

Application of new technology in clinical hyperthermia

Two areas of technical progress related to hyperthermic oncology are presented: (1) numerical modelling of absorbed power and temperature distributions; and (2) non-invasive thermometry using magnetic resonance imaging. The results represent achievements made during the past 5 years at Duke University Medical Center's Departments of Radiation Oncology and Radiology. They represent examples of progress in the technology of hyperthermia that have potential for greatly improving the delivery, monitoring and assessment of clinical hyperthermia.

Authors
Samulski, TV; Clegg, ST; Das, S; MacFall, J; Prescott, DM
MLA Citation
Samulski, TV, Clegg, ST, Das, S, MacFall, J, and Prescott, DM. "Application of new technology in clinical hyperthermia." International Journal of Hyperthermia 10.3 (1994): 389-394.
Source
scival
Published In
International Journal of Hyperthermia
Volume
10
Issue
3
Publish Date
1994
Start Page
389
End Page
394

Pulmonary angiography with MR imaging: preliminary clinical experience.

PURPOSE: To study the accuracy of magnetic resonance (MR) pulmonary angiography in 20 patients in whom pulmonary embolism (PE) was clinically suspected. MATERIALS AND METHODS: Fourteen patients (group 1) were recruited for the MR pulmonary angiography study before they underwent conventional pulmonary angiography (CPA) based on clinical findings. Six patients (group 2) did not undergo CPA but were considered to have PE on the basis of findings in other studies. MR venography was performed at the time of MR pulmonary angiography in 13 patients. RESULTS: MR pulmonary angiography had a sensitivity of 92%-100% and specificity of 62% for detection of PE. Performance of MR pulmonary arteriography and MR venography in a single examination to demonstrate thrombus in both the arterial and deep venous systems was proved feasible. CONCLUSION: This report describes an early clinical implementation of new MR pulmonary angiographic techniques. Further advances to improve specificity by enhancing sensitivity to slow flow and increasing spatial resolution are necessary before routine clinical use of MR pulmonary angiography is justified.

Authors
Grist, TM; Sostman, HD; MacFall, JR; Foo, TK; Spritzer, CE; Witty, L; Newman, GE; Debatin, JF; Tapson, V; Saltzman, HA
MLA Citation
Grist, TM, Sostman, HD, MacFall, JR, Foo, TK, Spritzer, CE, Witty, L, Newman, GE, Debatin, JF, Tapson, V, and Saltzman, HA. "Pulmonary angiography with MR imaging: preliminary clinical experience." Radiology 189.2 (November 1993): 523-530.
PMID
8210385
Source
pubmed
Published In
Radiology
Volume
189
Issue
2
Publish Date
1993
Start Page
523
End Page
530
DOI
10.1148/radiology.189.2.8210385

Accuracy of registration of PET, SPECT and MR images of a brain phantom.

Accuracy of a surface-fitting algorithm for three-dimensional image registration of single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance (MR) images was tested using a three-dimensional, water-fillable brain phantom. Multislice or volume image sets were acquired for each modality. Small fiducial markers were attached to assess accuracy of surface fitting and provide an alternate fitting technique. A maximum gradient technique was found to work well for SPECT and PET edge detection. Transformation parameters for translation, rotation and scaling were determined by surface fit to match each SPECT and PET scan with MR images. Using the markers, overall translation errors were found to be < 2 mm in each direction and rotational errors < 2 degrees in every case. Errors for specific internal regions were also determined to be < 2 mm for most regions, with only a few fits resulting in errors > 3 mm for some cortical regions. Results indicate surface fitting to be sufficiently accurate for visual comparison of registered images and for enhanced SPECT and PET region of interest (ROI) determination and image reconstruction.

Authors
Turkington, TG; Jaszczak, RJ; Pelizzari, CA; Harris, CC; MacFall, JR; Hoffman, JM; Coleman, RE
MLA Citation
Turkington, TG, Jaszczak, RJ, Pelizzari, CA, Harris, CC, MacFall, JR, Hoffman, JM, and Coleman, RE. "Accuracy of registration of PET, SPECT and MR images of a brain phantom." J Nucl Med 34.9 (September 1993): 1587-1594.
PMID
8355080
Source
pubmed
Published In
Journal of nuclear medicine : official publication, Society of Nuclear Medicine
Volume
34
Issue
9
Publish Date
1993
Start Page
1587
End Page
1594

Single-breath-hold venous or arterial flow-suppressed pulmonary vascular MR imaging with phased-array coils.

A method for acquiring pulmonary vascular magnetic resonance (MR) images with either venous or arterial flow suppression is described. The proposed method only marginally increases the overall imaging time compared with conventional flow-suppression techniques. This enables an acquisition to be completed within a single breath hold with some selectivity as to flow direction. Instead of applying a spatially selective presaturation pulse before each radio-frequency (RF) excitation pulse, the flow presaturation pulse is applied once every 16-20 RF excitation pulses. To avoid image artifacts and to maintain a steady state, each presaturation pulse interval is followed by a normal imaging segment but with data acquisition turned off. Overall imaging time is increased by two TR intervals for each presaturation segment. For a 256 x 128 matrix acquisition, venous flow presaturation increases overall imaging time by approximately 14 TR intervals, while arterial flow suppression increases imaging time by 10 TR intervals.

Authors
Foo, TK; MacFall, JR; Sostman, HD; Hayes, CE
MLA Citation
Foo, TK, MacFall, JR, Sostman, HD, and Hayes, CE. "Single-breath-hold venous or arterial flow-suppressed pulmonary vascular MR imaging with phased-array coils." J Magn Reson Imaging 3.4 (July 1993): 611-616.
PMID
8347954
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
3
Issue
4
Publish Date
1993
Start Page
611
End Page
616

Clot-blood contrast in fast gradient-echo magnetic resonance imaging.

RATIONALE AND OBJECTIVES: Contrast between clot and blood in magnetic resonance imaging (MRI) at 1.5T using fast gradient-echo pulse sequences (fast GRE), with 8 ms < TR < 20 mseconds was studied both in vitro and in clinical human deep venous thrombosis (DVT) to assess whether good contrast could be obtained at such short repetition times and at clinically relevant flow rates. METHODS: In vitro studies used an apparatus that contained flowing MnCl2[aq] (water adjusted with manganese chloride to have T1, T2 similar to blood) and an immobilized clot (T1, T2 similar to those in DVT) for flow velocities between 0 and 16.5 cm/sec. Seven patients with DVT were imaged with the fast GRE sequences to observe the clot-blood contrast in vivo. RESULTS: Peak contrast-to-noise ratio (CNR) was achieved using flip angles between 20 degrees and 40 degrees (increasing with flow velocity) with or without radiofrequency "spoiling," consistent with a natural spoiling effect of flow. The CNR between MnCI2[aq] and clot decreased less than 10% as TR was reduced 56% from 18 mseconds to 8 mseconds (30 degrees flip angle). In four patients with nonocclusive DVT, fast GRE imaging provided good contrast while in occlusive cases (three patients) the contrast was not as good as conventional GRE sequences with longer TR values (TR = 33 mseconds). CONCLUSION: A fast GRE sequence with TR = 8 mseconds, TE = 3 mseconds, and a flip angle = 40 degrees is a promising approach to speeding up the detection of nonocclusive clinical DVT.

Authors
Wu, JJ; MacFall, JR; Sostman, HD; Hedlund, LW
MLA Citation
Wu, JJ, MacFall, JR, Sostman, HD, and Hedlund, LW. "Clot-blood contrast in fast gradient-echo magnetic resonance imaging." Invest Radiol 28.7 (July 1993): 586-593.
PMID
8344807
Source
pubmed
Published In
Investigative Radiology
Volume
28
Issue
7
Publish Date
1993
Start Page
586
End Page
593

Normal brain F-18 FDG-PET and MRI anatomy.

Image registration techniques will become increasingly important in correlative multimodality imaging. In the case of PET, a structural imaging study can be invaluable in correlating structure metabolism relationships. A registered brain atlas of PET and MRI has been developed by the authors that allows clinicians, residents, fellows, and others to refer to a structural abnormality on MRI or metabolic abnormality on PET and correlate it neuro-anatomically.

Authors
Schifter, T; Turkington, TG; Berlangieri, SU; Hoffman, JM; MacFall, JR; Pelizzari, CA; Tien, RD; Coleman, RE
MLA Citation
Schifter, T, Turkington, TG, Berlangieri, SU, Hoffman, JM, MacFall, JR, Pelizzari, CA, Tien, RD, and Coleman, RE. "Normal brain F-18 FDG-PET and MRI anatomy." Clin Nucl Med 18.7 (July 1993): 578-582.
PMID
8344027
Source
pubmed
Published In
Clinical Nuclear Medicine
Volume
18
Issue
7
Publish Date
1993
Start Page
578
End Page
582

Poststenotic signal loss in MR angiography: effects of echo time, flow compensation, and fractional echo.

PURPOSE: To evaluate with steady and pulsatile flow the influence of echo time, gradient strength and duration, and flow compensation on the degree of turbulent signal loss, factors that have been implicated in MR angiography's overestimation of the degree of stenosis. METHODS: We examined poststenotic turbulent flow in two models, one that created a turbulent jet and another that simulated a plaque-like stenosis. The pulse sequence used in these experiments allowed for a single variable (flow compensation, echo time, or gradient strength) to be varied without changing the others. RESULTS: Poststenotic signal loss can lead to overestimation of the degree of a stenosis. The area of signal loss in the turbulent jet was influenced by fractional echo and flow compensation, but not by echo time. We found that the dominant mechanism in poststenotic signal loss is related to the strength and duration of the imaging gradients. CONCLUSIONS: Flow-compensated sequences with reduced gradient strength and duration will reduce poststenotic signal loss and may lead to more accurate estimations of the extent of stenotic lesions.

Authors
Evans, AJ; Richardson, DB; Tien, R; MacFall, JR; Hedlund, LW; Heinz, ER; Boyko, O; Sostman, HD
MLA Citation
Evans, AJ, Richardson, DB, Tien, R, MacFall, JR, Hedlund, LW, Heinz, ER, Boyko, O, and Sostman, HD. "Poststenotic signal loss in MR angiography: effects of echo time, flow compensation, and fractional echo." AJNR Am J Neuroradiol 14.3 (May 1993): 721-729.
PMID
8517365
Source
pubmed
Published In
American Journal of Neuroradiology
Volume
14
Issue
3
Publish Date
1993
Start Page
721
End Page
729

MR microscopy of the rat lung using projection reconstruction.

Projection reconstruction has been implemented with self-refocused selection pulses on a small bore, 2.0 T MR microscope, to allow imaging of lung parenchyma. Scan synchronous ventilation and cardiac gating have been integrated with the sequence to minimize motion artifacts. A systematic survey of the pulse sequence parameters has been undertaken in conjunction with the biological gating parameters to optimize resolution and signal-to-noise (SNR). The resulting projection images with effective echo time of < 300 microseconds allow definition of lung parenchyma with an SNR improvement of approximately 15 x over a more conventional 2DFT short echo gradient sequence.

Authors
Gewalt, SL; Glover, GH; Hedlund, LW; Cofer, GP; MacFall, JR; Johnson, GA
MLA Citation
Gewalt, SL, Glover, GH, Hedlund, LW, Cofer, GP, MacFall, JR, and Johnson, GA. "MR microscopy of the rat lung using projection reconstruction." Magn Reson Med 29.1 (January 1993): 99-106.
PMID
8419748
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
29
Issue
1
Publish Date
1993
Start Page
99
End Page
106

Pulsatile motion artifact reduction in 3D steady-state-free-precession-echo brain imaging

An image can be made from the echo of a steady-state-free-precession and pulse sequences for this purpose have been implemented on various commercial systems under such names as "CE-FAST" and "SSFP" (herein generically termed SSFP-Echo). Such sequences can be employed to achieve strong T2-weighting with reduced T2* effects, but are limited by their sensitivity to flow and motion which produce artifacts. Simple considerations indicate that this sensitivity is primarily related to the (implementation-dependent) moments of the imaging gradients. In this work, MR imaging of the brain using a standard implementation of the sequence with large moment "crusher" gradients on the slice select axis (to dephase the FID of the SSFP) is compared to a modified implementation with reduced moment gradient pulses and different radiofrequency (RF) phase cycling. Asymmetric echo acquisition and narrowed bandwidth was used to further reduce gradient moments. The sensitivity of this sequence to flow and motion artifacts, especially for motion perpendicular to the slice, is thus expected to be significantly reduced. The modified sequence was found to have flow and motion artifacts reduced by a factor of five in the axial plane and a factor of two in the coronal plane. These modifications can thus significantly reduce the flow and motion artifacts commonly seen in conventional images of the SSFP echo with little or no penalty in scan time or signal-to-noise ratio. © 1993.

Authors
Tien, RD; Bernstein, M; MacFall, J
MLA Citation
Tien, RD, Bernstein, M, and MacFall, J. "Pulsatile motion artifact reduction in 3D steady-state-free-precession-echo brain imaging." Magnetic Resonance Imaging 11.2 (1993): 175-181.
Source
scival
Published In
Magnetic Resonance Imaging
Volume
11
Issue
2
Publish Date
1993
Start Page
175
End Page
181
DOI
10.1016/0730-725X(93)90022-6

MRI in venous thromboembolic disease

We evaluated the ability of magnetic resonance (MR) imaging to detect deep venous thrombosis (DVT) and pulmonary embolism (PE). MR venography was performed on 217 patients suspected of having DVT. Cine-MR imaging of the pulmonary arteries was performed in 14 other patients who were thought to have PE based on other imaging studies. In a third group of 5 patients, MR pulmonary angiograms were performed in the sagittal and coronal planes with a multislice fast gradient recalled echo technique. All but one of the 217 MR venograms were technically adequate. In 72 patients with correlative imaging studies (venography and ultrasound) MR venography was 99% sensitive and 95% specific. On the basis of follow-up (mean 8.3 months), no false-negative MR venograms were detected in an additional 64 patients. In 11 other patients MR revealed a diagnosis other than DVT. Cine-MR showed PE in all 14 patients evaluated. MR pulmonary arteriography demonstrated filling defects consistent with acute PE in 2 of 3 patients with acute PE; in the third patient only a questionable filling defect was seen. Coarctations or webs were found in the pulmonary arteries of both patients with chronic PE. These preliminary data suggest that MR imaging may be able to evaluate both the peripheral venous and the pulmonary arterial component of venous thromboembolic disease. Further technical refinement and more extensive clinical experience will be required to establish the role of this method in diagnosing pulmonary embolism, but MR venography is now used routinely in our hospital for the diagnosis of deep venous thrombosis. © 1993 Springer-Verlag.

Authors
Sostman, HD; Debatin, JF; Spritzer, CE; Coleman, RE; Grist, TM; MacFall, JR
MLA Citation
Sostman, HD, Debatin, JF, Spritzer, CE, Coleman, RE, Grist, TM, and MacFall, JR. "MRI in venous thromboembolic disease." European Radiology 3.1 (1993): 53-61.
Source
scival
Published In
European Radiology
Volume
3
Issue
1
Publish Date
1993
Start Page
53
End Page
61
DOI
10.1007/BF00173525

Three dimensional MR gradient recalled echo imaging of the inner ear: Comparison of FID and echo imaging techniques

The detailed structures of the inner ear make this region a diagnostic challenge for radiologists. Thin section high resolution CT is the "gold standard" for studies of the fine bony detail of the inner ear. Although CT can delineate bony structures, fine soft tissue details surrounded by CSF/endolymph (such as nerves in the internal auditory canal) are not easily identified. Conventional MR spin-echo T2-weighted images provide good image contrast for such structures, but the current commercially available minimum slice thickness of approximately 2-3 mm is too thick for the inner ear. Volume gradient recalled echo (GRE) MR imaging techniques can be used to achieve thin slices (<2 mm) while maintaining adequate contrast for detailed examination. In the work reported here a volume GRE sequence that images the echo formed in a steady-state-free-precession (termed "CE-FAST" or "SSFP" on various commercial MRI systems and called SSFP-echo in this work) was used to image inner ear structures. This technique was compared with images generated using conventional volume GRE techniques (GRASS). While small flip angle volume GRE imaging has been used for inner ear imaging previously, the low contrast typical of such density weighting makes it difficult to distinguish soft tissue structures from surrounding CSF/endolymph. In this work, contrast-to-noise ratios (CNR) between CSF/endolymph and brain parenchyma were compared between the sequences at 15°, 30°, 60°, and 90° flip angles. The SSFP-echo sequence produced higher CNR for such structures and consistently outperformed GRASS sequences at flip angles of 30°, 60°, and 90°. Thus, it is concluded that SSFP-echo techniques may be useful for imaging the fine structural anatomy of the inner ear. © 1993.

Authors
Tien, RD; Felsberg, GJ; MacFall, J
MLA Citation
Tien, RD, Felsberg, GJ, and MacFall, J. "Three dimensional MR gradient recalled echo imaging of the inner ear: Comparison of FID and echo imaging techniques." Magnetic Resonance Imaging 11.3 (1993): 429-435.
Source
scival
Published In
Magnetic Resonance Imaging
Volume
11
Issue
3
Publish Date
1993
Start Page
429
End Page
435
DOI
10.1016/0730-725X(93)90077-Q

Observation of the Oxygen Diffusion Barrier in Soybean (Glycine max) Nodules with Magnetic Resonance Microscopy.

The effects of selected gas perfusion treatments on the spinlattice relaxation times (T(1)) of the soybean (Glycine max) nodule cortex and inner nodule tissue were studied with (1)H high resolution magnetic resonance microscopy. Three gas treatments were used: (a) perfusion with O(2) followed by N(2); (b) O(2) followed by O(2); and (c) air followed by N(2). Soybean plants with intact attached nodules were placed into the bore of a superconducting magnet and a selected root with nodules was perfused with the gas of interest. Magnetic resonance images were acquired with repetition times from 50 to 3200 ms. The method of partial saturation was used to calculate T(1) times on selected regions of the image. Calculated images based on T(1) showed longer T(1) values in the cortex than in the inner nodule during all of the gas perfusions. When nodules were perfused with O(2)-O(2), there was no significant change in the T(1) of the nodule between the two gas treatments. When the nodule was perfused with O(2)-N(2) or air-N(2), however, the T(1) of both the cortex and inner nodule increased. In these experiments, the increase in T(1) of the cortex was 2- to 3-fold greater than the increase observed in the inner nodule. A similar change in T(1) was found in detached live nodules, but there was no change in T(1) with selective gas perfusion of detached dead nodules. These observations suggest that cortical cells respond differently to selected gas perfusion than the inner nodule, with the boundary of T(1) change sharply delineated at the interface of the inner nodule and the inner cortex.

Authors
Macfall, JS; Pfeffer, PE; Rolin, DB; Macfall, JR; Johnson, GA
MLA Citation
Macfall, JS, Pfeffer, PE, Rolin, DB, Macfall, JR, and Johnson, GA. "Observation of the Oxygen Diffusion Barrier in Soybean (Glycine max) Nodules with Magnetic Resonance Microscopy." Plant Physiol 100.4 (December 1992): 1691-1697.
PMID
16653185
Source
pubmed
Published In
Plant physiology
Volume
100
Issue
4
Publish Date
1992
Start Page
1691
End Page
1697

Magnetization-prepared MR angiography with fat suppression and venous saturation.

Magnetization-prepared magnetic resonance (MR) angiography (MPMRA) is an inflow-based two-dimensional (2D) imaging sequence in which a preparation phase precedes rapid image acquisition. For maximal blood/tissue contrast, an inversion-recovery preparation nulls signal from static tissue. If needed, a second inversion suppresses signal from fat. Fully magnetized blood flows in after the inversion pulse(s), providing high signal intensity. The centric phase-encoding order, which ensures that the initial contrast is reflected in the image set, requires the use of a modified venous saturation technique. The sequence is described and its performance assessed with regard to (a) depiction of in-plane flow, (b) fat suppression, and (c) venous saturation. Phantom and volunteer studies showed good performance in all three areas. MPMRA images, acquired in just 2-4 seconds per image, had a blood/tissue contrast-to-noise ratio nearly twice that of standard 2D time-of-flight MR angiograms, acquired in 5-7 seconds. The technique is promising for restless patients and in anatomic areas plagued by motion degradation.

Authors
Richardson, DB; Bampton, AE; Riederer, SJ; MacFall, JR
MLA Citation
Richardson, DB, Bampton, AE, Riederer, SJ, and MacFall, JR. "Magnetization-prepared MR angiography with fat suppression and venous saturation." J Magn Reson Imaging 2.6 (November 1992): 653-664.
PMID
1446109
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
2
Issue
6
Publish Date
1992
Start Page
653
End Page
664

Non-invasive thermometry using magnetic resonance diffusion imaging: potential for application in hyperthermic oncology.

The proposition to use non-invasive thermometry based on magnetic resonance diffusion imaging for applications in therapeutic hyperthermia is examined. The measurement of proton motion predominantly associated with the self-diffusion of water can be characterized by a Boltzmann temperature dependence (i.e. e-Ea/kT). The activation energy (Ea) is on the order of 0.2 eV and, for a restricted range (approximately 30 degrees) at a base temperature of approximately 300 K, the relationship between the effective diffusion coefficient and temperature is approximately linear. This response has been empirically demonstrated in water-based gel phantoms using magnetic resonance imaging (MRI). Additionally, it is feasible to have compatibility between radiofrequency (RF) heating devices and MRI equipment. An MRI-compatible heating applicator that includes a hexagonal array of coherently phased dipoles was assembled. This heating array easily fits into a standard 1.5 T head imaging coil (diameter 28 cm). The RF fields associated with heating (130 MHz) and imaging (64 MHz) were decoupled using bandpass filters providing isolation in excess of 100 dB. This isolation was sufficient to allow simultaneous imaging and RF heating without deterioration of the image signal-to-noise ratio. In this report temperature, spatial and time resolution achieved in phantom are examined in order to assess the potential for using this non-invasive temperature measurement in applications of hyperthermic oncology. Using this system and conventional multi-slice imaging techniques, 0.5 degrees C resolution in a voxel size of less than 1 cm3 has been achieved using an acquisition time of 4.15 min.

Authors
Samulski, TV; MacFall, J; Zhang, Y; Grant, W; Charles, C
MLA Citation
Samulski, TV, MacFall, J, Zhang, Y, Grant, W, and Charles, C. "Non-invasive thermometry using magnetic resonance diffusion imaging: potential for application in hyperthermic oncology." Int J Hyperthermia 8.6 (November 1992): 819-829.
PMID
1479207
Source
pubmed
Published In
International Journal of Hyperthermia (Informa)
Volume
8
Issue
6
Publish Date
1992
Start Page
819
End Page
829

MR IMAGING OF PULMONARY EMBOLI IN A DOG-MODEL WITH 3D WHITE BLOOD FAST GRADIENT-ECHO SEQUENCES

Authors
MACFALL, J; WU, J; SOSTMAN, H; FOO, T
MLA Citation
MACFALL, J, WU, J, SOSTMAN, H, and FOO, T. "MR IMAGING OF PULMONARY EMBOLI IN A DOG-MODEL WITH 3D WHITE BLOOD FAST GRADIENT-ECHO SEQUENCES." RADIOLOGY 185 (November 1992): 217-217.
Source
wos-lite
Published In
Radiology
Volume
185
Publish Date
1992
Start Page
217
End Page
217

PULSATILE FLOW ARTIFACTS IN RAPID MAGNETIZATION-PREPARED MR IMAGING

Authors
RICHARDSON, D; MACFALL, J
MLA Citation
RICHARDSON, D, and MACFALL, J. "PULSATILE FLOW ARTIFACTS IN RAPID MAGNETIZATION-PREPARED MR IMAGING." RADIOLOGY 185 (November 1992): 272-272.
Source
wos-lite
Published In
Radiology
Volume
185
Publish Date
1992
Start Page
272
End Page
272

MRI of absent left pulmonary artery.

Unilateral absence of a pulmonary artery, more accurately referred to as unilateral proximal interruption of a pulmonary artery, is a rare congenital anomaly that may occur as an isolated lesion or in association with other congenital cardiovascular abnormalities. Diagnosis of associated lesions is imperative as early detection and intervention may significantly improve the patient's prognosis. We present the case of an adult patient who had come to our attention after suffering neurological decompression illness related to scuba diving. The patient's cardiopulmonary anatomy was evaluated using MRI gated spin echo, cine, and breath-held fast spoiled recalled echo sequences.

Authors
Debatin, JF; Moon, RE; Spritzer, CE; MacFall, J; Sostman, HD
MLA Citation
Debatin, JF, Moon, RE, Spritzer, CE, MacFall, J, and Sostman, HD. "MRI of absent left pulmonary artery." J Comput Assist Tomogr 16.4 (July 1992): 641-645.
PMID
1629426
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
16
Issue
4
Publish Date
1992
Start Page
641
End Page
645

Pulmonary vasculature: single breath-hold MR imaging with phased-array coils.

The authors obtained magnetic resonance images of the pulmonary vasculature with reduced artifacts caused by cardiac and respiratory motion by acquiring a series of moderately thin sections in a single breath-hold with an ultrafast gradient-echo pulse sequence. The series of two-dimensional images was postprocessed with a maximum-intensity projection algorithm. Time-of-flight inflow enhancement increased the signal intensity of arteries and veins while radiofrequency phase spoiling produced limited stationary spin suppression of the chest wall. Moderately thin (8-mm) section thicknesses were used to attain the resolution necessary to visualize smaller pulmonary vascular segments up to the chest wall while the number of acquired sections was minimized. Because the body coil did not provide an adequate signal-to-noise ratio (S/N) for a single excitation and thin-section acquisitions, phased-array coils covering either the right or left lung were used to single breath-holds prevented the misregistration and blurring that occurred in examinations performed with multiple breath-holds.

Authors
Foo, TK; MacFall, JR; Hayes, CE; Sostman, HD; Slayman, BE
MLA Citation
Foo, TK, MacFall, JR, Hayes, CE, Sostman, HD, and Slayman, BE. "Pulmonary vasculature: single breath-hold MR imaging with phased-array coils." Radiology 183.2 (May 1992): 473-477.
PMID
1561352
Source
pubmed
Published In
Radiology
Volume
183
Issue
2
Publish Date
1992
Start Page
473
End Page
477
DOI
10.1148/radiology.183.2.1561352

Thick-section, single breath-hold magnetic resonance pulmonary angiography.

RATIONALE AND OBJECTIVES: Approaches to performing magnetic resonance angiography (MRA) of the pulmonary vasculature are described using very fast (repetition time [TR] less than 13 mseconds) radiofrequency (rf)-spoiled, gradient-recalled pulse sequences and the standard quadrature body imaging coil of a commercial 1.5-T MR imaging system. METHODS AND RESULTS: Signal-to-noise (SNR) is improved by signal averaging (Nex greater than or equal to 4) in a two-dimensional, single thick-section approach and by volume acquisition (Nex = 1) in a three-dimensional approach. Blood signal loss is minimized by using short, asymmetric echoes (echo time [TE] less than or equal to 2.7 mseconds). Respiratory motion is eliminated by keeping the scan time short enough (approximately 15 seconds) for image acquisition within a single breath-hold. Cardiac motion artifacts are reduced with section orientations that avoid intersecting the heart and/or use of small flip angle (alpha less than or equal to 25 degrees). CONCLUSIONS: Images of healthy volunteers showed that while single thick sections have superior SNR, the three-dimensional approach appears to produce better visualization of the peripheral vascular segments and offers improved ability to process the images to remove overlapping structures.

Authors
MacFall, JR; Sostman, HD; Foo, TK
MLA Citation
MacFall, JR, Sostman, HD, and Foo, TK. "Thick-section, single breath-hold magnetic resonance pulmonary angiography." Invest Radiol 27.4 (April 1992): 318-322.
PMID
1601624
Source
pubmed
Published In
Investigative Radiology
Volume
27
Issue
4
Publish Date
1992
Start Page
318
End Page
322

An overview of digital spectrometers for MR imaging. Instrumentation Subcommittee of the SMRI Basic Science Council.

Most magnetic resonance (MR) imaging systems were originally designed with analog spectrometers, since that was the "state of the art" in the late 1970s, when they were developed. Advances in technology have allowed the design of radio-frequency electronics with a much larger percentage of digital components while the cost of such components has decreased. This has given manufacturers the incentive to develop new spectrometers that incorporate these electronics for cost reduction and potentially better performance. Upgrades and new models of MR units have become available with these so-called "digital spectrometers." Because of the interest in the new systems, the Instrumentation Subcommittee of the Basic Science Council of the Society for Magnetic Resonance Imaging has produced this report to review the basic features of analog and digital spectrometers to help the MR imaging community better understand the similarities and differences of these systems. Some details of actual commercial implementations were left out to focus on the basic features. Regardless, the authors hope they have provided a readable introduction to this important topic.

Authors
Holland, GN; MacFall, JR
MLA Citation
Holland, GN, and MacFall, JR. "An overview of digital spectrometers for MR imaging. Instrumentation Subcommittee of the SMRI Basic Science Council." J Magn Reson Imaging 2.2 (March 1992): 241-246.
PMID
1562779
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
2
Issue
2
Publish Date
1992
Start Page
241
End Page
246

Practical choices of fast spin echo pulse sequence parameters: Clinically useful proton density and T2-weighted contrasts

With the development of fast spin echo (FSE) MRI techniques, T2-weighted images of the brain may be obtained much more quickly than when using conventional spin echo techniques (CSE), because made the individual echoes on the FSE pulse sequence are phase encoded, allowing acquisition of the same spatial information as in CSE with less excitations. The pulse sequence parameters (echo train length, bandwidth, echo spacing) are discussed. Images were obtained on four volunteers using both CSE and FSE while varying repetition time, echo time and matrix. Comparison for signal intensity gray-white differentiation, fat and CSE signal, artifacts and vascular resolution showed that FSE images comparable in quality to those of CSE can be obtained in less than half the time. A practical choice of FSE parameters is recommended for clinical use. However, artifacts, possibly related to CSF and vascular pulsation, of which the radiologist should be aware, were identified on the FSE images.

Authors
Tien, RD; Felsberg, GJ; MacFall, J
MLA Citation
Tien, RD, Felsberg, GJ, and MacFall, J. "Practical choices of fast spin echo pulse sequence parameters: Clinically useful proton density and T2-weighted contrasts." Neuroradiology 35.1 (1992): 38-41.
Source
scival
Published In
Neuroradiology
Volume
35
Issue
1
Publish Date
1992
Start Page
38
End Page
41
DOI
10.1007/BF00588276

Fast spin-echo high-resolution MR imaging of the inner ear

Advances in MR imaging continue to improve our ability to evaluate temporal bone anatomy and disease. CT remains the procedure of choice for fine-detail imaging of bone structures such as ossicular anatomy, but it is not the ideal imaging technique for soft-tissue structures (e.g., the membranous labyrinth and neural structures). Conventional spin-echo MR techniques used to image these structures cannot yield excellent contrast and spatial resolution in clinically acceptable time frames. Conventional spin- echo T1-weighted images lack tissue contrast between fluid (e.g., CSF, endolymph, perilymph), neural tissue, otic capsule septa, and surrounding temporal bone. Conventional T2-weighted imaging of the inner ear is needed to reveal the natural contrast between fluid, neural structures, and bone; unfortunately, the use of conventional T2-weighted images is limited by time constraints when large-matrix, thin-section techniques with more than one excitation are used. Fast spin-echo imaging is a recently developed technique that can provide T2-weighted, thin-section (2-mm) high-resolution images with excellent contrast in a fraction of the time needed for conventional spin- echo techniques. This speed advantage allows us to obtain high-resolution images in clinically acceptable time frames. Images produced by this technique are a useful addition, in conjunction with routine T1- and T2- weighted spin-echo images, in the diagnosis of disorders of the inner ear.

Authors
Tien, RD; Felsberg, GJ; Macfall, J
MLA Citation
Tien, RD, Felsberg, GJ, and Macfall, J. "Fast spin-echo high-resolution MR imaging of the inner ear." American Journal of Roentgenology 159.2 (1992): 395-398.
Source
scival
Published In
American Journal of Roentgenology
Volume
159
Issue
2
Publish Date
1992
Start Page
395
End Page
398

Evaluation of complex cystic masses of the brain: Value of steady-state free-precession MR imaging

OBJECTIVE. This study evaluated the effectiveness of steady-state free- precession (SSFP) MR imaging of complex cystic masses of the brain compared with that of conventional T1- and T2-weighted spin-echo imaging. Our hypothesis is that SSFP MR images provide better characterization of these masses and facilitate more appropriate preoperative diagnoses and planning. SUBJECT AND METHODS. Axial T1-weighted and SSFP MR images and specimens for pathologic examination were obtained in seven consecutive patients, 9-81 years old, with cystic mass lesions of the brain and neurologic symptoms and signs directly related to the masses. Axial contrast-enhanced T1-weighted images were obtained in six patients, surgical exploration was done in five patients, and stereotaxic biopsy was done in two. After examination of the routine spin-echo and SSFP images, the usefulness of SSFP images was determined by how well they facilitated correct preoperative diagnosis. RESULTS. On SSFP MR images, the solid or inhomogeneous components of a cystic mass had extremely low signals in contrast to the high signal of surrounding fluid. On routine spin-echo images, however, the signals of these components were masked by the signal of the surrounding fluid. SSFP MR images helped markedly in diagnosis of hemorrhagic, epidermoid, and arachnoid cysts. In cases of enhancing brain tumors, SSFP MR images provided the same information that contrast-enhanced images did. Overall, when SSFP MR imaging was used, more information about the texture and constituents of the cystic mass was obtained, and a more useful diagnosis was made. CONCLUSION. Initial results show that SSFP MR imaging is a more useful technique than conventional spin- echo imaging for characterizing complex cystic masses of the brain. SSFP MR imaging (1) allows distinction of edema from tumor, (2) helps establish where biopsy has the best chance of providing tissue that will show pathologic changes, and (3) helps distinguish simple cysts from tumors, tumor-cyst, or multicompartmental cyst and may be particularly helpful in detecting the contents of hemorrhagic cysts.

Authors
Tien, RD; MacFall, J; Heinz, R
MLA Citation
Tien, RD, MacFall, J, and Heinz, R. "Evaluation of complex cystic masses of the brain: Value of steady-state free-precession MR imaging." American Journal of Roentgenology 159.5 (1992): 1049-1055.
Source
scival
Published In
American Journal of Roentgenology
Volume
159
Issue
5
Publish Date
1992
Start Page
1049
End Page
1055

AN OVERVIEW OF DIGITAL SPECTROMETERS FOR MR IMAGING

Authors
HOLLAND, G; MACFALL, J; CHARLES, H; DIXON, W; GLOVER, G; HOLLAND, G
MLA Citation
HOLLAND, G, MACFALL, J, CHARLES, H, DIXON, W, GLOVER, G, and HOLLAND, G. "AN OVERVIEW OF DIGITAL SPECTROMETERS FOR MR IMAGING." JMRI-JOURNAL OF MAGNETIC RESONANCE IMAGING 2.2 (1992): 241-246.
Source
wos-lite
Published In
Journal of Magnetic Resonance Imaging
Volume
2
Issue
2
Publish Date
1992
Start Page
241
End Page
246
DOI
10.1002/jmri.1880020221

MR imaging of microcirculation in rat brain: correlation with carbon dioxide-induced changes in blood flow.

Considerable interest has been shown in developing a magnetic resonance (MR) imaging technique with quantitative capability in the evaluation of tissue microcirculation ("perfusion"). In the present study, the flow-dephased/flow-compensated (FD/FC) technique is evaluated for measuring rat cerebral blood flow (CBF) under nearly optimal laboratory conditions. Imaging was performed on a 2.0-T system equipped with shielded gradient coils. Rat CBF was varied by manipulating arterial carbon dioxide pressure (PaCO2). In parallel experiments, optimized MR imaging studies (seven rats) were compared with laser Doppler flowmetry (LDF) studies (nine rats). LDF values showed a high degree of correlation between CBF and PaCO2, agreeing with results in the literature. MR imaging values, while correlating with PaCO2, showed considerable scatter. The most likely explanation is unavoidable rat motion during the requisite long imaging times. Because of this motion sensitivity, the FD/FC technique cannot provide a quantitative measure of CBF. It can, however, provide a qualitative picture.

Authors
Maki, JH; Benveniste, H; MacFall, JR; Piantadosi, CA; Johnson, GA
MLA Citation
Maki, JH, Benveniste, H, MacFall, JR, Piantadosi, CA, and Johnson, GA. "MR imaging of microcirculation in rat brain: correlation with carbon dioxide-induced changes in blood flow." J Magn Reson Imaging 1.6 (November 1991): 673-681.
PMID
1823172
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
1
Issue
6
Publish Date
1991
Start Page
673
End Page
681

PREMORTEM AND POSTMORTEM DIFFUSION-COEFFICIENTS IN RAT NEURAL AND MUSCLE TISSUES

Authors
MACFALL, J; MAKI, J; JOHNSON, G; HEDLUND, L; COFER, G
MLA Citation
MACFALL, J, MAKI, J, JOHNSON, G, HEDLUND, L, and COFER, G. "PREMORTEM AND POSTMORTEM DIFFUSION-COEFFICIENTS IN RAT NEURAL AND MUSCLE TISSUES." MAGNETIC RESONANCE IN MEDICINE 20.1 (July 1991): 89-99.
Source
wos-lite
Published In
Magnetic Resonance in Medicine
Volume
20
Issue
1
Publish Date
1991
Start Page
89
End Page
99
DOI
10.1002/mrm.1910200110

Pre- and postmortem diffusion coefficients in rat neural and muscle tissues.

Pulsed gradient diffusion-weighted spin-echo images (7 to 11 gradient strengths) were obtained in a coronal slice through the midbrain for five normal adult white rats before and after sacrifice in a 2-T CSI system with air temperature control. The pulse sequence was cardiac gated and respiratory synchronized in order to minimize motion artifacts (Tr greater than 2 s. Te = 30 ms). Diffusion coefficients reflecting several tissue compartments (D*) in brain and muscle were calculated and referenced to simultaneously imaged tubes of water. In the living animals, brain cortical matter had a value of D* = (0.82 +/- 0.02) x 10(-3) mm2/s. deeper brain regions had a value of D* = (0.73 +/- 0.02) x 10(-3) mm2/s, and the muscle had a value of D* = (1.4 +/- 0.1) x 10(-3) mm2/s. Postmortem the values in brain dropped by approximately 30%, while remaining constant in muscle. Signal intensity in the spin-echo images for muscle tissue rose by 50% over a 1- to 2-h interval after sacrifice while that of brain tissue remained relatively stable.

Authors
MacFall, JR; Maki, JH; Johnson, GA; Hedlund, LW; Cofer, GP
MLA Citation
MacFall, JR, Maki, JH, Johnson, GA, Hedlund, LW, and Cofer, GP. "Pre- and postmortem diffusion coefficients in rat neural and muscle tissues." Magn Reson Med 20.1 (July 1991): 89-99.
PMID
1943665
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
20
Issue
1
Publish Date
1991
Start Page
89
End Page
99

Diffusion/microcirculation MRI in the rat brain.

The CO2 fraction of an anesthetized rat's breathing mixture was changed (from 0 to 10%) to attempt to change the brain microcirculation and observe these changes in diffusion measurements of the neural tissue. Brain apparent diffusion coefficients were measured to be (0.71 +/- 0.01) X 10(-3) mm2/s before sacrifice and (0.39 +/- 0.01) X 10(-3) mm2/s after sacrifice. Multiple diffusion components were observed, consistent with flowing material, but the extra components did not increase with increased CO2. It is proposed that the additional components may be due to extracellular, extravascular water such as CSF.

Authors
MacFall, JR; Maki, JH; Johnson, GA; Hedlund, L; Benveniste, H; Copher, G
MLA Citation
MacFall, JR, Maki, JH, Johnson, GA, Hedlund, L, Benveniste, H, and Copher, G. "Diffusion/microcirculation MRI in the rat brain." Magn Reson Med 19.2 (June 1991): 305-310.
PMID
1908936
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
19
Issue
2
Publish Date
1991
Start Page
305
End Page
310

Muscle activity localization with 31P spectroscopy and calculated T2-weighted 1H images.

Using 31P spectroscopy and magnetic resonance imaging (MRI), the authors studied changes in muscle phosphorous metabolites and T2 with isometric knee extension to evaluate the potential role of T2 images in coil placement for exercise spectroscopy studies. Increased signal intensity was visible in active muscles on T2 images after exercise. Calculated T2-weighted values were elevated immediately after exercise in the quadriceps (P less than .01). T2 increases for individual quadricep muscles varied, with the largest changes in the rectus femoris and the least in the vastus lateralis. 31P spectroscopy studies demonstrated similar findings: percent change in T2 correlated positively with inorganic phosphorus to phosphocreatine ratio (Pi/PCr) (r = 0.89, P less than .01) and negatively with pH (r = -0.88, P less than .01). The correlations between imaging and spectroscopy suggest that T2 images may allow more precise placement of phosphorous coils in exercise studies. The heterogeneity of T2 changes within the quadriceps with exercise suggests that assumptions about muscle activity may be misleading. T2 images may provide muscle activity verification for exercise studies.

Authors
Weidman, ER; Charles, HC; Negro-Vilar, R; Sullivan, MJ; MacFall, JR
MLA Citation
Weidman, ER, Charles, HC, Negro-Vilar, R, Sullivan, MJ, and MacFall, JR. "Muscle activity localization with 31P spectroscopy and calculated T2-weighted 1H images." Invest Radiol 26.4 (April 1991): 309-316.
PMID
2032818
Source
pubmed
Published In
Investigative Radiology
Volume
26
Issue
4
Publish Date
1991
Start Page
309
End Page
316

Maximization of contrast-to-noise ratio to distinguish diffusion and microcirculatory flow.

Optimization of the contrast-to-noise ratio (CNR) is described for microcirculation magnetic resonance (MR) imaging techniques based on flow-compensated/flow-dephased sequences, both with and without even-echo rephasing. The authors present the most advantageous manner of applying flow-dephased gradients, such that dephasing is maximal while diffusion losses are minimal. The theoretical considerations include phase, diffusion, echo time, and bandwidth in the determination of the optimal parameters for microcirculation imaging. Studies in phantoms consisting of stationary and flowing copper sulfate in Sephadex columns demonstrate the validity of the calculations. Optimized in vivo images of a rat stroke model demonstrate the potential of the flow-compensated/flow-dephased technique and the importance of optimizing CNR.

Authors
Maki, JH; Benveniste, H; MacFall, JR; Johnson, GA
MLA Citation
Maki, JH, Benveniste, H, MacFall, JR, and Johnson, GA. "Maximization of contrast-to-noise ratio to distinguish diffusion and microcirculatory flow." J Magn Reson Imaging 1.1 (January 1991): 39-46.
PMID
1802129
Source
pubmed
Published In
Journal of Magnetic Resonance Imaging
Volume
1
Issue
1
Publish Date
1991
Start Page
39
End Page
46

The use of gradient flow compensation to separate diffusion and microcirculatory flow in MRI.

This paper describes a new MR imaging technique termed Modified Stejskal Tanner versus Flow Compensation (MST/FC) for the separation of diffusion and microcirculatory flow. The theory behind the sequence is explained, along with a five-component model of microcirculation applicable to any "perfusion" imaging technique. Phantom data is presented showing that (1) diffusion effects can be matched between MST and FC (suggesting the possibility of flow-compensated diffusion imaging), and (2) the technique is a quantitative method of separating diffusion and slow (less than 0.25 mm/s) tortuous flow through a Sephadex column. Furthermore, animal images show the technique to be feasible and quantitative in measuring rat brain microcirculation under normal, vasodilated (hypercarbia), and no-flow (post mortem) conditions.

Authors
Maki, JH; MacFall, JR; Johnson, GA
MLA Citation
Maki, JH, MacFall, JR, and Johnson, GA. "The use of gradient flow compensation to separate diffusion and microcirculatory flow in MRI." Magn Reson Med 17.1 (January 1991): 95-107.
PMID
1712421
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
17
Issue
1
Publish Date
1991
Start Page
95
End Page
107

More on the feasibility of using MRI for noninvasive thermometry in hyperthermia

A combination of RF heating and MR imaging equipment has been constructed in a fashion that allows simultaneous heating and MR diffusion imaging. Isolation between the RF heating and RF imaging frequencies is accomplished by means of filtering. This system has allowed a systematic estimate of temperature resolution and spatial resolution to be made using noninvasive MR tomography in a phantom model. The initial data indicates that 0.8°C resolution in ≤ 1 cm3 voxel is feasible using standard imaging techniques and an acquisition time of approximately 2 minutes.

Authors
Samulski, TV; MacFall, J; Zhang, Y; Palmer, D; Charles, C; Grant, W
MLA Citation
Samulski, TV, MacFall, J, Zhang, Y, Palmer, D, Charles, C, and Grant, W. "More on the feasibility of using MRI for noninvasive thermometry in hyperthermia." American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD 189 (1991): 57-60.
Source
scival
Published In
American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD
Volume
189
Publish Date
1991
Start Page
57
End Page
60

PULMONARY ANGIOGRAPHY WITH MR IMAGING

Authors
CRIST, T; MACFALL, J; SALLCE, D; SPRITZER, C; SOSTMAN, H
MLA Citation
CRIST, T, MACFALL, J, SALLCE, D, SPRITZER, C, and SOSTMAN, H. "PULMONARY ANGIOGRAPHY WITH MR IMAGING." RADIOLOGY 174.3 (March 1990): 1063-1063.
Source
wos-lite
Published In
Radiology
Volume
174
Issue
3
Publish Date
1990
Start Page
1063
End Page
1063

Truncated sinc slice excitation for 31P spectroscopic imaging.

The shortest possible delay (Td) between slice selection and data acquisition is important for producing high quality 31P spectra. In single slice multivoxel spectroscopic imaging, conventional excitation using sinc-shaped rf pulses within typical gradient limitations can have values of Td that lead to significant spectral distortion and loss of signal. Truncated sinc excitation, which ends the excitation close to the center of the main rf lobe has been suggested for MR angiographic applications to produce short values of Td. In this work, the slice profiles, spectral signal-to-noise ratio (SNR) and spectral distortions are compared using the minimum delay achievable on a commercial MRI system for conventional 'sinc' rf excitation and truncated sinc excitation. Slice profiles are calculated using the Bloch equations and measured with a phantom. SNR and spectral distortions are evaluated from whole slice spectra on a human volunteer. On an MRI system with 1 G/cm gradients (0.5 msec risetime), for a 2.5-cm slice at 31P frequencies, conventional excitation can be adjusted to achieve Td = 2.5 msec while truncated sinc excitation yields Td = 1.5 msec. The truncated sinc excitation's shorter value of Td leads to much smaller spectral distortions, but its slice profile has "dispersive tails" which increase as more of the rf is truncated. Slice profile corrected SNR for the beta-ATP peak of 31P on a human volunteer is equivalent for both sequences while, qualitatively, in the PDE region the truncated sinc approach has improved SNR.

Authors
MacFall, JR; Charles, HC; Prost, R
MLA Citation
MacFall, JR, Charles, HC, and Prost, R. "Truncated sinc slice excitation for 31P spectroscopic imaging." Magn Reson Imaging 8.5 (1990): 619-624.
PMID
2082133
Source
pubmed
Published In
Magnetic Resonance Imaging
Volume
8
Issue
5
Publish Date
1990
Start Page
619
End Page
624

MR diffusion measurements in stroke models in rat brains

It is shown that tissue self-diffusion coefficients can be calculated from a series of diffusion-weighted MR (magnetic resonance) images. By variation of the time between diffusion sensitizing gradient pulses, the motions of tissue water may be characterized on varying length scales from 10 μm to 100 μm. Typically, the diffusion coefficient decreases as this diffusion time increases. Such characterization of tissue water properties may be of use in the study of the course of pathology in disease models.

Authors
MacFall, JR; Benveniste, H; Maki, J; Johnson, GA; Hedlund, L; Copher, G
MLA Citation
MacFall, JR, Benveniste, H, Maki, J, Johnson, GA, Hedlund, L, and Copher, G. "MR diffusion measurements in stroke models in rat brains." Proceedings of the Annual Conference on Engineering in Medicine and Biology pt 1 (1990): 67-68.
Source
scival
Published In
Proceedings of the Annual Conference on Engineering in Medicine and Biology
Issue
pt 1
Publish Date
1990
Start Page
67
End Page
68

Non-invasive thermometry for local regional hyperthermia using magnetic resonance imaging of intra-voxel incoherent motion

Local/regional hyperthermia for cancer therapy encounters many formidable technical challenges. One of the most difficult is quantitatively assessing the temperature fields induced in tissue. Recently, D. LeBihan et al. have proposed that the measurement of free water diffusion with magnetic resonance (MR) can be used to non-invasively image temperature fields in tissue. The temperature dependence of the water diffusion constant has been measured in phantom materials using clinical magnetic resonance imaging (MRI) instruments. Additionally, it is feasible to combine imaging, heating and gradient coils into a single composite device. The requirements of non-invasive thermometry during hyperthermia therapy include acceptable spatial, time, temperature resolution carried out simultaneously with application of heating devices. This paper will review the basic principles involved in using MRI of free water diffusion to non-invasively determine temperature. It will also describe and discuss technical problems and progress towards using MRI thermometry in hyperthermia therapy.

Authors
Samulski, TV; MacFall, J; LeBihan, D
MLA Citation
Samulski, TV, MacFall, J, and LeBihan, D. "Non-invasive thermometry for local regional hyperthermia using magnetic resonance imaging of intra-voxel incoherent motion." American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD 147 (1990): 1-9.
Source
scival
Published In
American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD
Volume
147
Publish Date
1990
Start Page
1
End Page
9

Effects of intravoxel incoherent motions (IVIM) in steady-state free precession (SSFP) imaging: application to molecular diffusion imaging.

A theoretical analysis of the effects of diffusion and perfusion in steady-state free precession (SSFP) imaging sequences sensitized to intravoxel incoherent motions by magnetic field gradients is presented and supported by phantom studies. The capability of such sequences to image diffusion and perfusion quickly was recently demonstrated. The possible residual effects of T1 and T2 in diffusion measurements are evaluated, as are the effects of the sequence design and the acquisition parameters (repetition time, flip angle, gradient pulses). It is shown theoretically and confirmed by experiments on phantoms that diffusion coefficients can be directly measured from SSFP images when large enough diffusion gradient pulses are used.

Authors
Le Bihan, D; Turner, R; MacFall, JR
MLA Citation
Le Bihan, D, Turner, R, and MacFall, JR. "Effects of intravoxel incoherent motions (IVIM) in steady-state free precession (SSFP) imaging: application to molecular diffusion imaging." Magn Reson Med 10.3 (June 1989): 324-337.
PMID
2733589
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
10
Issue
3
Publish Date
1989
Start Page
324
End Page
337

Contrast and accuracy of relaxation time measurements in acquired and synthesized multislice magnetic resonance images.

The effects of interslice spacing, the number of data points and other factors on the accuracy of relaxation time measurements and contrast have been investigated for both acquired and synthesized multislice MR images using experiments and computer simulations. The cross-excitation between adjacent slices in multislice imaging affects both contrast and derived relaxation times. Such measurements also are affected by the T1 and T2 of the materials imaged, the pulse sequence timing parameters, and the number of data points used to estimate the relaxation times. Errors in T1 and T2 may be severe, particularly for slice spacings less than 0.5 slice thickness and for long T1 and T2 materials. Consequently, the difference in signal intensities between two materials with different relaxation times also varies with slice spacing and between acquired and synthetic images, particularly for strongly T1-weighed images.

Authors
Majumdar, S; Sostman, HD; MacFall, JR
MLA Citation
Majumdar, S, Sostman, HD, and MacFall, JR. "Contrast and accuracy of relaxation time measurements in acquired and synthesized multislice magnetic resonance images." Invest Radiol 24.2 (February 1989): 119-127.
PMID
2917832
Source
pubmed
Published In
Investigative Radiology
Volume
24
Issue
2
Publish Date
1989
Start Page
119
End Page
127

Integrated MR imaging and spectroscopy with chemical shift imaging of P-31 at 1.5 T: initial clinical experience.

A section-selective three-dimensional phosphorus-31 chemical shift imaging (CSI) experiment was evaluated as the spatial localization method for spectroscopy in an integrated clinical magnetic resonance (MR) imaging and spectroscopy examination. The results of a CSI experiment can be displayed as either spectra related to specific voxels or "metabolite maps," in which the relative concentration of a given metabolite is displayed as an overlay of the MR image. This method was applied to the study of a soft-tissue mass and to a meningioma. The total imaging time in each case was 17 minutes with a voxel size of 27 cm3 in the extremity and 64 cm3 in the brain. The total time to set up this part of the study was about 10 minutes. No additional shimming was necessary when the center of the field of view selected for the CSI experiment was located at or near isocenter. The promising results obtained with this approach make the CSI method an attractive choice of spatial localization method.

Authors
Lenkinski, RE; Holland, GA; Allman, T; Vogele, K; Kressel, HY; Grossman, RI; Charles, HC; Engeseth, HR; Flamig, D; MacFall, JR
MLA Citation
Lenkinski, RE, Holland, GA, Allman, T, Vogele, K, Kressel, HY, Grossman, RI, Charles, HC, Engeseth, HR, Flamig, D, and MacFall, JR. "Integrated MR imaging and spectroscopy with chemical shift imaging of P-31 at 1.5 T: initial clinical experience." Radiology 169.1 (October 1988): 201-206.
PMID
3420258
Source
pubmed
Published In
Radiology
Volume
169
Issue
1
Publish Date
1988
Start Page
201
End Page
206
DOI
10.1148/radiology.169.1.3420258

MR MICROSCOPY USING DRIVEN EQUILIBRIUM (DEFT)

Authors
MAKI, J; COFER, G; HEDLUND, L; MACFALL, J; JOHNSON, G
MLA Citation
MAKI, J, COFER, G, HEDLUND, L, MACFALL, J, and JOHNSON, G. "MR MICROSCOPY USING DRIVEN EQUILIBRIUM (DEFT)." INVESTIGATIVE RADIOLOGY 23.9 (September 1988): S21-S21.
Source
wos-lite
Published In
Investigative Radiology
Volume
23
Issue
9
Publish Date
1988
Start Page
S21
End Page
S21

Correction of spatially dependent phase shifts for partial Fourier imaging.

Partial Fourier MR images (PFI) are constructed from data that have fewer phase encoding views than are conventionally acquired using direct Fourier transform spin echo acquisition. The PFI data acquisition is structured to obtain the same spatial resolution as conventional acquisition, trading off signal-to-noise reduction for acquisition time improvement. The "missing" views can be zero filled or, if the data are Hermitian, supplied by symmetry (basic algorithm). The effect of spatially dependent phase shifts (SDPS) on PFI constructed with zero-fill or the basic algorithm is illustrated. The causes and typical magnitudes of such SDPS are discussed. In spin echo data only the low order, slowly varying SDPS, is shown to be significant. Through use of simulated and actual data sets these typical SDPS are shown to produce significant artifacts in PFI, when the amount of missing data is close to one-half. The artifacts are reduced when less data are missing. Good images can be generated with the zero-fill algorithm if less than 25% of the data is missing. Several methods of correcting phase shifts in PFI are developed: the basic Hermitian algorithm with frequency (x) direction correction (BAX), basic Fourier correction algorithm (BFC) and an improved iterative Fourier correction algorithm (IFC). The BFC and IFC can produce good images when as much as 46% of the data is missing. Data with rapidly varying SDPS, for example, gradient refocused data, make the phase correction task more difficult. With less than 25% of the data missing, however, acceptable gradient refocused PFI images can be created.

Authors
MacFall, JR; Pelc, NJ; Vavrek, RM
MLA Citation
MacFall, JR, Pelc, NJ, and Vavrek, RM. "Correction of spatially dependent phase shifts for partial Fourier imaging." Magn Reson Imaging 6.2 (March 1988): 143-155.
PMID
3374286
Source
pubmed
Published In
Magnetic Resonance Imaging
Volume
6
Issue
2
Publish Date
1988
Start Page
143
End Page
155

SNR improvement in NMR microscopy using DEFT

This paper examines the use of a driven equilibrium Fourier transform (DEFT) pulse sequence for improving the signal per unit time and hence image resolution in NMR microscopy. DEFT vs partial saturation (PS) is modeled and it is shown that DEFT is most useful in physiologic materials provided short TE values (TE ≪ T2) and short TR values (TR < T1) are used. Under these conditions, DEFT can yield up to a fourfold signal increase compared to PS. It is shown that DEFT can provide spin density and T1/T2-ratio-weighted images. DEFT is also shown to have SNR advantages as T1 increases-an important consideration at higher magnetic fields. Experimental data that verify the theoretical predictions and the functioning of a DEFT pulse sequence to produce high-quality 2D spin-warp images of a phantom are presented. Studies performed on small animals demonstrate the utility of the DEFT sequence in MR microscopy by providing increased SNR and new contrast mechanisms over limited fields of view. © 1988.

Authors
Maki, JH; Johnson, GA; Cofer, GP; MacFall, JR
MLA Citation
Maki, JH, Johnson, GA, Cofer, GP, and MacFall, JR. "SNR improvement in NMR microscopy using DEFT." Journal of Magnetic Resonance (1969) 80.3 (1988): 482-492.
Source
scival
Published In
Journal of Magnetic Resonance (1969)
Volume
80
Issue
3
Publish Date
1988
Start Page
482
End Page
492
DOI
10.1016/0022-2364(88)90243-0

Methodology for the measurement and analysis of relaxation times in proton imaging.

Measurements of proton T1 and T2 were performed on GdCl3 solutions (20 less than T2 less than 500 msec, 90 less than T1 less than 1000 msec) on large-bore NMR imaging systems operating at 1.0T and 1.5T. CPMG multi-echo (ME), multiple saturation recovery (MSR) and modified fast inversion recovery (MFIR) pulse sequences as well as a sequence that combines and interleaves T1 and T2 weighted data acquisition (which we call "multiple saturation-recovery multiple-echo" (MSRME) were used. The relaxation data are compared to those obtained on a small bore NMR spectrometer operated at 1.5T. T1 and T2 values for the solutions were found to be the same within 10% for the two fields. Reproducibility of measurements of T1, T2 and the unnormalized spin density of the solutions was better than 5%. Systematic errors, amenable to correction through calibration, are noted in the imager T1 and T2 values. T1 and T2 values for some typical neural tissues at 1.5T and body tissue at 1.0T for human volunteers were obtained and are tabulated.

Authors
MacFall, JR; Wehrli, FW; Breger, RK; Johnson, GA
MLA Citation
MacFall, JR, Wehrli, FW, Breger, RK, and Johnson, GA. "Methodology for the measurement and analysis of relaxation times in proton imaging." Magn Reson Imaging 5.3 (1987): 209-220.
PMID
3041152
Source
pubmed
Published In
Magnetic Resonance Imaging
Volume
5
Issue
3
Publish Date
1987
Start Page
209
End Page
220

Reproducibility of relaxation and spin-density parameters in phantoms and the human brain measured by MR imaging at 1.5 T.

The reproducibility of T1, T2, and proton density, measured in phantoms and the human brain was evaluated by proton imaging techniques. The sequence used to derive T1 and density values was a multiple-saturation recovery which consists of four pairs of 90 degrees pulses, followed by a 180 degrees phase reversal pulse, generating four T1-weighted images. T2 was derived from a multiple-echo sequence, generating four T2-weighted images. The data were analyzed by fitting the pixel intensities to the respective equations by means of nonlinear multiparameter least-squares analysis. Short-term reproducibility between four consecutive scans was evaluated to be 1-4% depending on location with a phantom covering the entire span of physiologic T1 and T2 values. A second phantom containing a series of identical samples served to study the dependence of the apparent T1 and T2 on position, both radially and axially, with respect to magnet isocenter. Reproducibility across the field of view was found to be better than 7% (T1 and T2). This phantom was further used to evaluate effects of long-term reproducibility, which at each location varied from 5-14% (T1) and 2-10% (T2). Finally, interinstrument reproducibility, tested by means of the same protocol on three different instruments, all operating at the same magnetic field and using largely identical hardware for each location, was found to be 1-14% (T1) and 2-10% (T2). The positional dependence of the apparent relaxation times appears to be systematic and may be due to variations in the effective field, caused by magnet and rf inhomogeneity. Finally, brain tissue relaxation and spin-density data were determined using the same protocol in 37 scans performed on 27 normal volunteers. The tissues analyzed were putamen, thalamus, caudate nucleus, centrum semiovale, internal capsule, and corpus callosum. Excellent accordance was further obtained between left and right hemispheres.

Authors
Breger, RK; Wehrli, FW; Charles, HC; MacFall, JR; Haughton, VM
MLA Citation
Breger, RK, Wehrli, FW, Charles, HC, MacFall, JR, and Haughton, VM. "Reproducibility of relaxation and spin-density parameters in phantoms and the human brain measured by MR imaging at 1.5 T." Magn Reson Med 3.5 (October 1986): 649-662.
PMID
3784884
Source
pubmed
Published In
Magnetic Resonance in Medicine
Volume
3
Issue
5
Publish Date
1986
Start Page
649
End Page
662

Time-of-flight MR flow imaging: selective saturation recovery with gradient refocusing.

A novel magnetic resonance flow-imaging technique is presented and its suitability evaluated for both qualitative and quantitative imaging of flow. The method is derived from a selective saturation-recovery scheme consisting of a tagging and detection pulse followed by a bipolar read gradient. The detrimental phase effects causing signal loss at fast flow are shown to be greatly reduced because of the absence of a 180 degrees pulse and its associated section-selection gradient. The second loss mechanism intrinsic to 180 degrees spin echoes, the washout of excited spins between excitation and detection pulse, likewise is not present with the discussed technique. Assuming a parabolic flow profile, the authors calculated the signal evolution curve and found it to be in agreement with the experimental washout curve. The technique is shown to provide high-intensity signals for arteries such as carotid and vertebral arteries. Arteries and veins can be differentiated by judiciously choosing interpulse intervals or by alternating selective and nonselective tagging pulses.

Authors
Wehrli, FW; Shimakawa, A; Gullberg, GT; MacFall, JR
MLA Citation
Wehrli, FW, Shimakawa, A, Gullberg, GT, and MacFall, JR. "Time-of-flight MR flow imaging: selective saturation recovery with gradient refocusing." Radiology 160.3 (September 1986): 781-785.
PMID
3526407
Source
pubmed
Published In
Radiology
Volume
160
Issue
3
Publish Date
1986
Start Page
781
End Page
785
DOI
10.1148/radiology.160.3.3526407

T2 estimates in healthy and diseased brain tissue: a comparison using various MR pulse sequences.

Fourteen patients and five healthy individuals underwent magnetic resonance (MR) imaging to determine an effective multiple spin echo pulse sequence for estimating T2. Lesions examined included infarction, glioma, multiple sclerosis, and acute hematoma. A pulse repetition time (TR) of 1,500 msec and echo delays (TEs) of 25, 50, 75, and 100 msec were used. Computed T2 images were derived from all four echoes, the first two echoes, and the first and fourth echoes. T2 values were obtained from specific brain locales using region-of-interest analysis. Use of either the first two echoes or the first and fourth in the T2 fit provided T2 estimates which closely correlated with that of the four-echo analysis. The noise level in T2 maps constructed from the 25- and 100-msec echoes was modestly (typically 10%) higher than that from four echoes; noise level from the 25- and 50-msec echoes was markedly higher, typically 60%. This behavior is remarkably consistent with that predicted from theory. All 19 subjects displayed consistent relative T2 values for specific brain structures; in 13, the absolute T2 values fell within a limited range. Despite the high sensitivity of T2 images, their specificity in the detection of most brain disease appears limited except in acute intracerebral hematoma, which exhibited a decreased T2 relaxation time using high-field-strength MR imaging.

Authors
Darwin, RH; Drayer, BP; Riederer, SJ; Wang, HZ; MacFall, JR
MLA Citation
Darwin, RH, Drayer, BP, Riederer, SJ, Wang, HZ, and MacFall, JR. "T2 estimates in healthy and diseased brain tissue: a comparison using various MR pulse sequences." Radiology 160.2 (August 1986): 375-381.
PMID
3726116
Source
pubmed
Published In
Radiology
Volume
160
Issue
2
Publish Date
1986
Start Page
375
End Page
381
DOI
10.1148/radiology.160.2.3726116

An analysis of noise propagation in computed T2, pseudodensity, and synthetic spin-echo images.

Methods are reviewed for estimating the transverse relaxation time T2 and the pseudodensity (PD) from spin-echo measurements acquired at an arbitrary set of echo times [TEi]. Least-squares fitting is applied to the logarithmically processed signals for the case in which the weights are proportional to the inverse of the logarithmically transformed signal variances (the minimum variance case). General formulas are derived for the estimated noise levels in the PD and T2 estimates due to the propagation of uncertainties in the original measurements. It is shown that the T2 and PD estimates are anticorrelated. Additionally, an expression is derived for the variance in a synthetic spin-echo signal subsequently formed from the PD and T2 estimates. It is shown that under many circumstances a signal synthesized at some echo time can have a signal-to-noise ratio superior to that in a signal directly acquired at that time. Experimental measurements made on phantoms match the theoretical predictions to a high degree.

Authors
MacFall, JR; Riederer, SJ; Wang, HZ
MLA Citation
MacFall, JR, Riederer, SJ, and Wang, HZ. "An analysis of noise propagation in computed T2, pseudodensity, and synthetic spin-echo images." Med Phys 13.3 (May 1986): 285-292.
PMID
3724687
Source
pubmed
Published In
Medical physics
Volume
13
Issue
3
Publish Date
1986
Start Page
285
End Page
292
DOI
10.1118/1.595956

A time-of-flight method of measuring flow velocity by magnetic resonance imaging

A new time-of-flight method for direct imaging of flow velocities by magnetic resonance is presented. The technique uses selective exciting and refocusing RF pulses to selectively affect planes oriented in orthogonal directions in space, with the region of excitation perpendicular to the flow and the refocusing region parallel to and including the flow. The positions of the sources of the resulting spin echoes are imaged, showing a displacement equal to the product of the velocity and the echo time. These images clearly show the profile of the velocity distribution, both in laminar and nonlaminar flows. © 1986.

Authors
Axel, L; Shimakawa, BSEEA; MacFall, J
MLA Citation
Axel, L, Shimakawa, BSEEA, and MacFall, J. "A time-of-flight method of measuring flow velocity by magnetic resonance imaging." Magnetic Resonance Imaging 4.3 (1986): 199-205.
Source
scival
Published In
Magnetic Resonance Imaging
Volume
4
Issue
3
Publish Date
1986
Start Page
199
End Page
205

Quantification of contrast in clinical MR brain imaging at high magnetic field.

The relative contrast between two tissues in a magnetic resonance (MR) image is shown to be quantifiable for any combination of pulse timing parameters, provided the intrinsic parameters are known. Based on multiple inversion-recovery and spin echo images, a region-of-interest T1, T2 and density analysis was conducted at 1.4T in selected patients with diagnosed neuropathology for various brain tissues. The resulting tissue parameters subsequently served to calculate the contrast-to-noise (C/N) ratio for typical tissue interfaces as a function of the operator-variable pulse timing parameters and the data were compared with the images. Although such calculations may be useful as a protocol selection aid, it is obvious that an optimized pulse protocol can only be established for a single tissue interface. The data also reveal that a T2-discriminating pulse sequence like Carr-Purcell-Meiboom-Gill with long repetition time, generally advocated as clinically most effective, may not always be ideal.

Authors
Wehrli, FW; Breger, RK; MacFall, JR; Daniels, DL; Haughton, VM; Charles, HC; Williams, AL
MLA Citation
Wehrli, FW, Breger, RK, MacFall, JR, Daniels, DL, Haughton, VM, Charles, HC, and Williams, AL. "Quantification of contrast in clinical MR brain imaging at high magnetic field." Invest Radiol 20.4 (July 1985): 360-369.
PMID
4044176
Source
pubmed
Published In
Investigative Radiology
Volume
20
Issue
4
Publish Date
1985
Start Page
360
End Page
369

Synthesized MR images: comparison with acquired images.

Synthesized and directly acquired spin-echo images were compared in order to assess the validity of magnetic resonance (MR) image synthesis as a method enabling retrospective formation of images by interactive manipulation of scan parameters. Synthetic images subjectively compared favorably in both accuracy and precision with acquired images when formed for the same values of echo (TE) and repetition times (TR) and for interpolated and extrapolated values of both TE and TR. Plots of synthetic and acquired signals within the same pixel sectors quantitatively showed comparable values for several regions of interest in the brain. Percent error and noise-normalized differences between acquired and synthetic images were tested as a quantitative measure of accuracy. Percent error was consistently less than 5% for brain parenchyma, and synthetic signals were accurate to within four times the noise level at acquisition. The apparent signal-to-noise ratio of synthetic images was comparable, superior, or inferior to similar acquired images, depending on the values of TE and TR. Total acquisition time required for synthetic formation of images for arbitrary values of TE and TR was equivalent to that of a single direct acquisition with a TR of 2,500 msec.

Authors
Bobman, SA; Riederer, SJ; Lee, JN; Suddarth, SA; Wang, HZ; MacFall, JR
MLA Citation
Bobman, SA, Riederer, SJ, Lee, JN, Suddarth, SA, Wang, HZ, and MacFall, JR. "Synthesized MR images: comparison with acquired images." Radiology 155.3 (June 1985): 731-738.
PMID
4001377
Source
pubmed
Published In
Radiology
Volume
155
Issue
3
Publish Date
1985
Start Page
731
End Page
738
DOI
10.1148/radiology.155.3.4001377

MR imaging of venous and arterial flow by a selective saturation-recovery spin echo (SSRSE) method.

Flow velocity imaging studies have been conducted by means of a selective saturation-recovery spin echo technique, and the dependence of signal amplitude on interpulse interval, echo delay, slice-selection gradient, and flow velocity was evaluated experimentally. The simple theory predicting a steady increase of signal intensity with increasing interpulse interval until this latter equals the transit time could be verified in phantoms and was shown to permit measurement of blood flow velocity in venous structures such as the femoral vein. The flow phantom experiments further showed that the final intensity, attained when inversion time (TI) = transit time, decreases with increasing flow velocity, an effect that cannot be explained by influx of spins between the 90 degree detection pulse and the 180 degree refocusing pulse. This signal reduction is due to slice-selection gradient-induced phase shifts across the pixel, caused by the intralumenal velocity gradient, leading to destructive interference of the spin isochromats. The velocity distribution can be mapped by plotting signal intensity as a function of interpulse interval for pixels in different radial positions. To highlight arterial flow, gating is required with the acquisition delay selected such that the interpulse period TI falls in a time zone of slow flow within the cardiac cycle. By subtracting images recorded with different acquisition delays, flow images showing arterial enhancement only can be obtained, as illustrated for the femoral artery in the thigh.

Authors
Wehrli, FW; Shimakawa, A; MacFall, JR; Axel, L; Perman, W
MLA Citation
Wehrli, FW, Shimakawa, A, MacFall, JR, Axel, L, and Perman, W. "MR imaging of venous and arterial flow by a selective saturation-recovery spin echo (SSRSE) method." J Comput Assist Tomogr 9.3 (May 1985): 537-545.
PMID
3989053
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
9
Issue
3
Publish Date
1985
Start Page
537
End Page
545

Cerebral magnetic resonance image synthesis.

The authors previously described magnetic resonance (MR) image synthesis, a process that enables the investigator to manipulate imaging parameters retrospectively and generate or "synthesize" the image that corresponds to various arbitrary scanning factors. They demonstrate the validity and utility of synthetic spin-echo images in cerebral imaging. As a test of their method, spin-echo images are synthesized for echo times identical to those of the original acquired images as well as for alternate values. Subjectively, the quality of synthetic and acquired images is comparable. It is shown quantitatively for several tissue types that the reconstructed synthetic signal matches the acquired signal within the uncertainty of the acquired images. Observed and measured noise levels in the acquired and synthetic images are comparable. Because of a signal-averaging effect, the synthetic images can have a higher signal-to-noise ratio than the source images, thereby providing improved boundary definition. Applications of MR image synthesis are discussed with respect to potential reduction in scanning time. The advantages of image synthesis versus analysis of computed images are discussed.

Authors
Bobman, SA; Riederer, SJ; Lee, JN; Suddarth, SA; Wang, HZ; Drayer, BP; MacFall, JR
MLA Citation
Bobman, SA, Riederer, SJ, Lee, JN, Suddarth, SA, Wang, HZ, Drayer, BP, and MacFall, JR. "Cerebral magnetic resonance image synthesis." AJNR Am J Neuroradiol 6.2 (March 1985): 265-269.
PMID
2984911
Source
pubmed
Published In
American Journal of Neuroradiology
Volume
6
Issue
2
Publish Date
1985
Start Page
265
End Page
269

PRECISION AND ACCURACY IN THE MEASUREMENT OF T1 ON AN IMAGING-SYSTEM

Authors
WINTER, T; JOHNSON, G; MACFALL, J
MLA Citation
WINTER, T, JOHNSON, G, and MACFALL, J. "PRECISION AND ACCURACY IN THE MEASUREMENT OF T1 ON AN IMAGING-SYSTEM." INVESTIGATIVE RADIOLOGY 20.6 (1985): S14-S14.
Source
wos-lite
Published In
Investigative Radiology
Volume
20
Issue
6
Publish Date
1985
Start Page
S14
End Page
S14

IMPROVED PRECISION IN CALCULATED T1 IMAGES USING MULTIPLE SPIN-ECHO DATA

Authors
RIEDERER, S; BOBMAN, S; WANG, H; LEE, J; FARZANEH, F; MACFALL, J
MLA Citation
RIEDERER, S, BOBMAN, S, WANG, H, LEE, J, FARZANEH, F, and MACFALL, J. "IMPROVED PRECISION IN CALCULATED T1 IMAGES USING MULTIPLE SPIN-ECHO DATA." INVESTIGATIVE RADIOLOGY 20.6 (1985): S44-S44.
Source
wos-lite
Published In
Investigative Radiology
Volume
20
Issue
6
Publish Date
1985
Start Page
S44
End Page
S44

Cerebral magnetic resonance: comparison of high and low field strength imaging.

Low field strength (0.12 Tesla resistive) and high field strength (1.0, 1.4, or 1.5 Tesla superconductive) magnetic resonance imagers were compared for their ability to detect central nervous system lesions. Sixteen adult patients with known lesions and three normal volunteers were studied. Contrast-enhanced computed tomography was used as the standard. The data demonstrate that imaging at high magnetic field strength is superior to low field strength imaging for the detection and delineation of lesions. This finding can be explained by the superior signal-to-noise ratio achievable at the higher magnetic field strengths. High field MR imaging was also found to outperform CT in demonstrating anatomic details and relationships. It is predicted that the use of low saturation (e.g., long TR spin echo technique) will make the gain in contrast-to-noise ratio even more significant.

Authors
Bilaniuk, LT; Zimmerman, RA; Wehrli, FW; Goldberg, HI; Grossman, RI; Bottomley, PA; Edelstein, WA; Glover, GH; MacFall, JR; Redington, RW
MLA Citation
Bilaniuk, LT, Zimmerman, RA, Wehrli, FW, Goldberg, HI, Grossman, RI, Bottomley, PA, Edelstein, WA, Glover, GH, MacFall, JR, and Redington, RW. "Cerebral magnetic resonance: comparison of high and low field strength imaging." Radiology 153.2 (November 1984): 409-414.
PMID
6541355
Source
pubmed
Published In
Radiology
Volume
153
Issue
2
Publish Date
1984
Start Page
409
End Page
414
DOI
10.1148/radiology.153.2.6541355

Magnetic resonance imaging of pituitary lesions using 1.0 to 1.5 T field strength.

Six patients with pituitary abnormalities and three normal volunteers were evaluated by high field superconductive (1.0, 1.4, or 1.5 Tesla) magnetic resonance (MR) imaging, low field resistive (0.12 Tesla) MR imaging, and contrast-enhanced, high-resolution CT. Four macroadenomas, one microadenoma, and one empty sella were demonstrated. Their morphology and anatomic relationship to the visual pathway and the internal carotid and anterior cerebral arteries were best demonstrated by high field MR imaging. The low field resistive MR studies were least effective in showing the lesions.

Authors
Bilaniuk, LT; Zimmerman, RA; Wehrli, FW; Snyder, PJ; Goldberg, HI; Grossman, RI; Bottomley, PA; Edelstein, WA; Glover, GH; MacFall, JR
MLA Citation
Bilaniuk, LT, Zimmerman, RA, Wehrli, FW, Snyder, PJ, Goldberg, HI, Grossman, RI, Bottomley, PA, Edelstein, WA, Glover, GH, and MacFall, JR. "Magnetic resonance imaging of pituitary lesions using 1.0 to 1.5 T field strength." Radiology 153.2 (November 1984): 415-418.
PMID
6484173
Source
pubmed
Published In
Radiology
Volume
153
Issue
2
Publish Date
1984
Start Page
415
End Page
418
DOI
10.1148/radiology.153.2.6484173

Automated MR image synthesis: feasibility studies.

The authors describe an automated technique of magnetic resonance (MR) image synthesis. Given a specific pulse sequence, MR signals are acquired for several pulse delay and/or repetition times and used to compute images of intrinsic parameters T1, T2, and N(H). Both the computed images and operator-specified pulse delay and repetition times are then used to "synthesize" a new image based on equations descriptive of MR signal behavior and comparable to that acquired by using the operator-specified parameters in an actual MR study. Instrumentation enabling rapid operator-interactive generation of synthesized images is described and initial results presented, allowing for dependence of the signal on T2 in spin echo images. Extension to full T1, T2, and N(H) dependence for arbitrary pulse sequences is described. Major advantages of this technique include retrospective optimization of contrast between arbitrary materials, rapid and systematic image analysis, and reduced scanning time; potential limitations include accuracy, noise, motion artifacts, and multicomponent behavior.

Authors
Riederer, SJ; Suddarth, SA; Bobman, SA; Lee, JN; Wang, HZ; MacFall, JR
MLA Citation
Riederer, SJ, Suddarth, SA, Bobman, SA, Lee, JN, Wang, HZ, and MacFall, JR. "Automated MR image synthesis: feasibility studies." Radiology 153.1 (October 1984): 203-206.
PMID
6089265
Source
pubmed
Published In
Radiology
Volume
153
Issue
1
Publish Date
1984
Start Page
203
End Page
206
DOI
10.1148/radiology.153.1.6089265

Mechanisms of contrast in NMR imaging.

Nuclear magnetic resonance pixel intensity and contrast-to-noise has been computed and presented in graphical form for various tissues in the normal central nervous system, on the assumption that the signal intensity is proportional to the macroscopic transverse spin magnetization at the time of detection. T1, T2, and spin density values were experimentally determined using chi-square minimization techniques. Additionally, spin density was derived from partial saturation scans obtained with a long repetition time compared with the spin-lattice relaxation time. Pulse sequences discussed comprise partial saturation, saturation recovery, spin echo, and Carr- Purcell - Meiboom -Gill ( CPMG ). The complicated dependence of signal and contrast-to-noise on the pulse timing parameters and the specific pulse sequence makes it appear desirable to display image intensity so that the dependence on the extrinsic (operator-selectable parameter) is eliminated. Whereas T2 images can be derived from CPMG scans without excessive time penalty, this is not the case for T1 and spin density.

Authors
Wehrli, FW; MacFall, JR; Shutts, D; Breger, R; Herfkens, RJ
MLA Citation
Wehrli, FW, MacFall, JR, Shutts, D, Breger, R, and Herfkens, RJ. "Mechanisms of contrast in NMR imaging." J Comput Assist Tomogr 8.3 (June 1984): 369-380.
PMID
6725682
Source
pubmed
Published In
Journal of Computer Assisted Tomography
Volume
8
Issue
3
Publish Date
1984
Start Page
369
End Page
380

The dependence of nuclear magnetic resonance (NMR) image contrast on intrinsic and pulse sequence timing parameters.

In Nuclear Magnetic Resonance (NMR) the image pixel value is governed by at least three major intrinsic parameters: the spin density N (H), the spin-lattice relaxation time T1, and the spin-spin relaxation time T2. The extent to which the signal is weighted toward one or several parameters is related to the history of the spin system preceding detection. On the simplifying, though not generally warranted assumption that the spin density does not vary significantly in soft tissues, relative tissue contrast can be predicted quantitatively provided the relaxation times are known. Signal intensities and contrast were computed on the basis of the Bloch equations and experimentally determined relaxation times as a function of pulse timing parameters and the data compared with those in images recorded at 0.5T field strength. Significant deviations from the equal density hypothesis were found for gray and white substance. Notably partial saturation but also spin echo and inversion-recovery images are not in full accordance with predictions made on the basis of relaxation times alone.

Authors
Wehrli, FW; MacFall, JR; Glover, GH; Grigsby, N; Haughton, V; Johanson, J
MLA Citation
Wehrli, FW, MacFall, JR, Glover, GH, Grigsby, N, Haughton, V, and Johanson, J. "The dependence of nuclear magnetic resonance (NMR) image contrast on intrinsic and pulse sequence timing parameters." Magn Reson Imaging 2.1 (1984): 3-16.
PMID
6530915
Source
pubmed
Published In
Magnetic Resonance Imaging
Volume
2
Issue
1
Publish Date
1984
Start Page
3
End Page
16

INVIVO FIELD-DEPENDENCE OF TISSUE RELAXATION-TIMES

Authors
JOHNSON, G; HERFKENS, R; MACFALL, J
MLA Citation
JOHNSON, G, HERFKENS, R, and MACFALL, J. "INVIVO FIELD-DEPENDENCE OF TISSUE RELAXATION-TIMES." INVESTIGATIVE RADIOLOGY 19.5 (1984): S33-S33.
Source
wos-lite
Published In
Investigative Radiology
Volume
19
Issue
5
Publish Date
1984
Start Page
S33
End Page
S33
DOI
10.1097/00004424-198409000-00154

COMPARISON OF SYNTHESIZED NMR IMAGES WITH THEIR SOURCE IMAGES

Authors
BOBMAN, S; LEE, J; SUDDARTH, S; WANG, H; RIEDERER, S; MACFALL, J
MLA Citation
BOBMAN, S, LEE, J, SUDDARTH, S, WANG, H, RIEDERER, S, and MACFALL, J. "COMPARISON OF SYNTHESIZED NMR IMAGES WITH THEIR SOURCE IMAGES." INVESTIGATIVE RADIOLOGY 19.5 (1984): S33-S33.
Source
wos-lite
Published In
Investigative Radiology
Volume
19
Issue
5
Publish Date
1984
Start Page
S33
End Page
S33
DOI
10.1097/00004424-198409000-00155

SIGNAL AND CONTRAST IN NMR IMAGING

Authors
WEHRLI, F; MACFALL, J; GRIGSBY, N; GLOVER, G; HAUGHTON, V; JOHANSEN, J
MLA Citation
WEHRLI, F, MACFALL, J, GRIGSBY, N, GLOVER, G, HAUGHTON, V, and JOHANSEN, J. "SIGNAL AND CONTRAST IN NMR IMAGING." NEURORADIOLOGY 26.2 (1984): 166-166.
Source
wos-lite
Published In
Neuroradiology
Volume
26
Issue
2
Publish Date
1984
Start Page
166
End Page
166

ANALYTICAL ASPECTS OF MAGNETIC-RESONANCE IMAGING

Authors
WEHRLI, F; MACFALL, J; SHIMAKAWA, A; CHARLES, H
MLA Citation
WEHRLI, F, MACFALL, J, SHIMAKAWA, A, and CHARLES, H. "ANALYTICAL ASPECTS OF MAGNETIC-RESONANCE IMAGING." ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 188.AUG (1984): 7-ANYL.
Source
wos-lite
Published In
ACS National Meeting Book of Abstracts
Volume
188
Issue
AUG
Publish Date
1984
Start Page
7
End Page
ANYL

PARAMETER DEPENDENCE OF PIXEL INTENSITY AND CONTRAST IN NMR IMAGES

Authors
WEHRLI, F; MACFALL, J; GRIGSBY, N; HAUGHTON, V; JOHANSEN, J
MLA Citation
WEHRLI, F, MACFALL, J, GRIGSBY, N, HAUGHTON, V, and JOHANSEN, J. "PARAMETER DEPENDENCE OF PIXEL INTENSITY AND CONTRAST IN NMR IMAGES." MAGNETIC RESONANCE IN MEDICINE 1.2 (1984): 270-271.
Source
wos-lite
Published In
Magnetic Resonance in Medicine
Volume
1
Issue
2
Publish Date
1984
Start Page
270
End Page
271

Pion-to-proton ratio for unaccompanied high-energy cosmic-ray hadrons at mountain altitude using transition-radiation detector

A transition-radiation (TR) detector, consisting of 24 modules of styrofoam radiators and multiwire proportional chambers, and an ionization calorimeter have been used to measure the pion-to-proton ratio among the unaccompanied cosmic-ray hadrons at a mountain altitude of 730 g cm-2. Using the characteristics of the TR detector obtained from calibrations with particle beams at accelerators, the p ratio has been determined for cosmic-ray hadrons as p=0.96±0.15 for hadron energy = 400-800 GeV, and p=0.45±0.25 for energy > 800 GeV. Monte Carlo simulations of hadron cascades in the atmosphere using the approximate criterion of unaccompaniment suggest that the observed p ratio as well as the previously reported neutral-to-charge ratio can be understood by assuming a value of about 13 for the charge exchange in nucleon-air-nucleus inelastic interactions at energies above 400 GeV. © 1983 The American Physical Society.

Authors
Ellsworth, RW; Ito, AS; MacFall, JR; Siohan, F; Streitmatter, RE; Tonwar, SC; Viswanath, PR; Yodh, GB
MLA Citation
Ellsworth, RW, Ito, AS, MacFall, JR, Siohan, F, Streitmatter, RE, Tonwar, SC, Viswanath, PR, and Yodh, GB. "Pion-to-proton ratio for unaccompanied high-energy cosmic-ray hadrons at mountain altitude using transition-radiation detector." Physical Review D 27.9 (1983): 2041-2055.
Source
scival
Published In
Physical Review D: Particles, Fields, Gravitation and Cosmology
Volume
27
Issue
9
Publish Date
1983
Start Page
2041
End Page
2055
DOI
10.1103/PhysRevD.27.2041

DEPENDENCE OF NUCLEAR MAGNETIC RESONANCE (NMR) IMAGE CONTRAST ON INTRINSIC AND OPERATOR-SELECTABLE PARAMETERS.

Authors
Wehrli, FW; MacFall, JR; Glover, GH
MLA Citation
Wehrli, FW, MacFall, JR, and Glover, GH. "DEPENDENCE OF NUCLEAR MAGNETIC RESONANCE (NMR) IMAGE CONTRAST ON INTRINSIC AND OPERATOR-SELECTABLE PARAMETERS." Proceedings of SPIE - The International Society for Optical Engineering 419 (1983): 256-264.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
419
Publish Date
1983
Start Page
256
End Page
264

THE DEPENDENCE OF NMR IMAGE-CONTRAST ON INTRINSIC AND OPERATOR-SELECTABLE PARAMETERS

Authors
WEHRLI, F; MACFALL, J; GLOVER, G
MLA Citation
WEHRLI, F, MACFALL, J, and GLOVER, G. "THE DEPENDENCE OF NMR IMAGE-CONTRAST ON INTRINSIC AND OPERATOR-SELECTABLE PARAMETERS." AMERICAN JOURNAL OF ROENTGENOLOGY 141.6 (1983): 1361-1361.
Source
wos-lite
Published In
AJR. American journal of roentgenology
Volume
141
Issue
6
Publish Date
1983
Start Page
1361
End Page
1361

A study of albedo from hadronic calorimeter for energies ≈100-2000 GeV

Characteristics of particles emitted backwards from high energy hadrons interacting in a calorimeter are studied. It is shown that there exists a substantial albedo of charged particles, neutrons and photons. The average yield of this albedo increases logarithmically with energy of the hadrons between 100 and 2000 GeV. This study shows that measurements of the charge of the particle or the number of particles, incident on the calorimeter, with detectors juxtaposed with the calorimeter are of limited value. © 1982.

Authors
Ellsworth, RW; Goodman, JA; Ito, AS; Macfall, JR; Siohan, F; Streitmatter, RE; Tonwar, SC; Viswanath, PR; Yodh, GB
MLA Citation
Ellsworth, RW, Goodman, JA, Ito, AS, Macfall, JR, Siohan, F, Streitmatter, RE, Tonwar, SC, Viswanath, PR, and Yodh, GB. "A study of albedo from hadronic calorimeter for energies ≈100-2000 GeV." Nuclear Instruments and Methods In Physics Research 203.1-3 (1982): 167-177.
Source
scival
Published In
Nuclear Instruments & Methods in Physics Research
Volume
203
Issue
1-3
Publish Date
1982
Start Page
167
End Page
177

Delayed hadrons in extensive air showers: Evidence for the iron-group nuclei in primary cosmic-ray flux at energies 1013-1015 eV

The distribution of arrival time of energetic hadrons in the near-core region of air showers of energies 104-106 GeV relative to the shower front has been studied experimentally at mountain altitude. The observed rate of hadron events with (i) energy >50 GeV in the calorimeter, (ii) associated shower particle density >18 m-2, and (iii) a signal 5 equivalent particles in a plastic scintillator T3 of area 0.54 m2 placed under 220 g cm-2 of absorber in the calorimeter is found to be 1.85×10-3 m-2sr-1sec-1. Of these events a fraction (0.55±0.05)% have shown the signal from T3 to be delayed by 15 nsec or greater relative to shower particles. Monte Carlo simulations of experimental observations have shown that these requirements on energy and shower density enhance the sensitivity of the observed rate to the contributions due to showers initiated by heavy nuclei. Calculations also show that observed delayed hadrons are mostly associated with showers due to heavy nuclei. For interpretation of observed features two models for primary composition have been considered. In the first model the power-law spectra for protons and lighter nuclei are assumed to have spectral index p and the heavy (iron group) nuclei the index Fe. An agreement between the expectation and observation requires the values of p and Fe to be significantly different as -2.68 and -2.39 in the energy range 103-106 GeV. In the second model the spectral index is assumed to be the same for all components and the spectra steepen by 0.5 at the same rigidity Rc. It is found that the values of and Rc should be -2.55 and 105 GV/c, respectively, to match the observations. It is concluded that a successful understanding of experimental observations requires a relative change between the energy spectra of protons and heavy nuclei in the energy range 104-106 GeV, which would make the proportion of iron-group nuclei about 40% of the primary flux at these energies. © 1982 The American Physical Society.

Authors
Goodman, JA; Ellsworth, RW; Ito, AS; MacFall, JR; Siohan, F; Streitmatter, RE; Tonwar, SC; Viswanath, PR; Yodh, GB
MLA Citation
Goodman, JA, Ellsworth, RW, Ito, AS, MacFall, JR, Siohan, F, Streitmatter, RE, Tonwar, SC, Viswanath, PR, and Yodh, GB. "Delayed hadrons in extensive air showers: Evidence for the iron-group nuclei in primary cosmic-ray flux at energies 1013-1015 eV." Physical Review D 26.5 (1982): 1043-1060.
Source
scival
Published In
Physical Review D: Particles, Fields, Gravitation and Cosmology
Volume
26
Issue
5
Publish Date
1982
Start Page
1043
End Page
1060
DOI
10.1103/PhysRevD.26.1043

A new measurement of σp-Feinel and σπ-Feinel at high energies

Measurements of the inelastic cross sections for hadron-iron nucleus interactions over the hadron energy range of 100-3000 GeV are reported. The cross sections were obtained from the observed attenuation of unaccompanied cosmic ray hadron beams inside an iron calorimeter containing wide-gap spark chambers. A transition radiation detector was used to measure directly the pion content of the hadron beam. The hadron-iron inelastic cross section is seen to increase by (12 ± 4)% over the energy interval 150 GeV to 1250 GeV. Using a value of 1.26 for the ratio σp-Fe/σπ-Fe derived from Glauber theory we deduce that the pion-iron inelastic cross section increases by (7.7 ± 3.4)% over this energy interval. © 1979.

Authors
Macfall, JR; Ellsworth, RW; Ito, AS; Siohan, F; Streitmatter, RE; Tonwar, SC; Viswanath, PR; Yodh, GB
MLA Citation
Macfall, JR, Ellsworth, RW, Ito, AS, Siohan, F, Streitmatter, RE, Tonwar, SC, Viswanath, PR, and Yodh, GB. "A new measurement of σp-Feinel and σπ-Feinel at high energies." Nuclear Physics, Section B 151.C (January 1, 1979): 213-225.
Source
scopus
Published In
Nuclear Physics B
Volume
151
Issue
C
Publish Date
1979
Start Page
213
End Page
225
DOI
10.1016/0550-3213(79)90436-X

A new measurement of σp-Feinel and σπ-Feinel at high energies

Measurements of the inelastic cross sections for hadron-iron nucleus interactions over the hadron energy range of 100-3000 GeV are reported. The cross sections were obtained from the observed attenuation of unaccompanied cosmic ray hadron beams inside an iron calorimeter containing wide-gap spark chambers. A transition radiation detector was used to measure directly the pion content of the hadron beam. The hadron-iron inelastic cross section is seen to increase by (12±4)% over the energy interval 150 GeV to 1250 GeV. Using a value of 1.26 for the ratio σp-Fe/σπ-Fe derived from Glauber theory the authors deduce that the pion-iron inelastic cross section increases by (7.7±3.4)% over this energy interval

Authors
Macfall, JR; Ellsworth, RW; Ito, AS; Siohan, F; Streitmatter, RE; Tonwar, SC; Viswanath, PR; Yodh, GB
MLA Citation
Macfall, JR, Ellsworth, RW, Ito, AS, Siohan, F, Streitmatter, RE, Tonwar, SC, Viswanath, PR, and Yodh, GB. "A new measurement of σp-Feinel and σπ-Feinel at high energies." Nucl. Phys. B (Netherlands) B151.2 (1979): 213-225. (Academic Article)
Source
manual
Published In
Nucl. Phys. B (Netherlands)
Volume
B151
Issue
2
Publish Date
1979
Start Page
213
End Page
225

Hadronic cascade curves in iron between 20 and 8000 GeV

Cascade curves produced by cosmic ray hadrons in an iron calorimeter with depth 960 g cm-2 have been studied in the energy range 100 < E < 8000 GeV. The longitudinal development of the hadronic cascade was found to be in good agreement with results obtained at accelerators and in Monte-Carlo calculations up to their respective limits 250 and 1000 GeV. The absorption of hadronic cascades beyond the maximum is well described in the form e -x L(E), with x in g cm-2, L(E) = (203±21)+(91±8)log10(E/100 GeV)g cm-2 in the range 20 < E < 8000 GeV. The lateral development of cascades was found to disagree with expectations from Monte-Carlo calculations. From this study important conclusions can be drawn concerning the use of thin calorimeters. © 1979.

Authors
Siohan, F; Ellsworth, RW; Ito, AS; MacFall, JR; Streitmatter, RE; Tonwar, SC; Viswanath, PR; Yodh, GB
MLA Citation
Siohan, F, Ellsworth, RW, Ito, AS, MacFall, JR, Streitmatter, RE, Tonwar, SC, Viswanath, PR, and Yodh, GB. "Hadronic cascade curves in iron between 20 and 8000 GeV." Nuclear Instruments and Methods 167.3 (1979): 371-379.
Source
scival
Published In
Nuclear Instruments and Methods
Volume
167
Issue
3
Publish Date
1979
Start Page
371
End Page
379

Neutral to charged ratio for unaccompanied high-energy cosmic-ray hadrons at mountain altitude

The neutral to charged ratio for unaccompanied high-energy cosmic-ray hadrons has been measured at a mountain altitude of 730 g cm-2 with well-defined geometric selection and good statistical precision. The ratio is found to be independent of energy over the energy range of 100 to 3000 GeV and has an average value of 0.37+or-0.02. Using the directly measured pion to proton ratio with transition radiation detectors for hadrons of energy greater than 400 GeV, this result yields a value for the neutron to proton ratio of 0.67+or-0.08, which is significantly different from the value obtained by Pal and Peters (1964) from phenomenological considerations.

Authors
MacFall, JR; Ellsworth, RW; Ito, AS; Siohan, F; Streitmatter, RE; Tonwart, SC; Viswanath, PR; Yodh, GB
MLA Citation
MacFall, JR, Ellsworth, RW, Ito, AS, Siohan, F, Streitmatter, RE, Tonwart, SC, Viswanath, PR, and Yodh, GB. "Neutral to charged ratio for unaccompanied high-energy cosmic-ray hadrons at mountain altitude." Journal of Physics G: Nuclear Physics 5.6 (1979): 861-869.
Source
scival
Published In
Journal of Physics G: Nuclear Physics
Volume
5
Issue
6
Publish Date
1979
Start Page
861
End Page
869
DOI
10.1088/0305-4616/5/6/012

A new measurement of σp-Feinel and σπ-Feinel at high energies

Measurements of the inelastic cross sections for hadron-iron nucleus interactions over the hadron energy range of 100-3000 GeV are reported. The cross sections were obtained from the observed attenuation of unaccompanied cosmic ray hadron beams inside an iron calorimeter containing wide-gap spark chambers. A transition radiation detector was used to measure directly the pion content of the hadron beam. The hadron-iron inelastic cross section is seen to increase by (12 ± 4)% over the energy interval 150 GeV to 1250 GeV. Using a value of 1.26 for the ratio σp-Fe/σπ-Fe derived from Glauber theory we deduce that the pion-iron inelastic cross section increases by (7.7 ± 3.4)% over this energy interval. © 1979.

Authors
Macfall, JR; Ellsworth, RW; Ito, AS; Siohan, F; Streitmatter, RE; Tonwar, SC; Viswanath, PR; Yodh, GB
MLA Citation
Macfall, JR, Ellsworth, RW, Ito, AS, Siohan, F, Streitmatter, RE, Tonwar, SC, Viswanath, PR, and Yodh, GB. "A new measurement of σp-Feinel and σπ-Feinel at high energies." Nuclear Physics, Section B 151.C (1979): 213-225.
Source
scival
Published In
Nuclear Physics B
Volume
151
Issue
C
Publish Date
1979
Start Page
213
End Page
225

Observation of energetic delayed hadrons in air showers-New massive particles?

An experiment to measure the arrival-time distribution of energetic hadrons with respect to air-shower fronts near shower cores was carried out at an altitude of 2900 m. Three events were observed with delays greater than 30 nsec and energies greater than about 45 GeV; these events constitute a fraction of 3.3×10-4 of the events. Estimates of backgrounds and conventional processes failed to provide an interpretation for these events. These events could indicate the production of relatively stable particles with mass 5 GeV/c2. © 1979 The American Physical Society.

Authors
Goodman, JA; Ellsworth, RW; Ito, AS; MacFall, JR; Siohan, F; Streitmatter, RE; Tonwar, SC; Vishwanath, PR; Yodh, GB
MLA Citation
Goodman, JA, Ellsworth, RW, Ito, AS, MacFall, JR, Siohan, F, Streitmatter, RE, Tonwar, SC, Vishwanath, PR, and Yodh, GB. "Observation of energetic delayed hadrons in air showers-New massive particles?." Physical Review D 19.9 (1979): 2572-2574.
Source
scival
Published In
Physical Review D: Particles, Fields, Gravitation and Cosmology
Volume
19
Issue
9
Publish Date
1979
Start Page
2572
End Page
2574
DOI
10.1103/PhysRevD.19.2572

Erratum: Composition of primary cosmic rays above 1013 eV from the study of time distributions of energetic hadrons near air-shower cores (Physical Review Letters (1979) 42, 18, (1246) )

Authors
Goodman, JA; Ellsworth, RW; Ito, AS; MacFall, JR; Siohan, F; Streitmatter, RE; Tonwar, SC; Vishwanath, PR; Yodh, GB
MLA Citation
Goodman, JA, Ellsworth, RW, Ito, AS, MacFall, JR, Siohan, F, Streitmatter, RE, Tonwar, SC, Vishwanath, PR, and Yodh, GB. "Erratum: Composition of primary cosmic rays above 1013 eV from the study of time distributions of energetic hadrons near air-shower cores (Physical Review Letters (1979) 42, 18, (1246) )." Physical Review Letters 42.18 (1979): 1246--.
Source
scival
Published In
Physical Review Letters
Volume
42
Issue
18
Publish Date
1979
Start Page
1246-
DOI
10.1103/PhysRevLett.42.1246.2

Composition of primary cosmic rays above 1013 eV from the study of time distributions of energetic hadrons near air-shower cores

An experimental study of the distribution of arrival time of energetic hadrons relative to associated air-shower particles has been made at a mountain altitude, under 730 g cm-2. Monte Carlo simulations have shown that these observations are sensitive to the composition of primary cosmic rays of energies 104-106 GeV. The energy spectra dNdE of primary protons and iron-group nuclei required to understand these observations are 1.5×104E-2.71±0.06 and 1.27E-2.36±0.06 m-2 sr-1 sec-1 (GeV/N)-1, respectively, where E is the energy per nucleon. © 1979 The American Physical Society.

Authors
Goodman, JA; Ellsworth, RW; Ito, AS; MacFall, JR; Siohan, F; Streitmatter, RE; Tonwar, SC; Vishwanath, PR; Yodh, GB
MLA Citation
Goodman, JA, Ellsworth, RW, Ito, AS, MacFall, JR, Siohan, F, Streitmatter, RE, Tonwar, SC, Vishwanath, PR, and Yodh, GB. "Composition of primary cosmic rays above 1013 eV from the study of time distributions of energetic hadrons near air-shower cores." Physical Review Letters 42.13 (1979): 854-857.
Source
scival
Published In
Physical Review Letters
Volume
42
Issue
13
Publish Date
1979
Start Page
854
End Page
857
DOI
10.1103/PhysRevLett.42.854

NEW MEASUREMENT OF SIGMA-P-FE(INEL) AND SIGMA-PI-FE(INEL) AT HIGH-ENERGIES

Authors
MACFALL, J; ELLSWORTH, R; ITO, A; SIOHAN, F; STREITMATTER, R; TONWAR, S; VISWANATH, P; YODH, G
MLA Citation
MACFALL, J, ELLSWORTH, R, ITO, A, SIOHAN, F, STREITMATTER, R, TONWAR, S, VISWANATH, P, and YODH, G. "NEW MEASUREMENT OF SIGMA-P-FE(INEL) AND SIGMA-PI-FE(INEL) AT HIGH-ENERGIES." NUCLEAR PHYSICS B 151.2 (1979): 213-225.
Source
wos-lite
Published In
Nuclear Physics B
Volume
151
Issue
2
Publish Date
1979
Start Page
213
End Page
225
DOI
10.1016/0550-3213(79)90436-X

Unaccompanied hadron flux at a depth of 730 g cm-2, 10 2<E<104 GeV

The energy spectrum of unaccompanied hadrons has been measured at a depth of 730 g cm-2 in the atmosphere. The energy was determined by a deep calorimeter (960 g cm-2) of area 4 m2. For charged hadrons unaccompanied in a 3.3 m2 spark chamber placed above the calorimeter, the observed flux was fitted in the energy range 100<E<10000 GeV.

Authors
Siohan, F; Ellsworth, RW; Ito, AS; MacFall, JR; Streitmatter, RE; Tonwar, SC; Yodh, GB
MLA Citation
Siohan, F, Ellsworth, RW, Ito, AS, MacFall, JR, Streitmatter, RE, Tonwar, SC, and Yodh, GB. "Unaccompanied hadron flux at a depth of 730 g cm-2, 10 2<E<104 GeV." Journal of Physics G: Nuclear Physics 4.7 (1978): 1169-1186.
Source
scival
Published In
Journal of Physics G: Nuclear Physics
Volume
4
Issue
7
Publish Date
1978
Start Page
1169
End Page
1186
DOI
10.1088/0305-4616/4/7/021

Transition effect between iron and liquid scintillator

The rate of muon-bursts depositing between 100 and 700 GeV of visible energy multilayer calorimeter of iron and liquid scintillattor was measured to be: R=(5.7 ± 1.5) × 10-5 bursts/m2 sr s kg cm-2, while the expected rate obtained by calculation is R′=1.7 R. These two results can be reconciled by attributing the difference to the transition effect between the iron absorber and the 7 cm thick liquid scintillators. © 1978.

Authors
Siohan, F; Ellsworth, RW; Ito, AS; MacFall, JR; Streitmatter, RE; Tonwar, SC; Yodh, GB
MLA Citation
Siohan, F, Ellsworth, RW, Ito, AS, MacFall, JR, Streitmatter, RE, Tonwar, SC, and Yodh, GB. "Transition effect between iron and liquid scintillator." Nuclear Instruments and Methods 155.1-2 (1978): 75-80.
Source
scival
Published In
Nuclear Instruments and Methods
Volume
155
Issue
1-2
Publish Date
1978
Start Page
75
End Page
80

MEASUREMENT OF FLUX OF ENERGETIC HADRONS DELAYED WITH RESPECT TO SHOWER FRONT

Authors
GOODMAN, J; ELLSWORTH, R; ITO, A; MACFALL, J; SIOHAN, F; STREITMATTER, R; TONWAR, S; VISHWANATH, P; YODH, G
MLA Citation
GOODMAN, J, ELLSWORTH, R, ITO, A, MACFALL, J, SIOHAN, F, STREITMATTER, R, TONWAR, S, VISHWANATH, P, and YODH, G. "MEASUREMENT OF FLUX OF ENERGETIC HADRONS DELAYED WITH RESPECT TO SHOWER FRONT." BULLETIN OF THE AMERICAN PHYSICAL SOCIETY 23.4 (1978): 511-511.
Source
wos-lite
Published In
Bulletin- American Physical Society
Volume
23
Issue
4
Publish Date
1978
Start Page
511
End Page
511

Measurement of the flux of charged hadrons at sea level between 250 and 10000 GeV

The flux of charged hadrons has been measured at sea level with an iron calorimeter of depth 960 g cm-2; the geometric factor was about 0.7 m2 sr. The total running time was 1.6*106 s. An upper limit to the flux of all hadrons has been obtained in the energy range 500<E<10000 GeV. It does not support the observation of a 'step' in the spectrum at about 3000 GeV.

Authors
Siohan, F; Ellsworth, RW; Lapointe, M; MacFall, JR; Stottlemyer, A; Yodh, GB
MLA Citation
Siohan, F, Ellsworth, RW, Lapointe, M, MacFall, JR, Stottlemyer, A, and Yodh, GB. "Measurement of the flux of charged hadrons at sea level between 250 and 10000 GeV." Journal of Physics G: Nuclear Physics 3.8 (1977): 1157-1164.
Source
scival
Published In
Journal of Physics G: Nuclear Physics
Volume
3
Issue
8
Publish Date
1977
Start Page
1157
End Page
1164
DOI
10.1088/0305-4616/3/8/024

On the high energy proton spectrum measurements

The steepening of the proton spectrum beyond 1000 GeV and the rise in inelastic cross sections between 20 and 600 GeV observed by the PROTON 1-2-3 satellite experiments may be explained by systematic effects of energy dependent albedo (back-scatter) from the calorimeter. © 1977 D. Reidel Publishing Company.

Authors
Ellsworth, RW; Ito, A; Macfall, J; Siohan, F; Streitmatter, RE; Tonwar, SC; Vishwanath, PR; Yodh, GB; Balasubrahmanyan, VK
MLA Citation
Ellsworth, RW, Ito, A, Macfall, J, Siohan, F, Streitmatter, RE, Tonwar, SC, Vishwanath, PR, Yodh, GB, and Balasubrahmanyan, VK. "On the high energy proton spectrum measurements." Astrophysics and Space Science 52.2 (1977): 415-427.
Source
scival
Published In
Astrophysics and Space Science
Volume
52
Issue
2
Publish Date
1977
Start Page
415
End Page
427
DOI
10.1007/BF01093876

MEASUREMENT OF FLUX OF CHARGED HADRONS AT 2900M

Authors
SIOHAN, F; ELLSWORTH, R; GOODMAN, J; ITO, A; MACFALL, J; STREITMATTER, R; TONWAR, S; YODH, G
MLA Citation
SIOHAN, F, ELLSWORTH, R, GOODMAN, J, ITO, A, MACFALL, J, STREITMATTER, R, TONWAR, S, and YODH, G. "MEASUREMENT OF FLUX OF CHARGED HADRONS AT 2900M." BULLETIN OF THE AMERICAN PHYSICAL SOCIETY 20.4 (1975): 727-728.
Source
wos-lite
Published In
Bulletin- American Physical Society
Volume
20
Issue
4
Publish Date
1975
Start Page
727
End Page
728

INTERACTION LENGTHS OF 200-1000 GEV COSMIC-RAY HADRONS IN IRON

Authors
ELLSWORTH, R; MACFALL, J; ITO, A; SIOHAN, F; STREITMATTER, R; TONWAR, S; YODH, G
MLA Citation
ELLSWORTH, R, MACFALL, J, ITO, A, SIOHAN, F, STREITMATTER, R, TONWAR, S, and YODH, G. "INTERACTION LENGTHS OF 200-1000 GEV COSMIC-RAY HADRONS IN IRON." BULLETIN OF THE AMERICAN PHYSICAL SOCIETY 20.4 (1975): 678-678.
Source
wos-lite
Published In
Bulletin- American Physical Society
Volume
20
Issue
4
Publish Date
1975
Start Page
678
End Page
678

OPERATING CHARACTERISTICS OF A COSMIC-RAY TRANSITION RADIATION DETECTOR

Authors
MACFALL, J; ELLSWORTH, R; MORRISON, T; TONWAR, S; ITO, A; STREITMATTER, R; SIOHAN, F; YODH, G
MLA Citation
MACFALL, J, ELLSWORTH, R, MORRISON, T, TONWAR, S, ITO, A, STREITMATTER, R, SIOHAN, F, and YODH, G. "OPERATING CHARACTERISTICS OF A COSMIC-RAY TRANSITION RADIATION DETECTOR." BULLETIN OF THE AMERICAN PHYSICAL SOCIETY 20.4 (1975): 728-728.
Source
wos-lite
Published In
Bulletin- American Physical Society
Volume
20
Issue
4
Publish Date
1975
Start Page
728
End Page
728

Computers in magnetic resonance imaging

Most of modern medical imaging would not be possible without compact, fast computer systems. This is particularly the case for magnetic resonance imaging (MRI), in which many complicated calculations must be carried out in order to create an image from the approximately 8 million data samples that are acquired during the typical patient examination. The future of MRI will see interesting architectural changes, as processor hardware costs decrease and system bus bandwidth requirements increase. True parallel processing arrangements will become more popular and adaptable architectures that can be dynamically configured for parallel, pipeline, or sequential operation will become more common. Indeed, as with array processors that are so important in existing MRI equipment, the bus architectures of the entire system will become key to performance

Authors
Jones, RD; MacFall, JR
MLA Citation
Jones, RD, and MacFall, JR. "Computers in magnetic resonance imaging." Comput. Phys. (USA) 2.5: 25-30. (Academic Article)
Source
manual
Published In
Comput. Phys. (USA)
Volume
2
Issue
5
Start Page
25
End Page
30
Show More

Research Areas:

  • Adipose Tissue
  • Adolescent
  • Adult
  • Afferent Pathways
  • Age Factors
  • Age of Onset
  • Aged
  • Aged, 80 and over
  • Aging
  • Alcohol-Related Disorders
  • Algorithms
  • Alleles
  • Amino Acid Substitution
  • Amygdala
  • Analysis of Variance
  • Animals
  • Anisotropy
  • Antibiotics, Antineoplastic
  • Anticonvulsants
  • Antidepressive Agents
  • Antigens, Neoplasm
  • Antimanic Agents
  • Antineoplastic Combined Chemotherapy Protocols
  • Apolipoprotein E4
  • Arterial Occlusive Diseases
  • Arteries
  • Arteriovenous Malformations
  • Artifacts
  • Atrophy
  • Autism
  • Basal Ganglia
  • Bipolar Disorder
  • Blood
  • Blood Flow Velocity
  • Blood Vessels
  • Body Temperature
  • Body Temperature Regulation
  • Body Water
  • Brain
  • Brain Diseases
  • Brain Injuries
  • Brain Ischemia
  • Brain Mapping
  • Brain Stem
  • Brain-Derived Neurotrophic Factor
  • Breast
  • Breast Neoplasms
  • Case-Control Studies
  • Caudate Nucleus
  • Cell Death
  • Cell Line, Tumor
  • Central Nervous System
  • Cerebellum
  • Cerebral Cortex
  • Cerebral Ventricles
  • Cerebrovascular Circulation
  • Cerebrovascular Disorders
  • Chemoradiotherapy
  • Chemotherapy, Adjuvant
  • Chemotherapy, Cancer, Regional Perfusion
  • Chi-Square Distribution
  • Child
  • Child Development Disorders, Pervasive
  • Child, Preschool
  • Children
  • Cisplatin
  • Clinical Trials as Topic
  • Clinical Trials, Phase III as Topic
  • Cluster Analysis
  • Cognition
  • Cognition Disorders
  • Cohort Studies
  • Combined Modality Therapy
  • Comorbidity
  • Computer Simulation
  • Congenital Abnormalities
  • Consensus
  • Continental Population Groups
  • Contrast Media
  • Coronary Circulation
  • Corpus Callosum
  • Cross-Sectional Studies
  • Cystic Fibrosis
  • Cysts
  • Data Interpretation, Statistical
  • Dementia
  • Dementia, Vascular
  • Demography
  • Demyelinating Diseases
  • Deoxyglucose
  • Depression
  • Depressive Disorder
  • Depressive Disorder, Major
  • Developmental Disabilities
  • Diabetes Mellitus
  • Diagnostic Imaging
  • Diagnostic and Statistical Manual of Mental Disorders
  • Diffusion
  • Diffusion Magnetic Resonance Imaging
  • Diffusion Tensor Imaging
  • Disease Models, Animal
  • Disease Progression
  • Disease-Free Survival
  • Dog Diseases
  • Dogs
  • Dominance, Cerebral
  • Dose-Response Relationship, Radiation
  • Doxorubicin
  • Drug Resistance
  • Drug Therapy, Combination
  • Echo-Planar Imaging
  • Electric Stimulation
  • Electroconvulsive Therapy
  • Empty Sella Syndrome
  • Energy Metabolism
  • Epilepsy
  • European Continental Ancestry Group
  • Executive Function
  • Extracellular Space
  • Feasibility Studies
  • Female
  • Fiber Optic Technology
  • Fibrosarcoma
  • Follow-Up Studies
  • Forelimb
  • Fourier Analysis
  • Fragile X Syndrome
  • Frontal Lobe
  • Functional Laterality
  • Gadolinium DTPA
  • Gels
  • Gene Expression Regulation, Neoplastic
  • Gene Frequency
  • Genetic Association Studies
  • Genetic Predisposition to Disease
  • Genomics
  • Genotype
  • Geriatric Assessment
  • Geriatrics
  • Glioblastoma
  • Globus Pallidus
  • Gyrus Cinguli
  • Head and Neck Neoplasms
  • Health Physics
  • Health Status
  • Heart
  • Heart Diseases
  • Helium
  • Hippocampus
  • Hot Temperature
  • Humans
  • Hydrogen
  • Hydrogen-Ion Concentration
  • Hypertension
  • Hyperthermia, Induced
  • Hypertrophy
  • Image Enhancement
  • Image Interpretation, Computer-Assisted
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional
  • Infant
  • Information Services
  • Injections, Intravenous
  • Isotopes
  • Kaplan-Meier Estimate
  • Lasers
  • Linear Models
  • Liposomes
  • Liver
  • Liver Neoplasms
  • Logistic Models
  • Longitudinal Studies
  • Lung
  • Lung Diseases
  • Magnetic Resonance Imaging
  • Magnetic Resonance Spectroscopy
  • Male
  • Manganese Compounds
  • Mathematical Computing
  • Mathematics
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Memory
  • Memory Disorders
  • Mental Disorders
  • Mental Status Schedule
  • Methionine
  • Mice
  • Microscopy
  • Middle Aged
  • Models, Biological
  • Models, Cardiovascular
  • Models, Genetic
  • Models, Statistical
  • Models, Structural
  • Models, Theoretical
  • Molecular Targeted Therapy
  • Monte Carlo Method
  • Motion
  • Motor Skills Disorders
  • Multiple Sclerosis
  • Muscle, Skeletal
  • Muscles
  • Myocardial Infarction
  • Myocardium
  • Neoadjuvant Therapy
  • Neoplasm Staging
  • Neoplasm Transplantation
  • Neoplasms
  • Nerve Fibers, Myelinated
  • Neural Pathways
  • Neurofibromatosis 1
  • Neuroimaging
  • Neuroma, Acoustic
  • Noise
  • Observer Variation
  • Occipital Lobe
  • Orbit
  • Organ Size
  • Oxygen
  • Paclitaxel
  • Partial Pressure
  • Patient Selection
  • Pattern Recognition, Automated
  • Perceptual Disorders
  • Perfusion
  • Phantoms, Imaging
  • Phosphorus
  • Physical Phenomena
  • Physics
  • Pilot Projects
  • Pituitary Neoplasms
  • Point Mutation
  • Polymerase Chain Reaction
  • Polymorphism, Genetic
  • Polymorphism, Single Nucleotide
  • Postoperative Complications
  • Predictive Value of Tests
  • Prefrontal Cortex
  • Prevalence
  • Prognosis
  • Promoter Regions, Genetic
  • Proportional Hazards Models
  • Prospective Studies
  • Protons
  • Psychiatry
  • Psychomotor Disorders
  • Psychomotor Performance
  • Pulmonary Diffusing Capacity
  • Pulmonary Embolism
  • Pulmonary Emphysema
  • Questionnaires
  • Radiation Oncology
  • Radio Waves
  • Radiotherapy
  • Radiotherapy Dosage
  • Rats
  • Rats, Inbred F344
  • Reaction Time
  • Receptor, Angiotensin, Type 1
  • Reference Values
  • Regional Blood Flow
  • Regression Analysis
  • Remission Induction
  • Reproducibility of Results
  • Retrospective Studies
  • Reverse Transcriptase Polymerase Chain Reaction
  • Risk Factors
  • Sarcoma
  • Sarcoma, Experimental
  • Schizophrenia
  • Sclerosis
  • Seizures
  • Seizures, Febrile
  • Sensitivity and Specificity
  • Serotonin Plasma Membrane Transport Proteins
  • Serotonin Uptake Inhibitors
  • Sertraline
  • Severity of Illness Index
  • Signal Processing, Computer-Assisted
  • Soft Tissue Neoplasms
  • Software
  • Spatio-Temporal Analysis
  • Spectrum Analysis
  • Spinal Cord Diseases
  • Spleen
  • Statistics as Topic
  • Stress, Physiological
  • Stress, Psychological
  • Sulfates
  • Supratentorial Neoplasms
  • Temperature
  • Temporal Lobe
  • Thalamus
  • Thermal Conductivity
  • Thermodynamics
  • Thermography
  • Thermometers
  • Time Factors
  • Tissue Distribution
  • Tomography, Emission-Computed
  • Tomography, X-Ray Computed
  • Treatment Outcome
  • Valine
  • Valproic Acid
  • Veins
  • Water
  • Xenon Isotopes