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Advanced Neuroimaging Methods Nearing Clinical Translation. Julie C. Chapman, PsyD Director of Neuroscience War Related Illness & Injury Study Center Veterans Affairs Medical Center, Washington, DC Assistant Professor of Neurology Georgetown University School of Medicine.
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Advanced Neuroimaging MethodsNearing Clinical Translation Julie C. Chapman, PsyD Director of Neuroscience War Related Illness & Injury Study Center Veterans Affairs Medical Center, Washington, DC Assistant Professor of Neurology Georgetown University School of Medicine
Advanced Neuroimaging MethodsNearing Clinical Translation Patrick M. Sullivan, MA Research Assistant Chapman Laboratory War Related Illness & Injury Study Center Veterans Affairs Medical Center, Washington, DC
Disclaimer The views expressed in this presentation are those of the author and DO NOT reflect the official policy of the Department of Veterans Affairs or the United States Government
Diffusion Tensor Imaging:What’s the big hairy deal? • DTI has been primarily used in research • However, DTI is currently used in some clinical settings • How can DTIbe helpful to healthcare providers? • A basic understanding of DTI aids literature review • Scientific findings influence the way we practice • DTI studies of mild TBI provide a good example
mTBI Diagnosis: A History • Dubious perception of mTBIwith persisting symptoms • Little physiologic evidence of injury: • Clinical brain scans Physical examination • Neuropsychologic data: differences between those with and without mTBI • Litigation inherently will be involved in some cases of mTBI.
mTBI Diagnosis: A History • 1980’s Positron Emission Tomography (PET) studies: • Humayun et al. (1984) • Rao et al. (1989) • PET studies found differences between groups with and without TBI. • Objective physiologic differences
mTBI and DTI PET DTI • Functional imaging method • Invasive • Costly • Structural imaging method • Non-Invasive • Less Costly
DTI Studies with differences between mTBIand Healthy Control Groups • Bazarianet al. 2007 • Benson et al. 2007 • Kraus et al. 2007 • Niogi et al. 2008 • Rutgers et al. 2008 • Wilde et al. 2008 • MacDonald et al. 2011
DTI as a Clinical Tool Goals for: • Diagnosis: Assist in the identification of diagnostic markers • Monitoring: Following the course of progressive diseases (i.e., MS, Alzheimer’s Disease) • Treatment: • identifying sites of disease-related abnormalities to guide treatment • Tracking the effects of treatment over time
Blast Injury Outcomes (BIO) StudymTBI+ PTSD vs. Control Group Fractional Anisotropy Tapetum_LT Chapman Lab
Blast Injury Outcomes (BIO) Study Preliminary Analysis, 2010
Type 2 Diabetes Mellitus StudyDM2 + Obese vs. Obese Groups Fractional Anisotropy Fornix Chapman Lab
mTBI and Obesity StudyObese only vs. Control Group Axial Diffusivity CingulateGyrus_LT Mehos & Chapman
mTBI and Obesity StudyObese only vs. Control Group Axial Diffusivity Genu of CC_LT Mehos & Chapman
Volumetric Analysis A method to compare the volume of specific brain regions between patients or groups AthinoulaA. Martinos Center for Biomedical Imaging
Volumetric Analysis Manually Drawn Methods Automated Methods • High anatomic validity (gold standard) • Extensive use of algorithms/atlas templates reduce anatomic validity
Volumetric Analysis Manually Drawn Methods Automated Methods • Time-intensive • Inter-rater reliability concerns • Allows high throughput & efficient workflow • Eliminates multiple rater effects
Volumetric Analysis • Automatic technique relies on distinguishing gray matter, white matter, and CSF • T1-weighted MRI images have good contrast between these types of tissue
Automated Volumetric Analysis • Automated tools for reconstruction of the brain’s cortical surface from structural MRI data
Automated Volumetric Analysis • Uses an algorithm to: • Strip away skull and facial tissue • Find border between the gray matter and subcortical white matter • Find border between the gray matter and the pia.
Automated Volumetric Analysis • Registers image to atlas template • automatically parcels brain into regions based on: • Atlastemplate • Anatomic properties of the subject brain.
Clinical Use of Volumetric Analysis • Automated programs accept standard clinical MRI images and produce objective results independent of rater effects. • The automatically parcellated brain regions are each measured for total volume.
Clinical Use of Volumetric Analysis • These amounts can be averaged into groups and group differences can be computed. • Volumetric differences are seen in many disease conditions such as Alzheimer’s, epilepsy, and depression
DTI and Volumetric Analysis • Potential to improve quality of care for Veterans • Close to Translation Line • Impact Clinical Practice
Contact Us EMAIL: Julie.Chapman@va.gov or Chapman.Research@va.gov VISIT OUR WEBSITE: www.warrelatedillness.va.gov/dc/