Joel Ramirez, Sunnybrook Research Institute 

Supervisor: Sandra Black, Sunnybrook Health Sciences Center

Based on a recent report from the Standards for Reporting Vascular Changes on Neuroimaging (STRIVE), the proposed project is a systematic and comprehensive evaluation of various neuroimaging biomarkers of cerebral small vessel subtypes and brain atrophy in Vascular Cognitive Disorders (VCD). Contrasting these markers with normal elderly (NC) and Alzheimer’s disease patients with (AD+SVD) and without significant small vessel disease (AD-SVD), the primary hypotheses is that a combined metric comprising of select biomarkers will allow better characterization and discrimination of vascular disorders from normal aging and neurodegeneration. Progression will be assessed with follow-up data. Using Lesion Explorer, the simultaneous quantification of small vessel disease and brain atrophy will be obtained from NC (n=100), VCD (n=152), and AD±SVD (n=256) recruited from the Sunnybrook Dementia Study (ClinicalTrials.gov NCT 01800214). Measures that will be examined include: periventricular and deep white subcortical hyperintensities, enlarged perivascular Virchow-Robin spaces, lacunar infarcts, and normal brain tissue. Cerebral microbleeds on T2* imaging will be evaluated with the Microbleed Anatomical Rating Scale (MARS) and white matter microstructural integrity will be assessed from diffusion tensor imaging (DTI). Hippocampal atrophy will be measured using the Sunnybrook Hippocampal Volumetry (SBHV) Tool. Cortical strokes (core and penumbra) will be manually traced with neuroradiologist confirmation. Neuropsychological tests (NP) for executive, visuospatial, language, memory, and depressive symptoms will be analyzed in the context of brain imaging. Partial Least Squares modelling will be used for analysis. Longitudinal progression will be assessed through annualized rates of change. Aligned with Theme 2 of the Canadian Vascular Network, the results of this comprehensive project may prove to be useful in guiding differential diagnostics and future therapeutic challenges common to both vascular and degenerative disorders.