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Abstract #0993

White Matter Degeneration in Early- And Late-Myelinating Tracts Through the Course of Alzheimers Disease

Andreana Benitez1, Els Fieremans2, Jens H. Jensen1, Maria F. Falangola1, Ali Tabesh1, Rachael L. Deardorff1, James S. Babb2, Dmitry S. Novikov2, Joseph A. Helpern1

1Center for Biomedical Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States; 2Center for Biomedical Imaging, Department of Radiology, New York University, New York, United States

We applied DKI-based white matter tract integrity metrics to the study of Alzheimers disease within the framework of retrogenesis; late-myelinating (LM) tracts are more susceptible to aging and AD, and are therefore hypothesized to decline more so than early-myelinating (EM) tracts, which remain comparatively stable. In our sample (N=41) of matched normal controls, amnestic mild cognitive impairment, and AD subjects, using atlas-based ROI analyses we found that in the course of AD, axonal density loss and myelin breakdown occur in LM tracts, but largely not in EM tracts, and that myelin breakdown in LM tracts correlates with poorer verbal fluency.

Keywords

according accuracy acquisition addition affected aging animals apart applies applying association atlas audience axial biomedical blue breakdown capsule cerebral characterization characterizes clinical cognitive comparatively consistent controls corrected correlate correlated correlation correlations course covariate decline declines decreased degenerate degeneration demographically density derive developmental diagnostic differ diffusion diffusional diffusivity disease early encoding expected fewer fibers findings fluency fraction function functional future gray hemispheres highlight impairment importance increasing integrity interaction internal introduced known label larger late limb linearly longitudinal loss maps maria marker matrix mediated medical metrics mild mixed model models oblique occur occurs parallel parametric part partial peduncles post posterior precursor predicted prior processing providing radiological radiology reflecting refocused registered registration related relates relevance remain remains represent review science scores shot significance significantly skeleton slice slices south space speed stable stages stratum strongly studies subjects suggest suggesting summarized superior susceptible system target task template tract tracts transformed transition type verbal white words worsens