Abstract TP236: Quantifying White Matter Microstructure and Cognitive Performance Following Ischemic Sub-Acute Stroke for Black and non-Black Individuals

Introduction: The microstructure of normal appearing white matter (NAWM) from MRI is an emerging biomarker for recovery following acute ischemic stroke. Individuals from disadvantaged health equity environments, such as Black Americans, exhibit medical risk factors that affect the structural properties of NAWM. We investigated whether diffusion MRI (dMRI) metrics differ between Black and non-Black stroke survivors and whether these metrics are associated with cognitive performance. Hypothesis: NAWM in Black stroke survivors will have atypical dMRI properties compared to non-Black stroke survivors, and these differences will be associated with cognitive function. Methods: Participants (PPT) with first-time acute mild ischemic stroke (n=28; 8 Black; 8 female; mean age 64.9±11.3 years, NIHSS median=0, IQR=0-1) were enrolled at onset. Imaging was performed on a 3T Siemens Prisma MRI scanner using an advanced multi-shell dMRI protocol and scored on the Montreal Cognitive Assessment (MoCA, median=26, IQR=25.75-27.75) at 1-month post-stroke. dMRI preprocessing followed established methods to estimate fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). Voxel-wise analyses compared groups and tested associations with MoCA performance (p<0.05, family-wise error corrected). Results: MoCA scores were significantly lower (p=0.042) for Black PPTs compared to non-Black PPTs, indicating that there is decreased cognitive performance at 1-month post-stroke. Fig. 1 shows that FA was positively associated with MoCA scores in NAWM (p=0.045) and lesioned tissue (p=0.041), including the splenium of the corpus callosum, accounting for 14% of significant voxels, and other non-lesioned tissue accounting for 34% of significant voxels. Fig. 2 shows the group comparison of FA and RD between Black PPTs and non-Black PPTs. There was decreased FA (p=0.028) that was primarily driven by increased RD (p=0.025) for the Black PPTs in cognitive regions of NAWM in comparison to non-Black PPTs. Conclusions: These preliminary findings suggest that white matter microstructural properties in not only infarcted tissue, but also in NAWM are potentially important biomarkers to better understand the trajectories of stroke recovery outcomes. Furthermore, Black stroke survivors may be at increased risk for poorer outcomes due to underlying alterations in white matter microstructure, potentially reflecting the cumulative impact of health equity disparities.