Abstract 66: Diffusion Imaging Demonstrates White Matter Alterations In Children With Moyamoya In Watershed Tracts

Introduction: Moyamoya is a progressive cerebrovascular disease leading to stenosis of arteries located in the circle of Willis which increases risk of hypoperfusion in specific areas of the brain called watershed regions. Using diffusion weighted magnetic resonance imaging (dMRI), adults with moyamoya have significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD) and radial diffusivity (RD) in their white matter compared to controls. These areas of white matter alterations have been associated with cognitive deficits as well. To our knowledge the examination of combined white matter tracts in the watershed regions of the brain in children with moyamoya has not been previously examined. Hypothesis: We hypothesize that children with moyamoya will have higher FA and lower MD and RD in the combined white matter tracts that are in the watershed region compared to control children. Methods: We compared a cohort of 15 children with moyamoya with 24 affected hemispheres without stroke to 25 children controls. We analyzed dMRI data using an unscented Kalman filter (UKF) tractography method and extracted major white matter pathways with a fiber clustering method. We compared the FA, MD, axial diffusivity (AD), and RD of the combined watershed white matter tracts using co-variate adjusted ANOVA. Results: Age and sex were not significantly different between children with moyamoya and controls. For the combined watershed white matter tracts, children with moyamoya had significantly lower FA and higher MD and RD. AD was also higher but not significant compared to control children (Table 1). Conclusion: Lower FA with higher MD and RD is consistent with alterations in white matter tracts concerning for unrecognized white matter injury from hypoperfusion. These dMRI findings could be used as a biomarker for children with moyamoya at risk for cognitive deficits due to hypoperfusion.