Small vessel dysfunction at 7T MRI locally predicts white matter damage progression in CADASIL.

Cerebral small vessel diseases (cSVDs) contribute significantly to stroke and dementia. Advanced 7 T MRI techniques have revealed small vessel dysfunction in cSVD patients, linked to global white matter damage cross-sectionally. However, it remains unclear whether these vascular deficits predict progressive tissue damage. This longitudinal study examined the spatial relationship between local vascular function and white matter damage progression in patients with Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). Twenty-two patients underwent baseline small vessel function assessment using 7 T MRI. Voxelwise blood-oxygenation level-dependent cerebrovascular reactivity (BOLD-CVR) to a hypercapnic was evaluated. White matter changes were assessed on 3 T MRI over two years, analyzing mean diffusivity changes and conversion of normal-appearing white matter to white matter hyperintensities (WMH). Results showed significant global increases in white matter damage over time. Voxelwise analysis revealed that lower baseline BOLD-CVR magnitude and higher dispersion were associated with increased white matter damage and WMH progression at specific locations at follow-up. However, whole-brain vascular function measures did not predict white matter changes at a global level. These findings suggest that local vascular function plays a key role in white matter damage progression in CADASIL, highlighting the importance of regional vascular health in cSVDs.