Identifying Distinct Spatiotemporal Patterns of Juxtacortical Microstructure in Alzheimer Disease Using Diffusion MRI–derived Free Water Fraction

Juxtacortical free water fraction, determined at diffusion MRI, was higher in participants with Alzheimer disease compared with cognitively normal controls and associated with amyloid-β, tau, and neurodegeneration biomarkers, revealing two distinct spatiotemporal progression patterns with different impacts on neuroanatomic signatures and cognitive performance.