MAPT and early-onset autosomal dominant Alzheimer disease: In addition, autopsy-proven studies should explore the added value of cortical mean diffusivity (alone or combined with white matter diffusion tensor imaging changes) to detect specific neuropathological signatures (i.e., prominent microstructural changes in the subcortical white matter in FTLD-Tau or widespread gray matter changes in Alzheimer’s disease with relative sparing of subcortical white matter) [46–48].