Henf J, et al. - An analysis was performed to assess gray matter (GM) mean diffusivity (MD) changes in Alzheimer's Disease (AD) and mild cognitive impairment (MCI) compared with healthy controls, and the effect of partial volume correction (PVC) on the diagnostic utility of MD. Collected evidence suggested that in the presence of brain atrophy, GM MD measurements were strongly confounded by partial volume effects (PVE). Thus, findings highlighted the necessity of PVC when using these measurements as specific metrics of microstructural tissue degeneration. Regional MD was not superior to regional volume in separating prodromal and clinical stages of AD from healthy controls, independently of PVC.