Our aims, using this new approach on MR scans within the DIAN‐Obs cohort were to: (1) identify differences in the T1w and FLAIR cortical intensity distribution in individuals with dominantly inherited Alzheimer disease‐causing mutations versus non‐carrier controls; (2) explore changes in the T1w and FLAIR cortical intensity distribution in individuals with these mutations along the disease trajectory from the asymptomatic to symptomatic stage; and (3) identify any relationship between these MR signal changes and amyloid and tau pathology as measured by amyloid PET and tau PET, respectively. Here, MAPT is linked to Alzheimer disease.