MAPT and Alzheimer disease: In AD, specific findings such as atrophy of the temporal and parietal lobes on brain morphology images, such as brain MRI, reflective of neurodegenerative diseases, decreased glucose metabolism in the temporal and parietal lobes on functional brain images, increased total tau and phosphorylated tau in cerebrospinal fluid, positive findings on amyloid PET scan reflecting cerebral Aβ accumulation, and decreased Aβ42 in cerebrospinal fluid, are useful for diagnosis [99].