MAPT and hippocampal atrophy: Neuroimaging biomarkers that can identify biological evidence of AD include Aβ positron emission tomography (PET) for brain amyloidosis, tau-PET for NFT pathology, structural magnetic resonance imaging (MRI) for hippocampal atrophy, and fluorodeoxyglucose (FDG) PET for brain metabolic changes [4, 5].