MAPT and Alzheimer disease: PET probes wereinitially developed for imaging β-amyloid (Aβ) aggregatedprotein, present as plaque deposits in Alzheimer’s disease(AD),2 then probes selective for proteintau aggregates, which form intracellular neurofibrillary tangles (NFT)in AD.3,4 In addition to AD, pathological tau aggregatesare a constituent feature of several other neurodegenerative disorders,collectively termed tauopathies;5−7 hence tau PET imaging is a keybiomarker technology.