MAPT and Alzheimer disease: The radioligand, [11C]pyridinyl‐butadienyl‐benzothiazole 3 ([11C]PBB3), binds to a wide range of tau fibrils, including AD, PSP, and putative CBD tau deposits.13, 14, 15 Other tracers, such as [18F]AV‐1451, produce a higher contrast for AD‐type tau tangles than it does for four‐repeat tau inclusions in PSP and CBD,16, 17 although [18F]AV‐1451 has enabled differentiation between groups of PSP patients and healthy controls.18 The distinct selectivity of the PET ligands could help identify tau isoforms contributing to unique neurodegenerative pathologies in each individual.19