Using cryo-EM, we previously identified two binding sites for another tau PET tracer compound, APN-1607 or PM-PBB3 (propanol modification of pyridinyl-butadienyl-benzothiazole 3), in the β-helix of PHFs and SFs, and a third site in the C-shaped cavity of SFs.9 Here, we used similar methods to examine the binding of flortaucipir to Alzheimer and CTE tau filaments, from a case of AD and a case of PART with additional CTE pathology. Here, MAPT is linked to Alzheimer disease.