Abstract
PURPOSE: Human post mortem studies have described the topographical patterns of tau pathology in progressive supranuclear palsy (PSP). Recent advances in tau PET tracers are expected to herald the next era of PSP investigation for early detection of tau pathology in living brains. This study aimed to investigate whether (18)F-Florzolotau PET imaging may capture the distribution patterns and regional vulnerability of tau pathology in PSP, and to devise a novel image-based staging system. METHODS: The study cohort consisted of 148 consecutive patients with PSP who had undergone (18)F-Florzolotau PET imaging. The PSP rating scale (PSPrs) was used to measure disease severity. Similarities and differences of tau deposition among different clinical phenotypes were examined at the regional and voxel levels. An (18)F-Florzolotau pathological staging system was devised according to the scheme originally developed for post mortem data. In light of conditional probabilities for the sequence of events, an (18)F-Florzolotau modified staging system by integrating clusters at the regional level was further developed. The ability of (18)F-Florzolotau staging systems to reflect disease severity in terms of PSPrs score was assessed by analysis of variance. RESULTS: The distribution patterns of (18)F-Florzolotau accumulation in living brains of PSP showed a remarkable similarity to those reported in post mortem studies, with the binding intensity being markedly higher in Richardson's syndrome. Moreover, (18)F-Florzolotau PET imaging allowed detecting regional vulnerability and tracking tau accumulation in an earlier fashion compared with post mortem immunostaining. The (18)F-Florzolotau staging systems were positively correlated with clinical severity as reflected by PSPrs scores. CONCLUSIONS: (18)F-Florzolotau PET imaging can effectively capture the distribution patterns and regional vulnerability of tau pathology in PSP. The (18)F-Florzolotau modified staging system holds promise for early tracking of tau deposition in living brains.