IMPORTANCE Progressive supranuclear palsy (PSP) is a 4-repeat tauopathy. Region-specific tau aggregates establish the neuropathologic diagnosis of definite PSP post mortem. Future interventional trials against tau in PSP would strongly benefit from biomarkers that support diagnosis.OBJECTIVE To investigate the potential of the novel tau radiotracer 18 F-PI-2620 as a biomarker in patients with clinically diagnosed PSP. DESIGN, SETTING, AND PARTICIPANTSIn this cross-sectional study, participants underwent dynamic 18 F-PI-2620 positron emission tomography (PET) from 0 to 60 minutes after injection at 5 different centers (3 in Germany, 1 in the US, and 1 in Australia). Patients with PSP (including those with Richardson syndrome [RS]) according to Movement Disorder Society PSP criteria were examined together with healthy controls and controls with disease. Four additionally referred individuals with PSP-RS and 2 with PSP-non-RS were excluded from final data analysis owing to incomplete dynamic PET scans.

FDG-PET shows that microglial activation might drive cerebral glucose uptake in mice and patients with AD.