Our PET study replicated postmortem spreading patterns of tau and amyloid-β pathologies. Unlike the diffuse accumulation of amyloid throughout the neocortex, tau spreading occurred in a stepwise fashion through the networks. Image-based tau staging may be useful for the objective assessment of AD progression. Ann Neurol 2016;80:247-258.

Tau PET imaging with (18)F-AV-1451 could serve as an in vivo biomarker for the evaluation of AD-related tau pathology and monitoring disease progression. The accumulation of pathologic tau is more closely related to functional and structural deterioration in the AD spectrum than β-amyloid.

The PSP and PD patients showed distinct subcortical F-AV-1451 binding patterns reflecting subcortical tau pathology in PSP and reduced nigral neuromelanin in PD. However, there was no correlation with the severity of motor dysfunction, no cortical regions with increased binding in PSP patients, and variable degrees of subcortical binding even in the controls. Therefore, the F-AV-1451 PET may be less than ideal for assessing tau pathology in PSP. Further studies will be required to validate the clinical correlation and to understand the clinical utility of F-AV-1451 PET for PSP patients. © 2016 International Parkinson and Movement Disorder Society.