Aβ-PET pathology accumulation index

The development of amyloid PET imaging was revolutionary for Alzheimer disease (AD). Enabling the visualization in patients of a hallmark pathologic protein aggregate previously seen only at autopsy, the emergence of amyloid PET radiotracers1 transformed AD clinical research by allowing confirmation of amyloid pathology in clinically suspected AD cases, atypical AD variants, and individuals with suspected mixed etiology and by permitting the tracking of longitudinal change in observational studies and especially therapeutic trials of amyloid-lowering drugs.2 Soon, 18F-labeled radiotracers emerged and eventually achieved clinical approvals, aiding diagnosis and management of patients suspected of having AD.3