Precision estimates of Relative and Absolute Cerebral Blood Flow in Alzheimer’s disease and Cognitively Normal individuals

Alzheimer’s disease is characterized by regional reductions in cerebral blood flow (CBF) and the gold standard for measuring CBF is [15O]H2O PET. Recently, proxies of relative CBF, derived from the early distribution phase of amyloid‐β and tau tracers, have gained attention. It has been hypothesized that relative CBF is likely to have higher precision (but not accuracy) than absolute CBF, as global variations in CBF are cancelled out. The present study assessed precision of [15O]H2O PET derived relative and absolute CBF measures, and compared them with relative CBF proxies estimated from [18F]florbetapir and [18F]flortaucipir scans.