MAPT and Alzheimer disease: Combined immunohistochemistry and in vitro autoradiography studies of human AD brain sections revealed that [18F]T807 (Figure 5a) and [18F]T808 (Figure 5b) both had higher binding to PHF-tau aggregates than to Aβ [138]; [18F]Flortaucipir (Figure 5a) had a logP of 1.7, predicting adequate brain penetration and fast washout.