Few studies have tested effects of APOE ε4 on tau PET imaging, but our results are consistent with a study in 62 (typical and atypical) AD patients, where the absence of APOE ε4 was associated with a greater 18F-AV-1451 signal in the neocortex and less signal in the entorhinal cortex (using a similar E/C ratio as here) [24]. Here, MAPT is linked to Alzheimer disease.