For both FFPE and frozen-tissue samples and in accordance with the immunohistochemical tau load, cortical [18F]PI-2620 binding ratios were significantly higher in AD tissue when compared to PSP (CWMRFFPE: 2.1-fold, p < 0.001; CWMRfrozen: 6.8-fold, p < 0.001) and HC (CWMRFFPE: 2.8-fold, p < 0.001; CWMRfrozen: 6.8-fold, p < 0.001). Here, MAPT is linked to Alzheimer disease.