Linking Tau PET to Medial Temporal Lobe Subregions With High Resolution MRI

This is a cross-sectional and longitudinal study using the radiotracer \[18F\]-PI-2620 to determine the relationship of tau pathology to both cross-sectional and longitudinal clinical and biomarker data of NACC cohort participants who are Cognitively Normal or MCI. All subjects will already be part of the longitudinal cohort study, known as the "NACC" cohort, of the PMC/ADC (protocol 068200). Participants will provide informed consent for this protocol before beginning any study procedures. After screening assessments, participants will undergo PET scan imaging with \[18F\]PI-2620. There will be one follow-up \[18F\]PI-2620 PET scan approximately 18 +/- 6 months after bas eline scan.