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

Inclusion Criteria:

• Males and females ≥ 60 years of age.

• Part of the NACC longitudinal cohort (IRB# 068200) of the PMC/ADCC with consensusconference designation of cognitively normal or Mild Cognitive Impairment (MCI) orAlzheimer's Disease (AD) Possible or Probable.

• NACC longitudinal visit completed or scheduled within 6 months before or afterenrollment in this study.

• Women must be post-menopausal or surgically sterile.

• An amyloid PET scan, completed as a part of the NACC protocol (IRB# 825943), must beperformed or scheduled within 12 months before or after the [18F]PI-2620 PET scan.

• A brain MRI, completed as a part of NACC protocol (IRB# 068200), must be performedor scheduled within 6 months before or after the [18F]PI-2620 PET scan. Scan shouldbe of adequate research quality, including 3 Tesla and/or 7 Tesla high-resolutionimaging of MTL structure.

Exclusion Criteria:

• Have any medical or psychiatric conditions that, in the opinion of the investigator,would compromise the subject's safety or successful participation in the study.

• Have evidence of structural abnormalities such as major stroke or mass on MRI thatis likely to interfere with analysis of the PET scan.

• Inability to tolerate or contraindication to imaging procedures in the opinion of aninvestigator or treating physician.

• Have a history of significant or ongoing alcohol abuse or substance abuse ordependence based on medical record review or self-reported.

The inclusion / exclusion criteria will be ascertained through self-report in conjunction with any medical history available through the participant's medical or research records (EPIC or the ADC database)