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

Eligibility Criteria

• * Males and females ≥ 60 years of age.
• * Part of the NACC longitudinal cohort (IRB# 068200) of the PMC/ADCC with consensus conference designation of cognitively normal or Mild Cognitive Impairment (MCI) or Alzheimer's Disease (AD) Possible or Probable.
• * NACC longitudinal visit completed or scheduled within 6 months before or after enrollment 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 be performed 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 performed or scheduled within 6 months before or after the \[18F\]PI-2620 PET scan. Scan should be of adequate research quality, including 3 Tesla and/or 7 Tesla high-resolution imaging of MTL structure.
• * 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 that is likely to interfere with analysis of the PET scan.
• * Inability to tolerate or contraindication to imaging procedures in the opinion of an investigator or treating physician.
• * Have a history of significant or ongoing alcohol abuse or substance abuse or dependence based on medical record review or self-reported.