Florbetapir Calibration to the Centiloid Scale

Inclusion Criteria: * Cognitively Normal Subjects * Males or females ≥ 21 and ≤ 45 years of age * Mini-mental state examination (MMSE) ≥ 29 * Clinically Diagnosed AD Subject * Males or females ≥ 50 years of age * Meet clinical criteria for dementia due to probable AD * MMSE ≥ 16 and ≤ 26 * Possible AD Subject * Males or females ≥ 50 years of age * Meet clinical criteria for dementia due to possible AD * MMSE ≥ 16 and ≤ 26 * MCI Subject * Males or females ≥ 60 years of age with cognitive impairment (not dementia) * MMSE \>24 and \<29 * At Risk Elderly Subject * Cognitively normal males or females that are known ApoE4 carriers and ≥ 75 years of age * MMSE ≥ 27 Exclusion Criteria: * Have had or currently have a diagnosis of neurodegenerative disorders other than AD * Have a current serious or unstable illness that could interfere with completion of the study * Subject has a known brain lesion, pathology or traumatic brain injury * Have received or participated in a trial with investigational medications in the past 30 days * Have had a radiopharmaceutical imaging or treatment procedure within 7 days of study imaging session * Females of childbearing potential who are not surgically sterile, not refraining from sexual activity or not using reliable methods of contraception