Follow up 18F-AV-1451 Scan in Confirmatory Cohort Subjects From Study 18F-AV-1451-A05

Inclusion Criteria: * Confirmatory cohort subjects who completed the 18F-AV-1451-A05 (NCT02016560) study Exclusion Criteria: * Current clinically significant cardiovascular disease, ECG abnormalities, risk factors for Torsades de Pointes (TdP), or are taking drugs known to cause QT prolongation * Current clinically significant infectious disease, endocrine or metabolic disease, pulmonary, renal or hepatic impairment, or cancer * Females of childbearing potential who are not surgically sterile, not refraining from sexual activity or not using reliable methods of contraception * Have had a non-study related radiopharmaceutical imaging or treatment procedure within 7 days prior to the study imaging session * Have received or participated in a trial with investigational medications in the past 30 days