Intervention: Flortaucipir F-18
Trial phase: Phase 2
ATC code: V09AX07
SMILES: Fc1ccc(-c2ccc3c(c2)[nH]c2ccncc23)cn1
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 125
Group description: Eight to ten year follow-up DLBS participants who were cognitively normal at the time of enrollment from 2008 to 2014.

[18F]AV-1451: The subject will receive up to a target dose of 370 megabecquerel (MBq) as a single IV bolus of [18F]AV-1451.

Positron Emission Tomography: Approximately 80 minutes after injection subjects will be placed in the UTSW PET/CT scanner for a 20-minute brain scan.
Eligibility criteria:
Inclusion Criteria:

Participated in Wave 1 or 2 of the DLBS study.
Subjects must indicate that they are not currently pregnant if they are women of child-bearing potential. Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and for 90 days following completion of therapy. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: 1) Has not undergone a hysterectomy or bilateral oophorectomy; or 2) Has not been naturally post-menopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months).
Volumetric Brain MRI Image (T-1 Weighted MPRage) collected as part of DLBS Wave 1, 2, or 3 protocol.
Completed at least 9 years of formal education, or the equivalent of freshman year of high school.
Fluent English speakers.
Tolerate laying 20 minutes on a flat table for the PET scan.
Ability to understand and the willingness to sign a written informed consent.

Exclusion Criteria:

Mini-Mental State Examination (MMSE) score lower than 22; all DLBS participants at the time of initial Wave 1 enrollment between 2008 - 2014 had an MMSE score of 26 or above, indicating normal cognitive function. However, in the time interval between Wave 1 and Wave 3, it is possible that mental capacity may have deteriorated. The investigators will exclude all participants in Wave 3 testing who have an MMSE lower than 22.
Taking some types of sedatives, benzodiazepines, or anti-psychotics.
Currently undergoing chemotherapy or radiation for cancer.
New history of substance abuse.
Has a history of drug or alcohol dependence within the last year, or prior prolonged history of dependence.
Recreational drug use in past six months.
Central nervous systems disease or brain injury that would preclude participation in the study.
Psychiatric or neurological disorder that would preclude participation in this study.
Has clinically significant hepatic, renal, pulmonary, metabolic or endocrine disturbances which pose safety risk.
Has a current clinically significant cardiovascular disease that poses a safety risk.
Has a current clinically significant infectious disease or a medical comorbidity which poses a safety risk.
Has either: 1) Screening electrocardiogram (ECG) with corrected QT Interval (QTc) > 450 millisecond (msec) if male, or QTc > 470 msec if female; or 2) A history of additional risk factors for Torsades de Pointes (TdP) (e.g., hypokalemia, family history of Long QT syndrome) or are taking drugs that are known to cause QT prolongation (a list of prohibited and discouraged medications is provided by the Sponsor); Patients with a prolonged QTc interval in the setting of intraventricular conduction block (examples right bundle branch block or left bundle branch block), may be enrolled with sponsor approval.
Has received or will receive investigational medication within the 30 days of PET/CT scan.
Has received or will receive a radiopharmaceutical for imaging or therapy within 24 hours of PET/CT scan.
Is a participant who, in the opinion of the investigator(s), is otherwise unsuitable for a study of this type.