F 18 T807 Tau PET Imaging in Dominantly Inherited Alzheimer's Network (DIAN Project)

The investigators hypothesize that in vivo tau imaging will ultimately:

- Demonstrate the presence of tau fibrils in the brain during the pre-symptomatic stages
of cognitive decline, prior to cerebral atrophy, hypometabolism (as measured by 18F-FDG
PET imaging), and dementia.

- Demonstrate that the phenoconversion from cognitively normal (CN) status to early stages
of cognitive impairment will be closely correlated with neocortical F 18 T807 uptake and
that amyloid positive CN individuals who are positive for F 18 T807 will demonstrate
conversion to early dementia.

- Correlate closely with the appearance of CSF markers of tau, including tau, p-tau, and
VILIP-1.

- Co-localize with specific cognitive deficits (i.e. patients with tau deposition in the
left lateral temporal lobe will have primarily language deficits).

- Predict the onset of dementia more accurately than existing biomarkers.

Inclusion Criteria:

1. Participants have met all eligibility criteria for enrollment into "Dominantly
Inherited Alzheimer's Network (DIAN) Performance Site" (IRB ID: 201109187)

2. Male or female participants, at least 18 years of age

3. Cognitively normal, or with mild dementia, as assessed clinically

4. Participant is able and willing to undergo testing (MRI or CT, PET, radioactive tracer
injection; for those unable to undergo an MRI, CT will be used to generate
regions-of-interest).

5. Pre-menopausal women will undergo a urine pregnancy test within 24 hours of drug
administration.

Exclusion Criteria:

1. Has any condition that, in the Investigator's opinion, could increase risk to the
participant, limit the participant's ability to tolerate the experimental procedures,
or interfere with the collection/analysis of the data (for example, participants with
severe chronic back pain might not be able to lie still during the scanning
procedures).

2. Is deemed likely unable to perform the imaging procedures for any reason.

3. Has a high risk for Torsades de Pointes or is taking medications known to prolong QT
interval.

4. Has hypersensitivity to F 18 T807 or any of its excipients.

5. Contraindications to PET, PET-CT or MR (e.g. electronic medical devices, inability to
lie still for long periods) that make it unsafe for the individual to participate.

6. Severe claustrophobia.

7. Currently pregnant or breast-feeding.