Imaging Inflammation in Alzheimer's Disease

This study is being done to determine the relationship between inflammation, cognitive
impairment, and amyloid burden in elderly subjects with different clinical and biomarker
profiles of Alzheimer's disease (AD). Participants will undergo amyloid PET imaging with
18F-Florbetaben with target number of completers being 15 amyloid-positive elders with
impairment, 15 amyloid-positive elders with normal cognition, 15 amyloid-negative elders with
impairment, and 15 amyloid-negative elders with normal cognition. Subjects will undergo
screen that includes neuropsychological testing, brain MRI, and PET imaging with
18F-florbetaben to define the above 4 groups. Subjects will have 11C-PBR28 PET imaging to
measure the 18 kDa translocator protein (a marker of inflammation). Subjects will have the
option to have lumbar puncture performed to measure CSF concentrations of amyloid,tau,
phospho-tau, and inflammatory markers.

Inclusion Criteria:

1. Age 60 and older.

2. Meet criteria for either a) amnestic mild cognitive impairment (single or mixed
domain) or mild Alzheimer's disease, or b) have no cognitive impairment based on
history, exam, neuropsychological testing, and consensus diagnosis. MCI and mild AD
patients must have Clinical Dementia Rating scale score of 0.5 or 1. Unimpaired
subjects must have Clinical Dementia Rating scale score of 0.

3. Subjects unable to provide informed consent must have a surrogate decision maker

4. Written and oral fluency in English or Spanish.

5. Able to participate in all scheduled evaluations and to complete all required tests
and procedures.

6. In the opinion of the investigator, the subject must be considered likely to comply
with the study protocol and to have a high probability of completing the study.

Exclusion Criteria:

1. Past or present history of certain brain disorders other than MCI or AD.

2. Certain significant medical conditions, which make study procedures of the current
study unsafe.

3. Contraindication to MRI scanning.

4. Conditions precluding entry into the scanners (e.g., morbid obesity, claustrophobia,
etc.).

5. Exposure to research related radiation in the past year that, when combined with this
study, would place subjects above the allowable limits.

6. Low affinity binding on TSPO genetic screen.

7. Participation in the last year in a clinical trial for a disease modifying drug for
AD.

8. Inability to have a catheter in subject's vein for the injection of radioligand.

9. Inability to have blood drawn from subject's veins.