The investigators will conduct a study of brain positron emission tomography (PET) using 11C-PIB for the imaging of brain amyloid in 250 participants in the Multiethnic study of atherosclerosis (MESA) at Columbia University Irving Medical Center in New York City. Participants will be imaged only once with Pittsburgh Compound B (PIB) PET.

This is a single center PET study of 11C-PIB. Eligible participants are current participants in the MESA study in New York City, without contraindications to MRI or PET procedures. Those eligible will have one brain PET scan with 11C-PIB within 12 months of a brain MRI. Vital signs will be checked prior to injection of 11C-PIB, 10 minutes after the injection, and again at the completion of the PET scan. The primary outcome measure for amyloid will be whole brain 11C-PIB SUVR. The relation between exposure groups and amyloid in the brain will be analyzed using linear regression.

Inclusion Criteria:

• Current participants in MESA study at Columbia University
• 60 years or older
• Fluent in English and/or Spanish.
• Able to participate in all scheduled evaluations and to complete all required tests and procedures.

Exclusion Criteria:

• Active treatment for cancer
• Any serious medical condition which would prevent long-term participation
• Pregnancy
• Weight >300 pounds
• Participants previously diagnosed or adjudicated to have dementia
• Participants unwilling to undergo cognitive testing
• Plans to leave the community within five years
• Language barrier (speaks other than English, Spanish, Chinese)
• Inability to give informed consent or to obtain consent from a Legally Authorized Representative (LAR)

Current participants in MESA study in New York City

Individual participant data (IPD) may be shared at the end of data collection with a mechanism supported by the National Institute on Aging