Tau PET/CT Imaging in the Mismatch Prospective Cohort Study (MPC-TAU)

This study adds a specialized brain scan called a Tau PET scan (using a tracer called AV-1451) to an existing research program, to help scientists learn more about how tau protein — a hallmark of Alzheimer's disease — builds up in the brain over time. **You may be eligible if...** - You are already enrolled in the Mismatch Prospective Cohort (MPC) study at the University of Pennsylvania or Massachusetts General Hospital - You have a reliable person (study partner) who can come with you to the scan - You had a high-quality brain MRI within the past 6 months **You may NOT be eligible if...** - You have a medical or psychiatric condition that would make participation unsafe - You have a large structural abnormality on your brain MRI (like a major stroke or mass) - You cannot tolerate or have contraindications to the PET scan Talk to your doctor to see if this trial is right for you.