Evaluation of [18F]MNI-777 PET as a Marker of Tau Pathology in Subjects With Tauopathies Compared to Healthy Subjects

All enrolled subjects will undergo an \[18F\]MNI-777 PET imaging visit. For individuals with AD or CTE, \[18F\]florbetapir imaging may also be performed to serve as a means of correlating disease severity by evaluating the relationship of β-amyloid uptake (measured by \[18F\]florbetapir imaging) and tau protein uptake (measured by \[18F\]MNI-777 PET imaging). For individuals with Parkinsonian symptoms, \[123I\]β-CIT SPECT imaging may be performed to evaluate for a reduction in dopamine transporter uptake.