F 18 T807 PET (Positron Emission Tomograph )Scan for HIV Infected & Uninfected

This protocol will demonstrate the presence of tau fibrils in older HIV+ patients with HIV associated neurocognitive disorders (HAND) compared to cognitively normal HIV+ individuals and HIV- controls. It will also demonstrate that the phenoconversion from cognitively normal (CN) status to HAND will be closely correlated with neocortical F 18 T807 uptake. In particular, HIV+ patients with MND will have greater tau cortical deposition compared to ANI individuals. The investigtors hypothesize that in vivo tau imaging will ultimately: * Demonstrate the presence of tau fibrils in older HIV+ patients with HIV associated neurocognitive disorders (HAND) compared to cognitively normal HIV+ individuals and HIV- controls. * Demonstrate that the phenoconversion from cognitively normal (CN) status to HAND will be closely correlated with neocortical F 18 T807 uptake. In particular, HIV+ patients with MND will have greater tau cortical deposition compared to ANI individuals.