The University of Alabama at Birmingham (UAB) Neuroinflammation in Parkinson's Disease-TSPO- Positron Emission Tomography (PET) Substudy

Inclusion Criteria for all cohorts: 1. Enrollment in either the UAB Innate and Adaptive Immunity in Parkinson Disease (Clinical Research Core) study or UAB Longitudinal \[18F\]DPA-714 Imaging in a Parkinson Disease Cohort study under the separate UAB-approved research protocols (IRB-300001745 and IRB-300011684 respectively, PI Yacoubian) 2. Negative urine or serum Human chorionic gonadotropin (hCG) test within 2 days of \[18F\]DPA-714-PET administration in women of childbearing potential. Women who are post-menopausal with at least 1 year since last menses or documented surgical sterilization will not require pregnancy testing. 3. High or mixed affinity binder for TSPO ligands based on genotyping for single nucleotide polymorphism (SNP) rs6971. Exclusion Criteria for all cohorts: 1. Meets any exclusion criteria for the UAB Innate and Adaptive Immunity in Parkinson's Disease (Clinical Research Core) study or UAB Longitudinal \[18F\]DPA-714 Imaging in a Parkinson's Disease Cohort study. 2. Contraindication to MRI and/or PET imaging 3. Inability to participate in the imaging studies due to severity of PD or other medical comorbidities. 4. Low-affinity binder for TSPO ligands based on genotyping for SNP rs6971. Inclusion Criteria specific for UDALL 5-year Follow-up Cohort 1\. Parkinson's Disease participant enrolled in UDALL Baseline Cohort. Baseline imaging to be completed no more than 6 years prior. Inclusion of Women and Minorities Participants 30 years of age or older will be eligible for study participation. No other discriminatory factors, including age, sex, or ethnic background will be used to determine eligibility. Every effort will be made to ensure that minorities are recruited for study participation.