There is an urgent need for developing diagnostic imaging biomarkers for Parkinson’s Disease (PD). In this work, we applied a standardized substantia nigra pars compacta (SNpc) mask based on neuromelanin-sensitive MR images from healthy subjects to investigate the diagnostic performance of the SNpc overlap percentage and R2* in the SNpc overlap in PD. R2* in the SNpc overlap volume was increased in PD patients as compared to controls. Furthermore, it was significantly positively correlated with the disease duration in PD. We found an excellent diagnostic accuracy for the SNpc overlap percentage (AUC, 0.927) in PD.