Parkinson’s disease is a progressive, neurodegenerative disorder characterized by asymmetrical onset of motor symptoms such as bradykinesia, rigidity, and tremor. The principal pathology in Parkinson's disease is the loss of melanized dopamine neurons in the substantia nigra pars compacta (SNpc) with iron deposited alongside this neuronal loss. Loss of SNpc neurons should remove barriers for diffusion and increase diffusivity of water molecules in regions undergoing this loss. Studies examining Parkinsonian SNpc microstructural changes using a single tensor model have yielded conflicting results. Here, we investigate PD-related microstructural changes in multiple compartment and single tensor models.