Parkinson's disease patients were investigated in order to reveal changes inside region-of-interest – substantia nigra. 31 volunteers were scanned using a well-established, quantitative free water mapping protocol. The region-of-interest is too small to obtain reliable segmentation for region-based analysis. Therefore, statistical, voxel-wise analysis of registered quantitative maps was performed. It revealed a decrease in the metrics (free water content, T1, T2* and combination of all three) in the vicinity of substantia nigra. We conclude that the reduction in total free water content could be due to a disruption of the deep grey matter integrity.