Sub-voxel QSM reveals the mechanism linking substantia nigra iron and temporal diamagnetism to PD gait.

The precise underlying mechanisms linking changes in brain iron and diamagnetic substances to abnormal gait in Parkinson's disease (PD) patients remain elusive. This study compared paramagnetic and diamagnetic susceptibility (χpara, χdia) in 29 PD patients and 35 healthy controls (HCs) using sub-voxel quantitative susceptibility mapping (QSM). The main result was in PD patients, increased χpara values in the substantia nigra pars reticulata (SNr) and reduced χdia values in the temporal cortices were correlated with gait parameters (p < 0.05). This study suggests that the SNr, crucial for gait regulation, and temporal lobe diamagnetic alterations may underlie PD-related gait dysfunction.