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

Figures

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  Fig. 1. Brain regions with magnetic susceptibility value differences between the PD patients and HCs. The color bar represents the absolute t value. The red areas denote the regions exhibiting differences between the two groups: a voxel-level threshold of p < 0.001 and a cluster-extent threshold of k > 30 voxels (cluster-level FWE corrected, p < 0.05). The graph explicitly labels the specific relationships regarding the magnetic susceptibility magnitudes. QSM quantitative susceptibility mapping; χpara paramagnetic susceptibility mapping; χdia diamagnetic susceptibility mapping.

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  Fig. 2. Correlations between the magnetic susceptibility values and the clinical and gait indicators of PD patients. As highlighted in the boxed section, the correlation analysis specifically examined the relationship between gait abnormalities and magnetic susceptibility values in the significantly relevant brain regions, namely the right substantia nigra pars reticulata, left temporal pole, and left inferior temporal gyrus.* p < 0.05, ** p < 0.01, *** p < 0.001. The color bar represents the magnitude of the correlation coefficient (r value). MDS-UPDRS-III Movement Disorder Society-Unified Parkinson’s Disease Rating Scale Part III, SSP self-selected pace, FP fast pace, Vel velocity (cm/s), Cad cadence (steps/min), StrTime stride time (s), StrLength stride length (cm), QSM quantitative susceptibility value, χpara paramagnetic susceptibility value, χdia diamagnetic susceptibility value.

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  Fig. 3. Processing flow of QSM. The color bar represents the range of magnetic susceptibility values. ANTs advanced normalization tools, QSM quantitative susceptibility mapping, χpara paramagnetic susceptibility mapping, χdia diamagnetic susceptibility mapping, ppm parts per million.