Mean magnetic susceptibility values in the ventral anterior substantia nigra are shown comparing Parkinson’s disease (PD) and healthy controls (HC). False discovery rate-corrected group, time and group × time interaction p-values were 0.042, 0.02, and 0.043, respectively. Comparisons were made adjusting for age and sex. The error bars represent ± 1 standard error of the mean.
Legend: PD - Parkinson’s disease; HC – healthy controls; SN–substantia nigra; ppb – parts per billion