Table 3.

Magnetic susceptibility values of significant regions of interest among participants

Regions	HC (n = 32)	PD-RBD- (n = 24)	PD-RBD+ (n = 27)	p-value	p-value (post hoc)
					HC vs PD-RBD-	HC vs PD-RBD+	PD-RBD- vs PD-RBD+
QSM (ppb)
right SNpc	65.16 ± 18.46	76.71 ± 18.04	78.93 ± 21.35	0.016*	0.03*	0.008**	0.683
left SNpc	61.38 ± 15.89	72.07 ± 16.79	73.68 ± 22.30	0.024*	0.035*	0.013*	0.757
χpara (ppb)
right SNpc	77.46 ± 19.79	93.06 ± 22.07	96.03 ± 25.81	0.004**	0.012*	0.002**	0.64
left SNpc	75.07 ± 18.12	86.93 ± 21.14	91.58 ± 25.96	0.014*	0.047*	0.005**	0.449

^*p < 0.05, **p < 0.01; QSM quantitative susceptibility mapping (value), χ_para paramagnetic susceptibility mapping (value), ppb parts per billion, SNpc substantia nigra pars compacta, PD-RBD^- Parkinson’s disease without rapid eye movement sleep behavior disorder, PD-RBD⁺ Parkinson’s disease with secondary rapid eye movement sleep behavior disorder.