Table 3.

Spearman rank correlation results between regions showing significant differences in the ROI analysis and clinical features or MRI indices in the second cohort.

		vs Clinical Features					vs Other Indices
		DD	HY	UPDRS	UMSARS	LEDD	ICVF	FW	FAT	RDT	MVF
White matter
MCP	ICVF	0.39	−0.52**	−0.44	−0.29	−0.24	–	−0.21	–	−0.88**	–
	FW	−0.23	0.44	0.46	0.22	0.22	−0.21	–	–	0.19	–
	RDT	−0.48*	0.50**	0.52**	0.21	0.14	−0.88**	0.19	–	–	–
	MVF	–	–	–	–	–	–	–	–	–	–
ICP	ICVF	0.11	−0.41	−0.43	−0.43	−0.34	–	0.02	–	–	–
	FW	0.02	0.19	−0.02	0.13	0.12	0.02	–	–	–	–
	MVF	–	–	–	–	–	–	–	–	–	–
PCT	MVF	–	–	–	–	–	–	–	–	–	–
CST	FW	−0.2	−0.08	−0.04	−0.07	−0.22	–	–	–	–	–
SNc
aSN	ICVF	0.14	0.27	0.34	0.31	0.36	–	−0.32	0.63**	−0.71*	–
	FW	0.076	−0.045	−0.20	−0.16	−0.28	−0.32	–	0.26	−0.25	–
	FAT	−0.12	0.27	0.018	−0.030	0.031	0.60	0.26	–	−0.84**	–
	RDT	−0.15	−0.31	−0.23	−0.14	−0.12	−0.71*	−0.25	−0.84**	–	–
pSN	ICVF	0.089	−0.13	−0.10	−0.43	0.18	–	0.36	0.84**	−0.84**	–
	FW	−0.13	−0.58	−0.41	−0.44	−0.48	0.36	–	0.042	−0.20	–
	FAT	0.32	0.31	0.29	0.32	0.44	0.84**	0.042	–	−0.87**	–
	RDT	−0.070	−0.045	0.055	0.049	−0.092	−0.84**	−0.20	−0.87**	–	–

CST corticospinal tract, FW free water, ICVF intracellular volume fraction, ICP inferior cerebellar peduncle, MCP middle cerebellar peduncle, MDS-UPDRS Movement Disorder Society-Unified Parkinson’s Disease Rating Scale, MVF myelin volume fraction, PCT pontine crossing tract, RD _T free water-corrected radial diffusivity, ROI region of interest, SNc substantia nigra pars compacta, UMSARA Unified Multiple System Atrophy Rating Scale.

*FDR corrected P < 0.05; **FDR corrected P < 0.01.