Table 3.

Region-of-interest analysis of diffusion tensor and free-water imaging indices in the white matter of Parkinson’s disease patients and healthy controls.

	WM Areas	HC		PD		P Value	t-Value	Cohen’s d
		Mean	SD	Mean	SD
DTI
FA	Anterior	0.48	0.014	0.47	0.018	0.019 *	2.46	0.78
	Posterior	0.61	0.021	0.60	0.021	0.011 *	2.69	0.85
MD	Anterior	0.80	0.035	0.83	0.048	0.014 *	−2.58	0.81
	Posterior	0.82	0.029	0.85	0.047	0.036 °	−2.18	0.69
AD	Anterior	1.25	0.043	1.28	0.058	0.038 °	−2.16	0.68
	Posterior	1.49	0.038	1.51	0.058	0.32	−1.00	0.32
RD	Anterior	0.57	0.032	0.61	0.046	0.010 *	−2.71	0.86
	Posterior	0.49	0.032	0.52	0.045	0.012 *	−2.65	0.84
FW imaging
FAT	Anterior	0.64	0.026	0.61	0.020	0.0021 *	3.30	1.04
	Posterior	0.75	0.018	0.75	0.019	0.40	0.85	0.27
MDT	Anterior	0.56	0.039	0.60	0.036	0.0014 *	−3.45	1.09
	Posterior	0.61	0.014	0.62	0.022	0.25	−1.16	0.37
ADT	Anterior	1.00	0.053	1.05	0.053	0.0025 *	−3.24	1.02
	Posterior	1.29	0.027	1.29	0.041	0.71	−0.38	0.12
RDT	Anterior	0.34	0.033	0.37	0.031	0.0016 *	−3.40	1.22
	Posterior	0.27	0.020	0.28	0.024	0.26	−1.14	0.36
FW	Anterior	0.21	0.016	0.23	0.042	0.079	−1.81	0.57
	Posterior	0.21	0.024	0.24	0.042	0.020 *	−2.44	0.77

AD, axial diffusivity; AD_T, free water-corrected axial diffusivity; DTI, diffusion tensor imaging; FA, fractional anisotropy; FA_T, free water-corrected fractional anisotropy; FW, free water; HC, healthy control; MD, mean diffusivity; MD_T, free water-corrected mean diffusivity; PD, Parkinson’s disease; RD, radial diffusivity; RD_T, free water-corrected radial diffusivity; SD, standard deviation; WM, white matter. * p ≤ 0.025; ° 0.025 < p < 0.05.