Fig 2. Hemispheric analysis of glioma impact on white matter.

(A_1-4). Hemispheric differences in the diffusion coefficient distributions (_1–4; MD, RD, AD, FA, respectively) depicted as mirrored probability distributions (red indicates ipsilesional and gray represents contralesional; solid vertical line represents the median) for a representative case. (B_1-4) A shift function analysis was used to compare differences over the entire distribution, by comparing the offsets of estimated deciles between the distributions (ILH = ipsilesional hemisphere, CLH = contralesional hemisphere). B_1-2, shift function curves indicate that for both the MD, RD distributions there is a positive shift for both tails (more pronounced for the right tail), suggesting that at all segments of the distribution those values are higher for the ipsilesional side. B₃, the shift function curve for AD shows a negative shift up to the median and then a steeper positive shift in the right tail of the distribution, indicating that likely the positive values in the right tail dominate the distribution and suggest an overall positive skew. B₄, shows a dramatic negative shift function curve for the FA, indicating that the ipsilesional hemisphere is composed of lower values along the distribution compared to the contralesional hemisphere. (C) Group data (n = 13) for the shift function analysis strongly replicates the representative case in A&B. (D) Non-parametric t-tests (Wilcoxon rank sum) applied to the hemispheric distributions for each diffusion coefficient resulted in significant differences supporting the shift function findings: the ipsilesional hemisphere exhibited higher MD (Z = 8.97, p = 3.1e-19), higher AD (Z = 6.06, p = 1.3e-9), higher RD (Z = 18.33, z = 5.03–75) and lower FA (Z = -12.24, p = 1.8e-34) compared to the contralesional hemisphere.