Results of the histogram comparisons for the whole-brain WM and the WM ROI.

Improved intensity histogram alignment is represented by reduced average absolute errors and maximum absolute errors between the target and reference distributions of the intensity standardised T1-weighted images and of the T1 maps, respectively. The results of the Wilcoxon Signed-ranks tests (Z, p) and the effect size r are shown. CHM cumulative histogram matching, NHM non-linear histogram matching, PHM piecewise linear histogram matching, RLS ROI-based linear standardisation, ROI region of interest, SPS segmentation-based piecewise linear standardisation, WM white matter.