Fig. 4

The multiple regression results of axial diffusivity (AD) with disease duration for post-infectious ME/CFS (PI-ME/CFS) patient group. Results are displayed in Montreal Neurological Institute (MNI) 152 standard space based on the reference FSL_HCP1065 fractional anisotropy 1 × 1 × 1 mm standard-space image. The top row shows the results from six different axial slices, where the z-coordinates in MNI space from left to right are z = −12 mm, −2 mm, 8 mm, 18 mm, 28 mm, and 38 mm, respectively. The middle row shows the results from six different coronal slices, where the y-coordinates in MNI space from left to right are y = −46 mm, −36 mm, −26 mm, −16 mm, −6 mm, and 4 mm, respectively. The bottom row shows the results from six different sagittal slices, where the x-coordinates in MNI space from left to right are x = −35 mm, −20 mm, −5 mm, 10 mm, 25 mm, and 40 mm, respectively. Blue-green clusters show the significant negative correlation of AD with disease duration for PI-ME/CFS patient group. The colour bar represents 1-p values, with higher values indicating greater levels of statistical significance.