Volume of white matter (WM) regions with significant pre-season to post-season change in MD, AD or RD in different WM tracts and the correlation between the diffusion tensor imaging change within significant regions with the total number of head impacts experienced during the season in the 22 participants in the non-collar group who underwent both pre-season and post-season MRI scans
| WM tracts | Volume | Correlation coefficient r (p) | ||||
| (mm3) | FA | MD | AD | RD | ||
| Region 01 | ATR, left | 1158 | −0.326 (ns) | 0.521 (0.013) | 0.474 (0.026) | 0.446 (0.038) |
| Region 02 | ATR, right | 836 | −0.181 (ns) | 0.349 (ns) | 0.255 (ns) | 0.315 (ns) |
| Region 03 | CST, left | 1005 | 0.073 (ns) | 0.240 (ns) | 0.178 (ns) | 0.171 (ns) |
| Region 04 | CST, right | 626 | −0.061 (ns) | 0.247 (ns) | 0.192 (ns) | 0.233 (ns) |
| Region 05 | Cingulum (CG part), left | 451 | −0.106 (ns) | 0.311 (ns) | 0.264 (ns) | 0.357 (ns) |
| Region 06 | Cingulum (CG part), right | 221 | 0.039 (ns) | 0.375 (ns) | 0.304 (ns) | 0.373 (0.087) |
| Region 07 | Cingulum (HC part), left | 22 | −0.584 (0.004) | 0.526 (0.012) | 0.045 (ns) | 0.060 (ns) |
| Region 08 | Cingulum (HC part), right | 17 | 0.118 (ns) | 0.147 (ns) | 0.145 (ns) | −0.053 (ns) |
| Region 09 | Forceps major | 417 | −0.321 (ns) | 0.354 (ns) | 0.241 (ns) | 0.453 (0.034) |
| Region 10 | Forceps minor | 2349 | −0.425 (0.049) | 0.479 (0.024) | 0.372 (ns) | 0.477 (0.025) |
| Region 11 | IFOF, left | 1053 | −0.328 (ns) | 0.498 (0.018) | 0.408 (0.059) | 0.516 (0.014) |
| Region 12 | IFOF, right | 1011 | 0.126 (ns) | 0.270 (ns) | 0.294 (ns) | 0.120 (ns) |
| Region 13 | ILF, left | 545 | −0.164 (ns) | 0.445 (0.038) | 0.216 (ns) | 0.396 (0.068) |
| Region 14 | ILF, right | 15 | −0.062 (ns) | 0.311 (ns) | 0.293 (ns) | 0.232 (ns) |
| Region 15 | SLF, left | 3022 | −0.210 (ns) | 0.371 (0.090) | 0.402 (0.064) | 0.364 (0.096) |
| Region 16 | SLF, right | 325 | −0.241 (ns) | 0.264 (ns) | 0.282 (ns) | 0.330 (ns) |
| Region 17 | UF, left | 601 | −0.449 (0.036) | 0.473 (0.026) | 0.299 (ns) | 0.542 (0.009) |
| Region 18 | UF, right | 137 | 0.054 (ns) | 0.189 (ns) | 0.222 (ns) | 0.099 (ns) |
| Region 19 | SLF (temporal), left | 30 | 0.367 (ns) | 0.130 (ns) | 0.177 (ns) | 0.142 (ns) |
| Region 20 | SLF (temporal), right | 4 | −0.025 (ns) | 0.141 (ns) | 0.055 (ns) | 0.154 (ns) |
The WM tracts were determined using WM atlas based on John Hopkins University’s ICBM WM tract probability map. The statistical significance derived from the correlation analyses were not corrected for multiple comparisons.
AD, axial diffusivity; ATR, anterior thalamic radiation; CG, cingulate gyrus; CST, corticospinal tract; FA, fractional anisotropy; HC, hippocampal; IFOF, inferior fronto-occipital fasciculus; ILF, inferior longitudinal fasciculus; MD, mean diffusivity; ns, not significant; RD, radial diffusivity; SLF, superior longitudinal fasciculus; UF, uncinate fasciculus.