A prospective study of physician-observed concussion during a varsity university hockey season: white matter integrity in ice hockey players. Part 3 of 4

Object. The aim of this study was to investigate the effect of repetitive head impacts on white matter integrity that were sustained during 1 Canadian Interuniversity Sports (CIS) ice hockey season, using advanced diffusion tensor imaging (DTI). Methods. Twenty-five male ice hockey players between 20 and 26 years of age (mean age 22.24 +/- 1.59 years) participated in this study. Participants underwent pre- and postseason 3-T MRI, including DTI. Group analyses were performed using paired-group tract-based spatial statistics to test for differences between preseason and postseason changes. Results. Tract-based spatial statistics revealed an increase in trace, radial diffusivity (RD), and axial diffusivity (AD) over the course of 1 season. Compared with preseason data, postseason images showed higher trace, AD, and RD values in the right precentral region, the right corona radiata, and the anterior and posterior limb of the internal capsule. These regions involve parts of the corticospinal tract, the corpus callosum, and the superior longitudinal fasciculus. No significant differences were observed between preseason and postseason for fractional anisotropy. Conclusions. Diffusion tensor imaging revealed changes in white matter diffusivity in male ice hockey players over the course of 1 season. The origin of these findings needs to be elucidated. (http://thejns.org/doi/abs/10.3171/2012.10.FOCUS12303)