title: Neuroimaging changes in the brain in contact versus noncontact sport athletes using diffusion tensor imaging.
abstract: OBJECTIVE
  Traumatic brain injury in contact sports has significant impact on short-term neurologic and neurosurgical function as well as longer-term cognitive disability. In this study, we aim to demonstrate that contact sport participants exhibit differences in diffusion tensor imaging (DTI) caused by repeated physical impacts on the brain. We also aim to determine that impact incurred by the contact sports athletes during the season may result in the differences between the pre- and postseason DTI scans.
  
  
  METHODS
  DTI data were collected from 10 contact-sport (mean age 20.4 ± 1.36 years) and 13 age-matched noncontact-sport (mean age 19.5 ± 1.03 years) male athletes on a 3-Tesla magnetic resonance imaging scanner. A single-shot, echo-planar imaging sequence with b-value of 1000 s/mm(2) and 25 gradient directions was used. Eight of the athletes were again scanned after the end of the season. The b0 nondiffusion-weighted image was averaged five times. Voxel-wise, two-sample t tests were run for all group comparisons, and in each case, the positive false-discovery rate was computed to assess the whole-map, multiple-comparison corrected significance.
  
  
  RESULTS
  There were significant differences in the fractional anisotropy values in the inferior fronto-occipital fasciculus, parts of the superior and posterior coronal radiate, and the splenium of the corpus callosum (CC) as well as smaller clusters in the genu and parts of the body of the CC. In addition, the external capsule also shows some difference between the contact and noncontact athlete brains. In addition, the preseason and postseason showed differences in these regions, however, the postseason P-values show significance in more areas of the CC.
  
  
  CONCLUSIONS
  There are significant DTI changes in the CC, the external capsule, the inferior fronto-occipital fasciculus, as well as regions such as the superior/posterior corona radiata the preseason contact versus the noncontact control athletes were compared and also when the postseason contact athletes with the control athletes were compared.
authors.affiliation: Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA. Electronic address: gajawell@usc.edu.
authors.forename: Niharika
authors.initials: N
authors.lastname: Gajawelli
authors.forename: Yi
authors.initials: Y
authors.lastname: Lao
authors.forename: Michael L J
authors.initials: ML
authors.lastname: Apuzzo
authors.forename: Russ
authors.initials: R
authors.lastname: Romano
authors.forename: Charles
authors.initials: C
authors.lastname: Liu
authors.forename: Sinchai
authors.initials: S
authors.lastname: Tsao
authors.forename: Darryl
authors.initials: D
authors.lastname: Hwang
authors.forename: Bryce
authors.initials: B
authors.lastname: Wilkins
authors.forename: Natasha
authors.initials: N
authors.lastname: Lepore
authors.forename: Meng
authors.initials: M
authors.lastname: Law
mesh_terms: D016880:Anisotropy; D001265:Athletic Injuries / Q000473:pathology*; D001914:Boxing / Q000293:injuries; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D020833:Diffuse Axonal Injury / Q000473:pathology; D056324:Diffusion Tensor Imaging / Q000379:methods*; D018450:Disease Progression; D005189:False Positive Reactions; D005538:Football / Q000293:injuries; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008297:Male; D059906:Neuroimaging / Q000379:methods*; D055815:Young Adult
keywords: CC; Corpus callosum; DTI; Diffusion tensor imaging; FA; Fractional anisotropy; MD; Magnetic resonance imaging; Mean diffusivity; TBI; Traumatic brain injury