title: Sex differences in white matter abnormalities after mild traumatic brain injury: localization and correlation with outcome.
abstract: OBJECTIVE
  To evaluate sex differences in diffusion-tensor imaging (DTI) white matter abnormalities after mild traumatic brain injury (mTBI) using tract-based spatial statistics (TBSS) and to compare associated clinical outcomes.
  
  
  METHODS
  The institutional review board approved this study, with waiver of informed consent. DTI in 69 patients with mTBI (47 male and 22 female patients) and 21 control subjects (10 male and 11 female subjects) with normal conventional magnetic resonance (MR) images were retrospectively reviewed. Fractional anisotropy (FA) maps were generated as a measure of white matter integrity. Patients with mTBI underwent serial neurocognitive testing with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). Correlation between sex, white matter FA values, ImPACT scores, and time to symptom resolution (TSR) were analyzed with multivariate analysis and TBSS.
  
  
  RESULTS
  No significant difference in age was seen between males and females (control subjects, P = .3; patients with mTBI, P = .34). No significant difference was seen in initial ImPACT symptom scores (P = .33) between male and female patients with mTBI. Male patients with mTBI had significantly decreased FA values in the uncinate fasciculus (UF) bilaterally (mean FA, 0.425; 95% confidence interval: 0.375, 0.476) compared with female patients with mTBI and control subjects (P < .05), with a significantly longer TSR (P = .04). Multivariate analysis showed sex and UF FA values independently correlated with TSR longer than 3 months (adjusted odds ratios, 2.27 and 2.38; P = .04 and P < .001, respectively), but initial symptom severity did not (adjusted odds ratio, 1.15; P = .35).
  
  
  CONCLUSIONS
  Relative sparing of the UF is seen in female compared with male patients after mTBI, with sex and UF FA values as stronger predictors of TSR than initial symptom severity.
authors.affiliation: From the Department of Radiology (S.F., K.Y., L.A.) and Sports Medicine Concussion Program (M.C.), University of Pittsburgh School of Medicine, 200 Lothrop St, Presby South Tower, 8th Floor, 8 North, Pittsburgh, PA 15213.
authors.forename: Saeed
authors.initials: S
authors.lastname: Fakhran
authors.forename: Karl
authors.initials: K
authors.lastname: Yaeger
authors.forename: Michael
authors.initials: M
authors.lastname: Collins
authors.forename: Lea
authors.initials: L
authors.lastname: Alhilali
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D011379:Prognosis; D012727:Sex Characteristics; D015599:Trauma Severity Indices; D055815:Young Adult