title: White matter abnormalities in veterans with mild traumatic brain injury.
abstract: OBJECTIVE
  It has been estimated that 10%-20% of U.S. veterans of the wars in Iraq and Afghanistan experienced mild traumatic brain injury (TBI), mostly secondary to blast exposure. Diffusion tensor imaging (DTI) may detect subtle white matter changes in both the acute and chronic stages of mild TBI and thus has the potential to detect white matter damage in patients with TBI. The authors used DTI to examine white matter integrity in a relatively large group of veterans with a history of mild TBI.
  
  
  METHODS
  DTI images from 72 veterans of the wars in Iraq and Afghanistan who had mild TBI were compared with DTI images from 21 veterans with no exposure to TBI during deployment. Conventional voxel-based analysis as well as a method of identifying spatially heterogeneous areas of decreased fractional anisotropy ("potholes") were used. Veterans also underwent psychiatric and neuropsychological assessments.
  
  
  RESULTS
  Voxel-based analysis did not reveal differences in DTI parameters between the veterans with mild TBI and those with no TBI. However, the veterans with mild TBI had a significantly higher number of potholes than those without TBI. The difference in the number of potholes was not influenced by age, time since trauma, a history of mild TBI unrelated to deployment, or coexisting psychopathology. The number of potholes was correlated with the severity of TBI and with performance in executive functioning tasks.
  
  
  CONCLUSIONS
  Veterans who had blast-related mild TBI showed evidence of multifocal white matter abnormalities that were associated with severity of the injury and with relevant functional measures. Overall, white matter potholes may constitute a sensitive biomarker of axonal injury that can be identified in mild TBI at acute and chronic stages of its clinical course.
authors.affiliation: Departments of Psychiatry and Radiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA. ricardo-jorge@uiowa.edu
authors.forename: Ricardo E
authors.initials: RE
authors.lastname: Jorge
authors.forename: Laura
authors.initials: L
authors.lastname: Acion
authors.forename: Tonya
authors.initials: T
authors.lastname: White
authors.forename: Diana
authors.initials: D
authors.lastname: Tordesillas-Gutierrez
authors.forename: Ronald
authors.initials: R
authors.lastname: Pierson
authors.forename: Benedicto
authors.initials: B
authors.lastname: Crespo-Facorro
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Magnotta
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D001753:Blast Injuries / Q000473:pathology; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology*; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging; D006801:Humans; D015601:Injury Severity Score; D054542:Iraq War, 2003-2011; D016014:Linear Models; D008297:Male; D059906:Neuroimaging; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D018709:Statistics, Nonparametric; D014728:Veterans / Q000706:statistics & numerical data