title: Quantitative diffusion tensor imaging and intellectual outcomes in spina bifida: laboratory investigation.
abstract: OBJECTIVE
  Patients with spina bifida (SB) have variable intellectual outcomes. The authors used diffusion tensor (DT) imaging to quantify whole-brain volumes of gray matter, white matter, and cerebrospinal fluid (CSF), and perform regional quantitative microstructural assessments of gray matter nuclei and white matter tracts in relation to intellectual outcomes in patients with SB.
  
  
  METHODS
  Twenty-nine children with myelomeningoceles and 20 age- and sex-matched children with normal neural tube development underwent MR imaging with DT image acquisition and assessments of intelligence. The DT imaging-derived metrics were the fractional anisotropy (FA), axial (parallel), and transverse (perpendicular) diffusivities. These metrics were also used to segment the brain into white matter, gray matter, and CSF. A region-of-interest analysis was conducted of the white and gray matter structures implicated in hydrocephalus.
  
  
  RESULTS
  The amount of whole-brain gray matter was decreased in patients with SB, with a corresponding increase in CSF (p < 0.0001). Regional transverse diffusivity in the caudate nucleus was decreased (p < 0.0001), and the corresponding FA was increased (p < 0.0001), suggesting reduced dendritic branching and connectivity. Fractional anisotropy in the posterior limb of the internal capsule increased in the myelomeningocele group (p = 0.02), suggesting elimination of some divergent fascicles; in contrast, the FA in several white matter structures (such as the corpus callosum genu [p < 0.001] and arcuate fasciculus) was reduced, suggesting disruption of myelination. Diffusion tensor imaging-metrics involving gray matter volume and the caudate nucleus, but not other structures, predicted variations in IQ (r = 0.37-0.50; p < 0.05).
  
  
  CONCLUSIONS
  Diffusion tensor imaging-derived metrics provide noninvasive neuronal surrogate markers of the pathogenesis of SB and predict variations in general intellectual outcomes in children with this condition.
authors.affiliation: Department of Diagnostic and Interventional Imaging, 2 Pediatrics University of Texas Health Science Center at Houston, Houston, TX, USA.
authors.forename: Khader M
authors.initials: KM
authors.lastname: Hasan
authors.forename: Ambika
authors.initials: A
authors.lastname: Sankar
authors.forename: Christopher
authors.initials: C
authors.lastname: Halphen
authors.forename: Larry A
authors.initials: LA
authors.lastname: Kramer
authors.forename: Linda
authors.initials: L
authors.lastname: Ewing-Cobbs
authors.forename: Maureen
authors.initials: M
authors.lastname: Dennis
authors.forename: Jack M
authors.initials: JM
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D002648:Child; D002657:Child Development; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D008591:Meningomyelocele / Q000175:diagnosis; D016135:Spinal Dysraphism / Q000175:diagnosis*