title: Diffusion MRI in corticofugal fibers correlates with hand function in unilateral cerebral palsy.
abstract: Diffusion MRI improves detection of abnormalities in white matter tracts in cerebral palsy (CP). Relationships between diffusion measurements and hand function are largely unexplored. We aimed first to assess microstructure of corticofugal fibers, and second to explore associations between tract injury as assessed by quantitative analysis of diffusion MRI and hand function in children with unilateral CP.
  
  
  METHODS
  In this cross-sectional study, 15 children with unilateral CP (6 boys, median age 12.4 years, min 7.2, max 17) and 24 controls were included (9 boys, median age 12.7 years, min 8.8, max 17.3). Hand function was assessed with the Box and Blocks (B&B) test. Magnetic resonance diffusion data (b value = 1,000 s/mm(2), 45 directions) were collected on a 1.5-T scanner. Fractional anisotropy (FA), mean diffusivity (MD), and tensor eigenvalues were measured bilaterally in the cerebral peduncle (ROI1), the posterior limb of the internal capsule (PLIC, ROI2), and corticofugal fibers connecting these regions.
  
  
  RESULTS
  In children with CP, FA in both ROIs and the partial tract corresponding to the affected hand was significantly lower compared to controls. This was caused by an increase in diffusivity perpendicular to the tract. After controlling for age, mean FA contralateral to the affected hand correlated with B&B scores, which was independent of lesion type or number of voxels in the partial tract, cerebral peduncle, or PLIC.
  
  
  CONCLUSIONS
  FA in corticofugal fibers is a sensitive marker of damage to the motor system and correlates with hand function in CP. Using FA may improve early prediction of outcome.
authors.affiliation: Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm Brain Institute, Stockholm, Sweden. linda.holmstrom@ki.se
authors.forename: Linda
authors.initials: L
authors.lastname: Holmström
authors.forename: F
authors.initials: F
authors.lastname: Lennartsson
authors.forename: A-C
authors.initials: AC
authors.lastname: Eliasson
authors.forename: O
authors.initials: O
authors.lastname: Flodmark
authors.forename: C
authors.initials: C
authors.lastname: Clark
authors.forename: K
authors.initials: K
authors.lastname: Tedroff
authors.forename: H
authors.initials: H
authors.lastname: Forssberg
authors.forename: B
authors.initials: B
authors.lastname: Vollmer
mesh_terms: D000293:Adolescent; D016880:Anisotropy; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology; D002547:Cerebral Palsy / Q000473:pathology* / Q000503:physiopathology; D002648:Child; D003430:Cross-Sectional Studies; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009434:Neural Pathways / Q000473:pathology; D010775:Photic Stimulation / Q000379:methods; D011149:Pons / Q000473:pathology; D013223:Statistics as Topic; D018709:Statistics, Nonparametric