title: Novel diffusion tensor imaging technique reveals developmental streamline volume changes in the corticospinal tract associated with leg motor control.
abstract: BACKGROUND
  Diffusion tensor imaging (DTI) has expanded our knowledge of corticospinal tract (CST) anatomy and development. However, previous developmental DTI studies assessed the CST as a whole, overlooking potential differences in development of its components related to control of the upper and lower extremities. The present cross-sectional study investigated age-related changes, side and gender differences in streamline volume of the leg- and hand-related segments of the CST in children.
  
  
  METHODS
  DTI data of 31 children (1-14 years; mean age: 6±4 years; 17 girls) with normal conventional MRI were analyzed. Leg- and hand-related CST streamline volumes were quantified separately, using a recently validated novel tractography approach. CST streamline volumes on both sides were compared between genders and correlated with age.
  
  
  RESULTS
  Higher absolute streamline volumes were found in the left leg-related CST compared to the right (p=0.001) without a gender effect (p=0.4), whereas no differences were found in the absolute hand-related CST volumes (p>0.4). CST leg-related streamline volumes, normalized to hemispheric white matter volumes, declined with age in the right hemisphere only (R=-.51; p=0.004). Absolute leg-related CST streamline volumes showed similar, but slightly weaker correlations. Hand-related absolute or normalized CST streamline volumes showed no age-related variations on either side.
  
  
  CONCLUSIONS
  These results suggest differential development of CST segments controlling hand vs. leg movements. Asymmetric volume changes in the lower limb motor pathway may be secondary to gradually strengthening left hemispheric dominance and is consistent with previous data suggesting that footedness is a better predictor of hemispheric lateralization than handedness.
authors.affiliation: Translational Imaging Laboratory, Children's Hospital of Michigan, United States.
authors.forename: David O
authors.initials: DO
authors.lastname: Kamson
authors.affiliation: Translational Imaging Laboratory, Children's Hospital of Michigan, United States; Department of Neurology, Wayne State University, United States; Department of Pediatrics, Wayne State University, United States.
authors.forename: Csaba
authors.initials: C
authors.lastname: Juhász
authors.affiliation: Translational Imaging Laboratory, Children's Hospital of Michigan, United States; Department of Neurology, Wayne State University, United States; Department of Pediatrics, Wayne State University, United States.
authors.forename: Harry T
authors.initials: HT
authors.lastname: Chugani
authors.affiliation: Translational Imaging Laboratory, Children's Hospital of Michigan, United States; Department of Neurology, Wayne State University, United States; Department of Pediatrics, Wayne State University, United States. Electronic address: jeongwon@pet.wayne.edu.
authors.forename: Jeong-Won
authors.initials: JW
authors.lastname: Jeong
mesh_terms: D000293:Adolescent; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000254:growth & development / Q000502:physiology; D006801:Humans; D007223:Infant; D007866:Leg / Q000254:growth & development / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009929:Organ Size; D011712:Pyramidal Tracts / Q000033:anatomy & histology* / Q000254:growth & development* / Q000502:physiology; D012727:Sex Characteristics; D066127:White Matter / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology
keywords: Children; Corticospinal tract; DTI; Development; Diffusion tensor imaging; MRI