title: Diffusion tensor imaging study of white matter fiber tracts in pediatric bipolar disorder and attention-deficit/hyperactivity disorder.
abstract: BACKGROUND
  To investigate microstructure of white matter fiber tracts in pediatric bipolar disorder (PBD) and attention-deficit/hyperactivity disorder (ADHD).
  
  
  METHODS
  A diffusion tensor imaging (DTI) study was conducted at 3 Tesla on age- and IQ-matched children and adolescents with PBD (n = 13), ADHD (n = 13), and healthy control subjects (HC) (n = 15). Three DTI parameters, fractional anisotropy (FA), apparent diffusion coefficient (ADC), and regional fiber coherence index (r-FCI), were examined in eight fiber tracts: anterior corona radiata (ACR), anterior limb of the internal capsule (ALIC), superior region of the internal capsule (SRI), posterior limb of the internal capsule (PLIC), superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF), cingulum (CG), and splenium (SP).
  
  
  RESULTS
  Significantly lower FA was observed in ACR in both PBD and ADHD relative to HC. In addition, FA and r-FCI values were significantly lower in ADHD relative to PBD and HC in both the ALIC and the SRI. Further, ADC was significantly greater in ADHD relative to both the PBD and HC in ACR, ALIC, PLIC, SRI, CG, ILF, and SLF.
  
  
  CONCLUSIONS
  Decreased FA in ACR implies an impaired fiber density or reduced myelination in both PBD and ADHD in this prefrontal tract. These abnormalities, together with the reduced fiber coherence, extended to corticobulbar tracts in ADHD. Increased ADC across multiple white matter tracts in ADHD indicates extensive cellular abnormalities with less diffusion restriction in ADHD relative to PBD.
authors.affiliation: Center for Cognitive Medicine, University of Illinois Medical Center at Chicago, 912 S Wood Street, Chicago, IL 60612-7327, USA. mpavuluri@psych.uic.edu
authors.forename: Mani N
authors.initials: MN
authors.lastname: Pavuluri
authors.forename: Shuohui
authors.initials: S
authors.lastname: Yang
authors.forename: Kiran
authors.initials: K
authors.lastname: Kamineni
authors.forename: Alessandra M
authors.initials: AM
authors.lastname: Passarotti
authors.forename: Girish
authors.initials: G
authors.lastname: Srinivasan
authors.forename: Erin M
authors.initials: EM
authors.lastname: Harral
authors.forename: John A
authors.initials: JA
authors.lastname: Sweeney
authors.forename: Xiaohong Joe
authors.initials: XJ
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology*; D001714:Bipolar Disorder / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009434:Neural Pathways / Q000473:pathology*