title: Diffusion abnormalities of the corpus callosum in patients with malformations of cortical development and epilepsy.
abstract: OBJECTIVE
  Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that can characterize white matter (WM) architecture and microstructure. DTI has demonstrated extensive WM changes in patients with several epileptic syndromes, but few studies have focused on patients with malformations of cortical development (MCD). Our aim was to investigate the quantitative diffusion properties of the corpus callosum (CC), a major commissural bundle critical in inter-hemispheric connectivity, in a large group of patients with MCD.
  
  
  METHODS
  Thirty-two MCD patients and 32 age and sex-matched control subjects were evaluated with DTI at 3.0 T. We analyzed the three major subdivisions of the CC (genu, body, and splenium) with deterministic tractography to yield fractional anisotropy (FA), mean diffusivity (MD), parallel diffusivity (λ||) and perpendicular diffusivity (λ⊥). We further assessed the CC with region of interest (ROI)-based analyses and evaluated different subgroups of MCD (polymicrogyria/schizencephaly, heterotopia, and cortical dysplasia). Partial correlations between diffusion changes and clinical parameters (epilepsy duration and age at disease onset) were also queried.
  
  
  RESULTS
  There were significant reductions of FA, accompanied by increases in MD and λ⊥ in all segments of the CC in the patients group with both analytical methods. The absolute differences in FA were greater on ROI-analyses. There were no significant differences between the MCD subgroups, and no correlations between clinical parameters of epilepsy and FA.
  
  
  CONCLUSIONS
  Our study indicates DTI abnormalities consistent with microstructural changes in the corpus callosum of MCD patients. The findings support the idea that patients with epilepsy secondary to cortical malformations present widespread WM changes that extend beyond the macroscopic MRI-visible lesions.
authors.affiliation: Department of Radiology, Universidade de São Paulo, São Paulo, Brazil; Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: Celi S
authors.initials: CS
authors.lastname: Andrade
authors.affiliation: Department of Radiology, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Claudia C
authors.initials: CC
authors.lastname: Leite
authors.affiliation: Department of Radiology, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Maria C G
authors.initials: MC
authors.lastname: Otaduy
authors.affiliation: Department of Radiology, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Katarina P
authors.initials: KP
authors.lastname: Lyra
authors.affiliation: Department of Psychiatry, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Kette D R
authors.initials: KD
authors.lastname: Valente
authors.affiliation: Department of Neurology, Universidade de Campinas, São Paulo, Brazil; Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: Clarissa L
authors.initials: CL
authors.lastname: Yasuda
authors.affiliation: Department of Neurology, Universidade de Campinas, São Paulo, Brazil.
authors.forename: Guilherme C
authors.initials: GC
authors.lastname: Beltramini
authors.affiliation: Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Beaulieu
authors.affiliation: Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada. Electronic address: donald.gross@ualberta.ca.
authors.forename: Donald W
authors.initials: DW
authors.lastname: Gross
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D002648:Child; D003337:Corpus Callosum / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D004827:Epilepsy / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000150:complications / Q000175:diagnosis*; D008875:Middle Aged; D015999:Multivariate Analysis; D055815:Young Adult
keywords: Corpus callosum; Diffusion tensor imaging; Epilepsy; Magnetic resonance imaging; Malformations of cortical development; Tractography