title: White matter abnormalities associate with type and localization of focal epileptogenic lesions.
abstract: OBJECTIVE
  To evaluate white matter (WM) integrity of distinct groups of patients with antiepileptic drug (AED)-resistant localization-related epilepsies.
  
  
  METHODS
  We used diffusion tensor imaging (DTI) fiber-tractography and voxel-based morphometry (VBM) to investigate differences of WM micro- and macrostructural integrity in patients with different drug-resistant localization-related epilepsies: 17 with temporal lobe epilepsy with magnetic resonance imaging (MRI) signs of hippocampal sclerosis (TLE-HS), 17 with TLE and normal MRI (TLE-NL), 14 with frontal lobe epilepsy and subtle MRI signs of focal cortical dysplasia (FLE-FCD), and 112 healthy controls. We performed fiber-tractography using a semiautomatic deterministic method to yield average fractional anisotropy (FA), axial (AD), and radial (RD) diffusivity ipsilateral and contralateral to the epileptogenic zone of the following tracts based on their functional and anatomic relevance: body of fornix (BoF), body of cingulum (BoC), inferior frontal occipital (IFO), and uncinate fasciculi (UF). In addition, we performed VBM of the WM maps to assess macrostructural integrity differences among groups.
  
  
  RESULTS
  TLE-HS had ipsilateral and contralateral decreased FA and increased RD for all tracts. VBM showed WM alterations mainly in the ipsilateral parahippocampal region and contralateral superior temporal gyrus. FLE-FCD showed bilateral FA decreases only in the BoC and ipsilateral RD increases also in the BoC. VBM showed WM reduction mainly in the ipsilateral precuneus and posterior and anterior cingulum. No significant WM alterations were found in the TLE-NL in DTI or VBM analysis.
  
  
  CONCLUSIONS
  WM abnormalities differ in distinct AED-resistant localization-related epilepsies. The diverse distribution of the WM damage in these patients suggests that the localization of the epileptic networks may play a role in the WM burden. However, the distinct degree of this damage, more accentuated in TLE-HS, also suggests that the underlying cause of the epilepsy is probably an additional factor to explain this WM damage.
authors.affiliation: Neuroimaging Laboratory, Department of Neurology, University of Campinas, Campinas, Brazil.
authors.forename: Brunno M
authors.initials: BM
authors.lastname: Campos
authors.forename: Ana C
authors.initials: AC
authors.lastname: Coan
authors.forename: Guilherme C
authors.initials: GC
authors.lastname: Beltramini
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Clarissa L
authors.initials: CL
authors.lastname: Yassuda
authors.forename: Enrico
authors.initials: E
authors.lastname: Ghizoni
authors.forename: Christian
authors.initials: C
authors.lastname: Beaulieu
authors.forename: Donald W
authors.initials: DW
authors.lastname: Gross
authors.forename: Fernando
authors.initials: F
authors.lastname: Cendes
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use; D001921:Brain / Q000473:pathology; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging; D004351:Drug Resistance; D017034:Epilepsy, Frontal Lobe / Q000150:complications / Q000188:drug therapy / Q000473:pathology*; D004833:Epilepsy, Temporal Lobe / Q000188:drug therapy / Q000473:pathology*; D005260:Female; D020712:Fornix, Brain / Q000473:pathology; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000150:complications / Q000473:pathology*; D008875:Middle Aged; D009929:Organ Size; D012598:Sclerosis; D066127:White Matter / Q000473:pathology*; D055815:Young Adult
chemical_list: D000927:Anticonvulsants
keywords: Diffusion tensor imaging; Frontal lobe epilepsy; Temporal lobe epilepsy; Voxel-based morphometry