title: Volumetric magnetic resonance imaging evidence of bilateral hippocampal atrophy in mesial temporal lobe epilepsy.
abstract: OBJECTIVE
  We measured absolute volumes and volume differences of hippocampi in patients with mesial temporal lobe epilepsy (MTLE) using volumetric magnetic resonance imaging (MRI) to determine the extent of bilateral atrophy in MTLE and to relate hippocampal volumes (HV) to outcome of temporal lobectomy.
  
  
  METHODS
  HV and hippocampal differences (HD) were measured in 40 patients with MTLE determined by pathology of hippocampal sclerosis (HS) and compared with those of age-matched controls. Results were matched with surgical outcome.
  
  
  RESULTS
  Hippocampi contralateral to lobectomy (right hippocampi 2.96 +/- 0.49 cm3, left 3.14 +/- 0.51 cm3) were significantly smaller than those of controls (right hippocampi 3.73 +/- 0.52 cm3, left 3.60 +/- 0.51 cm3) but were significantly larger than hippocampi ipsilateral to lobectomy (right hippocampi 2.63 +/- 0.61 cm3, 2.18 cm3) as compared across groups by analysis of variance (ANOVA: F = 27.2, p < 0.0001). The smaller hippocampus was ipsilateral to lobectomy in 39 of 40 cases. Seven of 40 MTLE patients (18%) had bilateral atrophy, defined by volumes of each hippocampi 2 SD lower than control means. Surgical outcome was independent of hippocampal asymmetry and bilateral atrophy measured by chi-square and Fisher's exact tests.
  
  
  CONCLUSIONS
  We determined that most patients with MTLE have some degree of bilateral, asymmetric hippocampal pathology. However, asymmetry and bilateral atrophy have no clear relation to surgical outcome.
authors.affiliation: Department of Neurology, University of Virginia, Charlottesville 22908, USA.
authors.forename: M
authors.initials: M
authors.lastname: Quigg
authors.forename: E H
authors.initials: EH
authors.lastname: Bertram
authors.forename: T
authors.initials: T
authors.lastname: Jackson
authors.forename: E
authors.initials: E
authors.lastname: Laws
mesh_terms: D000328:Adult; D001284:Atrophy; D016009:Chi-Square Distribution; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005260:Female; D007839:Functional Laterality; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012598:Sclerosis / Q000473:pathology; D013702:Temporal Lobe / Q000601:surgery; D016896:Treatment Outcome