title: Proton magnetic resonance spectroscopic imaging in patients with extratemporal epilepsy.
abstract: OBJECTIVE
  Reduced levels of N-acetylaspartate (NAA) in temporal lobes responsible for temporal lobe epilepsy have been observed consistently in proton magnetic resonance spectroscopy (MRS) studies.
  
  
  METHODS
  We investigated the potential of proton MRS to detect low NAA outside of the temporal lobes in patients with non-lesional partial extratemporal epilepsy. Proton MR spectroscopic imaging (MRSI) data of both frontal lobes and central/postcentral regions were obtained in 20 such patients and 16 normal control subjects. The epileptogenic region was determined by an extensive clinical-EEG investigation, including the recording of habitual seizures in each patient, and intracranial EEG recordings in 10 patients.
  
  
  RESULTS
  The relative NAA resonance intensities (i.e., NAA/phosphocreatine plus creatine (CR(t)), NAA/choline-containing metabolites (Cho(t)) and NAA/Cr(t) + Cho(t)), were all significantly reduced throughout the spectroscopic image as compared with that of the controls. Furthermore, reduction of the NAA ratios was greater in the epileptogenic region as compared with the nonepileptogenic regions, on EEG investigation.
  
  
  CONCLUSIONS
  In vivo proton MRSI of patients with nonlesional partial extratemporal epilepsy detected evidence of widespread neuronal damage or dysfunction that was greatest in the region of seizure focus.
authors.affiliation: Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Stanley
authors.forename: F
authors.initials: F
authors.lastname: Cendes
authors.forename: F
authors.initials: F
authors.lastname: Dubeau
authors.forename: F
authors.initials: F
authors.lastname: Andermann
authors.forename: D L
authors.initials: DL
authors.lastname: Arnold
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism*; D002794:Choline / Q000378:metabolism; D004567:Electrodes, Implanted; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000378:metabolism; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis / Q000378:metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D010725:Phosphocreatine / Q000378:metabolism; D011522:Protons
chemical_list: D011522:Protons; D010725:Phosphocreatine; D001224:Aspartic Acid; C000179:N-acetylaspartate; D002794:Choline