title: Magnetoencephalographically directed review of high-spatial-resolution surface-coil MR images improves lesion detection in patients with extratemporal epilepsy.
abstract: OBJECTIVE
  To determine whether (a) interictal magnetoencephalographic (MEG) epileptiform activity corresponds to anatomic abnormalities at magnetic resonance (MR) imaging, (b) high-spatial-resolution MR imaging depicts lesions in regions without MEG spike activity, (c) MEG-directed review of high-spatial-resolution MR images enables detection of abnormalities not apparent on conventional MR images, and (d) MEG information results in a greater number of diagnosed lesions at re-review of conventional MR images.
  
  
  METHODS
  Twenty patients with neocortical epilepsy were evaluated with MEG, conventional brain MR imaging with a head coil, and high-spatial-resolution MR imaging with either a surface coil (n = 17) or a high-spatial-resolution birdcage coil (n = 3). Abnormal MEG foci were compared with corresponding anatomic areas on conventional and high-spatial-resolution MR images to determine the presence (concordance) or absence (discordance) of anatomic lesions corresponding to foci of abnormal MEG activity.
  
  
  RESULTS
  Forty-four epileptiform MEG foci were identified. Twelve foci (27%) were concordant with an anatomic abnormality at high-spatial-resolution MR imaging, and 32 foci (73%) were discordant. Results of high-spatial-resolution MR imaging were normal in eight patients, and 23 lesions were detected in the remaining 12 patients. Twelve lesions (52%) were concordant with abnormal MEG epileptiform activity, and 11 (48%) were discordant (ie, there was normal MEG activity in the region of the anatomic abnormality). At retrospective reevaluation of conventional MR images with MEG guidance, four occult gray matter migration lesions that had initially been missed were observed. An additional patient with MEG-concordant postoperative gliosis was readily identified with high-spatial-resolution MR images but not with conventional MR images.
  
  
  CONCLUSIONS
  Review of MEG-localized epileptiform areas on high-spatial-resolution MR images enables detection of epileptogenic neocortical lesions, some of which are occult on conventional MR images.
authors.affiliation: Department of Radiology, Section of Neuroradiology, University of Utah School of Medicine, 50 N Medical Dr, 1A71 SOM, Salt Lake City, UT 84132, USA. kevin.moore@hsc.utah.edu
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Moore
authors.forename: Michael E
authors.initials: ME
authors.lastname: Funke
authors.forename: Tawnya
authors.initials: T
authors.lastname: Constantino
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Katzman
authors.forename: Jeffrey David
authors.initials: JD
authors.lastname: Lewine
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D004828:Epilepsies, Partial / Q000473:pathology*; D004830:Epilepsy, Tonic-Clonic / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D015225:Magnetoencephalography; D008297:Male