title: The correlation of magnetoencephalography to intracranial EEG in localizing the epileptogenic zone: a study of the surgical resection outcome.
abstract: OBJECTIVE
  To evaluate the agreement between magnetoencephalography (MEG) and intracranial electroencephalography (ICEEG) results, to determine the characteristics that lead to concordance, and to assess how these factors relate to favorable epilepsy surgery outcome.
  
  
  METHODS
  This retrospective study reviewed 50 patients who had positive MEG findings and ICEEG recordings between 2008 and 2010. The anatomical concordance between MEG and ICEEG recordings, the features of the MEG focus, and the relationship between the MEG focus and the surgically resected regions were correlated with the epilepsy surgery outcome.
  
  
  RESULTS
  Thirty-six of the 50 patients with positive MEG and ICEEG findings underwent epilepsy surgery, and 27 (75%) of the patients had an anatomical concordance of MEG/ICEEG. Among the patients with concordant MEG/ICEEG, the seizure free outcome rate was significantly higher compared to the discordant group [18/27 (66.7%) patients concordant vs. 1/9 (11.1%) patients discordant (p<0.006)]. Nineteen (53%) of the 36 patients had complete resection when the MEG focus overlapped with the resection area, and 15 (79%) of these 19 patients became seizure-free following surgery (p<0.001); 17 (47%) of the 36 patients had an MEG focus that was not completely resected (the MEG foci of 7 patients partially overlapped the resection areas, and 10 patients had MEG foci that were in a different area from the resection area), and 13/17 (76.5%) patients had seizure recurrences (p<0.001).
  
  
  CONCLUSIONS
  Both the anatomical concordance of MEG/ICEEG and the complete resection of the MEG foci significantly increased the chance of seizure-free outcomes following epilepsy surgery.
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA; MEG Lab, National Neurosciences Institute, King Fahad Medical City, Riyadh, Saudi Arabia; Pediatric Neurology Division, Pediatrics Department, University of Saskatchewan, Saskatoon, Canada. Electronic address: almubaraksa@hotmail.com.
authors.forename: Salah
authors.initials: S
authors.lastname: Almubarak
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Alexopoulos
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA; Epilepsy Center, University of Greifswald, Greifswald, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Von-Podewils
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA.
authors.forename: Z Irene
authors.initials: ZI
authors.lastname: Wang
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA; Epilepsy Division, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kakisaka
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Mosher
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Bulacio
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA.
authors.forename: Jorge
authors.initials: J
authors.lastname: González-Martínez
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA.
authors.forename: Williams
authors.initials: W
authors.lastname: Bingaman
authors.affiliation: Cleveland Clinic Epilepsy Center, Neurological Institute, Cleveland, OH, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Burgess
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002648:Child; D016000:Cluster Analysis; D004569:Electroencephalography; D004827:Epilepsy / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009493:Neurosurgery / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Cluster dipoles, Intractable epilepsy; Epilepsy surgery outcome; Intracranial EEG; Magnetoencephalography