title: Interictal magnetoencephalographic findings related with surgical outcomes in lesional and nonlesional neocortical epilepsy.
abstract: OBJECTIVE
  To investigate whether interictal magnetoencephalography (MEG) concordant with other techniques can predict surgical outcome in patients with lesional and nonlesional refractory neocortical epilepsy (NE).
  
  
  METHODS
  23 Patients with lesional NE and 20 patients with nonlesional NE were studied. MEG was recorded for all patients with a 275 channel whole-head system. Synthetic aperture magnetometry (SAM) with excess kurtosis (g2) and conventional Equivalent Current Dipole (ECD) were used for MEG data analysis. 27 Patients underwent long-term extraoperative intracranial video electroencephalography (iVEEG) monitoring. Surgical outcomes were assessed based on more than 1-year of post-surgical follow-up using Engel classification system.
  
  
  RESULTS
  As we expected, both favorable outcomes (Engel class I or II) and seizure freedom outcomes (Engel class IA) were higher for the concordance condition (MEG findings are concordant with MRI or iVEEG findings) versus the discordance condition. Also the seizure free rate was significantly higher (χ2=5.24, P<0.05) for the patients with lesional NE than for the patients with nonlesional NE. In 30% of the patients with nonlesional NE, the MEG findings proved to be valuable for intracranial electrode implantation.
  
  
  CONCLUSIONS
  This study demonstrates that a favorable post-surgical outcome can be obtained in most patients with concordant MEG and MRI results even without extraoperative iVEEG monitoring, which indicates that the concordance among different modalities could indicate a likelihood of better postsurgical outcomes. However, extraoperative iVEEG monitoring remains prerequisite to the patients with discordant MEG and MRI findings. For nonlesional cases, our results showed that MEG could provide critical information in the placement of intracranial electrodes.
authors.affiliation: Department of Neurosurgery, Brain Hospital Affiliated of Nanjing Medical University, Nanjing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Wu
authors.forename: Yingying
authors.initials: Y
authors.lastname: Wang
authors.forename: Hongyi
authors.initials: H
authors.lastname: Liu
authors.forename: Yuanjie
authors.initials: Y
authors.lastname: Zou
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Xiang
authors.forename: Chaoyong
authors.initials: C
authors.lastname: Xiao
authors.forename: Lu
authors.initials: L
authors.lastname: Yang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Fu
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D016343:Monitoring, Intraoperative / Q000379:methods; D019579:Neocortex / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult