title: Magnetoencephalography helps delineate the extent of the epileptogenic zone for surgical planning in children with intractable epilepsy due to porencephalic cyst/encephalomalacia.
abstract: OBJECTIVE
  Porencephalic cyst/encephalomalacia (PC/E) is a brain lesion caused by ischemic insult or hemorrhage. The authors evaluated magnetoencephalography (MEG) spike sources (MEGSS) to localize the epileptogenic zone in children with intractable epilepsy secondary to PC/E.
  
  
  METHODS
  The authors retrospectively studied 13 children with intractable epilepsy secondary to PC/E (5 girls and 8 boys, age range 1.8-15 years), who underwent prolonged scalp video-electroencephalography (EEG), MRI, and MEG. Interictal MEGSS locations were compared with the ictal and interictal zones as determined from scalp video-EEG.
  
  
  RESULTS
  Magnetic resonance imaging showed PC/E in extratemporal lobes in 3 patients, within the temporal lobe in 2 patients, and in both temporal and extratemporal lobes in 8 patients. Magnetoencephalographic spike sources were asymmetrically clustered at the margin of PC/E in all 13 patients. One cluster of MEGSS was observed in 11 patients, 2 clusters in 1 patient, and 3 clusters in 1 patient. Ictal EEG discharges were lateralized and concordant with MEGSS in 8 patients (62%). Interictal EEG discharges were lateralized and concordant with MEGSS hemisphere in 9 patients (69%). Seven patients underwent lesionectomy in addition to MEGSS clusterectomy with (2 patients) and without (5 patients) intracranial video-EEG. Temporal lobectomy was performed in 1 patient and hemispherectomy in another. Eight of 9 patients achieved seizure freedom following surgery.
  
  
  CONCLUSIONS
  Magnetoencephalography delineated the extent of the epileptogenic zone adjacent to PC/E in patients with intractable epilepsy. Complete resection of the MEGSS cluster along with PC/E can provide favorable seizure outcomes.
authors.affiliation: Division of Neurology and.
authors.forename: Odeya
authors.initials: O
authors.lastname: Bennett-Back
authors.forename: Ayako
authors.initials: A
authors.lastname: Ochi
authors.forename: Elysa
authors.initials: E
authors.lastname: Widjaja
authors.forename: Shohei
authors.initials: S
authors.lastname: Nambu
authors.forename: Akio
authors.initials: A
authors.lastname: Kamiya
authors.forename: Cristina
authors.initials: C
authors.lastname: Go
authors.forename: Sylvester
authors.initials: S
authors.lastname: Chuang
authors.forename: James T
authors.initials: JT
authors.lastname: Rutka
authors.forename: James
authors.initials: J
authors.lastname: Drake
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004678:Encephalomalacia / Q000150:complications*; D004827:Epilepsy / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D038421:Hemispherectomy; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D012189:Retrospective Studies; D014741:Video Recording
keywords: ECoG = electrocorticography; EEG = electroencephalography; MEG = magnetoencephalography; MEGSS = MEG spike sources; PC/E = porencephalic cyst/encephalomalacia; encephalomalacia; epilepsy; epileptogenic zone; magnetoencephalography; porencephalic cyst; surgical planning