THE UTILITY OF MAGNETOENCEPHALOGRAPHY IN PREDICTING THE EPILEPTOGENIC ZONE FOR PEDIATRIC EPILEPSY SURGERY
Abstract number :
1.417
Submission category :
Year :
2003
Submission ID :
3657
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Joyce Y. Wu, Susan Koh, Rinat Jonas, Raman Sankar, Maung Aung, Gary W. Mathern, W. Donald Shields Division of Pediatric Neurology, University of California, Los Angeles, Los Angeles, CA; Scripps Clinic, La Jolla, CA; Department of Neurosurgery, University
MEG is a non-invasive method for localizing epileptogenic zone in epilepsy patients. By detecting intracellular cerebral electrical activity, as opposed to extracellular activity seen on electroencephalograpy (EEG), MEG may offer more sensitive and superior localization for patients undergoing evaluation for epilepsy surgery. There is a paucity of literature on this topic as it applies to pediatric epilepsy patients.
We analyzed retrospectively the records of 12 pediatric patients at the University of California at Los Angeles, whose standard presurgical tests (PET, MRI, video EEG) revealed either discordant data or insufficient preoperative data for determining the extent of resection. MEG was utilized to either localize the epileptogenic zone for those patients with discordant data or to determine the extent of resection. MEG and electrocorticography (ECoG) results were compared. Postoperative seizure outcome was noted.
For 4 patients with discordant data, MEG aided in the localization of the epileptogenic zone. For 8 patients with insufficient data, either due to multiple cortical tubers from Tuberous Sclerosis or due to porencephalic cysts from abscess, infarct, prior surgery, or meningitis, MEG was important in determining the extent of resection. For all 10 postoperative patients (presurgical evaluation not yet completed for 2), MEG predicted preoperatively the area of resection as compared to ECoG. Furthermore, when compared to scalp ictal EEG, MEG defined a more restricted zone in 10 patients and a different zone in the remaining 2 patients. With a postoperative follow-up period ranging from 3 months to 1 year, 7 of the 10 patients are seizure-free, while the remaining 3 patients have seizure improvement (2 with greater than 50% seizure reduction, 1 unclear).
MEG aids greatly in the presurgical evaluation of pediatric epilepsy patients, especially when standard presurgical testing yields discordant or insufficient data. In addition, MEG may offer superior identification of the epileptogenic zone compared to scalp EEG, both in terms of location and extent for determining resective therapy.