Abstracts

Rationale: To assess the localization value of magnetoencephalography (MEG) as a presurgical evaluation modality in lesional pediatric epilepsy patients.Methods: We retrospectively reviewed 14 children (6 males and 8 females) who underwent focal lesional epilepsy surgery with MEG as a presurgical evaluation. MEG spikes were localized using equivalent current dipole method, and these dipoles were superimposed on the patient s MRI as magnetic source imaging (MSI). MEG dipoles were evaluated for hemispheric concordance (>50% of dipoles in the same lesional hemisphere), lobar concordance (>50% of dipoles in lesional lobe), and the pattern of distribution. Clinical information including other presurgical evaluations and postsurgical seizure outcomes were also reviewed.Results: The mean age at surgery was 8.0 years (range, 2.8~13.1 years) and mean follow up duration after the surgery was 34 months (range, 16~59 months). Hemispheric concordance rate was 100% and lobar concordance rate was 64% (9/14 patients). Lesionectomy was done based on the MRI findings and other presurgical evaluation results. Post-surgical seizure outcome according to the Engel s classification was as follows; IA (10/14 patients), IB (1/14 patients), II (2/14 patients), and III (1/14 patients). Among 13 patients who showed favorable outcome (class I and II), MEG dipoles were clustered exactly at or around the lesion in 54% (7/13) of the patients.Conclusions: Our data suggest that MEG is a useful evaluation method for lateralization and localization of epileptogenic foci in children with lesional focal epilepsy.