Clinical Utility of Magnetoencephalography in Epilepsy Evaluation: A Qualitative Systematic Review

Magnetoencephalography (MEG) is a non-invasive neurophysiological technique offering high spatial resolution for localizing epileptogenic zones in epilepsy, especially when traditional electroencephalography or magnetic resonance imaging (MRI) is inconclusive. A systematic evaluation of MEG's diagnostic and prognostic utility within combination strategies is crucial, particularly in countries like South Korea with limited MEG access. We conducted a qualitative systematic review of nine studies (n=354 focal epilepsy patients) to evaluate MEG's clinical performance in presurgical workup. Databases (MEDLINE, EMBASE, Cochrane, KoreaMed, KMbase, RISS) were searched. Data extraction focused on localization accuracy and surgical outcomes (Engel class I); risk of bias was assessed using quality assessment of diagnostic accuracy studies-2. MEG alone achieved up to the mid-70% range; however, integration with other modalities (e.g., with positron emission tomography/high-density electroencephalography) significantly improved both localization and surgical outcomes. Pediatric focal cortical dysplasia patients showed Engel class I outcomes of 67-87%. Most studies had low-to-moderate bias. Only one MEG system is operational in South Korea (introduced 2023), limiting accessibility. Canadian economic evaluations, despite higher initial costs, suggest MEG is long-term cost-effective, improving quality-adjusted life years. MEG offers complementary diagnostic value in epilepsy evaluation and surgical planning, enhancing localization and outcome prediction, especially for pediatric and MRI-negative patients. Considering this clinical utility, national support for MEG equipment and its regional expansion in South Korea is crucial to ensure equitable access and optimal patient care.