Clinical study of magnetoencephalographic(MEG) localization in intractable epilepsy surgery: a report of 51 cases

Objective To evaluate the value of magnetoencephalography(MEG) in preoperative localization of intractable epilepsy.Methods MEG, magnetic resonance imaging(MRI) and video electroencephalography(VEEG) were performed in 51 cases with intractable epilepsy before operation. The surgical methods included selective amygdalohippocampectomy, standard anterior temporal lobectomy and epileptogenic focus resection. Epileptogenic foci localized by MEG were resected under neuronavigation in 2 cases. Equi volume amygdalohippocampectomy was performed under neuronavigation in 2 cases.Results Among the 51 cases, 76.5% were seizure free, 11 8% greater than 75% reduction in seizures, 5 8% greater than 50% reduction in seizures and 5 8% less than 50% reduction in seizures after operation. Localization coincidence between MEG and VEEG plus ECoG were 82% and 96%, respectively. Localization sensitivity of MEG to medial temporal lobe epilepsy was not good enough. Resection of epileptogenic foci localized by MEG under neuronavigation could contribute to successful surgery with lower impairment of functional brain areas.Conclusions MEG is a noninvasive sensitive localization method for epileptogenic focus, it is a breakthough for epilepsy preoperative evaluation.