Magnetic source imaging in localizing epileptic focus and the primary somatosensory cortex of hands in rolandic epilepsy patients

Objective To observe the value of magnetic source imaging(MSI)in defining epileptic focus and somatosensory cortex of hands in rolandic epileptic patients.Methods Totally 11patients with rolandic epilepsy underwent magnetoencephalography(MEG)and MRI.The anatomy structures depicted by MRI and the findings of interictal discharge and somatosensory cortex of hands obtained by MEG were superimposed as MSI,and were compared with intraoperative electrocorticography(ECoG).Results Among 11patients,MRI showed 4with encephalomalacia,4with focal cortical dysplasia,1with arachnoid cyst in the left temporal pole,whereas 2were normal.Overall agreement of findings of spikes between ECoG and MEG was obtained in 9patients,the areas localized by ECoG were larger than MSI in 2patients.Postsurgical pathology showed focal cortical dysplasia(FCD)in 6patients,microdysgenesis in 1,gliosis in 4patients.The epileptic focus overlaid with somatosensory cortex of hands defined by MSI in 6cases,localized at the anterior-inner side of the somatosensory cortex in 1case,at posterior-inferior side in 2cases,localized about 2cm anteriorly in 1case and 2cm posteriorly in another case.Follow-up results showedⅠa in 10cases andⅢin 1case.There was no obvious dysfunction after operation in all patients.Conclusion MSI can identify the relationship of epileptogenic foci and the primary somatosensory cortex of hands in rolandic epileptic patients,therefore indicates advanced clinical treatment.