The application of magnetic source imaging in epileptic with MRI negative nodular gray matter heterotopia

Objective:To evaluate the value of magnetic source imaging(MSI) in epileptic with MRI negative nodular gray matter heterotopial.Methods:6 epileptic patients with MRI negative nodular gray matter heterotopia had MSI examination for localizing the epileptic focus.Results:The epileptic foci were localized at temporal lobe in 5 cases,the anterior temporal lobe and hippocampus were resected.The epileptic focus was localized at central zone of right frontoparietal lobe and resected in 1 case.All of the 6 patients were nodular gray matter heterotopia pathologically,together with focal cortical dysplasia or microdysplasia in 4 cases,hippocampal sclerosis in 4 cases.According to the assessing standard of Nanjing general military hospital,the result of follow up were satisfied in 5 cases and marked improved in 1 case.Conclusion:MSI can prompt the epileptic focus in patients with gray matter heterotopia.It is an effective location method preoperatively and the patients can achieve good outcome by surgery.