Application of MSI in MRI-negative focal cortical dysplasia patients with epilepsy

Background: Focal cortical dysplasia (FCD) is the most common cause of intractable epilepsy in children and adolescent. Purpose: To evaluate the application value of magnetic source imaging (MSI) in treatment of magnetic resonance imaging (MRI)-negative FCD patients with epilepsy. Methods: MSI characteristics of 17 cases of MRI-negative focal cortical dysplasia patients with epilepsy were retrospectively analyzed. All patients were treated by surgery. Results: In 17 patients, there were 3 cases of FCD Ia, 7 cases of FCDIb, 3 cases of FCDIIa and 4 cases of FCDIIb. FCD was located at temporal lobe in 8 cases, occipital lobe in 3 cases, frontal lobe in 2 cases and two lobes in 4 cases. In follow-up, 14 patients obtained satisfied curative effect. 1 patient was improved significantly and 2 patients were fine. The concordance between MSI and electrocorticogram in localizing epileptogenic foci was 65%. Conclusion: MSI is a new prospective noninvasive functional neuroimaging technique for identifying and delineating epileptogenic foci in MRI-negative FCD patients.