Abstracts

Rationale: Tuberous sclerosis complex (TSC) is a neurocutaneous disorder that often presents as a combination of cutaneous lesions, epilepsy and mental deficiency. Epileptic seizures occur in 74-90% of TSC patients[1]. Many TSC patients’ epilepsy is medically refractory. Due to the multi-lesional nature of TSC, identifying the specific tubers that are epileptogenic can be challenging. Magnetic Source Imaging (MSI) is the only method to map real-time neuronal activity non-invasively. It can help identify the epileptogenic tuber/s, making epilepsy surgery more feasible for this multifocal disease[2, 3].Methods: In 2003-2006, 11 patients (5 female, 6 male, average 10.10 yrs) had resective surgery due to medically refractory epilepsy in TSC patients at Minnesota Epilepsy Group, follow-up time (8 months to 14 yrs). All patients had MR imaging including 3D-SPGR, axial and coronal FLAIR sequences pre- and post- operatively. All patients underwent chronic cortical EEG recording. Five patients had MEG/EEG recording with a 148-channel whole head MEG system (4DNEUROIMAGING, Inc, San Diego, CA).Results: Ten out of the 11 patients with resective surgery with multiple tubers on both hemispheres on MR images. The other patient has a tuber at left superior temporal gyrus. Two patients with calcified tubers. In the 4/5 patients with MEG/MSI testing, MSI showed clusters of interictal spikes overlapped with cortical tubers on FLAIR MR images. Calcified tubers in 2 patients were identified by MSI to be epileptogenic. MSI data were utilized to guide the grid placement, and the MSI localization was confirmed with ECoG recording. The targeted catastrophic seizure type was removed by surgery in 10/11 patients. By using the modified Engel[4] scale, the outcome of the 11 patients is: Class I 5 patients, Class II 4 patients, Class IV 2 patients.Conclusions: Conclusion: Resective surgery can provide good seizure control in TSC patients with medically refractory epilepsy. With MEG localization information combined with MR structural imaging, the number of invasive EEG recording may be reduced.