Abstracts

Tuberous sclerosis complex (TSC) is a genetic disorder that often presents in childhood with seizures. Many of these patients have intractable epilepsy, but since TSC patients have multiple cortical tubers, identifying the specific tubers that are epileptogenic can be difficult. Magnetic Source Imaging (MSI) may help identify the tuber/s responsible for seizure onset, making epilepsy surgery more feasible for this multifocal disease. This study reports our early experience with MSI in children with TSC and intractable epilepsy. Three children with TSC and intractable seizures (ages 23-months to 10-years 8-months) were evaluated at the Minnesota Epilepsy Group, PA for epilepsy surgery. These evaluations included long-term video-EEG monitoring to establish the dominant seizure type/s and their potential site of onset. Following the inpatient evaluation, an outpatient interictal MSI was performed with a 148-channel Magnes 2500 WH System (4-D Neuroimaging, San Diego, CA) at Minnesota Epilepsy Group, PA and United Hospital, St. Paul, MN. Functional MSI was also done for motor, sensory, and/or language mapping when possible, if potentially epileptogenic tuber/s were located near suspected eloquent cortex. This additional pre-operative identification of the focus/foci and functional cortex has helped with the placement of indwelling electrodes. All patients had at least one potential focus identified with MSI that correlated with a specific cortical tuber identified by MSI and co-registered with MRI. This combined with ictal scalp EEG recordings were used to place indwelling electrodes in order to confirm seizure onset and functional mapping. Post-operative follow-up with regard to tubers/s, associated resected tissue, and seizure outcome will be discussed. Our preliminary results in a small number of children with TSC and intractable epilepsy support the use of MSI to assist in localization of the epileptogenic tuber/s. If these results are confirmed in a larger number of children, it may be possible to perform successful epilepsy surgery with as good or better outcomes than currently achieved, and with less invasive, safer diagnostic procedures than those currently used.