Temporal Spread Image to delineate MEG spike foci in epilepsy patients

In order to improve epileptic focus localization performance of non-invasive recording, we propose a new method to estimates and visualize the spatio-temporal spread pattern of the epileptic spike activities especially at the onset of spikes when the activity is too small for reliable source estimation. Result of this temporal spread imaging (TSI) method from the MEG data of five patients with intractable partial epilepsy in the course of presurgical evaluation were compared to the invasive focus localization with subdural grid recording. The TSI result were compatible with conventional equivalent current dipole estimation but indicated the epileptic focus better. This method will be a useful tool for non-invasive focus localization of epilepsy patients.