Key lesion localization and pre-surgical planning using magnetoencephalography in patients with medically refractory epilepsy: three case reports.

Abstract

Epilepsy is a common and debilitating disease affecting up to 50 million people worldwide. Nearly 30% of patients with epilepsy have disease refractory to treatment with medication alone. Even in medically refractory disease, neurosurgical resection can be curative when the epileptic focus is correctly identified. Several non-invasive techniques are available for epileptic focus localization and pre-surgical planning. These include electroencephalography (EEG), magnetic resonance imaging (MRI), and magnetoencephalography (MEG).Each of these techniques provides complementary information for precise lesion localization and targeted neurosurgical approach to minimize damage to important adjacent structures. We present three cases of medically refractory epilepsy. The cases show how the combination of EEG, MRI, and MEG allows for lesion localization and safe surgical planning in a variety of cases. They include epilepsy related to cortical dysplasia, grey matter heterotopia, and tumor recurrence. We emphasize the role of MEG and demonstrate how it can provide critical additional information which is not captured by conventional EEG and MRI alone.