Contribution of Multimodal Imaging (MRI, PET, MEG) in Pre-surgical Evaluation of Drug-resistant Focal Epilepsy

Epilepsy is the most common chronic neurological disorder in the world, affecting more than 50 million people worldwide. Approximately 35% of patients with epilepsy are refractory to all available antiepileptic drugs. Drug-resistant epilepsies are often partial or focal. Patients with drug-resistant focal epilepsy suffer from an increased risk of death, primarily due to seizure-related fatalities, in comparison with the general population. The only therapeutic option for this form of epilepsy is the surgical removal of the region of the brain responsible for seizures, called the epileptogenic zone (EZ). This requires the precise localization of the EZ based on a comprehensive pre-surgical evaluation of patients.

Today the gold standard for localizing the EZ and validating a non-invasive technique for localization of the EZ remains intracerebral stereo-EEG (stereo-electroencephalography or SEEG) recordings of spontaneous seizures. The implementation strategy of the intracerebral depth electrodes is guided by clinical and neuroimaging data, including anatomical Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET) with FDG (fluoro-Deoxy-Glucose) and MagnetoEncephaloGraphy (MEG). Although the contribution of each technique in the pre-surgical localization of the EZ has already been shown, no wide-scale study has examined the cumulative contribution of these three techniques.