Grant: Operating Grant

Epilepsy is a serious neurological disorder. About 54,000 Canadians have seizures that cannot be controlled by anti-seizure medications. In these cases, surgical removal of the seizure focus is the only treatment option. The seizure focus has three parts which may or may not overlap on one another: i) the epileptogenic lesion, which is an abnormal brain region causing seizures, ii) the irritative zone, which is the area that generates brief seizure-like discharges in between seizures, and iii) the seizure onset zone, which is the area where seizures begin. The objective of epilepsy surgery is to completely remove all three parts of the seizure focus. However, seizure cure is seen in less than 50% of patients because of difficulties associated with identifying the entire seizure focus and removing it completely. We will develop new magnetic resonance imaging (MRI) techniques to better identify the seizure focus. This will help to remove the entire seizure focus and improve the surgical outcome. We will use three novel MRI techniques to study 85 patients with uncontrolled epilepsy. We will better identify epileptogenic lesions using voxel-based relaxometry, the irritative zone using combined electroencephalography-functional MRI, and the seizure onset zone using MR arterial spin labeling. We will also determine whether our MRI techniques can predict a successful surgical outcome. This will be done by carefully examining the relationship between a period of 1-4 years with no seizure occurrence following surgery and the removal of the entire seizure focus. Identifying and removing the entire seizure focus is critical to successful epilepsy surgery. Our new techniques offer unprecedented sensitivity and precision and will allow us to accurately identify the seizure focus. Once the studies have been completed, we will conduct a large, multicentre clinical trial to formally assess whether our MRI techniques can direct epilepsy surgery and improve surgical outcome.