Grant: Project Grant

Epilepsy is a serious neurological disorder. About 54,000 Canadians have seizures that cannot be controlled by anti-seizure drugs. In these cases, the only available strategy is removal of the brain area generating seizures, called the seizure onset zone. However, seizure cure is <50% due to incomplete identification and removal of this area. We will use an established technique called Computerized Tomography Perfusion (CTP) to better identify and remove the entire seizure onset zone and improve post-surgical outcome. In routine clinical practice, the seizure onset zone is located by electroencephalographic recordings of seizures or single photon emission computerized tomography measures of blood flow during a seizure. However, these techniques have limited spatial resolution or are very labour-intensive and costly. Recently, we showed that seizures are followed by highly significant post-seizure blood flow reductions at the seizure onset zone lasting up to 1 hour that can be precisely measured using magnetic resonance imaging (MRI). These exciting findings suggest that the area of post-seizure hypoperfusion may be a novel seizure onset zone marker and better target for epilepsy surgery. Measuring post-seizure blood in clinical practice is hampered by difficulty in obtaining MRI scans within 1 hr. We will therefore measure post-seizure blood flow reductions in 150 patients using CTP as CT scanners are rapidly accessible. We will determine if CTP can better detect the full extent of the seizure onset zone compared to conventional methods (Aim 1) and if it can better predict post-surgical freedom (Aim 2). Our project is directly applicable to health care as we will determine if post-seizure hypoperfusion can better identify the full extent of the seizure onset zone and predict post-surgical outcome. Our study will ultimately allow clinicians to use this measure to direct surgery and improve surgical cure rates since CT scanners are widely available across Canada.