Surgical Treatment of Medically Refractory Epilepsy and Related Neuroimaging

Surgery is an option for eligible patients with medically refractory epilepsy. Presurgical neuroimaging is tailored to allow identification of structural abnormalities in areas corresponding to the epileptogenic zone, which is identified with other techniques, impacting postsurgical outcomes toward seizure freedom. In some cases, it is also important to identify the eloquent cortex and critical white matter tracts, which aid in surgical planning and counseling for patients. Invasive procedures such as hemispherectomy, corpus callosotomy, and lobectomy have existed for decades for the management of refractory epilepsy, but the arsenal of surgical options for epilepsy has expanded recently, with the introduction of newer minimally invasive treatments such as laser interstitial thermal therapy, focused US, gamma knife radiosurgery, and neuromodulatory procedures such as vagal nerve stimulation, deep brain stimulation, and responsive neurostimulation. Invasive intracranial monitoring, which includes placement of subdural electrodes and stereoelectroencephalography, is another important surgical procedure used for more precise localization of the epileptogenic zone before planning definitive surgery. The authors outline the indications, expected imaging appearances, and complications of invasive and minimally invasive surgical treatments of epilepsy to create familiarity with these procedures in the imaging community. Also discussed are MRI safety concerns involved in imaging patients with medically refractive epilepsy. ^©RSNA, 2025 Supplemental material is available for this article. See the invited commentary by Pai and Jabhedar Maralani in this issue.