Interictal cerebral metabolism and epilepsy in cavernous angiomas

We studied glucose metabolism in brain tissue surrounding cavernous angioma in 22 patients, using PET, and evaluated its relation to the size, site and epileptogenic nature of the vascular malformation, as well as to the post-surgical seizure outcome. Preoperatively, 18 patients suffered recurrent seizures, the origin of which could be clearly related to the vascular malformation in 14. Brain metabolism surrounding cavernous angiomas was normal in 18 patients (82%), and significantly decreased in four (18%). In these four patients, but in none of the 18 other cases, the vascular malformation disrupted connections between paralimbic areas and the adjacent temporal neocortex where hypometabolism was most pronounced. The latter did not correlate with the size nor with the epileptogenic nature of the cavernomas. Sixteen epileptic patients underwent surgical removal of their cavernoma, without resection of the surrounding cortex. At 1-year postoperatively, seizures have relapsed in seven patients (44%), including those four whose epilepsy could not be clearly related to the vascular malformation. Conversely, the four patients with perilesional hypometabolism on preoperative PET were seizure free postoperatively. Hypometabolism in brain tissue surrounding cavernomas is a rare finding which seems more likely to reflect deafferentation than the epileptogenic process itself.