Abstracts

With the advent of intraoperative navigation systems, structural lesions disclosed by MRI can now be removed more easily and accurately. But in cases receiving epilepsy surgery, the seizures can only be stopped by removing the surrounding epileptogenic areas together with the lesions themselves. To accomplish this, we need to functionally detect peri-lesional epileptogenic areas during surgery. Our group recently introduced a method of F18-fluorodeoxyglucose (FDG) and C11-flumazenil (FMZ) PET co-registration as a reference for the detection of epileptogenic areas during image-guided epilepsy surgery for patients with organic lesions. In this study we investigated the clinical role of multimodal navigation epilepsy surgery using FDG-PET and FMZ-PET., We studied a series of 10 patients who suffered from intractable epilepsy and were found to have organic lesions on MRI. All of the subjects underwent FDG-PET and FMZ-PET studies before their operations. Surgical specimens demonstrated cavernous angiomas in 2 patients and benign tumors in 8 (3 low-grade astrocytomas, 2 DNTs, 2 gangliogliomas, and 1 monomorphous angiocentric glioma). The lesions were located in the mesial temporal lobe (mT) in 6 patients and in the extra-mesial-temporal lobe (extra-mT) in 4. Our first steps were to examine the relationships between the organic lesions and hypometabolic areas on FDG-PET, and then to compare the FDG-hypometabolic areas and low-uptake areas on FMZ-PET. Next, we performed intraoperative electrocorticography (ECoG) in and around the hypometabolic areas to examine the epileptogenicity of the hypometabolic areas on FDG-PET and the low-uptake areas on FMZ-PET., 1) The hypometabolic areas on FDG-PET were much wider than the low-uptake areas on FMZ-PET in 8 cases, and slightly wider in 3 cases. 2) Spikes on intraoperative ECoGs were recorded in the hypometabolic areas in all 6 of the mT cases. 3) The hypometabolic areas were much wider than the ECoG-spiking areas in 2 of the 4 extra-mT patients, and slightly wider in the other 2. ECoG-spiking areas were wider than the low-uptake areas on FMZ. 4) Four of the 6 mT patients underwent anterior temporal lobectomy and the other 2 underwent lesionectomy along with anterior temporal resection. The extra-mT patients underwent lesionectomy along with resection of any ECoG-spiking areas which exhibited hypometabolism on FDG-PET and low-uptake on FMZ-PET. 5) All 10 patients became seizure-free during follow-up periods ranging from 6 to 24 months., The use of multi-modal navigation surgery by FDG-PET and FMZ-PET in combination with intraoperative ECoG may become an important method for focus resection in epileptic patients with organic lesions, especially in patients with extra-mesial temporal lobe epilepsy.,