Abstracts

Rationale: To present three patients with refractory epilepsy and ictal PET findings corresponding to histologically confirmed focal cortical dysplasias (FCD). Methods: Patients with focal refractory epilepsy studied with Video-EEG monitoring, brain MRI, and PET with F18-FDG injected immediately after electroclinical seizures. Case 1: male, 10 months old, left head version seizures since the age of 8 months, 10 seizures per day in average at surgery. Case 2: female, 28 years old, with complex partial seizures (CPS) since the age of 25, the average seizure frequency was three events per week. Case 3: male, 3 months old, with focal refractory epilepsy since the 5th life day. Seizure frequency was 6 to 8 per day. Results: Case 1: MRI: right frontal lesion suggesting FCD. Video-EEG: 12 seizures starting in right frontal region. Ictal PET: hypermetabolic area corresponding with MRI lesion (Fig. 1). Surgical resection was guided by intraoperatory ultrasound. Histology: type II-B FCD. Outcome: seizure free at 6-month follow-up. Case 2: MRI: right hippocampal increased signal, suggesting hippocampal sclerosis. Video-EEG: three electroclinical seizures starting in right mesial temporal region, and several electrographic ictal events in the same area. Ictal PET: very well localized right hippocampal hypermetabolism (Fig.2). Histology: type II-B FCD. Outcome: seizure free at 3-month follow-up. Case 3: MRI suggests right occipital FCD. Video-EEG shows ictal onset on the same area. Ictal PET: hypermetabolic area corresponding with MRI and EEG. The histological finding was a FCD type II-B. Conclusions: Interictal PET is a valuable tool in the pre-surgical evaluation of refractory focal epilepsy. However, ictal abnormalities and its correlation with histological findings and postsurgical outcome have not yet been delineated. In these patients, ictal PET had an excellent correlation with MRI lesions and with seizure onset on video-EEG. Although follow up is not long enough, we suggest ictal PET can be useful at least for FCD cases. Proper implementation requires continuous EEG recording before and during PET study. For another hand the expression Ictal PET could be changed to Peri-Ictal PET , because the injection with F18-FDG was immediately after the seizure and not during the seizure self.