Interictal and postictal 18F-FDG PET/CT in epileptogenic zone localization

Abstract Objective: To evaluate the performance of 18F-fluorodeoxyglucose positron-emission tomography/computed tomography ( 18F-FDG PET/CT) in localizing epileptogenic zones, comparing 18F-FDG injection performed in the traditional interictal period with that performed near the time of a seizure. Materials and Methods: We evaluated patients with refractory epilepsy who underwent 18F-FDG PET/CT. The reference standards for localization of the epileptogenic zone were histopathology and follow-up examinations (in patients who underwent surgery) or serial electroencephalography (EEG) recordings, long-term video EEG, and magnetic resonance imaging (in patients who did not). The 18F-FDG injection was performed whether the patient had an epileptic seizure during the EEG monitoring period or not. The 18F-FDG PET/CT results were categorized as concordant or discordant with the reference standards. Results: Of the 110 patients evaluated, 10 were in a postictal group (FDG injection after a seizure) and 100 were in the interictal group. The 18F-FDG PET/CT was concordant with the reference standards in nine (90%) of the postictal group patients and in 60 (60%) of the interictal group patients. Among the nine postictal group patients in whom the results were concordant, the 18F-FDG PET/CT showed hypermetabolism and hypometabolism in the epileptogenic zone in four (44.4%) and five (55.6%), respectively. Conclusion: Our data indicate that 18F-FDG PET/CT is a helpful tool for localization of the epileptogenic zone and that EEG monitoring is an important means of correlating the findings. In addition, postictal 18F-FDG PET/CT is able to identify the epileptogenic zone by showing either hypometabolism or hypermetabolism.

摘要
研究目的：评估18F-氟脱氧葡萄糖正电子发射断层扫描/计算机断层扫描（18F-FDG PET/CT）定位致痫灶的临床效能，对比传统发作间期注射与发作临近时点注射18F-FDG的定位效果。
材料与方法：纳入接受18F-FDG PET/CT检查的难治性癫痫患者。致痫灶定位的参考标准为：接受手术治疗的患者采用病理组织学检查结果及术后随访结果，未接受手术的患者采用系列脑电图（EEG）记录、长程视频脑电图及磁共振成像（MRI）检查结果。无论患者在脑电图监测期间是否出现癫痫发作，均完成18F-FDG注射。将18F-FDG PET/CT结果与参考标准比对，分为相符与不符两类。
结果：纳入评估的110例患者中，发作间期组100例，发作后组（癫痫发作后注射FDG）10例。发作后组9例（90%）的PET/CT结果与参考标准相符，发作间期组60例（60%）相符。在结果相符的发作后组9例患者中，18F-FDG PET/CT显示致痫灶呈高代谢者4例（44.4%），低代谢者5例（55.6%）。
结论：本研究数据表明，18F-FDG PET/CT是定位致痫灶的有效辅助工具，脑电图监测是关联影像学检查结果与临床定位的重要手段。此外，发作后18F-FDG PET/CT可通过显示高代谢或低代谢特征识别致痫灶。