Relationship between bilateral temporal hypometabolism and EEG findings for mesial temporal lobe epilepsy: Analysis of 18F-FDG PET using SPM

한글 요약

내측 측두엽 뇌전증 환자에서 양측 측두엽의 포도당 대사 저하가 어떤 임상적 의미를 갖는지 살핀 연구입니다. 수술을 받은 환자들의 발작간기 FDG PET 영상을 통계적 파라미터 지도(SPM)로 분석하고, 시각적 판독 결과와 뇌파(EEG) 소견을 함께 비교했습니다. SPM 분석은 눈으로 판독할 때보다 양측 대사 저하를 훨씬 더 많이 찾아냈고, 양측 대사 저하를 보인 환자군에서는 발작간기 뇌전증파와 발작 시작이 양쪽에서 독립적으로 나타나는 경우가 뚜렷히 많았습니다. 반면 발병 연령이나 유병 기간, 수술 결과 등에서는 두 군 사이에 차이가 없었습니다. 이 결과는 PET 영상의 통계적 분석이 양측 측두엽 흥분성을 가진 환자를 미리 가려내어 더 신중한 감시가 필요한 환자를 찾는 데 도움이 될 수 있음을 보여 줍니다.

PURPOSE: To investigate the clinical significance of bilateral temporal hypometabolism (BTH) for patients with mesial temporal lobe epilepsy (MTLE) by using statistical parametric mapping (SPM).

METHODS: Interictal 18F-FDG PET scans were performed for 29 patients with surgically treated MTLE. Clinical data, interictal epileptiform discharges (IEDs), ictal scalp EEG and intracarotid amobarbital test (IAT) were analyzed. To assess an 18F-FDG PET image, an SPM analysis as well as visual interpretation were applied.

RESULTS: In 9 of 29 patients, the 18F-FDG PET scan revealed BTH by the SPM analysis, while only 3 patients showed BTH by the visual assessment. When the patients were classified into the unilateral temporal hypometabolism (UTH) and BTH groups based on the SPM results, bitemporal IEDs occurred significantly more frequently in the BTH group than in the UTH group (66.7% versus 22.2%). Bilateral independent seizure onset seen on the scalp EEG and bitemporal epilepsy were present only in the BTH group. Lateralized ictal onset was present less frequently in the BTH group than in the UTH group (44.4% versus 83.3%). There was no statistically significant difference in age at onset, duration of epilepsy, generalized seizure, history of febrile convulsion and CNS infection, lateralization throughout the whole tracing, lateralization on the IAT test, and surgical outcome between the UTH and BTH groups.

CONCLUSION: Bilaterality of the EEG findings correlated with BTH on 18F-FDG PET by the SPM method. Our results suggest that analysis of 18F-FDG PET by using SPM may have a role in predicting those patients with bitemporal excitability or bitemporal independent epileptogenicity, and these patients should be monitored carefully.