POSITRON EMISSION TOMOGRAPHY IN PATIENTS WITH DRUG RESISTANT TEMPORAL LOBE EPILEPSY WITH DIFFERENT ICTAL PROPAGATION PATTERNS IN SCALP EEG

Abstract

Objective: In presurgical evaluation, positron emission tomography with fluorodeoxyglucose-F18 (FDG-PET) is an important tool in identifying epileptogenic area. The aim of this study was to evaluate glucose metabolism in FDG-PET in patients with temporal lobe epilepsy (TLE) showing ‘switch-of lateralisation’ (SL) and ‘bilateral asynchrony’ (BA) in ictal scalp EEG and compare their results with patients with TLE and none of these patterns. Methods: Twenty-four patients with TLE showing SL and/or BA in at least one of their seizures in video-EEG monitoring and 38 patients with TLE and without these patterns who had epilepsy surgery and a follow-up at least 5-years were included. The clinical, electrophysiological and imaging features were evaluated and a statistical comparison was performed between the groups. Results: Bilateral hypometabolism was more frequent in patients with SL and/or BA (39%) than in patients without these patterns (0%, p=0.040) in parallel with bilateral interictal epileptiform discharges and bilateral abnormalities in MRI. The presence of unilateral or bilateral hypometabolism was not related to postsurgical outcome in patients with SL and/or BA. Conclusion: The possibility of low accuracy in the lateralisation of hypometabolism in FDG-PET might be interpreted cautiously in TLE with bilateral independent ictal activity like SL and BA.

Keywords

• Temporal lobe epilepsy
• ictal propagation patterns
• switch-of lateralisation
• bilateral asynchronya
• FDG-PET
• functional imaging

YÜZEYEL EEG’DE FARKLI İKTAL YAYILIM PATERNLERİ GÖSTEREN İLACA DİRENÇLİ TEMPORAL LOB EPİLEPSİLİ HASTALARDA POZİTRON EMİSYON TOMOGRAFİ

Abstract

Amaç: Temporal lob epilepsili (TLE) hastaların cerrahi öncesi değerlendirilmesinde epileptojenik alanın belirlenmesi amacıyla yapılan flurodeoksiglukoz F 18’li positron emisyon tomografisi (FDG-PET) incelemesi önemli bilgiler sağlamaktadır. Bu çalışmada, yüzeyel iktal EEG kayıtlarında ‘switch-of lateralizasyon’ ve/veya ‘bilateral asenkroni’ izlenen TLE’li hastalarının interiktal FDG-PET incelemelerinde glukoz metabolizma verilerinin incelenmesi ve bu paternlerin izlenmediği TLE hastaları ile karşılaştırılması amaçlandı. Gereç ve Yöntem: Video-EEG monitörizasyon (VEM) incelemesinde en az bir nöbetinde ‘switch-of lateralizasyon’ ve ‘bilateral asenkroni’ saptanan 24 TLE’li hasta çalışmaya dahil edildi. Kontrol grubu olarak, bu iktal paternlerin izlenmediği, epilepsi cerrahisi geçirmiş ve 5 yıllık izlemi olan TLE hastaları belirlendi. Klinik, elektrofizyolojik ve görüntüleme bulguları değerlendirildi ve hasta grupları arasında istatistiksel olarak kıyaslandı. Bulgular: VEM’de ‘switch-of lateralizasyon’ ve/veya ‘bilateral asenkroni’ izlenen TLE’li hastalarda (%39), bu paternlerin izlenmediği gruba kıyasla (%0) FDG-PET incelemelerinde bilateral temporal hipometabolizma görülme oranı daha fazlaydı (p=0.040). Bu oran, bilateral interiktal epileptiform aktivite ve bilateral manyetik rezonans görüntülme anomalileri için de benzerdi. Opere olmuş ve VEM incelemelerinde ‘switch-of lateralizasyon’ ve/veya ‘bilateral asenkroni’ izlenen TLE’li hastalar içerisinde FDG-PET’de bilateral temporal hipometabolizma varlığı, cerrahi sonrası sonlanım açısından farklılık göstermemekteydi. Sonuç: Sonuçlarımız, cerrahi öncesi değerlendirmede VEM’de ‘switch-of lateralizasyon’ ve/veya ‘bilateral asenkroni’ izlenen TLE’li hastalarda FDG-PET bulgularının lateralizasyon değerlerinin dikkatli yorumlanması gerektiğini göstermiştir.

Keywords

• Temporal lob epilepsisi
• iktal yayılım paternleri
• switch-of lateralizasyon
• bilateral asenkroni
• FDG-PE
• FDG-PET
• fonksiyonel görüntüleme
• fonksiyonel görüntüleme

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