Comparative study of FDG PET and MRI in interictal temporal lobe epilepsy

Objective The localization of epileptogenic foci may be accomplished by clinical observations, electroencephalogram (EEG), MRI and 18 F DG PET scans. These tests have also been used at various epilepsy centers to help identify candidates who might benefit from such operation. Interictal PET scans have demonstrated hypometabolism in areas concordant with the epileptogenic. However, fluid attenuated inversion recovery (FLAIR) imaging shows high sensitivity in detecting epileptogenic foci, our purpose is to correlate the FLAIR MRI scan and 18 F DG PET. Methods FLAIR MR and 18 F DG PET scans of 32 interictal patients with temporal lobe epilepsy proved by clinical history and EEG were assessed, 26 cases had been operated and followed up. 3 patients were excluded beacuse of presence of bilaterial temporal foci, 1 patient was found to have glioma, another 2 were lost to follow up. Results The sensititivity of localizating epileptogenic foci by FLAIR sequence was 80.76%; 18 F DG PET 92.36%. PET showed higher sensitivity. However, MRI was more accurate in localization because of it's high resolution. Conclusion 18 F DG PET has high potential ability in the detection of epileptogenic foci. FLAIR sequence imaging with high signal intensity of CSF may become a routine test for localization of temporal epilepsy. Combined 18 F DG PET and FLAIR sequence would be of higher predictive value in the detection of epileptogenic foci before operation because of their complementary effect.(Shanghai Med J, 2000,23∶528 530)