Utility of FDG PET/CT scan in seizure focus localization in patients with non-lesion brain MRI

Brain MRI fails to reveal apparent abnormality in approximately ۲۰% of patients with medically refractory epilepsy. FDG PET/CT is highly sensitive in localizing epileptogenic foci and is able to provide information complementary to MRI imaging. This is a cohort study aiming to evaluate patients suffering from refractory epilepsy and unremarkable MRI. We stratified patients with regard to clinical epileptogenic focus as localized in temporal lobe, frontal lobe or partially localized and tried to find out in which group of patients PET/CT is most congruent with clinical and EEG findings.In this study we included ۹۹ patients. ۶۳ patients had their seizure focus localized in temporal lobe by means of clinical and EEG evaluation in which ۳۲ of them demonstrated exactly congruent PET/CT results (۵۰.۸%). Remainder of these patients demonstrated either partially congruent PET/CT results (۷ patients, ۱۱.۱%) or totally incongruent PET/CT findings (۲۴ patients, ۳۸.۱%). ۲۴ patients had their seizure focus localized in frontal lobe by means of clinical and EEG evaluation in which only ۳ (۱۲.۵%) of them demonstrated partial congruency with PET/CT results. The remainder of ۲۱ (۸۷.۵%) patients demonstrated incongruent PET/CT results and there was no case in frontal lobe focal seizures with congruent PET/CT results. ۱۲ patients had their seizure focus only partially localized in one hemisphere in which ۶ (۵۰%) patients demonstrated partial congruency with PET/CT results.FDG PET/CT is useful tool to evaluate patients with refractory seizure who had localized seizure in temporal lobe on clinical evaluation. Utility of FDG PET/CT scan in extratemporal seizure foci is much more limited. Our results need to be further validated in larger studies.