To evaluate the diagnostic value of ¹¹C-choline PET/CT brain imaging for localization of epileptogenic foci in hippocampal sclerosis-refractory temporal lobe epilepsy (HS-RTLE), and compare it with ¹⁸F-FDG and ¹¹C-flumazeni (FMZ) PET/CT.

From March 2017 and June 2020, a total of 62 patients (39 males, 23 females, age (30.3±11.2) years) with pathologically confirmed HS-RTLE in General Hospital of Northern Theater Command were retrospectively analyzed. All patients were preoperatively treated with multiple radionuclide (¹⁸F-FDG, ¹¹C-FMZ, ¹¹C-choline) PET/CT brain imaging. ¹¹C-choline PET imaging was used to acquire dynamic imaging data and time-activity curve (TAC) of ¹¹C-choline in bilateral hippocampal regions were drawn. With postoperative pathology as the " gold standard" , the positive detection rates and localization diagnostic efficacies of three radionuclide imaging agents for epileptogenic foci were analyzed. Then a prospective study including 46 patients (27 males, 19 females; age (32.9±11.9) years; between May 2019 and August 2020; General Hospital of Northern Theater Command) with drug-refractory epilepsy caused by clinically suspected hippocampal sclerosis was performed. The examination method was the same as that of retrospective study. Using intracranial electrode implantation or postoperative pathology as " gold standard" , the diagnostic efficacy of ¹¹C-choline TAC for localization of epileptogenic foci was verified, and ROC curve was drawn to evaluate the diagnostic value of three imaging agents for HS-RTLE epileptogenic foci. χ 2 test and Fisher exact probability method, Delong test were used to analyze the data.

In the retrospective study, the positive detection rate of ¹⁸F-FDG PET/CT was higher than that of ¹¹C-choline PET/CT (100%(62/62) vs 85.48%(53/62); P=0.003), and the localization accuracies of ¹¹C-choline and ¹¹C-FMZ PET/CT were both higher than that of ¹⁸F-FDG PET/CT (100%(53/53), 96.61%(57/59) vs 33.87%(21/62); both P<0.001). In the prospective study, 25 of 46 patients were diagnosed as HS-RTLE and 21 were non-HS induced epilepsy. The specificities of ¹¹C-choline, ¹¹C-FMZ and ¹⁸F-FDG PET/CT were 100%(21/21), 90.48%(19/21), 33.33%(7/21), respectively. The AUCs of ¹¹C-choline and ¹¹C-FMZ PET/CT were significantly higher than that of ¹⁸F-FDG PET/CT (0.920, 0.912, 0.627; z values: 4.93, 5.16, both P<0.01).

¹¹C-choline PET/CT can be used in the preoperative localization of epileptic foci. Compared with ¹⁸F-FDG and ¹¹C-FMZ PET/CT, the specificity of ¹¹C-choline PET/CT is higher, and the negative imaging of ¹¹C-choline is more significant for exclusion.

Epilepsy, temporal lobe; Choline; Carbon radioisotopes; Positron-emission tomography; Tomography, X-ray computed; Flumazenil; Fluorodeoxyglucose F18