Role of 18F-FDG PET in the preoperative evaluation of extratemporal lobe epilepsy / 中华核医学与分子影像杂志

ABSTRACT

Objective:To analyze the application value of 18F-FDG PET in the preoperative evaluation of patients with extratemporal lobe epilepsy (ETLE) and explore improved methods to enhance its localization accuracy. Methods:A total of 41 patients (25 males, 16 females, age (22.7±7.5) years) who underwent surgery and ultimately confirmed ETLE in Peking Union Medical College Hospital between January 2006 and November 2022 were enrolled. The accuracy of preoperative independent 18F-FDG PET imaging and the combined application of 18F-FDG PET and MRI in detecting epileptogenic foci and their impacts on treatment decisions were retrospectively analyzed by using visual and semi-quantitative methods. Fisher′s exact test was used to analyze the data. Results:In all 41 patients, 40 cases were found metabolic abnormalities in extratemporal lobe by independent 18F-FDG PET based on visual analysis. Among them, 26 showed unifocal metabolic abnormalities, which were localized as epileptogenic foci. Fourteen patients showed multifocal metabolic abnormalities, and the epileptogenic foci were further verified in 8 cases through semi-quantitative analysis. In 1 case with negative PET visual analysis, a micro-metabolism focus was found at the abnormal MRI signal area. Among 13 patients with negative independent MRI, 9 were found microstructures abnormalities in brain regions with hypometabolism. 18F-FDG PET improved clinical decision-making in 18 patients (43.9%, 18/41). There were 30 patients (73.2%, 30/41) with seizure-free postsurgery, and the prognosis was not significantly different between patients with unifocal 18F-FDG PET metabolic pattern and those with multifocal ones (73.1%(19/26) vs 10/14, P=1.000). Conclusions:18F-FDG PET can be a useful diagnostic tool for patients with ETLE. Semi-quantitative analysis helps to detect more epileptogenic foci with multifocal metabolic abnormalities. The combined evaluation of 18F-FDG PET and MRI can improve the accuracy in localizing epileptogenic foci outside the temporal lobe.