RESUMEN
Objective:To investigate the diagnostic value and imaging characteristics of MRI combined with 18F-fluorodeoxyglucose (FDG) positron-emission tomography (PET)/CT in focal cortical dysplasia (FCD) complicated with refractory epilepsy. Methods:A retrospective analysis was performed on 42 patients with FCD complicated with refractory epilepsy who were admitted to the Affiliated Hospital of Jining Medical University from January 2017 to December 2022. All patients underwent preoperative MRI and 18F-FDG PET/CT, and PET/MRI fusion was performed on the images. Chi-square test and Kappa consistency test were used to compare the localization diagnostic efficacy of PET/CT, MRI and PET/MRI fusion for epileptic foci. The patients were categorized based on gender, lesion location, pathological type, seizure type, and efficacy. Independent sample t-test and analysis of variance were used to compare maximum standardized uptake (SUVmax) values and asymmetry index (AI) of the patients between different groups. Results:Among the 42 patients, the positive rates of MRI, PET/CT, PET/MRI fusion examinations were 85.7%(36/42), 95.2%(40/42), 100.0%(42/42), the lateral localization rates were 71.4%(30/42), 92.9%(39/42), 95.2%(40/42), and the localization rates were 57.1%(24/42), 81.0%(34/42), 88.1%(37/42), respectively. There were significant differences in the lateral localization rates and localization rates of epileptogenic foci between MRI and PET/CT (χ 2=6.574, P=0.010; χ 2=5.570, P=0.018). There were significant differences in the positive rates of lesions, the lateral localization rates and the localization rates of epileptogenic foci between MRI and PET/MRI fusion (χ 2=6.385, P=0.012; χ 2=8.571, P=0.003; χ 2=10.118, P=0.001). There were no significant differences in the positive rates of lesions between MRI and PET/CT, and in the positive rates of lesions, the lateral localization rates and localization rates of epileptogenic foci between PET/CT and PET/MRI fusion (χ 2=2.184, P=0.139; χ 2=2.024, P=0.155; χ 2=0.210, P=0.647; χ 2=0.819, P=0.365). The Kappa consistency test of PET/CT and PET/MRI fusion imaging was performed for the location of epileptogenic foci, and the Kappa=0.721 was obtained, indicating that they were consistent in the location of epileptogenic foci. The SUVmax values of patients with temporal lobe epilepsy were lower, and the AI values were higher than that of patients with extra temporal lobe epilepsy (7.4±1.3 vs 9.6±1.6, 15.5±2.6 vs 12.9±2.4; t=5.154, 6.083; P=0.001, 0.001). The SUVmax values of patients with good efficacy (according to the Engel efficacy grading system, grades Ⅰ-Ⅱ indicating good efficacy) were higher, and the AI values were lower than that of patients with poor efficacy (according to the Engel efficacy grading system, grades Ⅲ-Ⅳ indicating poor efficacy; 9.5±1.9 vs 7.9±2.1, 13.5±3.3 vs 14.8±3.0; t=2.789, 3.722; P=0.042, 0.029). There were no significant differences in SUVmax and AI values among different genders, pathological types and seizure types (all P>0.05). Conclusions:The imaging characteristics of patients with different types of FCD complicated with refractory epilepsy are different. PET/MRI fusion is better than MRI in the diagnosis of FCD complicated with refractory epilepsy, and is consistent with PET/CT in the location of epileptogenic foci.