Seizure Outcome After Surgery for Refractory Epilepsy Diagnosed by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/MRI): A Systematic Review and Meta-Analysis

When magnetic resonance imaging (MRI) fails to detect an underlying epileptogenic lesion, the odds of a good outcome after epilepsy surgery are significantly lower (20%-65% compared with 60%-90% if a lesion is detected). We investigated the possible effects of introducing hybrid 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/MRI into the decision algorithm for patients with lesioned and nonlesioned drug-resistant epilepsy.Three databases were searched from January 1990 to October 2022. We registered the protocol with International Platform of Registered Systematic Review and Meta-analysis Protocols. Studies in which 18F-FDG PET/MRI was conducted with ≥12 months of postsurgical follow-up in patients with refractory epilepsy. Random-effects meta-analysis was used to calculate the proportion of patients with good outcomes. Metaregression was used to investigate sources of heterogeneity.We identified 8105 studies, of which 23 (1292 patients in total) were included. The overall good postoperative outcome rate was 71% (95% confidence interval 63.6-74.9). Good outcome was associated with the location of the refractory epileptic lesion (temporal lobe or extratemporal; risk ratio 1.27 [95% confidence interval 1.01-1.52], P = 0.009); Length of postoperative follow-up ≥40 months included in the same study accounted for 0.6% of the observed heterogeneity.Seventy-one percent of patients with refractory epilepsy and 18F-FDG PET/MRI epileptogenic lesion features had a good outcome of epilepsy after surgery. Our findings can be incorporated into routine preoperative consultations and emphasize the importance of the complete resection of the temporal lobe epileptogenic zone for 18F-FDG PET/MRI detection when safe and feasible.