Association between metabolic patterns in 18-FDG PET-CT scan and postsurgical seizure outcomes in patients with temporal lobe epilepsy.

Background: Temporal lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy in adults, and surgery is a standard treatment, offering seizure freedom in 60-70 % of patients. Despite advanced imaging, many TLE patients show inconsistent MRI findings, making functional imaging such as 18-FDG PET-CT scans essential in identifying epileptogenic zones. This study aims to assess the association between concordant or non-concordant metabolic patterns in presurgical 18-FDG PET-CT scans and postoperative outcomes in TLE patients.

Methods: This retrospective, observational study included people with epilepsy (PWE) who underwent TLE surgery at a clinic in Mexico City and had a presurgical 18-FDG PET-CT scan. Seizure outcomes were measured using Engel and ILAE classifications at a two-year follow-up. The concordant group had only temporal hypometabolism ipsilateral to the epileptogenic zone, while the non-concordant group had normal, extratemporal, or bitemporal hypometabolism.

Results: The study included 49 PWE: 28 with concordant PET-CT scans and 21 with non-concordant scans. Comparisons of seizure outcomes using the Engel and ILAE classifications at two years post-surgery revealed no significant differences between the groups (p = 0.972 and p = 0.279, respectively). The use of anti-seizure medications (ASM) after surgery did not differ significantly between groups (p = 0.649).

Conclusions: At our center, preoperative evaluation emphasizes the alignment of clinical findings, video-EEG, and MRI. At the two-year follow-up, no significant difference in seizure freedom was observed between patients with temporal lobe hypometabolism alone and those with other patterns.