Surgical targeting of lateralized 18F-fluorodeoxyglucose positron emission tomography hypometabolism relates to long-term epilepsy surgery outcomes.

Objective: Surgical resection of the seizure onset zone can be an effective treatment for patients with drug-resistant focal epilepsy. Clinical, electrophysiological, and imaging data are all gathered prior to surgery to localize the seizure onset zone. However, only ~62% of patients become seizure-free after surgery, highlighting the need for improved methods to prospectively predict seizure recurrence after resection. ¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) is routinely acquired to guide epilepsy surgery; however, these scans are often assessed qualitatively in the clinic. Here, we quantified the surgical targeting of lateralized FDG-PET hypometabolism and assessed its relationship to surgical outcomes.

Methods: We included 55 patients who underwent resective epilepsy surgery (46 with temporal lobe epilepsy). We calculated laterality of the patients' presurgical FDG-PET scans and used pre- and postsurgical magnetic resonance imaging to delineate the surgically resected regions. Surgical targeting of FDG-PET laterality was computed using the discriminability between resected and spared regions statistic.

Results: We found that surgical targeting of FDG-PET laterality could distinguish temporal lobe epilepsy patients who achieve freedom from disabling seizures in the long term (3 years) from those who do not (area under the curve [AUC] = .83), outperforming the standard clinical assessment (AUC = .68). We additionally found that this method generalized to the nine patients with extratemporal lobe focal epilepsy.

Significance: This study highlights the benefit of quantifying FDG-PET to guide epilepsy surgery. The presented quantitative FDG-PET method could be used prospectively in the clinic to aid in surgical guidance and patient counseling.