Presurgical lateralization of seizure focus and language dominant hemisphere with O-15 water PET imaging

Objectives - The purpose of this study was to assess the value of same day blood flow PET in both the identification of the language dominant hemisphe re and in the lateralization of the epileptic focus in patients who were pr eoperatively evaluated for complex partial seizures. Methods The charts of 24 patients who had temporal lobectomies for seizures were retrospectively reviewed. All PET scans were acquired by using O-15 water tracer ((H2O)-O-1 5) in both resting and language activation conditions. PET language lateral ity results were compared to Intracarotid amytal procedure (IAP) results. F or epileptic focus lateralizations, regions of interest (ROI) analysis of t emporal lobes was performed on resting scans. Results - IAP testing was dis cordant with PET language mapping in 1 out of 24 cases. This patient had a decline in cognitive abilities as measured by postoperative neuropsychologi c testing. For epileptic focus lateralization, the PET was highly sensitive (87%) and specific (100%). Lateralizations with the PET were in agreement with surgical sites in all cases. Eighteen patients (75%) were seizure free and 4 patients (17%) were significantly improved after surgery. Conclusion - The results suggest that O-15 water PET is sensitive and specific in bot h the lateralization of epileptic focus and the language dominant hemispher e and can be a cost-effective and noninvasive method in presurgical evaluat ion of patients with complex partial seizures.