Planned ictal FDG PET imaging for localization of extratemporal epileptic foci

Purpose: This work demonstrates the feasibility of planned ictal positron e mission tomography (PET) with [F-18] fluoro-2-deoxy-glucose (FDG) for local ization of epileptic activity in patients with frequent partial seizures of extratemporal origin. Methods: Ictal PET imaging was performed in four patients (two men and two women, ages 28-61) with continuous or very frequent (every 3-15 min) partia l seizures. All patients had abnormalities apparent on magnetic resonance ( MR) or computed tomographic (CT) imaging, two with extensive brain lesions that precluded precise localization of the seizure focus with interictal PE T or single-photon emission tomography (SPECT) imaging. Results: Ictal PET imaging demonstrated a restricted area of focal hypermet abolism concordant with surface electroen-cephalographic (EEG) recording in all cases. The PET images were registered to MR imaging data for further a natomic localization of hypermetabolic regions in three cases. The ictal PE T data were used to guide neurosurgical intervention in one case. Conclusions: We conclude that planned ictal PET imaging may be a useful and potentially superior approach to ictal SPECT for identifying the epileptic focus in a selected group of patients with continuous or frequent simple p artial seizures.