Abstracts

RATIONALE: Ictal SPECT is increasingly being used as a diagnostic tool in the localization of the epileptogenic focus in adults with epilepsy, but is less well studied in children. This study evaluates its utility in providing additive, not simply confirmatory, localizing information in extratemporal partial epilepsy. METHODS: We report the NYU experience in the use of peri-ictal SPECT in the evaluation of children with partial epilepsy from 1998-1999. The radionuclide 99mTc-ECD (Neurolite) was used for the peri-ictal injections. All injections were performed within 30 seconds of seizure onset, confirmed using video EEG monitoring. Subtraction SPECT coregisterd with MRI was performed in 6/11 (55%). RESULTS: Peri-ictal SPECT was obtained in 19 patients (median age 8 ys; range: one yr to 17 yrs). Peri-ictal SPECT was successfull in 16/19 patients (84%). All patients requiring sedation had successful scans. The peri-ictal SPECT scan was localizing in 17/19 (87%); 14 were extratemporal and only 3 were temporal. In contrast, MRI brain imaging demonstrated a probable lesion in only 7/19 (37%). Surface EEG recording was localizing in 9/19 (47%). Eleven patients subsequently had neocortical resections, all extratemporal. Six had identifiable lesions on MRI brain imaging. In Seven of the eleven (64%), the peri-ictal SPECT scan provided distinct localizing information that assisted with either invasive EEG monitoring or electrocorticography. All patients have been followed for over 6 months. If the peri-ictal SPECT was concordant with the eventual resected area (9/11; 82%), all 9 or 100% of the patients had a very favorable seizure outcome. CONCLUSIONS: This study demonstrates the sensitivity and specificity of peri-ictal SPECT, as well as its practical utility, in the evaluation of children with intractable partial epilepsy. The peri-ictal SPECT provides important localizing information in a high proportion of pediatric patients, many of whom have extratemporal nonlesional epilepsy. If the peri-ictal SPECT is concordant with the surgical resection, an excellent seizure outcome can be predicted.