INTERICTAL SPECT OF RCBF IS OF CLINICAL UTILITY IN THE PREOPERATIVE EVALUATION OF PATIENTS WITH PARTIAL EPILEPSY

Fifty-eight patients with drug-resistant partial epilepsy were studied preoperatively by interictal rCBF measurements using Tc-99m-HMPAO and a dedicated brain SPECT camera (Tomomatic 64). Follow-up of seizure o utcome, using the ''Engel score'', was at least 3 years. The data were analyzed in a blinded set-up, first visually and subsequently quantit atively by an automatic regional analysis. By visual analysis 95% of t he patients were considered abnormal in one part of the brain, of whom 27% were abnormal on CT, 45% on MRI and 98% on scalp EEG. Using a qua ntitative regional analysis subdividing each hemisphere into 17 larger regions, 85% of the patients had an abnormal rCBF compared to an age- matched control population of healthy volunteers (using the Wilcoxon.- sample test with Bonferroni's correction). The average number of abnor mal regions of interest was 4.7. The percentage of patients with abnor mal SPECT-CBF or the total number of abnormal regions of interest (ROT s) per patient showed no correlation to duration of epilepsy or seizur e load (number of seizures per year X epilepsy duration) or seizure ty pe. Neither were the rCBF changes prognostic for the outcome as measur ed by the Engel score. In 20 patients ictal SPECT of rCBF was addition ally performed. In 2 cases it added further information to the patient evaluation.