Interictal SPECT of rCBF is of clinical utility in the preoperative evaluation of patients with partial epilepsy.

Abstract

Fifty-eight patients with drug-resistant partial epilepsy were studied preoperatively by interictal rCBF measurements using 99mTc-HMPAO and a dedicated brain SPECT camera (Tomomatic 64). Follow-up of seizure outcome, using the "Engel score", was at least 3 years. The data were analyzed in a blinded set-up, first visually and subsequently quantitatively by an automatic regional analysis. By visual analysis 95% of the 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 quantitative 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 2-sample test with Bonferroni's correction). The average number of abnormal regions of interest was 4.7. The percentage of patients with abnormal SPECT-CBF or the total number of abnormal regions of interest (ROIs) per patient showed no correlation to duration of epilepsy or seizure load (number of seizures per year x epilepsy duration) or seizure type. Neither were the rCBF changes prognostic for the outcome as measured by the Engel score. In 20 patients ictal SPECT of rCBF was additionally performed. In 2 cases it added further information to the patient evaluation.