Abstracts

RATIONALE: The severity of cortical glucose hypometabolism surrounding the leptomeningeal angioma varies on PET scanning in epileptic patients with Sturge-Weber syndrome (SWS). We compared the extent and degree of glucose hypometabolism with interictal epileptiform activity in SWS patients with unilateral angioma. METHODS:_Patients underwent PET scanning using the tracer 2[F-18] fluoro-2-deoxyglucose, with concomitant interictal scalp EEG monitoring (N=13; 0.7-15 year; 5 Male, 8 Female). PET images were analyzed with a semi-automated method for definition of cortical asymmetry, and were classified as follows: I (<10% asymmetry), II (10 - 19% asymmetry), III (20 - 39% asymmetry), and IV(40%? asymmetry). The ratios of cortical surface areas for each class (I-IV) to the ipsilateral whole cortex surface area were calculated. RESULTS: Epileptic discharges were confined to the affected hemisphere in 6 patients (mean age 2.3y 2.3 SD) and were bilateral in 7 (mean age 8.1y 5.0). Glucose metabolism asymmetry area ratios were significantly different in patients with unilateral epileptic discharges (mean area ratios for class I: 0.40; II: 0.13; III: 0.33; IV: 0.14) compared to those with bilateral epileptic discharges (I: 0.73 (p=0.03); II: 0.15 (p=0.46); III: 0.09 (p=0.02); IV: 0.03 (p=0.03)). CONCLUSIONS: Patients with unilateral epileptic activity had larger cortical areas with severe hypometabolism (classes III and IV), whereas those with bilateral discharges had glucose metabolic abnormalities confined to an average of only 27% of cortex in the affected hemisphere. This suggests that large cortical regions with severe hypometabolism (representing nonviable calcified tissue) may have less of a deleterious effect on the contralateral hemisphere than less hypometabolic regions which continue to have a "nociferous" effect.