Abstracts

Rationale: Patients with tuberous sclerosis complex (TSC) and intractable epilepsy are potential surgical candidates if the epileptogenic region(s) can be accurately identified. AMT-PET can differentiate between epileptogenic and non-epileptogenic tubers in about 70% of cases. However, AMT-PET is not widely available. We determined whether diffusion tensor imaging (DTI), a more widely available imaging modality, is as effective as AMT-PET in localizing the epileptogenic tuber in TSC.Methods: AMT-PET and DTI analyses were performed in 20 TSC patients (14 boys, 6 girls; age range, 3 to 14 years; mean age, 7.2 years). The AMT-PET and MR image datasets were co-registered. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in all tubers using a region-of-interest (ROI) approach and compared to AMT-PET- uptake ratios for the corresponding tubers. Results: AMT-PET-uptake ratios were used to differentiate between epileptogenic and non-epileptogenic tubers. A total of 43 tubers had AMT-PET-uptake ratio of greater than 1.0 and hence were classified as potentially epileptogenic. 277 tubers were classified as probably non-epileptogenic with AMT-PET-uptake ratio less than 1.0. FA in epileptogenic tubers was reduced compared to non-epileptogenic tubers (p= 0.03). There was no difference in ADC between these two groups. A significant negative correlation was observed between AMT-PET-uptake ratio and FA values (r =0.121; p =0.034).Conclusions: Tubers with higher AMT-PET uptake ratio corresponded well with lower FA values in TSC patients. Although preliminary, these data suggest DTI parameters may also contribute to the differentiation between epileptogenic and non-epileptogenic tubers in TSC if used comprehensively with other methods, such as EEG.