Can Diffusion Tensor Imaging (DTI) Identify Epileptogenic Tubers in Tuberous Sclerosis Complex? Correlation With α-[11C]methyl-l-tryptophan ([11C] AMT) Positron Emission Tomography (PET)

Abstract

In this study, we determined whether diffusion tensor imaging (DTI), a more widely available imaging modality, is as effective as α-[11C]methyl-l-tryptophan (AMT)–positron emission tomography (PET) in localizing epileptogenic tubers in tuberous sclerosis complex. Following that, coregistration of AMT-PET and diffusion tensor imaging scans apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in all tubers using a region-of-interest approach and were compared with AMT-PET tuber/cortex uptake ratios, which were used to differentiate between epileptogenic and nonepileptogenic tubers. Forty-three tubers, out of a total of 320 tubers, had AMT-PET uptake ratios greater than 1 and hence were classified as potentially epileptogenic. FA in epileptogenic tubers was reduced compared with the other tubers ( P = .03). A significant negative correlation was observed between AMT-PET uptake ratio of epileptogenic tubers and FA values ( r = –.45; P = .003). Tubers with higher AMT-PET uptake ratios corresponded well with lower FA values in tuberous sclerosis complex patients.