DIFFUSION TENSOR IMAGING OF FOCAL CORTICAL DYSPLASIA
Abstract number :
2.226
Submission category :
Year :
2003
Submission ID :
4049
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Donald W. Gross, Alexandre Bastos, Christian Beaulieu, Barry Sinclair Department of Internal Medicine, University of Alberta, Edmonton, AB, Canada; Department of Radiology, University of Alberta, Edmonton, AB, Canada; Department of Biomedical Engineering,
Focal cortical dysplasia (FCD) is believed to be the underlying pathologic substrate in a significant proportion of patients with medically intractable epilepsy. At the present time, however, conventional MRI is not sensitive enough to detect all epileptogenic lesions. Efforts to improve detection of FCD include utilization of newly developed MR techniques, such as Diffusion Tensor Imaging (DTI). The purpose of this study was to characterize the diffusion properties of FCD using DTI.
Five patients with FCD were included in this study. All patients were scanned on a Siemens 1.5T Sonata MRI using standard (3 mm) and CSF-suppressed (8 mm) DTI. Three mm-thick contiguous axial slices of the brain were obtained with diffusion gradients along six non-collinear directions (b=1000 s/mm2) and one without diffusion weighting (b=0 s/mm2). Regions-of-interest analyses of different brain regions were stratified into lesions, major WM tracts, subcortical WM and cortical GM. Comparison were made with homologous brain regions contralateral to the lesion. Standard t-tests were used for statistical analysis.
Three patients had high T2 signal lesions compatible with FCD. Of the two remaining patients, one had cortical thickening and blurring of the cortical-subcortical junction and the other had no visible lesion on conventional high resolution MRI. Both subjects without high T2 signal lesions had pathological confirmation of FCD. Increased diffusion trace and reduced fractional anisotropy were observed in the three high signal T2 lesions. No diffusion abnormalities were identified in the two remaining patients (with normal T2 signal).
High T2 FCD lesions are associated with increased diffusion and reduced anisotropy. These findings emphasize the participation of similar mechanisms underlying the generation of both diffusion and T2 signal abnormalities. Elucidation of the different components involved in the generation of diffusion abnormalities in FCD is required in order to determine the sensitivity of DTI in the detection of FCD.