Determining the Extent of Diffusion Tensor Abnormalities in Focal Cortical Dysplasia
Summary
Focal cortical dysplasia (FCD) is a common finding in epilepsy surgery in pediatric patients. Children with intractable epilepsy would have extensive tests to identify the cause of epilepsy; this includes MR brain, video EEG and magnetoencephalography (MEG). The white matter next to FCD is frequently found to be abnormal on pathology. Diffusion tensor imaging (DTI) can be used to study the abnormal white matter and the area that often extends beyond the area that is visible.
Description
Focal cortical dysplasia (FCD) is a highly epileptogenic form of malformation of cortical development that may require surgical resection for epilepsy control. With abnormal development and organization of neurons within the cortex, the white matter projecting from the abnormal cortex is likely to be abnormal as well. The abnormality in the white matter involves not only the subcortical white matter, but also the long tracts in the deep white matter associated with the dysplastic cortex. Histologically, the subcortical white matter adjacent to the dysplastic cortex has been found to be abnormal. Studies using diffusion tensor imaging (DTI) to investigate the white matter adjacent to the MR visible abnormality have demonstrated reduced fractional anisotropy. However, electrographic abnormality in FCD often extends beyond the visible MR abnormality and surgical outcome of epilepsy surgery in FCD is dependent on excising the MR visible abnormality as well as electrographically abnormal area beyond the MR visible abnormality. The cortical and white matter abnormalities are therefore assumed to extend beyond the MR visible lesion. The short-term goal of this study is to determine whether quantitative measures of the abnormal white matter using DTI are able to provide surrogate markers for the extent of FCD. Whilst surgical outcome data is not available for the purpose of this study, these children will be followed up and in the longer term, the extent of FCD as determined by DTI will be compared with clinical outcome post surgery. This study will help determine the potential value of this technique in identifying areas of FCD that appear normal on structural MR. In the long term, this technique can be extended to study children with intractable epilepsy with (i) MR occult lesion and (ii) developmental tumor with MR occult FCD adjacent to the tumor.
Study Design
Observational Model: Cohort, Time Perspective: Prospective
Conditions
Focal Cortical Dysplasia
Intervention
Magnetoencephalography, MR imaging, Diffusion Tensor Imaging
Location
The Hospital for Sick Children
Toronto
Ontario
Canada
M5G 1X8
Status
Active, not recruiting
Source
The Hospital for Sick Children
Results (where available)
Links
- Source: http://clinicaltrials.gov/show/NCT00687024
- Information obtained from ClinicalTrials.gov on July 15, 2010
Medical and Biotech [MESH] Definitions
Diffusion Tensor Imaging
The use of diffusion ANISOTROPY data from diffusion magnetic resonance imaging results to construct images based on the direction of the faster diffusing molecules.
Molecular Imaging
The use of molecularly targeted imaging probes to localize and/or monitor biochemical and cellular processes via various imaging modalities that include RADIONUCLIDE IMAGING; ULTRASONOGRAPHY; MAGNETIC RESONANCE IMAGING; fluorescence imaging; and MICROSCOPY.
Diffusion Magnetic Resonance Imaging
A diagnostic technique that incorporates the measurement of molecular diffusion (such as water or metabolites) for tissue assessment by MRI. The degree of molecular movement can be measured by changes of apparent diffusion coefficient (ADC) with time, as reflected by tissue microstructure. Diffusion MRI has been used to study BRAIN ISCHEMIA and tumor response to treatment.
Technetium Tc 99m Pentetate
A technetium imaging agent used in renal scintigraphy, computed tomography, lung ventilation imaging, gastrointestinal scintigraphy, and many other procedures which employ radionuclide imaging agents.
Voltage-sensitive Dye Imaging
Optical imaging techniques used for recording patterns of electrical activity in tissues by monitoring transmembrane potentials via FLUORESCENCE imaging with voltage-sensitive fluorescent dyes.
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