Abstracts

Rationale: MRI findings in cortical dysplasia typically include a subcortical 'tail' extending radially from the cortical abnormality, toward the ventricle. The appropriate surgical aggressiveness toward this subcortical extent is unknown, but potential for morbidity higher. The ability to demonstrate descending motor fibers, such as with diffusion tensor imaging (DTI), as either separate, or distinct from, the dysplasia could guide surgical planning. Methods: Patients with DTI studies as part of the evaluation for surgical treatment of intractable epilepys were reviewed. Those with MRI evidence of cortical dysplasia near suspected motor cortex were reviewed. Descending corticospinal fibers were identified using seed values from motor fMRI studies. The relationship between these fibers and the subcortical extent of the dysplasia were reviewed. Results: Three patients (all male, ages 3,7, and 9) with lesions in or near motor cortex were identified. Motor areas were identified by functional MRI in all three. Descending motor fibers were identified in all. In one example, the fibers could be seen running through the dysplastic cortex (Figure). Conclusions: Despite the MRI abnormalities and the potential to interfere with fiber tracking, we demonstrate motor fibers that can run adjacent to, or even through, the deep extent of dysplastic lesions near motor cortex. This has implications for surgical management of such lesions in intractable epilepsy.