Regional analyses of the diffusion tensor imaging in the superficial white matter in patients with epilepsy due to focal cortical dysplasia

Abstract

Focal cortical dysplasias (FCD) are localized malformations of the cerebral cortex. Their neuropathological features classify them into three subtypes. FCD is one of the most frequent causes of drug-resistant focal epilepsies. White matter (WM) pathology is a well-defined hallmark feature in this type of epilepsy. Diffusion tensor imaging(DTI) is an MRI technique that allows noninvasive evaluation of the white matter (WM). It describes the magnitude (mean diffusivity-MD) and directionality (fractional anisotropy-FA) of the movement of water molecules. DTI studies have demonstrated deep fiber tract alterations in patients with FCD, but the superficial white matter (SWM) immediately below the cortex has so far been neglected despite its proximity to neocortical regions and key role in maintaining cortico-cortical connectivity. Emerging evidence suggests that SWM may be implicated in neurological disorders, and can play an important role in diseases such as epilepsy. But the study of this region needs a novel technical approach due to the complicated morphology of the human cortex. In order to achieve this purpose, new analysis techniques are being implemented recently based on DTI regional analyses (not tract based).Our objective is to analyze the microstructural integrity of the SWM in FCD patients and healthy controls.This study will help us to understand better the meaning of DTI regional findings in SWM in epilepsy patients with FCD and their correlation with visual MRI features and histopathological classification. (AU)