Voxel-based diffusion tensor imaging in patients with focal epilepsies: comparative analyses of microstructural damage and anatomical connectivity between benign and refractory mesial temporal lobe epilepsy and frontal lobe epilepsy

• Grant number: 16/05985-3
• Support type: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): May 01, 2016
• Effective date (End): July 31, 2020
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal researcher: Fernando Cendes
• Grantee: Hebel Oziel Urquia Osorio
• Home Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 13/07559-3 - BRAINN - The Brazilian Institute of Neuroscience and Neurotechnology, AP.CEPID
• Associated scholarship(s): 19/15161-6 - Regional analyses of the diffusion tensor imaging in the superficial white matter in patients with epilepsy due to focal cortical dysplasia, BE.EP.DD

Abstract

DTI is an MRI technique based on the directional movement of water. It creates a virtual, in vivo, noninvasive three-dimensional representation of the white matter fiber tracts by analyzing the preferred direction of water given by the diffusion tensor in each image voxel (volumetric pixel). The diffusion tensor is a mathematical description of the magnitude (mean diffusivity-MD) and directionality (anisotropy) of the movement of water molecules. In the white matter, the presence of microstructures, such as myelin, limits the random Brownian movement of water molecules restricting the real diffusion of water.Studies on Mesial Temporal Lobe Epilepsy (MTLE) and Hippocampal Sclerosis (HS) analyzing DTI changes showed reduced FA and increased MD in the limbic system and ipsilateral temporal lobe of these patients. Whether these findings correspond to a cause (such as a developmental malformation possibly underlying the epileptogenic process) or a consequence (such as structural modification induced by seizures) of MTLE and HS is still debated. In addition, few studies have investigated DTI changes in frontal lobe epilepsy (FLE) associated with focal cortical dysplasia. Our objective is to analyze DTI images in patients with benign MTLE with and without HS compared to patients with refractory MTLE, FLE with focal cortical dysplasia and normal controls. We hope that through the comparative analyses of microstructural damage and anatomical connectivity between benign and refractory mesial temporal lobe epilepsy and frontal lobe epilepsy we will be able to clarify the pathophysiological correlations of DTI changes in MTLE and FLE, as well as different anatomical connectivity changes according to severity, hemispheric lateralization of the epileptogenic focus as well as the presence and type of MRI lesions. (AU)