High-field structural and diffusion-weighted MRI in the Pilocarpine Model of Temporal Lobe Epilepsy

Abstract

This study aims to evaluate gray matter morphometry by structural MRI and microstructural changes in the white matter of the brain of Wistar rats by diffusion-weighted MRI. The analyses will focus on images made before and during the epileptogenesis latency period, and after the development of spontaneous seizures induced by pilocarpine. We aim to optimize a protocol for analyses of structural MRI and DTI in rats in our newly installed preclinical Brucker BioSpec 7 Tesla MRI in order to measure gray matter volume of the brain of Wistar rats before and after pilocarpine-induced status epilepticus (SE) and compare with the control group; to evaluate the integrity of the white matter (hippocampus, amygdala, piriform and entorhinal cortex, and thalamus) of the brain of Wistar rats before and after pilocarpine-induced SE and compare with the control group; and to calculate the values of mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (AD) of the brain of Wistar rats before and after pilocarpine-induced SE and compare with the control group.This is a longitudinal and experimental study. We will acquire MRI in 30 male Wistar rats (305-474g) with a mean age of two months and free of specific pathogens (15 sham controls and 15 with SE induced by pilocarpine). We acquired MRI prior to any intervention and then 48 hours, 15 and 30 days after pilocarpine-induced status epilepticus (SE).MRIs will be acquired with our preclinical Brucker BioSpec 7 Tesla MRI, using a rat-specific head coil (Brucker, Germany) with resources for positioning, fixing, and anesthesia. We will process VBM (3D T2-weighted images) with the Statistical Parametric Mapping 8 (SPM12, Wellcome Trust Centre for Neuroimaging) toolbox and software in MATLAB. The pre-processing and analysis of the diffusion data will be performed using tools of the software FSL 5.0. (AU)