Evaluation of white matter changes in patients with hippocampal sclerosis and correlation with postoperative outcome using diffusion tensor imaging (DTI)

Abstract

Mesial temporal lobe epilepsy (MTLE) is the most frequent form of refractory focal epilepsy in adults, and hippocampal sclerosis is its most common and widely studied pathological substrate. Hippocampal sclerosis is present in 60% to 70% of patients with MTLE who are indicated for surgery for failure of clinical treatment. Currently, special attention has been given to the neuronal damage affecting extratemporal regions, as well as other limbic structures and extratemporal white matter (WM), that appear to be related to the clinical and surgical prognosis. New techniques using voxel-based morphometry (VBM) and diffusion tensor image analysis (DTI) corroborated the involvement of these structures in MTLE. The present study aims to correlate the magnitude of the microstructural damage of temporal and extratemporal white matter tracts with surgical prognosis (seizure-free/seizure reduction). For this, eltm patients followed at the outpatient epilepsy clinic of the department of neurology at UNICAMP who underwent surgery will be retrospectively evaluated, with at least 1 year of post-surgical follow-up, divided into 2 groups, based on Engel's classification (seizure-free x persistence of seizures).Quantitative data, such as fractional anisotropy (FA) and mean diffusivity (MD), obtained from preoperative DTI processing may serve as biomarkers capable of assisting in predicting the surgical prognosis of patients with MTLE with hippocampal sclerosis. (AU)