T2 relaxometry analysis in contralateral hippocampus after temporal lobe surgery: immediate and long-term evaluation

Abstract

Epilepsy is a severe neurological condition of major prevalence in the world and it affects the quality of life of sick individuals. Surgical removal of mesial structures is performed in cases of refractory Mesial temporal lobe epilepsy (MTLE), yielding a seizure control in approximately 65% of patients, regardless the selected surgical approach (selective amigdalohipocampectomy or anterior temporal lobectomy).Despite the successful seizure control, few studies have evaluated the post-operatory follow-up and brain abnormalities that arise after the operation; little information exist about postoperative structural changes in the contralateral hemisphere. Considering the importance of the hippocampus for memory and cognitive functions, it is important to predict changes arising after surgery, in order to further the understanding of changes observed after surgery. Thereby, it would be possible to predict long-term hippocampal changes as well as late neuropsychological deficits with more precise details. Our group have evaluated memory and contralateral hippocampal volume after surgery with an average interval of about 8 years and identified a significant reduction in contralateral hippocampus, suggesting a dynamic process after surgery. Objective: We aim to evaluate changes in relaxometry measurement of T2 in the contralateral hippocampus before and after temporal lobe epilepsy surgery; the increase of the T2 signal is a marker of hippocampal sclerosis and indicative of increased water in the tissues as a consequence of gliosis, Hypothesis: We expect to observe elevated T2 signal in post operated contralateral hippocampus of patients with persistent seizures , and a decrease of T2 signal in the contralateral hippocampus of seizure-free patients. Methods: This study will be conducted in the neuroimaging lab at HC-UNICAMP with data from patients operated between 2010 and 2014. We intend to analyze acute changes (in the first week after the procedure) and chronic (after 6 months), comparing to the preoperative data and surgical outcomes of 50 patients and 130 images already in existence in the database, it will be used the AFTERVOXEL software for analysis of the T2.