Different patterns of white matter changes after successful surgery of mesial temporal lobe epilepsy

Abstract

ObjectivesTo explore the dynamic changes of white matters following anterior temporal lobectomy (ATL) in mesial temporal lobe epilepsy (MTLE) patients who achieved seizure-free at two-year follow-up.MethodsDiffusion tensor imaging (DTI) was obtained in ten MTLE patients at five serial time points: before surgery, three months, six months, 12 months and 24 months after surgery, as well as in 11 age- and sex-matched healthy controls at one time point. Regions with significant postoperative fractional anisotropy (FA) changes and their dynamic changes were confirmed by comparing all preoperative and postoperative data using Tract-Based Spatial Statistics (TBSS).ResultsAfter successful ATL, significant FA changes were found in widespread ipsilateral and contralateral white matter regions (P <.05, FWE correction). Ipsilateral external capsule, cingulum, superior corona radiate, body of corpus callosum, inferior longitudinal fasciculus, optic radiation and contralateral inferior cerebellar peduncle, inferior longitudinal fasciculus showed significant FA decrease at three months after surgery, without further changes. Ipsilateral superior cerebellar peduncle and contralateral corpus callosum, anterior corona radiate, external capsule, optic radiation showed significant FA decrease at three months follow up but increase later. Ipsilateral cerebral peduncle and contralateral middle cerebellar peduncle showed significant FA decrease at three months follow up, with further decrease after that. While ipsilateral posterior limb of internal capsule, retrolenticular part of internal capsule and contralateral posterior corona radiate showed significant FA increase after surgery.ConclusionsFA changes after successful ATL presented as four distinct patterns, reflecting different structural adaptions following epilepsy surgery. Some FA increases indicated the reversibility of preoperative diffusion abnormalities and the possibility of structural reorganization, especially in the contralateral hemisphere.

Dynamic gray matter and intrinsic activity changes after epilepsy surgery

“…All participants were native Chinese speakers and right‐handed assessed by the Edinburgh Inventory handedness test. All participants were the same as our DTI study 25 except one patient in previous study (subject 1, female, 25 years old, left TLE) was replaced by a new patient (TLE07, male, 21 years old, left TLE) because of some data problem of her preoperative rs‐fMRI scan.…”

“…We previously explored the dynamic time course of fractional anisotropy of white matters at five serial timepoints after successful ATL, revealing four distinct patterns reflecting post‐surgical structural adaption 25 . In the present study, we aimed to depict the dynamic structural and functional brain network alterations following ATL in mTLE patients who achieved seizure‐free at least for 24 months after surgery, by exploring the longitudinal changes of gray matter volume and intrinsic brain activity at five serial timepoints similar to our prior study 25 : before surgery, three months, six months, 12 and 24 months after surgery.…”

18F-FDG PET-guided diffusion tractography reveals white matter abnormalities around the epileptic focus in medically refractory epilepsy: implications for epilepsy surgical evaluation

“…This finding suggests that investigation of WM at this distance from epileptic tissue may better inform clinicians about whether surgery is an option, and if so, how to properly resect the EF without damaging surrounding healthy brain tissue. This is especially important to assess in WM affecting memory, language, and visual pathways in the brain, which are of prime importance in perioperative planning (Lin et al 2008;James et al 2015;Sivakanthan et al 2016;Li et al 2019).…”

Microstructural Investigations of the Visual Pathways in Pediatric Epilepsy Neurosurgery: Insights From Multi-Shell Diffusion Magnetic Resonance Imaging

“…It has been documented previously that as a result of surgery there is some reorganization that takes place in the brain (Taylor et al, 2018), and that it is generally associated to increased anisotropy in the contralateral hemisphere (Yogarajah et al, 2010;Winston et al, 2014b). However, a recent study (Li et al, 2019) shows that this trend is more prominent after 6 months following surgery, following an initial decrease in anisotropy documented at 3 months postsurgery in the contralateral optic radiation. The pediatric cohort studied here had varied intervals for follow-up imaging limiting the conclusions that can be drawn regarding the timescale of possible re-organization and its effect on diffusion metrics.…”