Abstracts

Rationale: The aim of this study was to disclose the regional changes of cortical thickness between the healthy control and mTLE patients in cross-sectional study. In addition, we also investigated the progressive cortical thickness changes of mTLE in the longitudinal MRI study.Methods: We selected 14 mTLE patients (7 left mTLE and, 7 right mTLE, mean age±S.D.= 30.0±8.9 years, 8 female) who had been diagnosed as unilateral mTLE with ipsilateral HS on a previous brain MRI. Mean age at first scan was 30.0±8.9 years (19 – 47.4). Patients underwent a repeat MRI scan 1.8 to 7.3 years (3.8±1.8) later. All patients were seizure free after surgery. Twenty-three (12 women, 11 men) sex, age matched normal controls (33.4±7.86 years) were also included. All subjects underwent Spoiled Gradient Recalled in the steady state (SPGR). Acquired T1 MRI images were preprocessed by intensity inhomogeneity correction. The corrected images were classified into WM, GM, CSF, and background using an advanced neural-net classifier. The surfaces of the inner and outer cortex were automatically generated using the Constrained Laplacian-Based Automated Segmentation with Proximities (CLASP) algorithm. To compare the thicknesses of corresponding regions between mTLE patients and the controls, we performed the t-test. To analyze the cumulative epileptic effect, we used the paired t-test between the first and the second MRI of the epilepsy group.Results: Compared with the healthy control group, epilepsy group showed the significant thinning of cortical thickness in temporal lobe (fusiform gyrus, inferior-, middle-, superior temporal gyrus, supramarginal gyrus), limbic lobe (uncus, parahippocampal gyrus, and cingurate), frontal lobe (paracentral lobule, inferior, superior, middle- and mesial frontal gyrus), parietal lobe (precuneus, inferior-, superior parietal lobule and postcentral gyrus) and occipital lobe (cuneus, lingual gyrus) in the bilateral hemisphere. The first and the second MRI of the epilepsy group revealed significant reduction of cortical thickness in bilateral inferior-, superior-, medial frontal gyrus, pre- and postcentral gyrus, ipsilateral lingual gyrus and inferior occipital gyrus, and contralateral anterior cingurate gyrus.Conclusions: We confirmed that mTLE with HS effected the multiple deficits of temporal, frontal, parietal and limbic lobe in cross-sectional study. The mTLE patients showed longitudinal reduction of cortical thickness in bilateral frontal areas, lingual gyrus of ipsilateral hemisphere and anterior cingulate of contralateral hemisphere, which may be consequences of repetitive seizures.