Combined Structural And Functional MRI Studies In Epilepsy With Generalized Tonic-Clonic Seizures

Epilepsy is a common neurological disorder, and its electrophysiology characteristic is abnormally high excitability and synchronization of the neural activity. Epilepsy with generalized tonic–clonic seizures (GTCS) represents a common subsyndrome of Idiopathic generalized epilepsies (IGE), characterized by typical seizure symptoms of muscle rigidity, tic of limbs and loss of consciousness. Visual inspection of structural MRI in GTCS patients is usually normal. So it is significant to detect regional subtle structural abnormalities and resting-state functional abnormalities in the GTCS patients.The aim of our research is to investigate the abnormal region in the GTCS patients using structural and resting-state functional MRI analysis, which will provide significant clues for the study of pathophysiological mechanism of epilepsy. The main contents and innovations of this thesis are as follows:1. Using voxel- based morphometry (VBM), we found that GTCS patients showed significantly gray matter (GM) volume reductions in the bilateral thalami, frontal lobe, insula and cerebellum, suggesting that there are structural abnormalities in these regions involved in generalized epilepsies. In addition, the bilateral thalamic and left medial frontal gyrus GM volume had a negative correlation with the duration of epilepsy, which indicates that epilepsy may directly impair the thalamus and frontal lobe.2. Regional homogeneity (ReHo) and Amplitude of low frequency fluctuation (ALFF) were used to investigate functional abnormalities in the GTCS patients. Compared with the healthy controls, GTCS patients showed increased ReHo in the bilaterally thalami, cerebellum, brain stem and insula regions, decreased ReHo mainly in default mode network (DMN). In addition, increased ALFF regions were observed in the bilaterally thalami, cerebellum, insula, superior frontal gyrus and right caudate nucleus.These findings demonstrate that the regions of reduced GM volume are similar with the ones of increased ReHo and ALFF in the GTCS patients and mainly distributed in the cerebello-thalamo-cortical pathways, reflecting that these regions not only exist functional abnormalities but also subtle structural abnormalities. The current results suggest that the neurons may have structural impairment when long-term under conditions of high excitability and synchronization.