| Chapter one:Surface-based morphometry study of the brain in non-lesion focal epilepsy and idiopathic generalized epilepsyBackground:Both focal epilepsy(FE)and idiopathic generalized epilepsy(IGE)are associated with extensive cortical structural abnormalities.Non-lesion focal epilepsy(nl-FE)is an important subgroup of focal epilepsy.Normal image findings,normal interictal state,and no neurological focal defects is the characteristic clinical manifestation.However,compared with MRI positive patients,MRI negative patients have delayed seizures,lower incidence of febrile seizures,less impairment of memory function,and poorer surgical results.Patients with idiopathic generalized epilepsy(IGE)usually have normal interictal state,no nervous system defects,and normal performance on conventional MRI.The surface based morphological computing model can better display the cortical and subcortical structures,which is helpful to analyze the relationship between cortical regions and provide superior visualization effect.The cortical and subcortical structural abnormalities in epileptic patients have been widely accepted,but there are few studies on the cortical structural differences between two MRI negative epileptic groups.Objective:This study was to evaluate and compare the cortical structural changes of nl-FE,IGE patients and healthy controls(HC)by using surface-based morphometry study.method:According to the diagnostic criteria of epilepsy and epilepsy syndrome proposed by ILAE in 2017,there were 20 patients with non-lesion focal epilepsy(9 female and 11 male),19 patients with idiopathic generalized epilepsy(13 female and 8 male).Surface based morphometry was used to assess the morphology of the cerebral cortex Objective:to analyze and evaluate the correlation between the morphological indexes of cerebral cortex and the duration of epilepsy.Result:Compared with the healthy control group,the brain morphology of nl-FE and IGE patients,including cortical thickness and volume,cortical curvature,had significant changes in many areas.1)In the IGE group,the curvature of the left superior frontal was decreased;the thickness of the right lateral occipital,caudal middle frontal was decreased and the pericalcarine cortical thickness increased;in the left precentral,the cortical volume of the IGE group was decreased,but there was no difference in the nl-FE group;in the right pericalcarine,the cortical volume of the nl-FE group was increased,but there was no difference in the IGE group.In addition,there were significant differences between nl-FE group and IGE group in the volume of left precentral cortex and the thickness of right lateral occipital and caudal middle frontal,especially in IGE group.2)In IGE group,the curvature of left superior frontal was negatively correlated with the duration of epilepsy;in IGE group,the volume of left precentral cortex was negatively correlated with the duration of epilepsy;in nl-FE group,the volume and thickness of right pericalcarine were positively correlated with the duration of epilepsy;the thickness of right caudal middle frontal and lateral occipital was negatively correlated with the duration of epilepsy.Conclusion:1)This study confirmed that epilepsy will have structural changes in the cerebral cortex,and concluded the prefrontal lobe,caudal middle frontal,pericalcarine,superior frontal and precentral other brain areas that are most likely to be affected2)A variety of cortical morphological indexes,such as cortical thickness,cortical volume and cortical mean curvature,are of great significance in indicating cortical structural changes;3)The change of cortical structure is related to the duration of epilepsy.Chapter 2:Default model network and significance network analysis of the decrease of covariance connection in MRI negative focal epilepsy structureBackground:Non-lesional focal epilepsy(nl-FE)is a nervous system disease,and its symptoms depend in part on the anatomical location of the epileptic foci.About a third of the population has a difficult drug treatment for epilepsy,leading to a significant increase in mortality.The failure of epilepsy treatment may be attributed to the incomplete understanding of the epilepsy brain network.It has been proved that nl-FE patients are characterized by functional brain network structure disorder outside the epileptic seizure area.How to clarify the "epilepsy network" and its central node of focal epilepsy has become the central focus and difficulty of neuroimaging research.Therefore,we need to use more brain function imaging analysis methods to explore the "epilepsy network" mechanism of focal epilepsy,determine the central node of epilepsy network,and provide objective basis for surgical treatment and evaluation of focal epilepsy.DMN is the most prominent resting state network in human brain network.The network is mainly composed of medial prefrontal cortex,posterior cingulate gyrus/anterior wedge and horn gyrus.There is a lot of evidence that DMN damage has occurred in FE patients.The decrease of DMN functional connectivity may be related to the impairment of executive control function,or the basis of epilepsy related cognitive abnormality.The patients with focal epilepsy also have the characteristics of salience network(SN)changes,which involve attention,mutual feelings and emotional processes.The focus of this part is to explore the structural covariance connectivity of DMN and SN in patients with focal epilepsy,and the decrease of gray matter volume in the reduced connectivity area,which provides a structural basis for the further study of DMN and Sn functional connectivity disorders in focal epilepsy patients.Objective:The main purpose of this study is to examine whether the structural covariance connectivity of DMN and Sn in MRI negative focal epilepsy patients affects brain network function,which leads to dysfunction.Method:16 patients with MRI negative focal epilepsy and 22 healthy controls were included in this study.1)Obtain T1 structure image of each participant.2)The structure covariance connectivity of DMN and Sn in FE patients was studied by seed based structural covariance connectivity.3)Further changes in gray matter volume in the brain area of the patient show changes in structural connectivity.4)The results were analyzed by spss22.0 software.Result:1)We found that the connectivity of the posterior cingulate cortex and the left medial prefrontal cortex,hippocampus and orbital frontal cortex in patients with focal epilepsy was lower than that of the control group,while the connectivity between the right frontal Island cortex and the left insular lobe and orbital frontal cortex was decreased,and the connectivity of the inferior prefrontal cortex and the right medial prefrontal cortex decreased.2)The loss of gray matter volume is also found in the areas of significantly lower structural covalent connectivity in the brain of patients with focal epilepsy.Conclusion:The decrease of structural connectivity of DMN and Sn may be related to atrophy of gray matter in patients.These results highlight the important role of DMN and Sn in the pathology of nl-FE patients,and provide the structural basis for these two kinds of network dysfunction.chapter three Track-based spatial statistics diffusion tensor imaging research for non-lesion focal epilepsy and idiopathic comprehensive epilepsyBackground:Epilepsy,according to the consensus of the International League Against Epilepsy(ILAE)in 2017,is conceptually defined as a short-term sign and/or symptom caused by abnormal excessive or synchronous neuronal activity in the brain.Epilepsy has long been considered a gray matter disease.With the development of diffusion tensor imaging technology,the integrity of white matter in the whole brain can be quantified without any damage.The regional specificity and the overall white matter integrity changes in epilepsy patients are also found.Because of the non-invasive nature of DTI,DTI has become a common technology to study nervous system diseases,and can visualize the white matter pathway of human brain.In recent years,DTI has made great progress in the research of epilepsy,especially in enhancing our understanding of epilepsy as a kind of network obstacle.Focal epilepsy(FE)and Generalized epilepsy(GE)are the most common epilepsy.Patients have extensive white matter abnormalities.Non-lesion focal epilepsy(nl-FE)is an important sub group of focal epilepsy,the image character is normal(or negative).Patients with idiopathic generalized epilepsy(IGE)usually have normal interval state and no neurofocal defects.However,there are relatively few comparative studies on the two groups.Objective:To investigate the diffusing tensor changes of the nl-FE,IGE and healthy control group(HC),evaluated and compared by using the Track-based spatial statisticsMethod:The diagnostic criteria of epilepsy are based on the diagnostic criteria for epilepsy and epilepsy syndrome proposed by the International Association Against Epilepsy(ILAE)in 2005.19 patients were negative focal epilepsy(8 were female and 11 were male),with an average age of 26.05 ± 6.67 years;16 patients with idiopathic comprehensive epilepsy(10 were female and 6 were male),The average(24.69 ±6.55)years old and 24 volunteers with no difference in HC age and gender were(28.33 ± 3.76)who received epilepsy package scan(T1,T2,FLAIR)to diagnose and locate.After excluding other intracranial lesions,DTI and 3d-T1 were scanned.1)The mean diffusion rate(MD)was significantly different in the white matter area of the brain between the two groups.2)The relationship between FA and MD parameters and the age and duration of epilepsy was evaluated.Result:1)FA decreased and MD increased in multiple brain regions in epilepsy group;FA of left Superior corona radiate and left Superior longitudinal fasciculu in IGE group were significantly lower than those in control group.FA in the body of corpus callosum of nl-FE group was lower than that of HC.FA in left Superior corona radiate and the body of corpus callosum of nl-FE group was lower than that of IGE group.2)The MD values of left cingulate gyrus,right cingulate gyrus and right inferior fronto-occipital tract were significantly increased in nl-FE and IGE groups.3)FA value of the body of corpus callosum in nl-FE group was negatively correlated with the duration of onset;MD value of left and right cingulate gyrus in nl-FE group and right cingulate gyrus in IGE group was positively correlated with the duration of onset.Conclusion:Our study showed that nl-FE and IGE patients showed similar regional specificity and overall white matter integrity changes,with overlapping in some brain regions and differences in some brain regions.DTI is of great significance in showing the structural changes of white matter in patients with epilepsy. |
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