MRI Study Of Brain In Cirrhoticpatients Based By Surface-based Morphometry And Resting-state Network Analysis Method

Research background Hepatitis B virus(HBV)related cirrhosis is one of the major clinical problems of liver diseases.About 40% of patients with HBV-related cirrhosis exhibit severe complications,such as neurological impairment.Clinical symptoms of cirrhosis-related neurological impairment include hepatic encephalopathy,slow response,cortical blindness and attention deficit.However,the structural basis and pathophysiological mechanism of cerebral hypofunction related to cirrhosis are still unclear.Magnetic resonance imaging(MRI)has been widely used in the diagnosis and research of disease related brain changes.Structural MRI studies have shown that cirrhotic patients exhibit extensive cirrhosis-related brain morphological changes and neuroanatomic abnormalities,such as leukopenia and gray matter loss in cirrhotic patients.Previous quantitative gray tissue concentrations were based on voxel morphometry(VBM),and there was a potential inaccuracy in the standardization of VBM when compared directly with two different groups of participants.Surface morphometry(SBM)using non-linear aligned cortical folding patterns provides accurate standardization of participants’ brains,which may be useful in examining cortical morphology.By measuring cortical thickness,gray to white matter contrast(GWC),surface area,cortical volume,cortical microstructure and macrostructure,SBM provides the possibility to reveal the mechanism of brain changes and clarify the neural problems associated with cirrhosis.Previous studies have focused on observing changes in the whole brain in cirrhotic patients,but little is known about abnormalities in specific brain areas,especially in visual-related brain areas,in cirrhotic patients.A few cases of cirrhosis have reported that visual-related brain areas are affected in patients with cirrhosis and may cause transient blindness.This blindness is thought to be affected by visual cortex,cortical blindness associated with hepatic encephalopathy.Although blindness is rare in patients with hepatic encephalopathy,visual impairment has been reported in cirrhotic patients without hepatic encephalopathy.However,the pathophysiology of how cirrhosis affects functional changes in visual related regions is unclear.Brain network analysis method can provide a new way to understand the process of human brain function and study the brain structure of dysfunction in brain changes.A growing body of evidence suggests that a systematic study of different brain networks can provide an important perspective to reveal the mechanism of brain changes.As far as the authors know,none of the MRI studies used brain network analysis to study changes in visual related areas,which may provide a systematic perspective for systematic insight into visual related areas.A more comprehensive view of cirrhosis.Therefore,brain network analysis may be a useful method to further quantify the pathophysiological changes associated with disease in these regions.Research objectives(1)Study one: To study the changes of GWC,thickness,surface area,cortical volume and cortical folding structure in cirrhotic patients.(2)study two: study the neurological changes in visual related areas of cirrhotic patients.Research methods(1)Study one: 3D T1-weighted MRI data were collected from 18 patients with HBV associated cirrhosis,without clinical symptoms of hepatic encephalopathy (CSHE)and 18 healthy controls(HC).We used Free Surfer to assess changes in GWC,thickness,surface area,cortical volume,and cortical folding between groups,and their relationship to ammonia levels in the patient group.Based on the SBM study,a linear SVM classifier is then used to distinguish patients and HC groups.(2)Study two: Structural and functional MRI data were collected from 20 HBV related cirrhosis patients without hepatic encephalopathy and 20 HC.Voxel-based morphometry(VBM)and brain network analysis were performed to detect abnormalities in brain structure and function.Research results(1)Study one: Compared with the control group,SBM analysis showed a significant increase in GWC in a wide area of the cortex and mantle in cirrhotic patients,while other SBM measurements showed no significant difference.Correlation analysis showed that there was a significant correlation between serum ammonia level and GWC in the left pericalcarine.Using the GWC values from important regions as features,the linear SVM showed classification accuracy of83.3% and sensitivity of 88.9%.(2)Study two: The most significant reduction in regional gray matter in cirrhotic patients was mainly in the visual-related brain regions,including bilateral lingual gyrus,left putamen,right fusiform gyrus,right talus gyrus,and other significant decreases in the gray matter were distributed in bilateral hippocampus.Based on a structural survey of visual-related areas,brain network analysis showed that the functional connectivity between brain networks in the visual-related areas(main visual network(PVN),high visual network(HVN),and visual spatial network(VSN)in the patient group was lower than that in the HC group.Research conclusion(1): The changes of GWC in patients with cirrhosis are mainly located in the areas related to vision and movement,which may reflect the microstructure changes of gray matter and white matter in these areas.Based on SVM classification,GWC may help diagnose and provide preventive interventions for cirrhotic patients.(2): The structure and function of the visual-related brain regions in cirrhotic patients without hepatic encephalopathy were significantly impaired.However,the pathophysiology and clinical relevance of these changes have not been determined.