Study On Brain Network Of Patients With Vascular Cognitive Impairment Based On Multimodal Analysis Of Magnetic Resonance

Objective1.By collecting and analyzing the structural phase and resting magnetic resonance data,the differences of brain network between patients with vascular cognitive impairment(VCI)and normal persons was studied by graph theory analysis,and the correlation between the topological properties of brain network and clinical cognitive score was analyzed to explore the neurological mechanism of cognitive function changes in patients with VCI.2.To explore and analyze the relationship between the topological properties of VCI brain network and TCM syndromes,TCM classification was conducted according to different symptoms of patients with VCI,and the brain area differences between the node flexibility of resting state magnetic resonance network in patients with different syndromes of VCI and normal patients were analyzed.The topological properties of brain network in the group with liver-kidney Yin deficiency and the group with kidney deficiency group were compared and analyzed.Methods1.28 patients with VCI were included as the case group(male:16 cases,female:12 cases),and 30 patients with normal cognitive function(male:13 cases,female:17 cases)were included as the control group.The structural phase and resting state brain networks were constructed and the topological properties and local topological properties of the whole brain network were calculated.Using GRETNA software package and taking gender,age and education level as covariables,two independent sample t tests were used to compare the differences between global and local topological attribute indexes of the two groups of subjects.Under the control of gender,age and education level,partial correlation analysis method was adopted to analyze the correlation between network topology attribute indexes with inter-group differences in VCI group and MoCA score,respectively.2.According to the comprehensive evaluation of clinical and imaging data,a total of 36 patients were diagnosed as VCI patients,including 20 males and 16 females.30 patients with normal cognitive function(13 males and 17 females)were selected as controls.On the basis of TCM syndrome differentiation criteria,the patients were mainly divided into four types,namely qi deficiency and blood stasis,kidney deficiency,liver and kidney Yin deficiency,and phlegm turbidity obstruction.Using GRETNA software package,gender,age and education level as covariates,two independent samples t tests were used to compare and analyze the differences of brain network node flexibility between VCI patients with different syndromes and normal subjects,and two independent samples t-test was used to analyze the differences of brain network topological attributes between liver-kidney Yin deficiency group and kidney deficiency group.Results1.Results in morphological brain network analysis based on gray matter volume:Within the range of sparsity of 0.0507-0.3907 and step size of 0.02,the clustering coefficients of VCI group and control group after standardization were much larger than 1,and the shortest path length was about 1,which all accorded with "small world attributes".Taking sex,age and education level as covariates,the global properties of morphological brain network in VCI group and normal group were analyzed.There was no significant difference between them(clustering coefficient t=1.267 P=0.211,shortest path length t=-1.561 P=0.125,global efficiency t=1.485 P=0.144,modular t=-0.836 P=0.407),P>0.05.2.Local topological properties of T1 brain structure networks in the VCI group and the control group.(1)Compared with the control group,the intermediate centrality of nodes in the right superior frontal gyrus,right inferior frontal gyrus and paraorbital gyrus,left posterior cingulate gyrus,right corpus callosum fissure,peripheral cortex and left superior occipital gyrus in the VCI group was significantly reduced,while the intermediate centrality of nodes in the right temporal gyrus was significantly increased in the VCI group(P<0.05).(2)Compared with the control group,the nodal degree of VCI group in the left olfactory cortex and left thalamus was significantly reduced,while the nodal degree of VCI group in the left superior occipital gyrus and left temporal gyrus was significantly increased(P<0.05).(3)Compared with the control group,the node efficiency of VCI group in the left olfactory cortex,right lenticular nucleus and pallidum,left hypothalamus was significantly reduced,while node efficiency of VCI group in the left superior occipital gyrus was significantly increased(P<0.05).3.Results in the whole brain functional network analysis:Within the range of 0.1-0.4 sparsity and 0.05 step size,the clustering coefficients of VCI group and control group after standardization are far greater than 1,and the shortest path length is about 1,which conforms to the "small world attribute".Taking sex,age and education level as covariates,the global attributes of the whole brain functional network in VCI group and normal group were analyzed.The results showed that there was no significant difference between the two groups(synchrony t=-0.846 P=0.402,small world index 0.247 P=0.806,global efficiency t=0.427 P=0.671,coordination 309 P=0.759),P>0.05.4.Local topological properties of resting state brain networks in the VCI group and the control group.(1)Compared with the control group,the node efficiency of VCI group in the right ventromedial prefrontal cortex was significantly reduced,and the node efficiency of the lower part of the right cerebellar hemisphere was significantly increased(P<0.05).(2)Compared with the control group,the intermediate centrality of nodes in the left anterior cuneate lobe,the left inferior parietal lobule,the right dorsal anterior cingulate gyrus,the right fusiform gyrus and the left occipital lobe was significantly reduced in the VCI group,and the intermediate centrality of nodes in the right parietal sulcus and the left temporal lobe was significantly increased in the VCI group(P<0.05).(3)Compared with the control group,the node flexibility of the right parietal sulcus,the left posterior cingulate gyrus,the left temporal lobe and the lower part of the left cerebellum was significantly reduced in the VCI group,and the node flexibility of the right hemispheric occipital lobe was significantly increased in the VCI group(P<0.05).5.Correlation analysis of functional brain network topology attribute index and cognitive scale in VCI group:Under the control of gender,age and education level,local topological properties of brain functional network in multiple brain regions in the VCI group were correlated with cognitive scores.The right anterior cingulate gyrus(r=-0.467,P=0.012)and the posterior left occipital lobe(r=-0.466,P=0.012)were negatively correlated with MoCA score.The node efficiency of the left ventromedial prefrontal cortex(r=-0.397,P=0.037)and the node efficiency of the posterior right cingulate gyrus(r=-0.423,P=0.025)were negatively correlated with MoCA score.The node flexibility of the right dorsolateral prefrontal cortex(r=-0.399,P=0.035)and the node flexibility of the posterior right occipital lobe(r=-0.387,P=0.042)were negatively correlated with MoCA score.However,in the left hemisphere,the internode centrality(r=0.514,P=0.005)and node flexibility(r=0.393,P=0.039)were positively correlated with MoCA.6.Differences in brain network node flexibility between different TCM syndromes VCI and the normal control group.(1)Compared with the control group,node flexibility in the qi deficiency and blood stasis group was significantly reduced in the left parietal lobe,left temporal lobe and right temporal lobe(P<0.05).(2)Compared with the control group,the node flexibility in the kidney deficiency group was significantly reduced in the right anterior cingulate gyrus,left thalamus,right temporal lobe and left temporal lobe,and significantly increased in the right precuneus(P<0.05).(3)Compared with the control group,the node flexibility in the liver-kidney Yin deficiency group was significantly decreased in the right upper frontal lobe,left precuneus,right lateral ventral prefrontal lobe,right middle insula lobe,right temporal lobe,ventral frontal lobe,auxiliary motor area,and left lateral cerebellum,and significantly increased in the basal ganglia(P<0.05).(4)Compared with the control group,the node flexibility in the phlegm turbidity obstruction group was significantly decreased in the right precuneus,the left posterior insula,and significantly increased in the left lower temporal lobe,the left temporal lobe,and the right occipital lobe(P<0.05).7.Differences in topological properties of brain network between the VCI kidney deficiency group and the liver-kidney Yin deficiency group.(1)Compared with the kidney deficiency group,the node efficiency of the liver-kidney Yin deficiency group was significantly decreased in the right posterior cingulate gyrus,left posterior cingulate gyrus,right occipital lobe,left middle insula lobe and left lower cerebellum(P<0.05).(2)Compared with the kidney deficiency group,the node intermediate centrality of the liver-kidney Yin deficiency group was significantly increased in the right lower temporal lobe,the left parietal lobe,the ventral frontal lobe and the left occipital lobe(P<0.05).(3)Compared with the kidney deficiency group,the node flexibility of the liver-kidney Yin deficiency group was significantly decreased in the left posterior cingulate gyrus,left occipital lobe and auxiliary motor area,and significantly increased in the left superior frontal lobe(P<0.05).Conclusion1.In the analysis of brain network based on morphology and resting state,the global brain network of VCI group and control group accorded with "small world property".By analyzing the attributes of brain network nodes,we found that default network,occipital visual network,prefrontal advanced cognitive control network and cerebellum may play a key role in VCI-related cognitive impairment,which provides a new perspective for the study of the pathogenesis of vascular cognitive impairment.2.In this study,there is a linear correlation between brain network indicators such as node-mediated centrality,node efficiency,node flexibility and cognitive score,suggesting that node-mediated centrality,node efficiency and node flexibility can be used as imaging markers reflecting VCI to some extent,and can be used for early clinical diagnosis,individualized treatment,course monitoring,dynamic observation and prognosis evaluation of VCI.3.Compared with normal subjects,the flexibility of brain network nodes in VCI patients with different syndromes is significantly different in many brain regions.The clinical manifestations of different syndromes may be related to the flexibility of brain network nodes to some extent.The pathogenesis of various clinical syndromes in VCI patients with different syndromes can be clarified to some extent by analyzing the flexibility of brain network nodes.4.Through the analysis of brain network attributes of liver-kidney Yin deficiency group and kidney deficiency group with similar clinical syndromes,it was found that there were significant differences in brain network topological attributes such as node-mediated centrality,node efficiency and node flexibility between the two groups.It was revealed that there might be many differences in clinical pathological mechanism between the two groups.