Lu-Bin Gou1, Wei Zhang2, Da-Jing Guo2, Wei-Jia Zhong2, Xiao-Jia Wu2, Zhi-Ming Zhou2. 1. Department of Radiology, First Hospital of Lan Zhou University, Gansu, China. 2. Department of Radiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Abstract
PURPOSE: We aimed to investigate the multilevel impairments of brain structural network in patients with minimal hepatic encephalopathy (MHE). METHODS: Twenty-two patients with MHE and 22 well-matched healthy controls (HC) underwent structural magnetic resonance imaging (MRI) brain scans and neuropsychological evaluations. Individual brain structural networks were constructed using diffusion tensor imaging. Comparing with HC, we investigated the possible impairments of brain structural network in MHE, by applying graph-theory approaches to analyze the topological organization at global, modular, and local levels. The correlations between altered brain structural network and neuropsychological tests scores and venous ammonia levels were also examined in MHE patients. RESULTS: In the MHE group, small-worldness showed significant decrease and normalized characteristic path length showed increase at the global level. In the modular section, six modules were identified. The inter-modular connective strengths showed significant increase between modules 2 and 4 and between modules 4 and 5. The results of node analysis showed similar hub distributions in the MHE and HC groups except for the right postcentral gyrus, which was only found in the MHE group. No significant differences were found in connective strength of edges between MHE and HC groups using network-based statistics. CONCLUSION: The altered brain structural networks with reduced network integration and module segregation were demonstrated in patients with MHE. The dysconnectivity of brain structural network could provide an explanation for the brain dysfunctions of MHE.
PURPOSE: We aimed to investigate the multilevel impairments of brain structural network in patients with minimal hepatic encephalopathy (MHE). METHODS: Twenty-two patients with MHE and 22 well-matched healthy controls (HC) underwent structural magnetic resonance imaging (MRI) brain scans and neuropsychological evaluations. Individual brain structural networks were constructed using diffusion tensor imaging. Comparing with HC, we investigated the possible impairments of brain structural network in MHE, by applying graph-theory approaches to analyze the topological organization at global, modular, and local levels. The correlations between altered brain structural network and neuropsychological tests scores and venous ammonia levels were also examined in MHE patients. RESULTS: In the MHE group, small-worldness showed significant decrease and normalized characteristic path length showed increase at the global level. In the modular section, six modules were identified. The inter-modular connective strengths showed significant increase between modules 2 and 4 and between modules 4 and 5. The results of node analysis showed similar hub distributions in the MHE and HC groups except for the right postcentral gyrus, which was only found in the MHE group. No significant differences were found in connective strength of edges between MHE and HC groups using network-based statistics. CONCLUSION: The altered brain structural networks with reduced network integration and module segregation were demonstrated in patients with MHE. The dysconnectivity of brain structural network could provide an explanation for the brain dysfunctions of MHE.
Authors: Graham L Baum; Rastko Ciric; David R Roalf; Richard F Betzel; Tyler M Moore; Russell T Shinohara; Ari E Kahn; Simon N Vandekar; Petra E Rupert; Megan Quarmley; Philip A Cook; Mark A Elliott; Kosha Ruparel; Raquel E Gur; Ruben C Gur; Danielle S Bassett; Theodore D Satterthwaite Journal: Curr Biol Date: 2017-05-25 Impact factor: 10.834