ABSTRACT
Objective To analyze the topological characteristics of the brain structural network in primary angle-closure glaucoma (PACG) patients by applying graph theoretical approaches.Methods From October 2015 to April 2017, nineteen PACG patients and nineteen gender-and age-matched healthy controls (HCs) were enrolled to undergo MRI scan. The whole brain was parceled into 90 regions by automated anatomical labeling template, and the brain structural network was constructed by the fiber distribution of continuous tracking method.Both the weighted and unweighted network analyses were performed.The global and regional properties were computed by graph theoretical analysis.To compare the brain network regional properties between two groups, two-sample t-test was utilized.The correlations between the brain structural network properties and clinical parameters were further analysed. Results Both two groups were found to follow the efficient small-world characteristics. Compared to HCs, the brain structural network in PACG patients showed no statistical significance in the small-worldness, average shortest path, clustering coefficient, global efficiency and local efficiency(P＞0.05). Compared to the HCs, the PACG patients showed decreased nodal efficiency in the right superior frontal gyrus, right inferior frontal gyrus, left median cingulate and paracingulate gyri, left amygdala and left cuneus(P＜0.05). Compared to HCs, the PACG patients showed decreased node degree in left superior frontal gyrus, medial orbital, right inferior frontal gyrus, left amygdala, left cuneus and left lingual gyrus(P＜0.05). Compared with the hub regions in healthy controls'network, we found that two hub regions disappeared.Those hubs were right inferior parietal lobule and left middle temporal gyrus. Node degree in left amygdala showed negatively correlated with visual ability (r=-0.679, P=0.001). Node degree in left lingual gyrus showed negatively correlated with vertical CDR(r=-0.791, P=0.001),which showed positively correlated with visual acuity(r=0.538, P=0.018).Conclusions The brain structural network in PACG patients showed small-worldness properties as HCs group. The alterations of local properties in visual, emotion-cognition brain regions were observed, manifesting that PACG can affect the topology properties of the structural brain network.