Kuang Yangying, Wu Xiaojia, Lai Hua, Wang Zhigang, Lei Qiang, Zhong Weijia, Yang Ya, Deng Chen, Zhou Zhiming
Department of Radiology, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
Department of Radiology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Ann Transl Med. 2021 Oct;9(20):1579. doi: 10.21037/atm-21-5109.
Although overt hepatic encephalopathy (OHE) patients were shown to have bilaterally symmetrical structural and functional abnormalities in the whole brain, few studies have focused on the bilateral cerebral hemisphere commissural fibers and measured functional coordination between bilateral hemispheres. This study aimed to investigate the structural changes of the corpus callosum (CC) and interhemispheric functional coordination in patients with OHE and to test the hypothesis that abnormal CC induced by OHE impairs interhemispheric functional coordination in cirrhosis patients.
The microstructural integrity and the volumes of each subregion of the CC were analyzed by diffusion tensor imaging (DTI) and three-dimensional T1-weighted imaging. Voxel-mirrored homotopic connectivity (VMHC) was derived from resting-state functional magnetic resonance imaging (MRI).
Compared with the healthy controls (HCs) and patients without hepatic encephalopathy (noHE), the OHE group showed decreased volumes in all subregions of the CC. In OHE patients, the decreased fractional anisotropy (FA) of CC-5 correlated with decreased VMHC in the middle occipital gyrus (MOG) and precuneus. The value of FA in CC-5 and the volumes of CC-3, CC-4, and CC-5 showed correlations with neuropsychological performance in patients with OHE.
These findings suggest that impairment of interhemispheric white matter pathways may disturb the functional connectivity associated with coordination and neurocognitive performance.
尽管有研究表明，显性肝性脑病（OHE）患者全脑存在双侧对称的结构和功能异常，但很少有研究关注双侧大脑半球连合纤维，也未对双侧半球间的功能协调性进行测量。本研究旨在探讨OHE患者胼胝体（CC）的结构变化及半球间功能协调性，并验证OHE导致的CC异常会损害肝硬化患者半球间功能协调性这一假说。
采用扩散张量成像（DTI）和三维T1加权成像分析CC各亚区的微观结构完整性和体积。体素镜像同伦连接性（VMHC）来自静息态功能磁共振成像（MRI）。
与健康对照（HC）组和无肝性脑病（noHE）患者相比，OHE组CC各亚区体积均减小。在OHE患者中，CC-5的分数各向异性（FA）降低与枕中回（MOG）和楔前叶的VMHC降低相关。OHE患者中，CC-5的FA值以及CC-3、CC-4和CC-5的体积与神经心理学表现相关。
这些发现表明，半球间白质通路受损可能会干扰与协调性和神经认知表现相关的功能连接。
