Background & Aims: Numerous studies have demonstrated thalamus-related structural, functional, and metabolic abnormalities in minimal hepatic encephalopathy (MHE). We conducted the first study to investigate thalamic structural connectivity alterations in MHE. Methods: DTI-based probabilistic tractography was employed to determine the structural linkage between thalamus and cortical/subcortical regions in 52 cirrhotic patients [22 with MHE; 30 without MHE (NHE)], and 30 controls. We measured these thalamic connections, which included connectivity strength (CS), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), and then compared these among three groups. Neurocognitive assessment was also performed. Correlation analysis was conducted to investigate the relationship between neurocognitive performance and the above measurements. Classification analysis was performed to determine whether thalamic connection measurements can distinguish MHE from NHE. Results: The probabilistic tractography revealed thalamic structural connections, which were disrupted in cirrhotic patients (as reflected by a decrease in CS/FA and an increase in MD/AD/RD). Abnormal thalamic connections primarily involved prefrontal cortex, sensorimotor cortex, parietal cortex, medial temporal cortex and hippocampus, and striatum. Thalamic connectivity abnormalities deteriorated from NHE to MHE, and they were correlated with patients’ neurocognitive performance. The moderate classification accuracy was obtained using CS and MD as discriminating index. Conclusion: Our results demonstrated the altered thalamic structural connectivity involving both cortical and subcortical regions in MHE, which could be regarded as a representative of the MHE-related widespread impairments in white matter pathways. The disturbed thalamic connectivity may underlie the mechanism of cognitive deficits in MHE and may potentially be utilized as a biomarker for diagnosing MHE and in monitoring disease progression. In addition to thalamic-cortical/subcortical connections, further studies are recommended to explore the structural alterations in other white matter pathways in MHE.

中文翻译：

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轻度肝性脑病的丘脑结构连接异常

背景和目的：大量研究表明，轻度肝性脑病 (MHE) 中丘脑相关的结构、功能和代谢异常。我们进行了第一项研究以调查 MHE 中的丘脑结构连接性改变。方法：采用基于 DTI 的概率纤维束成像来确定 52 名肝硬化患者的丘脑和皮质/皮质下区域之间的结构联系 [22 名患有 MHE；30 没有 MHE (NHE)]，和 30 控制。我们测量了这些丘脑连接，包括连接强度 (CS)、分数各向异性 (FA)、平均扩散率 (MD)、轴向扩散率 (AD) 和径向扩散率 (RD)，然后在三组之间进行比较。还进行了神经认知评估。进行相关分析以研究神经认知表现与上述测量之间的关系。进行分类分析以确定丘脑连接测量是否可以区分 MHE 和 NHE。结果：概率纤维束成像显示丘脑结构连接，在肝硬化患者中被破坏（表现为 CS/FA 减少和 MD/AD/RD 增加）。异常的丘脑连接主要涉及前额叶皮层、感觉运动皮层、顶叶皮层、内侧颞叶皮层和海马以及纹状体。丘脑连接异常从 NHE 到 MHE 恶化，并且与患者的神经认知表现相关。使用 CS 和 MD 作为判别指标，获得了中等的分类精度。结论：我们的研究结果表明，MHE 中涉及皮质和皮质下区域的丘脑结构连接发生了改变，这可以被视为白质通路中与 MHE 相关的广泛损伤的代表。被扰乱的丘脑连接可能是 MHE 认知缺陷机制的基础，并且可能被用作诊断 MHE 和监测疾病进展的生物标志物。除了丘脑-皮质/皮质下连接外，建议进一步研究以探索 MHE 中其他白质通路的结构改变。被扰乱的丘脑连接可能是 MHE 认知缺陷机制的基础，并且可能被用作诊断 MHE 和监测疾病进展的生物标志物。除了丘脑-皮质/皮质下连接外，建议进一步研究以探索 MHE 中其他白质通路的结构改变。被扰乱的丘脑连接可能是 MHE 认知缺陷机制的基础，并且可能被用作诊断 MHE 和监测疾病进展的生物标志物。除了丘脑-皮质/皮质下连接外，建议进一步研究以探索 MHE 中其他白质通路的结构改变。