Department of Radiology, Fujian Medical University Union Hospital, Fuzhou, 350001, China.
Department of Interventional Radiology, Fujian Medical University Union Hospital, Fuzhou, 350001, China.
Metab Brain Dis. 2019 Dec;34(6):1519-1529. doi: 10.1007/s11011-019-00457-6. Epub 2019 Jul 30.
The hippocampus is a crucial pathological node for minimal hepatic encephalopathy (MHE) and it is associated with various cognitive impairments. Investigations on alterations involving hippocampal morphology and functional connectivity (FC) in MHE are limited. This study aimed to simultaneously evaluate hippocampal volume and FC alterations and their association with cognitive decline in MHE. Twenty-two cirrhotic patients with MHE, 31 cirrhotic patients without MHE (NHE), and 43 healthy controls underwent high-resolution T1-weighted imaging, resting-state functional magnetic resonance imaging, and cognition assessment based on Psychometric Hepatic Encephalopathy Score (PHES). The structural images were preprocessed using a voxel-based morphometry method, during which hippocampal volume was measured. The hippocampal connectivity network was identified using seed-based correlation analysis. Hippocampal volume and FC strength were compared across the three groups and correlated against the PHES results of the cirrhotic patients. Compared to the controls, MHE patients exhibited a significantly lower bilateral hippocampal volume. A slight decrease in hippocampal volume was obtained from NHE to MHE, but it did not reach statistically significance. In addition, the average FC strength of the bilateral hippocampal connectivity network was significantly lower in the MHE patients. In particular, the MHE patients showed a decrease in FC involving the left hippocampus to bilateral posterior cingulate gyrus and left angular gyrus. The MHE patients also showed FC reduction between the right hippocampus and bilateral medial frontal cortex. A progressive reduction in hippocampal FC from NHE to MHE was also observed. The bilateral hippocampal FC strength (but not hippocampal volume) was positively correlated with the PHES results of the cirrhotic patients. Our assessment of MHE patients revealed decreased hippocampal volume, which suggests regional atrophy, and reduced hippocampal connectivity with regions that are primarily involved in the default-mode network, thereby suggesting a functional disconnection syndrome. These alterations reveal the mechanisms underlying cognitive deterioration with disease progression.
海马体是轻微型肝性脑病（MHE）的关键病理节点，与各种认知障碍有关。关于 MHE 中海马形态和功能连接（FC）改变的研究有限。本研究旨在同时评估 MHE 中海马体积和 FC 的改变及其与认知衰退的关系。22 例 MHE 肝硬化患者、31 例非 MHE（NHE）肝硬化患者和 43 例健康对照者接受了高分辨率 T1 加权成像、静息态功能磁共振成像和基于心理测肝性脑病评分（PHES）的认知评估。结构图像采用基于体素的形态测量方法进行预处理，在此过程中测量了海马体体积。使用基于种子的相关分析确定海马连接网络。比较了三组之间的海马体体积和 FC 强度，并与肝硬化患者的 PHES 结果进行了相关性分析。与对照组相比，MHE 患者双侧海马体体积明显降低。从 NHE 到 MHE，海马体体积略有下降，但无统计学意义。此外，MHE 患者双侧海马连接网络的平均 FC 强度明显降低。特别是，MHE 患者的左侧海马与双侧后扣带回和左侧角回的 FC 降低。MHE 患者还显示右侧海马与双侧内侧额皮质之间的 FC 减少。还观察到从 NHE 到 MHE 的海马 FC 逐渐减少。双侧海马 FC 强度（而非海马体体积）与肝硬化患者的 PHES 结果呈正相关。我们对 MHE 患者的评估显示，海马体体积减小，提示区域性萎缩，以及与主要参与默认模式网络的区域的海马体连接减少，这表明存在功能连接中断综合征。这些改变揭示了疾病进展中认知恶化的潜在机制。
