Department of Diagnostic Radiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
PLoS One. 2012;7(5):e36986. doi: 10.1371/journal.pone.0036986. Epub 2012 May 18.
Cerebral edema, a well-known feature of acute liver disease, can occur in cirrhotic patients regardless of hepatic encephalopathy (HE) and adversely affect prognosis. This study characterized and correlated functional HE abnormalities in the brain to cerebral edema using resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI). Forty-one cirrhotic patients (16 without HE, 14 minimal HE, 11 overt HE) and 32 healthy controls were assessed. The HE grade in cirrhotic patients was evaluated by the West Haven criteria and neuro-psychological examinations. Functional connectivity correlation coefficient (fc-CC) of the default mode network (DMN) was determined by rs-fMRI, while the corresponding mean diffusivity (MD) was obtained from DTI. Correlations among inter-cortical fc-CC, DTI indices, Cognitive Ability Screening Instrument scores, and laboratory tests were also analyzed. Results showed that gradual reductions of HE-related consciousness levels, from "without HE" or "minimal HE" to "overt HE", correlated with decreased anterior-posterior fc-CC in DMN [F(4.415), p = 0.000)]. The MD values from regions with anterior-posterior fc-CC differences in DMN revealed significant differences between the overt HE group and other groups. Increased MD in this network was inversely associated with decreased fc-CC in DMN and linearly correlated with poor cognitive performance. In conclusion, cerebral edema can be linked to altered cerebral temporal architecture that modifies both within- and between-network connectivity in HE. Reduced fc-CC in DMN is associated with behavior and consciousness deterioration. Through appropriate targets, rs-fMRI technology may provide relevant supplemental information for monitoring HE and serve as a new biomarker for clinical diagnosis.
脑水肿是急性肝疾病的一个显著特征，无论是否存在肝性脑病 (HE)，都会在肝硬化患者中发生，并对预后产生不利影响。本研究采用静息态功能磁共振成像（rs-fMRI）和弥散张量成像（DTI），对大脑中功能性 HE 异常与脑水肿的关系进行了特征描述和相关性分析。共纳入 41 例肝硬化患者（16 例无 HE，14 例轻微 HE，11 例显性 HE）和 32 例健康对照者。采用 West Haven 标准和神经心理学检查对肝硬化患者的 HE 分级进行评估。通过 rs-fMRI 确定默认模式网络（DMN）的功能连接相关系数（fc-CC），通过 DTI 获得相应的平均弥散度（MD）。还分析了皮质间 fc-CC、DTI 指标、认知能力筛查工具评分与实验室检查之间的相关性。结果表明，随着 HE 相关意识水平从“无 HE”或“轻微 HE”逐渐降低到“显性 HE”，DMN 的前后 fc-CC 逐渐降低[F(4.415)，p = 0.000)]。DMN 中前后 fc-CC 差异区域的 MD 值在显性 HE 组与其他组之间存在显著差异。该网络中的 MD 值增加与 DMN 中的 fc-CC 降低呈负相关，与认知功能下降呈线性相关。结论：脑水肿可能与大脑时间结构的改变有关，从而改变 HE 患者脑内和脑间的连接。DMN 中的 fc-CC 降低与行为和意识恶化有关。通过适当的靶点，rs-fMRI 技术可能为监测 HE 提供相关的补充信息，并作为临床诊断的新生物标志物。
