3.0T MRS 对肝性脑病的研究初探

A preliminary study of MR spectroscopy in hepatic encephalopathy with 3.0T MR system

摘要:

目的 应用磁共振氢质子波谱（1H-MRS）技术对肝性脑病（HE）患者后扣带回和右侧苍白球区 进行检测，研究脑代谢物的变化及其与血氨、神经心理学测试和Child 分级的相关性。方法 20 例经临床检查证 实的肝性脑病患者（HE 组）和20 例健康志愿者（对照组）纳入本研究。所有研究对象在MRI 检查前进行数 字连接实验-A（NCT-A）及数字符号实验（DST）。均行后扣带回和右侧苍白球的1H-MRS 扫描，观测指标为： N- 乙酰天门冬氨酸（NAA）、胆碱复合物（Cho）、肌酸（Cr）及肌醇（mIns）曲线下面积，记录HE 组患者的静 脉血氨值并进行Child-Pugh 分级。结果 与对照组比较，HE 组后扣带回和右侧苍白球脑区的Cho/Cr、mIns/Cr 值降低，差异有统计学意义（P <0.05），NAA/Cr 的差异无统计学意义（P >0.05）。HE 组后扣带回、右侧苍 白球的mIns/Cr 及Cho/Cr 指标与血氨呈负相关（P <0.05），后扣带回、右侧苍白球的mIns/Cr 与NCT-A、 DST 存在相关性（P <0.05），后扣带回、右侧苍白球的mIns/Cr 及Cho/Cr 指标与Child-Pugh 分级呈负相关（P < 0.05）。结论 本研究证实1H-MRS 可从代谢水平揭示HE 患者认知功能相关脑区存在相应的病理改变，后扣 带回、右侧苍白球的Cho/Cr 比值下降可能是HE 患者认知障碍的重要生物学标志。

Abstract:

Objective To compare the differences of the posterior cingulate gyrus and the right globus pallidus by proton magnetic resonance spectroscopy (1H-MRS) between the patients with hepatic encephalopathy (HE) and the patients without HE, and discuss the changes of brain metabolism and their correlations with blood ammonia, neuropsychological tests and Child classification. Methods In this study 20 patients with HE proven by clinical examinations (HE group) and 20 healthy volunteers (control group) were investigated. All patients were subjected to number connectivity test-A (NCT-A) and digit symbol test (DST) before MRI examination. 1H-MRS of the posterior cingulate gyrus and the right globus pallidus was performed. The observation indexes were N-acetylaspartate (NAA), choline complex (Cho), creatine (Cr) and inositol (mIns), then their ratios such as NAA/Cr, Cho/Cr, mIns/ Cr were counted and assessed with statistical analysis. Venous blood ammonia values were recorded and Child- Pugh classification was performed in the patients of HE. Results Compared with the control group, mIns and Cho in the posterior cingulate gyrus and the right globus pallidus were decreased in the HE group, there was no statistical significance in the difference of NAA. The mIns/Cr and Cho/Cr ratios in the posterior cingulate gyrus and the right globus pallidus were negatively correlated with the serum ammonia level in the patients (P < 0.05). In the HE group, the mIns/Cr ratios in the posterior cingulate gyrus and the right globus pallidus were correlated with NCT-A and DST (P < 0.05), the mIns/Cr and Cho/Cr ratios in the posterior cingulate gyrus and the right globus pallidus were negatively correlated with the Child-Pugh classification in the patients (P < 0.05). Conclusions 1H-MRS can reveal the pathological changes in the brain areas related to cognitive function of the patients with hepatic encephalopathy which can be confirmed from the metabolic level. The decrease of Cho/Cr ratio in the posterior cingulate gyrus and the right globus pallidus may be one of the most important biomarkers of cognitive dysfunction in the patients with hepatic encephalopathy.