Huda A, Guze B H, Thomas A, Bugbee M, Fairbanks L, Strouse T, Fawzy F I
Department of Radiological Sciences, School of Medicine, University of California Los Angeles, USA.
Psychosom Med. 1998 Sep-Oct;60(5):550-6. doi: 10.1097/00006842-199809000-00006.
The purpose of this project was to correlate neuropsychological test results with in vivo measures of regional cerebral biochemistry determined by 1H MRS in patients with subclinical and mild hepatic encephalopathy.
Baseline 1H MRS scans and neuropsychological testing of patients occurred at entry into the study. The primary localized volume chosen for the 1H MRS study was the posteromedial parietal cortex, which consisted predominantly of white matter. Some of these patients were scanned again if they received a liver transplantation. In a subset of patients, the effect on cerebral biochemistry and neuropsychological test performance due to a dietary intervention of reduced protein intake was monitored. These patients underwent a baseline examination and a repeat examination after 2 weeks of dietary intervention. Measures were made of the correlation between the dietary intervention and 1H MRS determined biochemistry and the results of neuropsychological tests. Results in both patient groups (dietary intervention and no dietary intervention) were compared with healthy control subjects.
Subclinical and low grade HE patients showed a significant reduction in mI/Cr and Cho/Cr ratio when compared with healthy control subjects. These patients also showed impairment in frontal lobe mediated cognitive tasks and in motor ability that were not appreciated in a bedside examination. The patients did not return to normal cerebral metabolic states within 30 to 60 days of liver transplantation. In fact, reductions remained in mI/Cr. Cho/Cr values increased after transplantation compared with healthy control subjects.
1H MRS studies showed changes in regional cerebral biochemistry associated with all grades of HE. There was a reduction in mI/Cr and a reduction in Cho/Cr in patients with low grade and subclinical forms of HE compared with normal subjects. The reduction in mI correlated well with abnormalities observed in neuropsychological tests. Liver transplantation was not associated with significant improvement in these variables.
本项目旨在将亚临床和轻度肝性脑病患者的神经心理学测试结果与通过1H磁共振波谱（1H MRS）测定的局部脑生化指标的体内测量结果进行关联。
患者在进入研究时进行基线1H MRS扫描和神经心理学测试。1H MRS研究选择的主要局部体积是后内侧顶叶皮质，主要由白质组成。如果这些患者接受肝移植，则再次进行扫描。在一部分患者中，监测了蛋白质摄入量减少的饮食干预对脑生化和神经心理学测试表现的影响。这些患者在饮食干预2周后进行了基线检查和重复检查。测量了饮食干预与1H MRS测定的生化指标以及神经心理学测试结果之间的相关性。将两个患者组（饮食干预组和非饮食干预组）的结果与健康对照受试者进行比较。
与健康对照受试者相比，亚临床和低度肝性脑病患者的肌醇/肌酸（mI/Cr）和胆碱/肌酸（Cho/Cr）比值显著降低。这些患者在额叶介导的认知任务和运动能力方面也表现出损害，而床边检查未发现这些损害。患者在肝移植后30至60天内未恢复到正常脑代谢状态。事实上，mI/Cr仍保持降低。与健康对照受试者相比，移植后Cho/Cr值升高。
1H MRS研究显示与各级肝性脑病相关的局部脑生化变化。与正常受试者相比，低度和亚临床形式肝性脑病患者的mI/Cr和Cho/Cr降低。mI的降低与神经心理学测试中观察到的异常密切相关。肝移植与这些变量的显著改善无关。
