质子磁共振波谱分析定量检测肝脏脂肪含量方法的建立与临床应用

Measurement of intrahepatic triglyceride stores by ^1H magnetic resonance spectroscopy： study with rat models and in patients

目的在动物水平和人体水平评价质子磁共振波谱分析（^1H MRS）定量检测肝脏脂肪含量的稳定性和精确性，初步建立应用^1HMRS无创性定量检测肝脏脂肪含量的方法。方法建立Wistar大鼠脂肪肝动物模型，应用^1H MRS测定并计算肝脏脂肪峰与水峰的峰下面积比值，与肝组织病理切片脂肪染色测定的脂肪含量百分比进行比较，应用^1H MRS测定方法对11例脂肪肝患者进行初步检测评价。结果应用^1H MRS在高脂饮食组大鼠肝脏内检测到了脂肪峰，在脂肪肝患者中亦检测到稳定的脂肪峰。动物水平，脂肪峰与水峰的峰下面积比值（0．22）与病理学测定肝脏脂肪含量（5．45％）呈高度正相关（r=0．899，P〈0．001）；人体水平，脂肪含量（45％）与面积比值（0．45）呈高度正相关（r=0．814，P〈0．001）。结论在动物水平建立了应用^1H MRS定量检测肝脏脂肪含量的方法，并在人体水平验证其与病理学测定之间相关性良好。

Objective To evaluate the accuracy of proton magnetic resonance spectroscopy （^1H MRS） in quantitative measurement of intra-hepatic triglyceride （TG） stores in fatty liver at the levels of animal model and human body. Methods 40 male Wistar rats were randomly divided into 2 equal groups： fatty liver model group, fed with high fat diet for 16 weeks, and control group, fed with standard diet. Every 4 weeks 5 rats from each group underwent ^1H MRS to examine the intra-hepatic triglyceride contents and then were sacrificed. The liver tissues were stained with Sudan Ⅲ to detect the fat content. Eleven hospitalized patients with fatty liver suspected or confirmed by CT and with indications of liver puncture underwent ^1H MRS and then liver puncture within 7 days. Linear regression was conducted to analyze the correlation between the results of ^1H MRS and liver pathology. Results Intrahepatic lipid was detected in all the rat models, some rats of the control group, and the patients with fatty live. The lipid peak area and the ratio of the CH2 lipid peak area relative to the water peak area increased along with the duration of high fat diet feeding. In the rat models there was a close positive correlation between the hepatic TG content measured in vivo by ^1H MRS and pathological measurement of liver fat content [r = 0. 899; P 〈0001 ; slope 14.45; y- intercept -0.51 ]. The similar correlation existed in the patients too [ r = 0. 814; P 〈0001 ; slope 33.72; y-intercept 27.04 ]. When the data of the rats and patients were analyzed together, the percentage of liver fat was highly positively correlated with the ratio of area under fat peak to the area under water peak （ r = 0. 878 ; P 〈 0001 ; slope 56.33 ; y-intercept - 0.68）. Conclusion A relative quantitative method to measure intrahepatic lipid content by ^1H MRS, a safe, non-invasive method, is primarily established at the animal level and has been verified in humans with a good correlation with the pathological examination.