活体H磁共振波谱分析在大鼠脂肪肝中应用价值的初步研究

目的与磁共振化学位移成像方法对比,初步探讨1H MRS在脂肪肝中的诊断应用价值.方法对5只正常和13只不同程度脂肪肝(4只轻度,3只中度和6只重度)SD大鼠在临床用场强 1.5 T 核磁仪上进行磁共振成像(In phase和Out phase序列) 和1H MRS多体元化学位移成像自旋回波序列(2D CSI SE)对比检查.结果 1H MRS示5例正常肝脏在1.25 ppm位置不能见到正常波形;13只不同程度脂肪肝内甘油三酯(-CH2)n实测和理论谱形吻合均佳,化学位移值为0.89～1.31 ppm;波峰下面积随脂肪变程度增加:正常与轻度脂肪肝之间差异无明显意义(P>0.05),与中、重度之间差异显著(P<0.05),中重度之间差异无明显意义(P>0.05).1H MRS与磁共振成像Out phase序列相对In phase序列信号降低率反映脂肪肝病变程度基本一致;与组织病理学分级高度相关(r=0.93,P<0.05).结论 1H MRS是磁共振抑脂成像(In phase和Out phase序列)诊断脂肪肝的互为补充的有效方法.

Preliminary evaluation of fatty liver in rats by in vivo 1

Objective To study the usefulness of 1H MRS in fatty liver. Methods MR-chemical shift imaging (In phase sequence versus Out phase sequence) and 1H MRS using 2D chemical shift imaging SE sequence at 1.5 T were performed on 13 fatty rat livers (4 mild,3 moderate,6 severe) and 5 normal rat livers. Results There were no methylene spectrum at 1.25 ppm in normal livers, whereas the methylene (-CH 2)n measured spectrum fitted well with the theoretical spectrum at 0.89-1.31 ppm in 13 fatty livers. The mean spectra integral of (-CH 2)n increased with fat content: there was distinct difference between mild and severe fatty liver ( P <0.05), while the difference was not statistically significant between normal and mild fatty liver, as well as moderate and severe fatty liver ( P >0.05). The measurement of fatty content change of 1H MRS was similar with the decreased percentage of signal intensities on the Out phase sequence versus the In phase sequence of MR Imaging. There was a high correlation between 1H MRS and histology grade ( r =0.93, P =0.000). Conclusion It suggested that 1H MR spectroscopy using the technique of CSI SE is useful to detect and quantify fatty infiltration in liver.