脂肪肝CT、MRI定量诊断的对照实验研究

A comparative experimental study of quantitative diagnosis of fatty liver by CT and MRI

目的:探讨肝脏脂肪含量与肝脏、肌肉CT值比、肝脏CT值及脂肪抑制前后肝脏信号强度衰减率之间的相关关系及相关强度。方法:对正常组和随机抽取的2 3只实验组家兔行肝脏CT平扫及化学饱和法脂肪抑制前后肝脏MRI(SE序列,T1WI) ,测得肝脏CT值、竖脊肌CT值,计算肝脏、肌肉CT值比及脂肪抑制前后肝脏信号强度衰减率。对实验动物的肝脏进行组织学检查,并用显微图像分析仪测定肝中脂滴占肝脏单位体积的百分比(Vv 值)。结果:肝脏肌肉CT值比值与Vv 值之间存在有意义的高度线性负向相关关系(r =- 0 .896 ,t =- 10 .2 89,P <0 .0 0 1) ;肝脏CT值与Vv 值之间存在有意义的中度线性负向相关关系(r =- 0 .818,t =- 7.2 4 9,P <0 .0 0 1) ;脂肪抑制前后肝脏信号强度衰减率与Vv值之间存在有意义的中度线性正相关关系(r =0 .5 5 6 ,t =3.4 0 7,P =0 .0 0 2 )。结论:肝脏肌肉CT值比值较肝脏CT值绝对值、脂肪抑制前后肝脏信号强度衰减率具有与Vv 值更高的相关强度,该指标可望用于活体无创估计肝脏脂肪含量。

Objective:To evaluate the correlation and the degree of relationship between hepatic fat content and liver-to-muscle CT value ratio (LMVR)、liver CT value (CTVL) and MR liver signal intensity attenuation ratio (SILAR) before and after fat-suppressed T 1WI respectively.Methods:Non-contrast CT scan,non-fat-suppressed and fat-suppressed spin-echo sequences T 1-weighted MRI were performed in the 5 rabbits of the control group and 23 rabbits randomly chosen from the experimental group.LMVR、CTVL、CTVM and SILAR of each rabbit were measured or calculated. Liver specimens were examined histologically. The ratio of hepatic fat content to liver volume (V v value) was measured by microscopic image pattern analyzer.Results:Significant high degree linear negative correlation (r=-0.896,t=-10.289,P<0.001)was found between LMVR and V v value. Significant moderate degree linear negative correlation (r=-0.818,t=-7.249,P<0.001)was found between CTVL and V v value. Significant moderate degree linear positive correlation (r=0.556,t=3.407,P=0.002) was found between SILAR and V v value.Conclusion:LMVR has higher degree of relationship than CTVL and SILAR with V v value. This index could be used to assess the degree of fatty infiltration of liver in vivo and noninvasively.