超早期ONFH股骨头微环境变化的CT与MR定量研究

Quantitative Study on the Microenvironment Changes of the Femoral Head in the Ultra-early Stage of ONFH with Micro-CT and MR

目的研究超早期股骨头缺血坏死(ONFH)CT与MR定量参数的变化规律。方法新西兰大白兔45只,30只建立ONFH模型,15只用作对照,各组分成5批次(造模后5、7、9、11、13d)行股骨头Micro-CT、MR T2mapping与T2~*mapping扫描及病理组织学检查,分析两种技术所获参数值的变化规律及其相关关系。结果实验组第5天时T2值、T2~*值减低最明显,之后逐步升高,第13天仍低于对照组(P<0.05);BMD、Tb.Th逐渐降低,Tb.Sp、Tb.N则逐渐增高,其中,Tb.Sp、BMD、Tb.Th、Tb.N最早呈现显著性变化的时间分别为5、7、9d(P<0.05)。两种技术测量指标分析显示,Tb.Sp与T2值、T2~*值多数观察时间点呈正相关关系,Tb.Th与T2值、T2~*值则多呈负相关关系。实验组第13天的空骨陷窝率>40%。结论 MR T2mapping、T2starmapping技术可敏感探知ONFH骨髓的变化,可先于CT定量技术预测ONFH的发生。

Objective To investigate the changes of quantitative parameters of CT and MR in the ultra-early stage of osteonecrosis of the femoral head(ONFH).Methods 45 New Zealand white rabbits were randomly divided into the experiment group(n=30)and control group(n=15).After the ONFH model were established,the scanning and histopathologic examination with micro-CT,MR T2mapping and MR T2*mapping were carried out at the 5th,7th,9th,11th and 13th day to analyze the change rule of the parameter values and their correlations.Results The values of T2 and T2*values decreased most obviously at the 5th day in the experiment group and then they gradually increased,but they were still significantly lower than those in the control group at the 13th day(P<0.05).The values of BMD and Tb.Th decreased gradually,while the values of Tb.Sp and Tb.N increased gradually.The earliest significant changes of Tb.Sp,BMD,Tb.Th and Tb.N appeared at the 5th,7th,7th and 9th day respectively(P<0.05).The analysis of the parameter values showed the Tb.Sp value had a positive correlation with the values of T2 and T2*at most observation time points,while the value of Tb.Th had a negative correlation with the values of T2 and T2*.The rate of empty bone lacuna in the experiment group was more than 40%at the 13th day.Conclusion The MR T2mapping and T2 mapping technology could sensitively explore the changes of bone marrow in ONFH,so the MR technology can predict the occurrence of ONFH earlier than the CT technology.