计算机超声纹理定征法评价不同缺血时间心肌组织声像图特征的实验研究

Experimental study of computer echocardiographic texture characterization for evaluating the changes of myocardial tissue at different times after ischemia

目的 :探讨利用超声图像纹理分析法评价犬急性心肌缺血 6h内组织声像图变化的特征。方法 :11只犬进行左冠状动脉前降支结扎术建立急性心肌缺血模型 ,分别对其基础状态 (未结扎左冠状动脉前降支 )、结扎左冠状动脉前降支后 30min以及 1h、2h、3h、4h、5h和 6h的二维超声图像进行采集 ,并对各个时间段舒张末期的左心长轴切面前间隔及乳头肌短轴的前壁声像图取样分析 ,采用四种纹理参数 (二次角矩、对比度、熵和反差矩 )对上述不同时间段所采集的二维超声图像进行分析。结果 :左心长轴切面与乳头肌短轴切面的纹理参数比较 ,发现 :①结扎 30min时 ,在左心长轴切面及乳头肌短轴切面上 ,四种纹理参数各时间段与基础状态比较均存在差异 ,P <0 .0 5 ;②左冠状动脉前降支结扎后 2h、3h、4h及 5h时间段之间比较 ,在左心长轴切面及乳头肌短轴切面上 ,四种纹理参数未见显著性差异 ,P >0 .0 5。结论 :计算机超声图像纹理分析法可对不同时间缺血心肌的声像图纹理改变进行定量描述 ,在评价缺血后心肌组织变化特征方面具有一定价值 ,值得深入研究。

Objective To characterize the changes of tissue using ultrasonographic texture analysis in acute myocardial ischemia of 6 hours in the open-chest dogs. Methods Left anterior descending coronary arteries(LAD) were ligated 6 hours to produce the acute myocardial ischemic model in 11 dogs. Different times after operation(30 min, 1 h,2 h,3 h,4 h,5 h,6 h), 4 parameters of texture of anterior septal wall on left ventricular long-axis across-section and anterior wall myocardium on short-axis across-section at the papillary muscle level, including the angular second moment(ASM), the contrast(CON), the entropy(ENT), and the inverse difference moment(IDM), were measured in all phases. Result 4 parameters of post-ligation texture in all phases on long-axis view of the left ventricular and short-axis views at the papillary muscle level were compared with that of baseline, and a significant difference occured at 30min, P <0.05. However, There were not significant difference in the above mentioned parametes among 2 h, 3 h, 4 h and 5 h after ligation of LAD, P >0.05. Conclusion Computer ultrasonography texture analysis allows to characterize changes of echocardiographic texture in the ischemic myocardium at different times, and has an important role in evaluating the changes of myocardial tissue and may deserve further investigation.