二维斑点追踪技术评价冠状动脉狭窄的研究

Evaluation of Coronary Artery Stenosis Using 2DSpeckle Tracking Imaging

目的：应用二维斑点追踪技术分析心肌长轴应变,以此评价其与冠状动脉狭窄程度的相关性。方法：对66例疑似心绞痛患者行常规超声心动图,采集心尖四腔观、长轴观及二腔观图像,并应用二维斑点追踪技术评价左室17节段心肌长轴应变。于超声心动图检查24 h内行冠状动脉造影或冠状动脉CT血管成像（computed tomography angiography,CTA）检查,结合冠状动脉造影/冠状动脉CTA结果将冠状动脉灌注区域心肌节段分为3组：A组为灌注区域无血管狭窄节段（612个节段）;B组为灌注区域血管狭窄〈50%节段（193个节段）;C组为灌注区域血管狭窄〉50%节段（317个节段）。结果：A组长轴应变收缩期峰值（peak systolic longitudinal strain,LSp）为（-21.38±4.70）%,高于B组和C组[（-17.15±6.49）%和（-13.07±6.11）%],差异有统计学意义（P〈0.01）。受试者工作特征（receiver operating characteristic,ROC）曲线分析显示,LSp的ROC曲线下面积0.80（95%可信区间：0.771~0.831,P〈0.01）,以LSp=-16.69%为截断点,判断灌注区域血管狭窄程度〉50%的敏感性为75.0%,特异性为75.9%。A组、B组和C组收缩早期心肌出现矛盾运动的发生率升高,分别为12.91%（79/612）、29.53%（57/193）及68.77%（218/317）;且对应应变值增大,分别为（0.34±0.64）%、（0.70±1.30）%和（0.83±1.12）%（P〈0.01）。结论：二维斑点追踪技术能够评价心肌主动收缩能力,可用于节段心肌收缩功能的量化评价,其与冠状动脉CTA及冠状动脉造影检查结果具有良好的相关性。

Objective：To evaluate the relation between the extent of coronary artery stenosis and longitudinal strains of their left ventricular segments by 2D speckle tracking imaging（STI）.Methods：A total of 66 patients from Jan2011 to Jun2012 with suspected angina were enrolled.All the participants received routine echocardiography examination and their apical four-chamber view,long axial view and two-chamber view images were recorded.Longitudinal strains of left ventricular segments were measured offline in Qlab 8.0workstation.Among them,48 patients received coronary angiography（CAG）and 18 patients received coronary computed tomography angiography（CTA）within24 h after echocardiography examination.Patients in whom perfused vessels of left ventricular segments were normal were taken as Group A（612 segments）.Patients in whom stenosis of perfused vessels was less than 50% were taken as Group B（193 segments）and patients in whom stenosis of perfused vessels was more than 50% were taken as Group C（317 segments）.Results：Peak systolic longitudinal strains（LSp）in Group A was（-21.38± 4.70）%,which was significantly higher than those in Group B and Group C[（-17.15±6.49）%and（-13.07±6.11）%],P 0.01.The areas under receiver operating characteristic（ROC）curve of LSp was 0.80（95 % confidence interval：0.771~ 0.831,P〈0.01）.Sensitivity and specificity for diagnosing stenosis of perfused vessels less than 50 % using cut-off value of-16.69% were 75.0%and 75.9 %,respectively.Ratios of early systolic paradoxical movements in Group A,Group B and Group C were 12.91%（79/612）,29.53 %（57/193）and 68.77 %（218/317）,and their corresponding strains were（0.34± 0.64）%,（0.70±1.30）%and（0.83±1.12）%（P〈0.01）.Conclusions：STI can be used to evaluate regional functions of myocardium in patients with coronary heart diseases through assessment of myocardial active contraction.The results of STI show good correlation with CAG and coronary CTA.