Ran Hong, Zhang Ping-Yang, Fang Ling-Ling, Ma Xiao-Wu, Wu Wen-Fang, Feng Wang-Fei
Department of Echocardiography, Nanjing First Hospital affiliated to Nanjing Medical University, Nanjing, Jiangsu, China.
Echocardiography. 2012 Jul;29(6):688-94. doi: 10.1111/j.1540-8175.2012.01690.x. Epub 2012 Apr 4.
To evaluate whether myocardial strain under adenosine stress calculated from two-dimensional echocardiography by automatic frame-by-frame tracking of natural acoustic markers enables objective description of myocardial viability in clinic.
Two-dimensional echocardiography and two-dimensional speckle tracking imaging (2D STI) at rest were performed first and once again after adenosine was infused at 140 ug/kg/min over a period of 6 minutes in 36 stable patients with previous myocardial infarction. Then radionuclide myocardial perfusion/metabolic imaging served as the "gold standard" to define myocardial viability was given in all patients within 1 day. Two-dimensional speckle tracking images were acquired at rest and after adenosine administration. An automatic frame-by-frame tracking system of natural acoustic echocardiographic markers was used to calculate 2D strain variables including peak-systolic circumferential strain (CS(peak-sys)), radial strain (RS(peak-sys)), and longitudinal strain (LS(peak-sys)). Those segments with abnormal motion from visual assessment of two-dimensional echocardiography were selected for further study. As a result, 126 regions were viable whereas 194 were nonviable among 320 abnormal motion segments in 36 patients according to radionuclide imaging. At rest, there were no significant changes of 2D strain between the viable and nonviable myocardium. After adenosine administration (140 ug/kg/min), CS(peak-sys) had a little change of the viable myocardium while RS(peak-sys) and LS(peak-sys) increased significantly compared with those at rest. In nonviable group, CS(peak-sys), RS(peak-sys), and LS(peak-sys) had no significant changes during adenosine administration. After adenosine administration, RS(peak-sys) and LS(peak-sys) in viable group increased significantly compared with nonviable group. Obtained strain data were highly reproducible and affected in small intraobserver and interobserver variabilities. A change of radial strain more than 9.5% has a sensitivity of 83.9% and a specificity of 81.4% for viable whereas a change of longitudinal strain more than 14.6% allowed a sensitivity of 86.7% and a specificity of 90.2%.
2D STI combined with adenosine stress echocardiography could provide a new and reliable method to identify myocardium viability.
评估通过对自然声学标记进行逐帧自动跟踪从二维超声心动图计算得出的腺苷负荷下的心肌应变是否能够在临床上客观描述心肌活力。
对36例既往有心肌梗死的稳定患者，首先进行静息状态下的二维超声心动图和二维斑点追踪成像（2D STI）检查，然后以140μg/kg/min的速度静脉输注腺苷6分钟后再次进行检查。所有患者在1天内接受放射性核素心肌灌注/代谢成像检查，将其作为定义心肌活力的“金标准”。在静息状态和腺苷给药后采集二维斑点追踪图像。使用自然声学超声心动图标记的自动逐帧跟踪系统计算二维应变变量，包括峰值收缩期圆周应变（CS(peak-sys)）、径向应变（RS(peak-sys)）和纵向应变（LS(peak-sys)）。从二维超声心动图的视觉评估中选择运动异常的节段进行进一步研究。结果，根据放射性核素成像，36例患者的320个运动异常节段中，126个节段心肌存活，194个节段心肌无存活。静息时，存活心肌和无存活心肌的二维应变无显著变化。腺苷给药后（140μg/kg/min），存活心肌的CS(peak-sys)略有变化，而RS(peak-sys)和LS(peak-sys)与静息时相比显著增加。在无存活组中，腺苷给药期间CS(peak-sys)、RS(peak-sys)和LS(peak-sys)无显著变化。腺苷给药后，存活组的RS(peak-sys)和LS(peak-sys)与无存活组相比显著增加。获得的应变数据具有高度可重复性，观察者内和观察者间的变异性较小。径向应变变化超过9.5%时，对存活心肌的敏感性为83.9%，特异性为81.4%；纵向应变变化超过14.6%时，敏感性为86.7%，特异性为90.2%。
二维斑点追踪成像联合腺苷负荷超声心动图可为识别心肌活力提供一种新的可靠方法。
