Rasmussen S, Lovelace D E, Knoebel S B, Ransburg R, Corya B C
J Am Coll Cardiol. 1984 Mar;3(3):733-43. doi: 10.1016/s0735-1097(84)80249-1.
The purpose of this study was to determine the potential of a clinically adaptable two-dimensional echocardiographic system using computer enhancement and a mathematically defined integrated backscatter ratio for the early detection of ischemic and infarcted myocardium. Fifteen dogs had two-dimensional echocardiograms recorded during either open chest coronary occlusion (n = 5), closed chest occlusion (n = 5), occlusion followed by reperfusion (n = 3) or sham coronary occlusion (n = 2). A serial increase in integrated backscatter ratio, representing differences in returned ultrasound intensities between a reference point and specific myocardial regions, was detected between 7 and 12 minutes of complete occlusion in 9 of 12 animals (p less than 0.05), and at minutes 18, 43 and 67 in the remaining 3 animals. Reperfusion after 20 minutes of occlusion in two studies resulted in normalization of the backscatter ratio. An increase in backscatter ratio was not detected when 5 minute occlusion periods were used or during the 5 hour sham occlusion studies. The computer enhancement techniques utilized in this study provided increased visual detail of intracardiac structures over that provided by routine two-dimensional echocardiograms; myocardial tissue was identifiable in what appeared to be echo-free segments; and boundaries that appeared as noncontiguous horizontal lines on the routine echocardiograms were identifiable as trabeculae. The results indicate that: 1) significant increases in backscatter from nonperfused myocardium are detectable echocardiographically within 12 minutes of coronary occlusion and temporal changes can be assessed in the canine model, and 2) the echocardiographic data acquisition and computer analysis system utilized provide a clinically adaptable approach to identify and map myocardial characteristics in human beings.
本研究的目的是确定一种临床适用的二维超声心动图系统的潜力，该系统使用计算机增强技术和数学定义的综合背向散射比来早期检测缺血和梗死心肌。15只狗在开胸冠状动脉闭塞（n = 5）、闭胸闭塞（n = 5）、闭塞后再灌注（n = 3）或假冠状动脉闭塞（n = 2）期间记录二维超声心动图。在12只动物中的9只动物完全闭塞7至12分钟时检测到综合背向散射比的连续增加，代表参考点与特定心肌区域之间返回超声强度的差异（p小于0.05），其余3只动物在18、43和67分钟时检测到。两项研究中闭塞20分钟后再灌注导致背向散射比恢复正常。使用5分钟闭塞期或在5小时假闭塞研究期间未检测到背向散射比增加。本研究中使用的计算机增强技术提供了比常规二维超声心动图更多的心脏内结构视觉细节；在看似无回声的节段中可识别心肌组织；常规超声心动图上显示为不连续水平线的边界可识别为小梁。结果表明：1）在冠状动脉闭塞12分钟内可通过超声心动图检测到非灌注心肌背向散射的显著增加，并且可以在犬模型中评估时间变化；2）所使用的超声心动图数据采集和计算机分析系统提供了一种临床适用的方法来识别和绘制人体心肌特征。
