DIFFERENTIATION BETWEEN ACUTELY ISCHEMIC MYOCARDIUM AND ZONES OF COMPLETED INFARCTION IN DOGS ON THE BASIS OF FREQUENCY-DEPENDENT BACKSCATTER
DIFFERENTIATION BETWEEN ACUTELY ISCHEMIC MYOCARDIUM AND ZONES OF COMPLETED INFARCTION IN DOGS ON THE BASIS OF FREQUENCY-DEPENDENT BACKSCATTER
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DOI：
10.1121/1.397977
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发表时间：
1989-06-01
影响因子：
2.4
通讯作者：
MILLER, JG
中科院分区：
文献类型：
--
作者：
WEAR, KA;MILUNSKI, MR;MILLER, JG
这项工作的目的是确定表观后向散射系数的频率依赖性（未校正心肌内的衰减）是否可以区分体内完全的远端梗死和急性心肌损伤。6只犬冠状动脉闭塞致心肌梗死。1至12个月后，通过结扎供应梗死区附近心肌区域的冠状动脉，在每只狗中诱导急性缺血性损伤。梗死区、缺血区和正常区用5-MHz，圆形，0.5-in。直径，宽带，聚焦，压电传感器安装在一个充满水的隔离装置，放置在暴露的，跳动的心脏。在37mhz以内的频率范围内测量了视后向散射系数。频率依赖关系由对数视后向散射系数随对数频率的斜率得到。在缺血2小时内，正常心肌和急性缺血心肌的频率依赖性无显著差异。相比之下，远端梗死区域的频率依赖性为1.8。0.1，平均值+-。标准误差)显著低于急性缺血或非缺血区域(2.3 .+-。0.1) （p < 0.01）。这些结果表明，基于后向散射的频率依赖性，可以将远端心肌梗死与急性损伤但仍有可能在体内恢复的心肌区分开来。
The goal of this work was to determine whether the frequency dependence of apparent backscatter coefficient (not corrected for attenuation within the myocardium) could differentiate completed, remote infarction from acute myocardial injury in vivo. Myocardial infarcts were produced in six dogs by coronary artery occlusion. One to 12 months later, acute ischemic injury was induced in each dog by ligation of a coronary artery that supplied a region of myocaridum adjacent to the established infarct. Infarct, ischemic, and normal regions were interrogated with a 5-MHz, circular, 0.5-in. diam, broadband, focused, piezoelectric transducer mounted in a water-filled stand-off device placed against the exposed, beating heart. Apparent backscatter coefficients were measured over the range of frequencies from 37 MHz. The frequency dependence was obtained from the slope of log apparent backscatter coefficient versus log frequency. No significant difference in frequency dependence was found between normal and acutely ischemic myocardium for periods of up to 2 h of ischemia. In contrast, frequency dependence in regions of remote infarct (1.8 .+-. 0.1, mean .+-. standard error) was significantly lower than that in acutely ischemic or nonischemic regions (2.3 .+-. 0.1) (p < 0.01). These results suggest that remote myocardial infarction can be differentiated from acutely injured but still potentially salvageable myocardium in vivo on the basis of the frequency dependence of backscatter.