Verdonk E D, Hoffmeister B K, Wickline S A, Miller J G
Washington University, Department of Physics, St. Louis, Missouri 63130, USA.
J Acoust Soc Am. 1996 Jun;99(6):3837-43. doi: 10.1121/1.415001.
Clinical implementation of quantitative ultrasonic tissue characterization is likely to require imaging the heart with sound propagating at varying angles relative to the fibers of the heart. Under these circumstances, the variation of the ultrasonic properties of myocardium with the angle of propagation relative to the myofibers may represent a significant source of potential misinterpretation. In the present study, the systematic approach of assessing the impact of anisotropy on quantitative myocardial tissue characterization is extended by reporting results of a recent in vitro study to measure the anisotropy of the slope of ultrasonic attenuation in specimens of formalin fixed human myocardium. Data obtained from regions of remote infarct are presented and compared to data acquired from regions identified to be free of infarct. The slope of attenuation for both regions exhibit a sinusoid-like dependence on angle that is approximately doubled for propagation parallel to the fibers as compared to perpendicular. These results are, in turn, compared to an earlier study from the laboratory that examined the effects of myocardial infarction on ultrasonic attenuation and interstitial collagen content in freshly excised canine hearts. Discussion regarding the analysis and interpretation of measurements of slope of attenuation is presented as well as a discussion of the possible influence of formalin fixation on our results.
定量超声组织表征的临床应用可能需要以相对于心肌纤维不同角度传播的声音对心脏进行成像。在这种情况下，心肌超声特性随相对于肌纤维传播角度的变化可能是潜在错误解读的一个重要来源。在本研究中，通过报告最近一项体外研究的结果来扩展评估各向异性对定量心肌组织表征影响的系统方法，该研究测量了福尔马林固定的人心肌标本中超声衰减斜率的各向异性。展示了从远隔梗死区域获得的数据，并与从确定无梗死区域获得的数据进行比较。两个区域的衰减斜率均呈现出类似正弦曲线的角度依赖性，与垂直于纤维传播相比，平行于纤维传播时该依赖性大约翻倍。这些结果反过来又与该实验室早期的一项研究进行比较，该研究检查了心肌梗死对新鲜切除的犬心超声衰减和间质胶原含量的影响。本文还讨论了衰减斜率测量的分析和解读，以及福尔马林固定对我们结果可能产生的影响。
