Shung K K, Fei D Y, Ballard J O
J Clin Ultrasound. 1986 May;14(4):269-75. doi: 10.1002/jcu.1870140406.
Two-dimensional echocardiography has been found to be an effective clinical tool in diagnosing intracardiac thrombi. Misdiagnosis may, however, still frequently occur because of the difficulty in differentiating the thrombi from other intracavitary masses based only on the echographic appearance of these structures. Ultrasonic tissue characterization techniques have been used in attempts to minimize this diagnostic uncertainty. Previously, we have shown that all ultrasonic parameters of blood, including ultrasonic backscatter, a quantitative measure of echogenicity, at 7.5 MHz increase rapidly following clotting. In this article, we report recent results on the measurements of attenuation and backscatter of thrombi as a function of time following clotting over the frequency range of 3 MHz to 8 MHz. These results indicate that ultrasonic backscatter from thrombi 12 h old is at least 18 dB higher than that of unclotted blood over the frequency range of 3 MHz to 8 MHz, and the slope of the attenuation coefficient is increased to 0.43 dB/cm-MHz. Comparison with the backscatter of bovine myocardium shows that the myocardium is more echogenic than fresh thrombi and is less echogenic than thrombi 12 to 24 h old. Similar results were also obtained for integrated backscatter measurements over the same frequency range.
二维超声心动图已被证明是诊断心内血栓的一种有效临床工具。然而，由于仅根据这些结构的超声表现难以将血栓与其他心腔内肿块区分开来，误诊仍可能经常发生。超声组织表征技术已被用于试图最小化这种诊断不确定性。此前，我们已经表明，血液的所有超声参数，包括超声背向散射（一种在7.5 MHz时对回声性的定量测量），在凝血后会迅速增加。在本文中，我们报告了关于血栓在3 MHz至8 MHz频率范围内凝血后随时间变化的衰减和背向散射测量的最新结果。这些结果表明，在3 MHz至8 MHz频率范围内，12小时龄血栓的超声背向散射比未凝血的血液至少高18 dB，并且衰减系数的斜率增加到0.43 dB/cm-MHz。与牛心肌的背向散射比较表明，心肌比新鲜血栓更具回声性，并且比12至24小时龄的血栓回声性更低。在相同频率范围内进行的积分背向散射测量也获得了类似结果。
