Shung K K, Fei D Y, Yuan Y W, Reeves W C
J Clin Ultrasound. 1984 Mar-Apr;12(3):147-53. doi: 10.1002/jcu.1870120306.
Recently ultrasound has been found to be extremely useful in detecting intracardiac thrombi as well as intracranial hemorrhages in neonates. The principal criterion used for clinical diagnosis of thrombus has been an increase in the echogenicity of clotted blood. However, echogenicity is a rather nonspecific and qualitative description of tissue ultrasonic properties. A rise in echogenicity could be the result of an increase in ultrasonic backscatter, or a decrease in attenuation, or a combination of both. In order to ascertain the mechanism responsible for the clinically observed increase in echogenicity and thus put the technique on a firm foundation, we have measured serially the ultrasonic velocity, attenuation and backscatter in human blood up to 24 hours following the onset of coagulation. Preliminary results show that all three ultrasonic properties increase during this time period. At 24 hours following clotting, the mean rises in velocity, attenuation and backscatter are 3.36 +/- 0.35 X 10(3) cm/sec, 2.3 +/- 0.22 db/cm and 18.5 +/- 1.2 dB per unit volume of blood (at 7.5 MHz and a temperature of 23 degrees C), respectively. These results indicate that the increase in echogenicity of a thrombus is due to a substantial increase in ultrasonic backscatter, which is moderated to a certain extent by the accompanied increase in attenuation.
最近发现，超声在检测新生儿心内血栓以及颅内出血方面极为有用。血栓临床诊断所采用的主要标准一直是凝血血液回声增强。然而，回声是对组织超声特性相当非特异性和定性的描述。回声增强可能是超声背向散射增加、衰减降低或两者共同作用的结果。为了确定导致临床上观察到的回声增强的机制，从而使该技术有坚实的基础，我们在凝血开始后长达24小时连续测量了人血中的超声速度、衰减和背向散射。初步结果表明，在此时间段内所有这三种超声特性均增加。凝血后24小时，速度、衰减和背向散射的平均升高分别为3.36±0.35×10³厘米/秒、2.3±0.22分贝/厘米和每单位体积血液18.5±1.2分贝（在7.5兆赫和23摄氏度温度下）。这些结果表明，血栓回声增强是由于超声背向散射大幅增加，而这种增加在一定程度上被伴随的衰减增加所缓和。
