Machi J, Sigel B, Beitler J C, Coelho J C, Justin J R
J Clin Ultrasound. 1983 Jan;11(1):3-10. doi: 10.1002/jcu.1870110103.
The mechanism of echogenicity of flowing blood during real-time ultrasonography was investigated experimentally in vivo by scanning venous and arterial blood and venous blood subjected to varying degrees of obstruction. Luminal echoes were more intense in flowing blood of the vena cava than in aortic blood of dogs. Vena cava and portal echoes increased in intensity as flow was decreased progressively by obstruction. We believe that an important cause of echogenicity of flowing blood is red cell aggregation which is greatest at low shear rates (low flow velocity). Echogenicity decreases with increase in shear rate (higher flow velocity) which causes red cell disaggregation.
通过对静脉血、动脉血以及不同程度梗阻的静脉血进行体内扫描，对实时超声检查时流动血液的回声机制进行了实验研究。腔静脉内流动血液的管腔回声比狗主动脉内的血液回声更强。随着梗阻使血流逐渐减少，腔静脉和门静脉的回声强度增加。我们认为，流动血液产生回声的一个重要原因是红细胞聚集，这种聚集在低剪切率（低流速）时最为明显。随着剪切率增加（较高流速）导致红细胞解聚，回声性降低。
