在心血管的超声检查中经常注意到血液系统内部的回声。这些回声的来源被归因为红细胞或其它小体。先前的一些研究表明红细胞聚集对造成停滞的未凝固血液的低强度回声起着重要作用,它也可引起流动的血液产生回声。为弄清这个问题,作者用新鲜抗凝人血作了一系列体外实验。红细胞聚集取决于多种因素,如红细胞压积,红细胞膜情况,血浆大分子和分离率。在低分离率时,正常血液可显示红细胞聚集。在高分离率时,聚集被打破而分成各个红细胞。分离率与流速和血管口径有关。作者在实验中评价了流动血液中作为产生回波反射一个原因的红细胞聚集的作用。方法是将新鲜的抗凝人血放于封闭的乳胶管圈 Often the echoes inside the blood system are noticed in cardiovascular ultrasound. The source of these echoes is attributed to red blood cells or other bodies. Some previous studies have shown that erythrocyte aggregation plays an important role in the hypoechoic echogenicity of stagnant, non-coagulated blood, which can also cause echo in flowing blood. To clarify this issue, the authors made a series of in vitro experiments with fresh anticoagulant human blood. Erythrocyte aggregation depends on a variety of factors such as hematocrit, erythrocyte membrane conditions, plasma macromolecules, and resolution. At low rates of separation, normal blood can show erythrocyte aggregation. At high rates of separation, aggregation is broken down into individual erythrocytes. Separation rate and velocity and vascular caliber related. The authors evaluated the role of erythrocyte aggregation in mobile blood as a cause of echogenic reflex in experiments. The method is to put fresh anticoagulant human blood in a closed latex tube