Université François Rabelais-INSERM U 930 ERL CNRS 3106, 10 bd Tonnellé BP2332 37032 Tours Cedex, France.
Ultrasound Med Biol. 2010 Feb;36(2):295-305. doi: 10.1016/j.ultrasmedbio.2009.10.010. Epub 2010 Jan 4.
This study evaluates the sensitivity of a new in vitro high frequency ultrasound test of the whole blood coagulation process. A rat model of anticoagulant treatment is reported. Many recent studies of the role of red blood cells in the whole blood coagulation process have revealed an increasing demand for global tests of the coagulation process performed on whole blood instead of plasma samples. In contrast to existing optical tests, high frequency ultrasound presents the advantages of characterizing the mechanical properties of whole blood clotting. Ultrasound longitudinal wave velocity and integrated attenuation coefficient (IAC) were simultaneously assessed in a 10 to 30 MHz frequency range during the whole blood coagulation process in vitro in rats under anticoagulant therapy. Differences between humans and rats were also clearly emphasized in non-clotting blood and in clotting blood using specific criteria deduced from acoustic parameters (ultrasound velocity for non-clotting blood:=1574+/-2m/s for rats and 1583+/-3m/s for humans and IAC=2.25+/-0.14 dB/cm for rats and 1.5+/-0.23 dB/cm for humans). We also measured the coagulation time t(0) from the acoustic velocity (t(0) =11.15+/-7 min for control rat blood and 43.3+/-11.4 min for human blood). Different doses of heparin were administered to rats. The sensitivity of the ultrasound device to the effects of heparin was evaluated. Differences between non-treated rats and chronically and acutely treated rats were recorded and quantified. We particularly noted that the slope S and the amplitude I of the variations in acoustic velocity were linked to clot retraction, which is a good indicator of the platelet function. The amplitude of the variations in S was between (20+/-8) x1 0(-3) m/s(2) for control group rats, and (0.92+/-0.35) x 10(-3) m/s(2) for chronic heparin-treated group rats. The values of I were 15 times higher for control group rats than for chronic heparin-treated group rats.
本研究评估了一种新的全血凝血过程体外高频超声检测的灵敏度。报告了一种抗凝治疗大鼠模型。许多最近的关于红细胞在全血凝血过程中的作用的研究表明，人们越来越需要对全血而不是血浆样本进行凝血过程的整体测试。与现有的光学测试相比，高频超声具有对全血凝血的机械性能进行特征化的优势。在抗凝治疗大鼠的体外全血凝血过程中，在 10 至 30MHz 的频率范围内，同时评估了超声纵波速度和积分衰减系数（IAC）。使用从声学参数推导出的特定标准，在非凝血和凝血血液中也清楚地强调了人与大鼠之间的差异（非凝血血液的超声速度：大鼠为 1574+/-2m/s，人类为 1583+/-3m/s，IAC=2.25+/-0.14dB/cm 大鼠和 1.5+/-0.23dB/cm 人类）。我们还从声速测量了凝血时间 t(0)（对照大鼠血液的 t(0)=11.15+/-7 分钟，人类血液的 t(0)=43.3+/-11.4 分钟）。向大鼠给予不同剂量的肝素。评估了超声设备对肝素作用的灵敏度。记录和量化了未经处理的大鼠与慢性和急性处理的大鼠之间的差异。我们特别注意到，声速变化的斜率 S 和幅度 I 与血小板功能良好的血小板回缩有关。对照大鼠的 S 变化幅度在（20+/-8）x10(-3)m/s(2)之间，慢性肝素治疗组大鼠的 S 变化幅度在（0.92+/-0.35）x10(-3)m/s(2)之间。对照大鼠的 I 值比慢性肝素治疗组大鼠高 15 倍。
