Brazilian Air Force Academy, Pirassununga, Brazil; Biomedical Engineering Program-COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Biomedical Engineering Program-COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Ultrasound Med Biol. 2022 Jan;48(1):111-123. doi: 10.1016/j.ultrasmedbio.2021.09.017. Epub 2021 Oct 19.
Blood coagulation is a process involving several chemical reactions governed by coagulation factors, during which the shear elastic coefficient, μ, varies as the medium transitions from liquid to gel phase. This work used ultrasound to measure μ during the clotting of human plasma samples by tracking the motion of a glass sphere located inside a cuvette filled with the plasma. A 2.03 MHz ultrasonic system generated an impulsive acoustic radiation force acting on the sphere, and a 4.89 MHz pulse-echo ultrasonic system tracked the sphere displacement induced by that force. Measurements of μ were determined by fitting a μ-dependent theoretical model to the motion waveform of the sphere immersed in clotting normal plasma and plasma samples with fibrinogen (FI) concentrations of 1.2 (FI-deficiency) and 3.6 (FI-normal) g/L. For normal plasma, μ started at 14.22 Pa and increased rapidly until 2 min, then slowly until it reached 210.23 Pa at 35 min after the clotting process started. A similar trend was exhibited in plasma samples with FI concentrations of 1.2 and 3.6 g/L, with μ reaching 120.55 and 679.42 Pa, respectively. A theoretical model, related to the kinetics of clot-structure formation, describes the time changes of μ for the clotting plasma samples. The sphere-motion-based acoustic-radiation-force approach allowed us to measure the shear elastic coefficient during the coagulation process of plasma samples with normal and deficient FI concentrations. Our results suggest that the method used in this study is capable of being used to detect bleeding disorders.
血液凝固是一个涉及多个化学反应的过程，由凝血因子控制，在此过程中，剪切弹性系数 μ 随着介质从液相向凝胶相转变而变化。本工作使用超声测量了人血浆样品凝固过程中 μ 的变化，方法是跟踪位于充满血浆的比色皿内的玻璃球的运动。一个 2.03MHz 的超声系统产生了一个脉冲声辐射力作用在球体上，而一个 4.89MHz 的脉冲回波超声系统跟踪了这个力引起的球体位移。通过将一个依赖于 μ 的理论模型拟合到球体在凝固正常血浆和纤维蛋白原（FI）浓度为 1.2（FI 缺乏）和 3.6（FI 正常）g/L 的血浆样品中运动的波形，确定了 μ 的测量值。对于正常血浆，μ 从 14.22Pa 开始迅速增加，直到 2 分钟后缓慢增加，直到凝血过程开始 35 分钟后达到 210.23Pa。在纤维蛋白原浓度为 1.2 和 3.6g/L 的血浆样品中也表现出类似的趋势，μ 分别达到 120.55 和 679.42Pa。一个与血凝块结构形成动力学相关的理论模型描述了凝血血浆样品中 μ 的时间变化。基于球体运动的声辐射力方法允许我们测量正常和纤维蛋白原缺乏的血浆样品在凝固过程中的剪切弹性系数。我们的结果表明，本研究中使用的方法能够用于检测出血性疾病。
