Bardelli M, Carretta R, Dotti D, Fabris B, Fischetti F, Cominotto F, Ussi D, Calci M, Candido R
Istituto di Patologia Medica dell'Università di Trieste.
Boll Soc Ital Biol Sper. 1994 Apr;70(4):97-104.
A new ultrasonographic machine (FRP II) has been developed to measure vessel wall shear stress. A multigate ultrasound probe sends an ultrasound beam simultaneously focused in subsequent points 0.2 mm from each other along the transverse axis of a blood vessel. Blood velocity is measured by cross-correlation technique, which allows a rapid and economical analysis. Thus, the instantaneous (every 5 msec) blood velocity profile is reconstructed for the duration of the entire cardiac cycle. In order to verify the precision and sensitivity of the FRP II in measuring shear stress, 36 measurements were performed on the common carotid artery in 9 hypertensive subjects in different hemodynamic conditions. The FRP II-measured shear stress (the product of the shear rate and blood viscosity) was compared to that calculated by the Womersley's mathematical model (Y = 2K.Vcl/D, where Y = shear rate, Vcl = vessel center line blood velocity, D = vessel diameter). A good correlation (r = 0.77, p < 0.0001) was found between the peak systolic shear stresses measured by FRP II and that calculated by the Womersley's mathematical model, although an underestimation for higher values was observed with the latter method. In conclusion, we propose a new ultrasonographic instrument to measure "in vivo" the vessel wall shear stress.
一种新型超声设备（FRP II）已被开发用于测量血管壁剪切应力。一个多门超声探头沿着血管横轴同时发射超声束，这些超声束聚焦在彼此相距0.2毫米的后续点上。通过互相关技术测量血流速度，该技术能够进行快速且经济的分析。因此，在整个心动周期内重建瞬时（每5毫秒）血流速度剖面。为了验证FRP II在测量剪切应力方面的精度和灵敏度，在9名处于不同血流动力学状态的高血压受试者的颈总动脉上进行了36次测量。将FRP II测量的剪切应力（剪切速率与血液粘度的乘积）与通过沃默斯利数学模型计算的剪切应力进行比较（Y = 2K.Vcl/D，其中Y = 剪切速率，Vcl = 血管中心线血流速度，D = 血管直径）。尽管使用后一种方法观察到较高值存在低估情况，但在FRP II测量的收缩期峰值剪切应力与通过沃默斯利数学模型计算的应力之间发现了良好的相关性（r = 0.77，p < 0.0001）。总之，我们提出了一种新的超声仪器来“在体”测量血管壁剪切应力。
