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Numerical Fluid-Mechanical Analysis of Accuracy of Ultrasound Doppler Catheter Velocimetry for Measurement of Blood Flow Velocity

超声多普勒导管测速仪血流速度测量精度的数值流体力学分析

基本信息

批准号：
01571241
负责人：
KAGIYAMA Mitsuyasu
金额：
$ 1.02万
依托单位：
Kawasaki College of Allied Health Professions
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01571241/
关键词：
Numerical fluid-mechanics Ultrasound Doppler catheter Simulation 数値流体力学冠血管

项目摘要

In the previous model-tube experiment, we indicated that 20-MHz ultrsound Doppler catheter velocimetry provides a reliable measure for evaluation relative velocity changes, although it underestimates the blood velocity. To explain this result fluid mechanically, we analyzed the influence of the catheter insertion on the accuracy of Doppler catheter velocimetry by solving numerically the equations of motion for blood flow in a catheterized tube.[Method] A catheterized tube was modeled by a rigid cylindrical tube into which a cylindrical catheter is inserted coaxially. We assumed that fluid is incompressible and Newtonian, and that flow is axisymmetric in the tube. Velocity distribution of the steady flow in the tube was calculated by solving the vorticity and stream function equations transformed from two dimensional Navier-Stokes equations and continuity equation in a cylindrical coordinate system. Dufort and Frankel's method was used to solve the velocity equation, and Liepmann's method was used to solve the stream function iteratively.[Results] Calculations were carried out under the assumption that (1) the flow direction is away from the catheter tip, (2) the inner diameter of the vessel is 7mm, (3) the size of the catheter is 1mm and (4) the Reynolds number is 400. The velocity profile was M-shaped or blunt pattern across the vessel at 1-3 tubular diameter from the catheter tip. The center line velocity was depressed up to 8-10 tubular diameters distal to the catheter tip.[Concluding Remarks] The M-shaped or blunt flow pattern may be the major cause for greater under-estimation of away flow velocity than that of toward-flow velocity.

在以前的模型管实验中，我们指出，20 MHz超声多普勒导管测速提供了一个可靠的措施，评价相对速度的变化，虽然它低估了血液速度。为了解释这一结果的流体力学，我们分析了导管插入的影响，多普勒导管测速的准确性，通过数值求解的运动方程的导管中的血液流动。[方法]将导管插入刚性圆柱管中，并将圆柱形导管同轴插入刚性圆柱管中。我们假定流体是不可压缩的牛顿流体，并且管内的流动是轴对称的。通过求解柱坐标系下由二维Navier-Stokes方程和连续性方程转化而来的涡量方程和流函数方程，计算了管内定常流动的速度分布。采用Dufort和Frankel方法求解速度方程，采用Liepmann方法迭代求解流函数。[结果]在假设（1）流动方向远离导管尖端、（2）血管内径为7 mm、（3）导管尺寸为1 mm和（4）雷诺数为400的情况下进行计算。在距导管头端1-3管直径处，流速分布呈M形或钝形。中心线速度被压低至导管尖端远端8-10个管状直径。【结论】M型或钝型流型可能是造成远向流速低估大于向向流速低估的主要原因。