1990 Fiscal Year Final Research Report Summary
Numerical Fluid-Mechanical Analysis of Accuracy of Ultrasound Doppler Catheter Velocimetry for Measurement of Blood Flow Velocity
| Project/Area Number |
01571241
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
医学一般
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| Research Institution | Kawasaki College of Allied Health Professions |
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Principal Investigator |
KAGIYAMA Mitsuyasu Kawasaki College of Allied Health Professions, Department of Medical Electronics, Lecturer, 医用電子技術科, 講師 (60204335)
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| Co-Investigator(Kenkyū-buntansha) |
KAJIYA Fumihiko Kawasaki College of Allied Health Professions, Department of Medical Electronics, 医用電子技術科, 教授 (70029114)
MITO Keiichiro Kawasaki College of allied Health Professions, Department of Medical Electronics, 医用電子技術科, 助教授 (40078027)
JIKUYA Kazuaki Kawasaki College of Allied Health Professions, Department of Medical Electronics, 医用電子技術科, 講師 (90206350)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Numerical fluid-mechanics / Ultrasound Doppler catheter / Simulation / 数値流体力学 |
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| Research Abstract |
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.
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