Measurement of mean velocity during pulsatile flow using time-averaged maximum frequency of Doppler ultrasound waveforms.
It has been suggested that mean velocity of flow could be estimated by the time-averaged maximum frequency over an integral number of cardiac cycles (Gill 1985). The present study verified this theory experimentally with a computer-controlled flow phantom. The effects of some parameters on the relationship between mean velocity and time-averaged maximum frequency were also studied. Parameters investigated included beam-vessel angle, diameter of tubing, pulsatility, flow rate and stenosis. The velocities measured by the Doppler system were compared with the actual velocities. A simple theoretical model was also developed to compare with the experimental results. The results showed that, in a long straight tube, the mean velocity can be estimated to within about 5% from the time-averaged maximum Doppler shift at various flow rates and pulsatilities. The error due to geometrical spectral broadening, especially for large beam-vessel angles, can be estimated to within 3% and therefore corrected.
Li
S
S
Department of Medical Physics and Medical Engineering, Royal Infirmary of Edinburgh, UK.
Hoskins
P R
PR
Anderson
T
T
McDicken
W N
WN
D001783:Blood Flow Velocity; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008433:Mathematics; D008955:Models, Cardiovascular; D011673:Pulsatile Flow; D014463:Ultrasonography / Q000379:methods*