Peak velocity estimation in arterial stenosis models using colour vector Doppler.

Maximum velocity as measured from spectral Doppler is dependent on the angle theta between the bean and the direction of motion of blood. The Doppler shift is dependent on the velocity component in the direction of the ultrasound beam, hence theta cannot be determined accurately. These factors produce errors in the estimation of arterial stenosis from velocity. In this study, a 2D colour vector Doppler technique was tested using a flow model with simulated arterial stenoses. Colour-flow images obtained from different bean directions were compounded, giving estimates of velocity magnitude and angle. The maximum velocity magnitude increased with the degree of stenosis, and there was no dependence on the beam-vessel angle. This technique does not require manual entry of beam-vessel angle, nor does it have the angle dependence associated with spectral estimation of maximum velocity. This may help reduce the errors in assessment of arterial stenosis.