Effects of beam steering in pulsed-wave ultrasound velocity estimation.
Experimental and computer simulation methods have been used to investigate the significance of beam steering as a potential source of error in pulsed-wave flow velocity estimation. By simulating a typical linear-array transducer system as used for spectral flow estimation, it is shown that beam steering can cause an angle offset resulting in a change in the effective beam-flow angle. This offset primarily depends on the F-number and the nominal steering angle. For example, at an F-number of 3 and a beam-flow angle of 70 degrees , the velocity error changed from -5% to + 5% when the steering angle changed from -20 degrees to + 20 degrees . Much higher errors can occur at higher beam-flow angles, with smaller F-numbers and greater steering. Our experimental study used a clinical ultrasound system, a tissue-mimicking phantom and a pulsatile waveform to determine peak flow velocity errors for various steering and beam-flow angles. These errors were found to be consistent with our simulation results.
Steinman
Aaron H
AH
Vivosonic Inc., Toronto, ON, Canada.
Yu
Alfred C H
AC
Johnston
K Wayne
KW
Cobbold
Richard S C
RS
D001783:Blood Flow Velocity; D003198:Computer Simulation; D004867:Equipment Design; D006801:Humans; D008954:Models, Biological; D019047:Phantoms, Imaging; D011673:Pulsatile Flow; D014159:Transducers; D014465:Ultrasonics; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods*