Angle-insensitive flow measurement using Doppler bandwidth

摘要

The ability to measure the velocity of blood flow independent ofnthe orientation of the blood vessel could aid in evaluation of manyndisease processes, such as coronary lesions. Conventional ultrasonicnDoppler techniques require knowledge of the beam-to-flow angle, and thenDoppler effect vanishes when this angle is 90°. By employing anspherically symmetrical range cell and the Doppler bandwidth instead ofnthe Doppler shift, preliminary results show that flow measurement ofnideal uniform flow that has a blunt velocity profile can be made withoutnknowledge of tile orientation of the vessel, even when the angle ofnorientation is around 90°. But when the technique is applied to anreal how that has a parabolic velocity profile, the Doppler bandwidthndecreases as the beam-to-flow angle increases. Although the Dopplernbandwidth is sensitive to the transducer angle in this situation, thenerror in determining flow velocity might be acceptable if the transducernangle can be estimated to be within a small range. For this method to benregarded as practical for clinical use, however, a consistentnrelationship between bandwidth and flow velocity must be demonstratednover some set of clinically relevant conditions. The experimentalntechniques and results for how measurements of both the ideal uniformnflow and the real flow are presented in this paper