Preliminary study on modeling blood flow velocity profile for ultrasonic measurement of wall shear stress

The wall shear stress (WSS) contains useful information for the diagnosis of vascular diseases. To improve the accuracy of WSS measurements by ultrasound, some studies have attempted to correct the underestimation of the WSS by approximating a blood flow velocity profile measured by ultrasound to a velocity distribution model such as laminar flow. In this study, a blood flow velocity profile measured by ultrasound was modeled by the Womersley flow model, in order to correct underestimation of WSS in cases of measurements of vessels with complex geometries such as stenotic vessels. The simulation results showed that the rms error of the estimated WSSs was 45.8% from the stenotic vessel with a stenotic ratio of 40% when the spatial gradient was estimated by fitting a linear model to the measured flow profile. Such an error was improved from 45.8% to 25.3% by fitting a Womersley flow model to the measured blood velocity profile.