Wall shear stress (WSS) plays an important role in the formation, growth, and rupture of atherosclerotic plaques in arteries. This study measured WSS in diseased carotid artery phantoms with degrees of stenosis varying from 0 to 60% with both steady and pulsatile flow. Experiments were performed using in silico and real flow phantoms. Blood velocities were estimated using plane wave (PW) vector Doppler. Wall shear stress was then estimated from the velocity gradient near the wall multiplied by the viscosity of a blood-mimicking fluid. The estimated WSS using the in silico phantom agreed within 10% of the ground-truth values (root-mean-square error). The phantom experiment showed that the mean WSS and maximum WSS increased with the increasing degree of stenosis. The simulation and experiment results provide the necessary validation data to give confidence in WSS measurements in patients using the PW vector Doppler technique.

In recent years, plane wave ultrasound has received significant research interest due to its high frame rate capabilities. The image quality of plane wave ultrasound imaging is largely influenced by beamformer performance. Coherent plane wave compounding has been developed as a method to enhance image quality through the coherent summation of data from various transmission angles. Additionally, coherence factor-based beamformers have been developed to improve image contrast. In this study, we investigated the impact of compounding on three types of coherence-based beamformers using ultrasound simulations and phantom experiments. The results demonstrated that coherence factor beamformers, generalized coherence beamformers, and phase coherence beamformers achieve higher image quality in terms of lateral resolution, contrast ratio and generalized contrast to noise ratio as the number of compounding angles increases. These results suggest that plane wave compounding can enhance the image quality of coherence-based beamformers.