4D Cardiac Gated Vector Flow Imaging Accurately Measures WSS in a Pressurized Closed-Loop System

Wall shear stress plays a critical role in atherosclerotic plaque remodeling and risk of rupture. High framerate volumetric imaging is required to capture potentially malignant hemodynamic forces on the plaque. We show that accurate volumetric wall shear stress estimation over time is feasible by sweeping a linear array transmitting plane wave vector Doppler sequences, with gated acquisitions. Pulsatile flow in a pressurized straight tube CIRS peripheral vascular phantom generated mimicked “end diastolic” and “peak systolic” wall shear stresses of 0.26 Pa and 1.63 Pa, respectively. The 4D vector flow imaging overall tracked changes in WSS along the tube with <15% error relative to the analytical ground truth, with slightly more underestimation near the sides of the tube. Together, the results demonstrate that, despite the poor elevational resolution of a linear array, volumetric WSS can be measured throughout the cardiac cycle. This approach may be relevant to volumetric evaluation of WSS in human carotid arteries, with extension to incorporating volumetric interrogation of plaque composition and structure.