Zimmermann J, et al. - This simulated and prospective study examined the robustness of wall shear stress (WSS) and oscillatory shear index (OSI) estimation based on 4D flow MRI against vessel wall motion, spatiotemporal resolution, and velocity encoding (VENC) with the intention of assessing blood flow characteristics and evaluating flow-mediated lesions in the aorta. Findings illustrated systematic over-/underestimation of WSS when different spatial resolution and VENC-depending phase noise were given. Thus, it was discovered that sufficient spatial resolution and velocity to noise ratio as well as accurate tracking of the vessel wall was required for a reliable image-based WSS estimation, thereby it ought not to be neglected in the presence of wall motion.