Abstract 5031: A Novel Ultrasound-based Wall Shear Stress Biomarker (Echo Particle Image Velocimetry) to Generate Hemodynamic Vascular Profiles in Carotid Arteries: Clinical Studies on 16 Healthy Subjects

Abstract

Introduction: Hemodynamic vascular profiling using Wall Shear Stress (WSS) may allow prediction of plaque progression and/or rupture in carotid arteries. However, there is no easy-to-use method to accurately measure WSS and develop carotid vascular profiles clinically. We previously described in vitro and in vivo validation of a novel contrast-enhanced ultrasound-based velocimetry technique (Echo PIV) that can generate high-resolution spatially-and temporally-resolved velocity vector and WSS maps of complex vascular flows. Here, we evaluate the utility of Echo PIV to generate baseline vascular profiles of normal carotid hemodynamics. Methods: Echo PIV was used to obtain high resolution (temporal resolution: 0.7 ms; spatial resolution: 0.4 mm) velocity vector, flow rate, and WSS maps of carotid hemodynamics, as well as internal diameter, and curvature of the internal carotid sinus (ICS). Results: Regression analysis found that mean WSS was inversely related to common carotid artery (CCA) diameter (r=−0.88, P<0.0001; Figure ) at the CCA and to mean curvature (r=−0.92, P<0.01) at the ICS. At the CCA, there was a strong association between peak WSS and peak velocity (r=0.82, P<0.001), but not between mean WSS and peak velocity (r=0.17, P=0.52). No association was found between mean blood flow and mean WSS at CCA (r=0.15, P=0.57), or at ICA (r=−0.28, P=0.50). Conclusions: Echo PIV can generate vascular profiles of human carotid arteries that include WSS, blood flow and vessel morphology, and appears to hold promise as a simple-to-obtain biomarker for evaluating vascular plaque vulnerability.