Combined ARFI Variance of Acceleration (VoA), Vector Flow, and Wall Shear Stress for Assessing Atherosclerotic Risk: Ex-Vivo Human Cadaveric Results

Vascular hemodynamics and plaque composition are better indicators of stroke risk than degrees of stenosis alone. In silico work previously indicated that the acoustic radiation force impulse (ARFI) derived parameter, variance of acceleration (VoA), may be implemented with plane wave (PW) acquisitions to offer a high frame rate method of differentiating plaque components. Vector flow imaging methods such as multi-angle plane wave vector Doppler further allow 2D blood flow tracking and assessments of wall shear stress (WSS) to better predict rupture potential. We hypothesize ARFI VoA and plane wave vector Doppler may be efficiently combined to interrogate plaque structure and composition and estimate WSS in human carotid arteries. While focused ARFI - VoA best predicts feature size compared to PW acquisitions, PW ARFI-VoA offers comparable resolution, but contrast of lower SNR features is reduced. The PW ARFI-VoA sequence may be supplemented with a steered PW sequence to additionally visualize blood flow and estimate wall shear stress at potential real time frame rates. This work demonstrates the feasibility of the technique to an ex-vivo left carotid from a recently deceased 63-year-old female.