Cardiac flow mapping using high frame rate diverging wave contrast enhanced ultrasound and image tracking

High frame-rate (HFR) contrast enhanced echocardiography (CE), based on pulse inversion (PI), diverging wave transmission, was recently proposed for improving the image contrast over standard CE with focused transmission [M. Toulemonde, IUS 2016]. Comparing to ∼30Hz in standard CE, HFR CE can reach a frame rate of up to 6000Hz, allowing accurate tracking of fast flow structure and dynamics in cardiac chambers. A recent study shows the benefit of HFR cardiac imaging for flow vortex detection by using a Duplex mode (B-mode + Doppler) but without microbubble contrast agents, the signals from blood cells are weak [J. Faurie, UFFC, 2017]. Another clinical research shows the potential of visualising and tracking vortex with a CE at a frame rate of 204 ± 39 frames / s but the field of view is limited and the frame rate is still low for tracking the very fast cardiac flow [H. Abe, Cardiovascular Imaging, 2013]. The aim of this work is to demonstrate the feasibility of flow mapping using HFR CE in-vivo cardiac imaging.