The subharmonic amplitude of SonoVue increases with hydrostatic pressure at low incident acoustic pressures

Physiologically important pressures in the heart and aorta are currently assessed with invasive pressure catheters. The subharmonic signal from ultrasound contrast agents, however, may be exploited to estimate pressures non-invasively. The objective of this work was (i) to develop a static phantom from commercially-available components for easy replication across different laboratories, and (ii) to investigate the subharmonic response of the ultrasound contrast agent SonoVue (Bracco, Milan, Italy) at physiological pressures within the phantom.