Vaporising phase change ultrasound contrast agent in microvascular confinement

The sub-micron perfluorocarbon-based phase change contrast agents (PCCAs) have shown great potential for imaging both microvasculature and tumour microenvironment. However the effect of geometrical confinement on the acoustic vaporisation has not been explored. We report the investigation of the difference in PCCA-produced contrast increase after activation with and without a microvessel confinement using in vitro experiment phantom. The results demonstrated that the acoustic vaporisation of PCCAs in the 200-micron cellulose tube was significantly different from that in the open environment, with contrast enhancement suppressed by up to several fold.