Optical observation of lipid- and polymer-shelled ultrasound microbubble contrast agents

The behavior of a lipid and polymer-shelled ultrasound microbubble contrast agent was studied using high-speed cameras capable of visualizing individual contrast microbubble responses to acoustic interrogation in real time. A high speed camera interfaced to a custom microscope was used to capture still and streak images of individual microbubbles. The lipid-shelled agent expanded after two-cycle pulse and both the shell and its contents fragment as the pressure approaches to 1 MPa. The polymer-shelled agent remained intact at pressures up to 1.5 MPa and exhibited a different destruction mechanism.