Ultrasound Biomicroscopy in Small Animal Research: Applications in Molecular and Preclinical Imaging

Figure 5

Targeted US of endothelial antigens in vessels of a tumor tissue. On the top of the figure time/video intensity analysis before and after high-power destructive pulse and bottom a diagram representation of destructive methodology. Endothelial cells of vessels (orange) of tumor tissues expresses specific antigens. After intravenous administration targeted microbubbles float in vessels and remaining exclusively in the vascular compartment. Many of them bind to antigens of endothelial cells, whereas others remains in the vessel lumen freely circulating. After high-power destructive pulse, all microbubbles are destroyed (bound + circulating), following circulating microbubbles that arrive from outside of scan plane, which remain freely circulating for several seconds. Contrast intensity is the sum of the intensity from tissue, intensity from microbubbles not bound to receptors (circulating microbubbles), and intensity from microbubbles bound to receptors on endothelial cells. After digital subtraction of the video intensity calculated on 300 predestruction frames from video intensity calculated on 300 postdestruction frames, resulting video intensity is due only to bound microbubbles.