Detection of ultrasound contrast agents in perfused myocardium

Ultrasound (US) imaging is used routinely for assessment of cardiac function. While movement of the valves and the myocardium are well visualized one of the main prospects of using ultrasound for the measurements of cardiac function, myocardial perfusion, has not been achieved. The technique of "Second Harmonic Imaging" is now employed in clinical US imaging systems, allowing better visualization of tissue by measuring its non-linear response. Meanwhile, Contrast Agents (CA) are used to enhance the visualization of the ventricular cavities and large vessels. Since the bubbles (i.e. CA) also respond non-linearly to US-their visualization in tissue by this technique is not good enough. The objective of this study is to detect minute amounts of contrast agents in small vessels, by studying their response to pressure waves-and enhance the difference versus the response of tissue.