Current and future contrast agents

This article focuses on current and new contrast agents for opacification of left-sided cardiac chambers and myocardium after intravenous injection. The first generation of contrast agents, such as agitated saline, hydrogen peroxide, indocyanine green dye, and iodinated contrast, required aortic or intracoronary injection to opacify the left heart. Second generation agents, such as sonicated 5% human albumin-containing air bubbles, were capable of transpulmonary passage but often failed to produce adequate imaging of the left heart. Newer agents containing fluorocarbon gases within albumin, surfactant, lipid, or polymer shells hold great promise to achieve myocardial perfusion via intravenous injection. The characteristics of these agents and the results of early clinical trials will be discussed.