Ultrasound contrast agents: a review.

During the past 25 years, many attempts have been made to establish effective ultrasound contrast agents for both cardiac and noncardiac applications. The ideal ultrasound contrast agent would be: (a) nontoxic; (b) injectable intravenously; (c) capable of passing through the pulmonary, cardiac and capillary circulations; and (d) stable for recirculation. A variety of potential ultrasound contrast agents have been or are now under development. Present and future ultrasound contrast agents should provide for increased diagnostic capabilities in a variety of normal and abnormal vessels and organs throughout the body. These agents will enhance tumor vascularity, delineate areas of ischemia, as well as improve visualization of vascular stenosis. Future developments with modification of ultrasound equipment should increase the capabilities of these agents to improve imaging as well as Doppler sensitivity.