Cavitation-induced risks associated with contrast agents used in ultrasonography

Abstract

The risks associated with the introduction of ultrasound contrast agents (UCAs) into the body and the subsequent insonation by diagnostic or therapeutic ultrasound are caused, in addition to microemboli and toxicity, by cavitation-conditioned phenomena. Microbubbles, which enhance ultrasound contrast, provide cavitation nuclei and may cause cavitation in the ultrasound field. Generally, in biological objects, cavitation phenomena can have chemical effects, such as production of free radicals, or can result in cell surface erosion by microjets. Microbubbles, which can travel in body fluids, could nucleate cavitation in a part of the body subjected to subsequent ultrasound or shock wave treatment. Therefore, the use of UCAs, which may cause or enhance cavitation under certain circumstances, should be restricted to cases where they are of proven benefit. Ultrasound or shock wave therapy of body parts in which UCAs can be entrapped should be performed with a sufficient time interval to allow for the elimination of cavitation nuclei.