Molecular ultrasound imaging: Clinical applications

Abstract

Contrast-enhanced ultrasound imaging is increasingly being used in clinical applications, particularly for cardiovascular and liver diagnostics. In this context the availability of new molecular contrast agents and the initiation of clinical translation promises new options for pathomechanistic diagnostics. Analysis of the current literature on the development of molecular ultrasound contrast agents, the detection methods as well as the applications in preclinical and clinical studies. Molecular contrast agents have become established in preclinical research for the detection of inflammation and angiogenesis and have been continuously refined over recent years. They consist of gas filled microbubbles with a diameter of 1-5 µm and the gas core is stabilized by a shell made of lipids, proteins or polymers to which biomolecules are conjugated that determine the target specificity. The agent BR55 is the first clinically evaluated molecular ultrasound contrast agent. It binds to the angiogenesis marker vascular endothelial growth factor receptor 2 (VEGFR2) and has been studied in several preclinical and clinical phase I and II studies on tumor diagnostics and characterization. Molecular ultrasound imaging is rapidly evolving in preclinical research for a broad field of applications. Translation to clinical practice is conceivable for many indications and is already ongoing for BR55.