Fritzsch Th, Schartl M, Siegert J. Preclinical and clinical results with an ultrasonic contrast agent. Invest Radiol 1988;23(Suppl 1):S302-S305. In comparison to diagnostic radiology, ultrasound diagnostics has had no real contrast media. Theoretical considerations indicate that gas liquid systems seem to be favorable. The echocontrast agent SH U 454 is a system that releases minute gas bubbles that provide the contrast properties. Preclinical and clinical trials in more than 500 patients with right-heart lesions proved the efficacy and tolerance of the agent. Initial investigations showed that SH U 454 also may be useful in fields (eg, urology, gynecology) other than cardiology.