[Summary of technical principles of contrast sonography and future perspectives]

Ultrasound contrast agents have considerably expanded the range of ultrasound diagnostics. Up to date ultrasound machines with contrast-specific software allow the selective demonstration and quantification of contrast agents in real-time based on the specific signal signature of oscillating contrast agent microbubbles. After intravenous injection the microbubbles are transported with the bloodstream and distributed purely intravascularly. This allows an artefact-free representation of the vascular architecture and delineation of the vascular lumen, independent of blood flow velocity and with high spatial resolution. Traumatic lesions and active bleeding can be detected with high sensitivity. Blood volume in vessels and organs can be assessed qualitatively and quantitatively. The possibility of short-term destruction of microbubbles within the ultrasound field allows the measurement of blood flow velocity during replenishment and based on that the assessment of perfusion in parenchymal tissue. Target-specific microbubbles for imaging of molecular surface structures as well as drug-loaded microbubbles for local ultrasound-mediated therapy are under development.