Add to ORKG__Abstract__ Ultrasound contrast agent was discovered serendipitously by Gramiak and Shah in I968 when they injected indocyanine green dye into the heart and observed increased echogenicity of the blood containing the dye. Small cavitation bubbles that were formed upon injection of the dye were traced to be the source of the enhanced echoes. Nowadays, ultrasound contrast agent still consists of small bubbles that are free flowing in the blood stream. However, as the uncontrolled process of cavitation and violent collapse is considered harmful for cells and tissue, contrast agent is usually prepared under controlled conditions outside the body and injected through a vein where they are taken up into the blood stream and transporte...