Albunex-a new ultrasound contrast agent

Albunex (Molecular Biosystems Inc (MBI), San Diego, USA and Nycomed Imaging AS, Oslo, Norway) is the first ultrasound contrast agent that is stable enough to show transpulmonary passage. This implies that the contrast agent can be injected intravenously and still give contrast in the left side of the heart. Albunex is made by sonication of a 5% solution of human albumin. This process generates air bubbles encapsulated by a shell of aggregated albumin. The air-filled microspheres have characteristics similar to those of air bubbles in water, with respect to both backscatter and attenuation of the ultrasound signal. Clinical studies have shown that Albunex is a safe product. We have documented the diagnostic efficacy of Albunex for the study of the anatomy and function of the heart, but more research needs to be done to document its diagnostic efficacy for the study of myocardial perfusion and Doppler enhancement. Acoustical properties of Albunex are discussed