Contrast opacification of left ventricular myocardium following intravenous administration of sonicated albumin microspheres

Albunex is a new echocardiographic (2-D echo) contrast agent that traverses the pulmonary vasculature when injected intravenously in humans. We examined whether intravenous Albunex resulted in changes in myocardial intensity of sufficient magnitude to produce time intensity curves (TICs). Thirty mildly hypertensive patients were divided into three groups of 10. Each patient received three injections of intravenous Albunex (group I dosages: 0.01, 0.03, and 0.04 cm³/kg; group II: 0.04, 0.06, and 0.08 cm³/kg; group III: 0.08, 0.1, and 0.12 cm³/kg) and two control injections of 5% human serum albumin while imaging with 2-D echo (phased-array; apical four-chamber). Fourty-three injections showed complete opacification of the left ventricle. Videointensity analysis of digitized end-diastolic frames produced myocardial TICs (total as well as background-substracted intensity curves) in 20 of 43 injections. By visual inspection, a myocardial contrast effect was seen in 10 of 43 injections. Detection of myocardial TICs was dose-related (0 of 7 in group I, 9 of 18 in group II, 11 of 18 in group III) and always paralleled the degree of left ventricular opacification. No myocardial contrast effect was observed in any patient during control injections of albumin or in any patient in whom the injection of Albunex did not result in left ventricular opacification. Thus myocardial opacification with intravenous Albunex can be detected simultaneously with good left ventricular opacification. The potential significance of the myocardial opacification observed is discussed.