After Intravenous Injection Of A New Ultrasound Contrast Agent Evaluation Of Myocardial Perfusion

Assessing regional myocardial perfusion after intravenous injections of ultrasound agents is a new non-invasive and convenient technique. It shows the great potential in outpatient, emergency, operating room, and cardiac catheterization laboratory and bedside. The purpose of this study was to determine whether the new contrast agent, FX, could distinguish normal and abnormal myocardial perfusion. Also we want to know which imaging condition is better and its potential applications in clinic.In theory, altering microbubble gas composition could change opacification in ventricular cavity and myocardium. Visual myocardial echocardiographic contrast is possible after intravenous injection microbubbles containing a gas with high molecular weight, less diffusivity and less solubility. In this study, we have first proven this phenomenon with second harmonic image in our country. We regarded that the curve of gas molecular and myocardial contrast is the shape of "S" , not a beeline. 10 open chest dogs received 68 injections of sonicated dextrose albumin containing room air, sulfur hexafluoride, three kinds of fluorocarbon (C3F8, C4F10, C5F12). The myocardial ultrasound contrast after intravenous injections of perfluorocarbon-exposed sonicated dextrose albumin was strongest, myocardial acoustic densitomitries were 14.72 ±2.7dB(FX330), 14.3 ± 2.4dB(FX430) and 13.78 ± 2.24dB(FX530). Slight myocardial contrast could be discerned after intravenous injections of sulfur hexafluoride microbubbles (6.24 ± 1.58dB). There was almost no visually discernible myocardial echocardiographic contrast after injections of room air microbubbles agent (2.35 ± 0.78dB), even no marked contrast in left ventricle cavity (11.3 ± 4.96dB). FX contrast agent was an effective contrast agent.Dose is a very important factor in myocardial contrast echocardiography. A lower dose injection of contrast agent produces slight myocardial contrast, but a larger dose produces a strong shadow that prevents imaging posterior wall of left ventricle. We studied 10 dogs to observe myocardial contrast changes produced by intravenous injections of different doses of contrast agent FX530. Larger dose of agent produced stronger myocardial contrast. The acoustic densitometry of left ventricular anterior wall (0.0025, 0.005, 0.01, 0.02ml/kg) was 8.48 ± 1.48dB vs 11.44 ± 1.58dB vs 12.66 ± 2.02dB vs 14.32 ± 2.27dB, p<0.01. There was no shadowing in 0.0025ml/kg, a little shadowing lasting about 2.6 ± 0.8seconds in...