In vitro, animal, and human characterization of OPTISON infusions for myocardial contrast echocardiography

Traditionally, performing myocardial contrast echocardiography with OPTISON required maximal bolus dosing. However, sustained and consistent opacification of the myocardium would be preferable for perfusion imaging. Methods: Images of 5 anesthetized dogs and 6 human volunteers were obtained with a second harmonic ultrasound system during bolus administration of OPTISON and 2 infusion techniques. One infusion technique used diluted OPTISON, and the other used the buoyant properties of OPTISON microspheres by placing the contrast agent between an infusion source and the intravenous site in a vertically oriented extension line (ELT). Myocardial intensities and in vitro microsphere characteristics were analyzed to assess the consistency of microsphere delivery over time. Results: In addition to providing higher myocardial opacification intensity than diluted infusions, ELT infusions provided consistent microsphere concentration, phantom enhancement, and near-peak bolus-level myocardial opacification for 7 to 15 minutes. The myocardial intensity at 3 and 5 minutes in human subjects during ELT infusions (30 mL/h; 2.5 mL) was lower (220 arbitrary units [au] and 165 au, respectively) but not significantly different (P = .3 and .1, respectively) than the peak myocardial intensity (265 au) after bolus administration. Conclusion: This new ELT infusion method provides an acceptable alternative to bolus administration of OPTISON for prolonged myocardial opacification.