Rationale and objectives: Inhaled gas mixtures with increased amounts of oxygen cause air containing ultrasound contrast agents to lose efficacy faster than during the inhalation of air. The authors hypothesized that contrast materials containing relatively insoluble gases would decrease the effects of inhaled gases on the ultrasound contrast.
Methods: Anesthetized dogs were ventilated with compressed air and different oxygen/nitrogen gas mixtures. Video densitometric analysis was performed on end diastolic ultrasound images of the heart after administration of Albunex (air-filled microspheres) or Optison (perfluoropropane-filled microspheres).
Results: Increased concentrations of oxygen caused no change in the contrast intensity produced by Optison in the left ventricular chamber. In the myocardium, however, increases in oxygen caused Optison to produce significantly less enhancement of the myocardial tissue.
Conclusions: The use of perfluoropropane within albumin microspheres prevented the effects of inhaled gas mixtures on contrast produced within the left ventricular chamber. In the myocardium, increased concentrations of oxygen in the inhaled gas mixtures reduce contrast intensity.