Effect of pressure on echocardiographic videodensity from sonicated albumin: an in vitro model.

The effect of different pressures (0, 10, 30, 60, 80, 100, 120, or 180 mm Hg) on the ultrasound contrast effect obtained from sonicated albumin was evaluated by videodensity decay curves in an in vitro model immersed in a water tank. Decay rates and half-times were calculated from the videodensity decay curves at each pressure. A significant (P < 0.0001) relation was found between contrast disappearance and pressure: the higher the pressure the more rapid the contrast disappearance. Release of pressure did not result in contrast reappearance. Contrast decrease with pressure may result from microbubble destruction or alteration in acoustic properties by pressure. These findings may help explain the limited success of sonicated albumin for systemic ultrasonographic arteriography and myocardial perfusion imaging after intravenous injection. An ideal contrast agent for contrast echo studies should be stable at physiologic pressures.