Effect of static pressure on acoustic transmittance of Albunex(R) microbubble suspensions

Abstract

Albunex (ALX), an albumin-stabilized microbubble echo contrast agent, is sensitive to pressures similar to those produced by the heart. The tested hypothesis was that the acoustic transmittance of ALX suspensions will increase with increasing hydrostatic pressure (Ps). The test involved an acoustic setup analogous to a spectrophotometer. The acoustic transmittance of microbubble suspensions was strongly Ps dependent. Transmittance at 1 MHz was essentially zero at ambient pressure, increasing to approximately 50%, approximately 63%, and nearly 100% at Ps of 80, 120, and 400 mm Hg, respectively. The ultrasound pulses used to interrogate samples were without measurable effect on the acoustic transmittance of suspensions maintained at ambient pressure during experimental measurements. The data indicate that many of the microbubbles are destroyed at Ps comparable to those produced by the heart.

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

“…Further, it was seen that the contrast reduction was an irreversible process. Gottlieb et al [52] and Brayman et al [53] reported similar observations.…”

Ultrasound attenuation by encapsulated microbubbles: time and pressure effects

“…This allowed better imaging of the various organs, but also opened up other objectives (e.g., the measurement of pressure). The use of UCAs for noninvasively measuring blood pressure in specified locations within the cardiovascular system is a promising clinical application (Shapiro et al 1990;Brayman et al 1996;Bouakaz et al, 1999). The first attempts to use US and air bubbles to measure blood pressure (Fairbank and Scully 1977;Hok 1981;Shankar et al 1986) proved the concept, but it could not be implemented because the bubbles dissolved very fast.…”

Modeling subharmonic response from contrast microbubbles as a function of ambient static pressure

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