Destruction of Contrast Agent Microbubbles in the Ultrasound Field: The Fate of the Microbubble Shell and the Importance of the Bubble Gas Content
Section snippets
Rationale and Objectives
Disappearance of ultrasound (US) contrast agents (gas-filled microbubbles) after contrast agent administration in the bloodstream occurs by way of several mechanisms. First, microbubbles are filtered and captured by various organs, including uptake by Kupffer cells in the liver (1, 2). Second, gas diffuses from the microbubble core and dissolves in the surrounding medium, leaving the nonechogenic shell behind (3). The third process is the most rapid and important for the practice of diagnostic
Microbubble Preparation and Purification
Optison (Mallinckrodt) microbubble dispersion in albumin solution was subjected to multiple centrifugal washes in perfluoropropane-saturated saline. Removal of soluble albumin was necessary to avoid blocking of the Petri dish surface so microbubbles could attach to the dish surface. A vial of Optison was outfitted with two 25-gauge needles, a long one for withdrawal and addition of the infranatant aqueous phase and a short one connected to the barrel of a tuberculin syringe for venting. Gaseous
Results
Albunex is much more prone to the loss of echogenicity (ie, gas core) in the bloodstream than Optison (11). This is also true for the loss of gas induced by insonification. The destruction rate of Albunex microbubbles filled with air appeared to be considerably higher than the rate of destruction of Optison microbubbles that contain perfluoropropane gas, maintained in a perfluoropropane-saturated environment (compare Fig 1A–C and 1D–F). Gas interchange between the surrounding medium and the
Conclusion
Destruction of gas-filled microbubbles in the ultrasound field of the medical imaging system is influenced by the nature of the gas inside the bubbles. For air-filled bubbles, deflation is substantially faster than for perfluorocarbon-containing microbubbles in the perfluorocarbon-saturated medium. The shell of the deflated Optison bubble stays mostly as a sheetlike structure, whereas the shell of the phospholipid-coated MP1950 after deflation turns into smaller particulates that are shed into
References (17)
- et al.
Destruction of contrast microbubbles during ultrasound imaging at conventional power output
J Am Soc Echocardiogr
(1997) - et al.
Interactions between microbubbles and ultrasound: in vitro and in vivo observations
J Am Coll Cardiol
(1997) - et al.
Increased ultrasound contrast and decreased microbubble destruction rates with triggered ultrasound imaging
J Am Soc Echocardiogr
(1996) - et al.
Real-time visualization of myocardial perfusion and wall thickening in human beings with intravenous ultrasonographic contrast and accelerated intermittent harmonic imaging
J Am Soc Echocardiogr
(1999) - et al.
Potential advantage of flash echocardiography for digital subtraction of B-mode images acquired during myocardial contrast echocardiography
J Am Soc Echocardiogr
(1999) - et al.
Improved left ventricular endocardial border delineation and opacification with Optison (FS069), a new echocardiographic contrast agent
J Am Coll Cardiol
(1998) - et al.
Human biodistribution of an ultrasound contrast agent (Quantison) by radiolabelling and gamma scintigraphy
Br J Radiol
(1997) - et al.
Biodistributions of air-filled albumin microspheres in rats and pigs
Biochem J
(1994)