Microvascular rheology of definity microbubbles after intra-arterial and intravenous administration

Jonathan R. Lindner, Ji Song, Ananda R. Jayaweera, Jiri Sklenar, Sanjiv Kaul

Research output: Contribution to journalArticlepeer-review

247 Scopus citations


The microvascular rheology and extent of pulmonary retention of second-generation microbubble ultrasound contrast agents has not previously been well characterized. We assessed the microvascular behavior of Definity, a lipid-shelled microbubble agent containing perfluoropropane gas, using intravital microscopy of either rat spinotrapezius muscle or mouse cremaster muscle. Immediately after intra-arterial injection, which was performed to model pulmonary retention, larger microbubbles (> 5 μm) were entrapped within small arterioles and capillaries. The retention fraction of microbubbles was low (1.2% ± 0.1%) and entrapment was transient (85% dislodged by 10 minutes), resulting in no adverse hemodynamic effects. Leukocyte or platelet adhesion at the site of entrapment was not seen. After intravenous injection, no microbubble entrapment was observed and the velocities of microbubbles in arterioles, venules, and capillaries correlated well with those of red blood cells. We conclude that after intravenous injection and pulmonary passage, the microvascular rheology of Definity microbubbles is similar to that of red blood cells. Microbubble entrapment within the pulmonary microcirculation after venous injection should be negligible and transient. These findings are important for establishing the safety of this agent.

Original languageEnglish (US)
Pages (from-to)396-403
Number of pages8
JournalJournal of the American Society of Echocardiography
Issue number5
StatePublished - May 2002
Externally publishedYes

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine


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