Microbubble formation: in vitro and in vivo observation.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Cardiovascular Research

Background:

• Sonography can detect signal clouds from liquid injections into circulation.
• Blood flow through stenotic conduits generates sonographic clouding.
• Microbubbles are implicated in sonographic signal generation.

Purpose of the Study:

• To investigate the characteristics and effects of microbubbles generated during blood injection into the microcirculation.
• To observe microbubble persistence and impact on blood flow in real-time.

Main Methods:

• Catheterization of the descending aorta in 15 rats.
• Injection of autologous blood to generate microbubbles.
• Real-time videographic observation of rat mesenteric microcirculation at 400X magnification.
• Light microscopy to confirm microbubble size (10-100 microns).

Main Results:

• Microbubbles were successfully generated and observed in the rat microcirculation.
• Injected microbubbles lodged in arterioles, causing temporary obstruction of blood flow (up to 200 seconds).
• Microbubbles persisted for up to 3.5 minutes before shrinking and allowing flow restitution.

Conclusions:

• Sonographically detectable microbubbles can be generated from blood injection.
• These microbubbles can cause transient microvascular obstruction.
• Understanding microbubble dynamics is crucial for applications involving intravascular injections and sonography.