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Updated: May 17, 2026
Induction of Microstreaming by Nonspherical Bubble Oscillations in an Acoustic Levitation System
Published on: May 9, 2021
Preliminary observations on the spatial correlation between short-burst microbubble oscillations and vascular
Hong Chen1, Andrew A Brayman, Andrew P Evan
1Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA.
Abstract:
The objective of this preliminary study was to examine the spatial correlation between microbubble (MB)-induced vessel wall displacements and resultant microvascular bioeffects. MBs were injected into venules in ex vivo rat mesenteries and insonated by a single short ultrasound pulse with a center frequency of 1 MHz and peak negative pressures spanning the range of 1.5-5.6 MPa. MB and vessel dynamics were observed under ultra-high speed photomicrography. The tissue was examined by histology or transmission electron microscopy for vascular bioeffects. Image registration allowed for spatial correlation of MB-induced vessel wall motion to corresponding vascular bioeffects, if any. In cases in which damage was observed, the vessel wall had been pulled inward by more than 50% of the its initial radius. The observed damage was characterized by the separation of the endothelium from the vessel wall. Although the study is limited to a small number of observations, analytic statistical results suggest that vessel invagination comprises a principal mechanism for bioeffects in venules by microbubbles.
Insights
Microbubbles (MBs) can cause damage to blood vessels. This study found that inward vessel wall motion, or invagination, is a primary mechanism for microbubble-induced bioeffects in venules.
Area of Science:
- Biomedical Engineering
- Microvascular Physiology
- Ultrasound Therapeutics
Background:
- Microbubbles (MBs) are widely used in medical imaging and therapies.
- Understanding the bioeffects of MBs is crucial for optimizing their clinical applications.
- Previous studies have explored MB-induced cavitation and its effects, but the precise mechanism of vessel wall interaction requires further elucidation.
Purpose of the Study:
- To investigate the spatial correlation between microbubble-induced vessel wall displacements and microvascular bioeffects.
- To determine the mechanical threshold for MB-induced vascular damage.
- To elucidate the primary mechanism of MB-induced bioeffects in venules.
Main Methods:
- Ex vivo rat mesenteric venules were used.
- Microbubbles were injected and insonated with ultrasound pulses (1 MHz, 1.5-5.6 MPa).
- MB and vessel dynamics were captured using ultra-high speed photomicrography, followed by histological and electron microscopy analysis.
Main Results:
- Vessel wall invagination exceeding 50% of the initial radius was correlated with observed damage.
- Damage manifested as endothelial-vessel wall separation.
- Statistical analysis suggested vessel invagination as a principal mechanism for MB-induced bioeffects.
Conclusions:
- Microbubble-induced vessel wall invagination is a key mechanism leading to microvascular bioeffects.
- This finding has implications for the safe and effective use of microbubbles in therapeutic ultrasound applications.
- Further research with larger sample sizes is warranted to confirm these preliminary findings.
