Abstract:

Understanding the coupled interactions between acoustically activated microbubbles and surrounding tissues is important for both diagnostic and therapeutic applications. However, little is known about ultrasound‐induced coupled interactions between microbubbles and blood vessels. In this work, high‐speed microscopy was used to investigate the coupled interactions inside vessels of ex vivo rat mesentery. A 1‐MHz focused ultrasound transducer was used to transmit a single pulse to tissue samples having blood vessel diameters of 10–100 μm. Bubble‐tissue interactions were captured with a high‐speed camera and an inverted microscope. For pressure amplitudes ranging from 1 to 7 MPa, several phenomena were observed: (a) microbubble oscillations caused localized dilation and invagination of the vessels, (b) microbubble jetting occurred where most jets were directed away from the adjacent vessel wall, and (c) connective tissue surrounding the vessels moved with the vessels. The talk will focus on quantitative measurements of vessel motion, strain, and jet velocities. [Work supported by NIH Grants 5R01EB000350, 5R01AR053652, 5P01DK043881, and DK070618.]