Direct In Vivo Visualization of Intravascular Destruction of Microbubbles by Ultrasound and its Local Effects on Tissue

TLDR

The study aimed to observe ultrasound‑induced intravascular microbubble destruction in vivo and characterize resulting bioeffects. Intravital microscopy of the spinotrapezius muscle in 15 rats was used to image ultrasound delivery. Ultrasound‑induced microbubble destruction ruptured ≤7‑μm microvessels and produced non‑viable adjacent cells, with vessel rupture and cell damage linearly correlated to ultrasound energy, indicating potential for local drug delivery, angiogenesis, vascular remodeling, or tumor destruction.

Abstract

Background —Our aim was to observe ultrasound-induced intravascular microbubble destruction in vivo and to characterize any resultant bioeffects. Methods and Results —Intravital microscopy was used to visualize the spinotrapezius muscle in 15 rats during ultrasound delivery. Microbubble destruction during ultrasound exposure caused rupture of ≤7-μm microvessels (mostly capillaries) and the production of nonviable cells in adjacent tissue. The number of microvessels ruptured and cells damaged correlated linearly ( P <0.001) with the amount of ultrasound energy delivered. Conclusions —Microbubbles can be destroyed by ultrasound, resulting in a bioeffect that could be used for local drug delivery, angiogenesis, and vascular remodeling, or for tumor destruction.