Direct in vivo visualization of intravascular destruction of microbubbles by ultrasound and its local effects on tissue

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 less than or equal to 7-mu m 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.