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 mic robubble destruction in vivo and to characterize any resultant bioeffe cts. Methods and Results-Intravital microscopy was used to visualize t he spinotrapezius muscle in 15 rats during ultrasound delivery. Microb ubble destruction during ultrasound exposure caused rupture of less th an or equal to 7-mu m microvessels (mostly capillaries) and the produc tion of nonviable cells in adjacent tissue. The number of microvessels ruptured and cells damaged correlated Linearly (P<0.001) with the amo unt of ultrasound energy delivered. Conclusions-Microbubbles can be de stroyed by ultrasound, resulting in a bioeffect that could be used for local drug delivery angiogenesis, and vascular remodeling, or for tum or destruction.