Consequences of lithotripter shockwave interaction with gas body contrast agent in mouse intestine

Purpose: Shockwave lithotripsy can involve complications associated with hemorrhage and internal bleeding which appear to be due to acoustic cavitation. Gas-body-based contrast agents recently developed for diagnostic ultrasound can enhance cavitational bioeffects under some conditions. This study examined the occurrence and progression of vascular damage in mouse intestine when a contrast agent was present during shockwave treatment. Materials and Methods: Anesthetized hairless mice were injected with Albunex(R) contrast agent or a gas-body-free blank, and exposed to sham, 200 or 800 lithotripter shockwaves. Results: Exposure of the mouse abdomen to lithotripter shockwaves produced petechiae in the intestinal wall and hemorrhage into the lumen. Contrast-agent gas bodies greatly enhanced the numbers of petechiae (but not the hemorrhages), relative to the blank agent. When evaluation of these effects was delayed for one day, both effects decreased, and the gas-body-associated petechiae seemed to disappear. However, survival significantly decreased for mice with added gas bodies and shockwave treatment. Conclusions: The presence of a gas-body-based ultrasound contrast agent enhances vascular side effects of shockwave lithotripsy. Although there are great uncertainties in relating these observations to human clinical conditions, a delay in planned treatment might be prudent for patients scheduled for shockwave lithotripsy soon after receiving gas-body-based ultrasound contrast agents.