Ultrasonic detection of in-vivo cavitation and pressure effects of high-speed injections through catheters.

The fluid stream which emerges from an injection catheter of the type used in standard radiologic practice produces cavitation at high flow rates. Cavitation bubbles were detected within the aorta of dogs using an ultrasonic echo technique. Echo patterns produced by cavities in blood are characteristic. Fine bubbles produced by catheter injection occur only in the region of the effluent jet. Pressure recordings from the aorta proximal and distal to a rapid ejection show that pressure can drop below atmospheric in the region behind the jet flow. The effect of the injection on intravascular pressure is a function of the injection rate.