The future of urodynamics: non-invasive ultrasound videourodynamics.

A totally non-invasive transperineal urodynamic technique using Doppler ultrasonography has been developed. Normal urine doesn't have blood cells so urine was thought not to produce Doppler effects. However, basic studies confirmed that the decrease of pressure at high velocity (Bernoulli effects) caused dissolved gas to form microbubbles, which are detected by Doppler ultrasonography. Subjects sat and a probe was advanced via remote control to achieve gentle contact with the perineal skin. The digital uroflow data signals and the color Doppler ultrasound video images were processed on a personal computer. This method was viable to diagnose the degree of bladder outlet obstruction. The advantage of being rapid, effective, and equipped with no special attachments allows it to surpass any other non-invasive urodynamic methods. The difference between the echocardiogram and the ultrasound urodynamic system is only the frequency of obtaining velocity information: more than 50 times per minute vs once every several hours, respectively. Although the ultrasound urodynamic system is more difficult to develop than the echocardiogram, one principle is shared by both methods. The patient can void freely without interruptions, there is no contact between the penis and the equipment and it is specifically directed toward non-invasive diagnosis. The development of non-invasive Doppler ultrasound videourodynamics will dramatically expand understanding of voiding function.