[Visualization of the intravesical urine stream].

Although many urodynamic techniques have been used to evaluate the function of the lower urinary tract, the principles of these measurements are only based on a relationship between flow rate and pressure. In addition to these measurements, the intravesical urine stream would provide useful information on urodynamics. We have experimentally attempted to visualize the urine stream in a bladder using transrectal ultrasound examination. Since an air-particle is a good target for ultrasound visualization, we instillated a 10% glycerine solution into the bladder for the maintenance of air-particles. Before instillation, this glycerine solution was strongly shaken so that air-particles were kept in the solution. The urine stream was successfully observed throughout the whole process of voiding. In video-recording analysis, the velocity of urine stream was measured by tracing some air-particles. The velocity of urine stream was approximately 28.4 cm/sec in the body and increased to 116.6 cm/sec at the bladder neck. Thus, the urine stream was accelerated toward the urethra during voiding. Therefore, it seems that visualization of the urine stream offers a new parameter for evaluation of urodynamic studies.