A Velocity-Based Approach to Noninvasive Methodology for Urodynamic Analysis

Purpose: To date, invasive urodynamic investigations have been used to define most terms and conditions relating to lower urinary tract symptoms. This invasiveness is almost totally due to the urethral catheter. In order to remove this source of dis-comfort for patients, the present study investigated a noninvasive methodology able to provide diagnostic information on bladder outlet obstruction or detrusor underactivity without any contact with the human body. Methods: The proposed approach is based on simultaneous measurements of flow rate and jet exit velocity. In particular, the jet exit kinetic energy appears to be strongly related to bladder pressure, providing useful information on the lower urinary tract functionality. We developed a new experimental apparatus to simulate the male lower urinary tract, thus allowing exten-sive laboratory activities. A large amount of data was collected regarding different functional statuses. Results: Experimental results were compared successfully with data in the literature in terms of peak flow rate and jet exit ve-locity. A new diagram based on the kinetic energy of the exit jet is proposed herein. Using the same notation as a Schafer dia-gram, it is possible to perform noninvasive urodynamic studies. Conclusions: A new noninvasive approach based on the measurement of jet exit kinetic energy has been proposed to replace current invasive urodynamic studies. A preliminary assessment of this approach was carried out in healthy men, with a speci-ficity of 91.5%. An additional comparison using a small sample of available pressure-flow studies also confirmed the validity of the proposed approach.