Advancing Toward a Catheter-Free Pressure Flow Study: Ultrasound-Based Subharmonic-Aided Pressure Estimation of the Human Bladder

This study explores the feasibility of using subharmonic-aided pressure estimation (SHAPE), an ultrasound-based technology, as a non-invasive alternative to traditional urodynamic tests for measuring bladder pressure. Urodynamic tests typically require a urethral catheter, leading to non-physiologic pressure flow readings. In previous work, SHAPE was shown to effectively measure pressure in a bladder phantom. This study extends that research by applying SHAPE technology in adult female volunteers. The researchers hypothesized that SHAPE could serve as a viable catheter-free method for bladder pressure estimation. Using a GE Healthcare LOGIQ® E10 ultrasound scanner and Lumason® contrast agent, the study measured bladder pressure during filling, ranging from 60 to 270 mL at a rate of 30 mL/min. Subjects performed Valsalva maneuvers to increase bladder pressure, while both transabdominal and transperineal ultrasound probe placements were tested. The results demonstrated an inverse linear relationship between SHAPE signals and bladder pressure changes, confirming that SHAPE accurately detected pressure variations during both filling and post-filling phases. The conversion factors for SHAPE were calculated, showing strong correlations (R2=0.86 and 0.93) for transabdominal and transperineal measurements, respectively. These findings suggest that SHAPE could be a promising alternative for non-invasive bladder pressure monitoring, potentially eliminating the need for catheters in urodynamic studies. However, further validation is needed to fully assess SHAPE’s clinical efficacy during voiding.