Sophia Yeras
Pronouns: she/her
Research Mentor(s): J Fowlkes
Co-Presenter: Chen, Amy
Research Mentor School/College/Department: Radiology / Medicine
Presentation Date: April 20
Presentation Type: Poster
Session: Session 3 – 1:40pm – 2:30 pm
Room: League Ballroom
Authors: Sophia Yeras, Amy Chen, Kourosh Kalayeh, J. Brian Fowlkes, William W. Schultz, Bryan S. Sack
Presenter: 33
Abstract
A cystometrogram (CMG) is a part of a urodynamic test that measures bladder filling and voiding pressures. During a CMG, a catheter is inserted into the bladder which is then filled with saline until the bladder is full. The patient is then asked to void while the catheter remains in the bladder. The bladder pressure is recorded for the entirety of the test. The presence of the catheter during voiding can obstruct free flow of the fluid out of the bladder, causing non-physiological elevated voiding pressures and low flow. In some cases, pressure-flow studies are not even attainable due to complete occlusion of urethra and/or anxiety associated with catheter. In this project, we propose to use pressure-dependent acoustic properties of ultrasound contrast agents (UCAs) to measure bladder phantom pressures without catheter, through a technique known as SubHarmonic Aided Pressure Estimation (SHAPE). SHAPE is based on an inverse relationship between subharmonic emissions of the microbubbles and ambient pressure. Our benchtop experimental setup consists of a bladder phantom capable of simulating clinically relevant pressures, a GE LE 10 ultrasound scanner equipped with SHAPE software, and typical CMG equipment. A laboratory made-equivalent of a commercial UCA was diluted in 0.9% normal saline with dilution factor of 1:1667, and infused into the bladder phantom through the CMG catheter. Simultaneous with benchtop bladder phantom pressurization, subharmonic signal scattered by the UCA was acquired with the ultrasound scanner and calibrated with a linear fit to yield SHAPE measurements for multiple events during a CMG (taking up to 30 minutes). Events consist of a filling and multiple post-filling events, corresponding to voiding happening at different time points of a CMG, since not all patients can initiate voiding right after filling is stopped. We find a strong correlation between microbubble scattered subharmonic signal and bladder phantom pressures for each of the events, indicating that SHAPE can measure benchtop bladder phantom pressure. This is the first step towards creating a catheter-free voiding bladder pressure measurement using SHAPE.
Biomedical Sciences
