Assessment of pressure in a brain mimicking phantom using shear wave elasticity imaging

A non-invasive method for monitoring Intracranial Pressure (ICP) is needed for monitoring different brain conditions. ICP changes can be measured by assessing changes in brain stiffness. While SWEI can be used to evaluate soft tissue stiffness, ultrasound is challenged by the presence of the skull. Recently, the FDA approved Longeviti implants, which provide an acoustic window to assess the brain using ultrasound. In this study, we investigate the feasibility of quantifying pressure in a brain-mimicking phantom using SWEI. The phantoms were constructed using gelatin with a balloon to vary pressure by injecting water. The changes in pressure in the phantom are reproducible and consistent, as verified by the Miller pressure catheter. SWEI was measured on the phantom using the Verasonics Vantage Ultrasound system with the L74 transducer, while pressure was increased to 5 mmHg in increments of 1 mmHg. The phantom Young’s modulus was 20.7 kPa at the ambient pressure of 49 mmHg without water and was increased to 25.9 kPa when the pressure increased to 5 kPa. Changes in Young’s modulus versus pressure followed a linear trend with R² = 0.73. Future work will investigate the effect of baseline elasticity and Longeviti implants on the Young’s modulus versus pressure relationship.