Performance evaluation of portable viscoelastic response ultrasound imaging system

VisR ultrasound, an “on-axis” acoustic radiation force-based elastography method, qualitatively assesses tissue viscoelastic properties from peak displacement (PD), relative elasticity (RE), and relative viscosity (RV) parameters. In this work, VisR was implemented on the portable us4R-lite + platform (us4us, Poland) with an L7-4 linear array (4.33 MHz excitation pulse with 70 μs duration and two cycles 5.9 MHz tracking pulse) and evaluated by imaging 4.7, 8.6, 34.0, and 70.9 kPa inclusions (6.49 mm diameter) embedded in a 16.7-kPa background of industry-standard elasticity phantom by varying the focal depth at 30 and 37 mm. (PD, RE, and RV)-derived contrast-to-noise ratio (CNR) of four inclusions was (3.45,1.54, 3.43), (3.71, 1.16, 3.12), (1.73, 1.03, 1.39), and (3.24, 1.48, 2.23) for focal depth of 30 mm. There was, on average, a 35.5%, 41.5%, and 30.7% reduction in PD, RE, and RV’s CNR when the inclusion was centered at 37 compared to 30 mm. Complex inertia correction was not applied to the RV. Acoustic pressure was not adjusted for the higher depth. Future works will evaluate the performance of the portable VisR in viscoelastic phantoms and biological tissues. The study is the first step towards implementing VisR on a portable ultrasound system for point-of-care clinical applications.