Constructive shearwave interference (CSI): Concept and feasibility

This paper introduces the design of a constructive shear wave interference (CSI) probe: a hemi-torroid annular mechanical ring array with a center ultrasonic tracking element. The idea is to induce shear wave displacements in a ring, then track the resultant constructively interfering displacement sum at the center. The target application is in sclerotic skin conditions where current ARFI and SWEI methods are SNR limited, and could benefit from large displacements without increasing acoustic exposure. This study demonstrates in simulations and in phantoms the feasibility of using this technique and probe in a range of material stiffnesses to accurately represent the expected shear wave speed (SWS). Finally, the results were validated against a custom Siemens S3000 STL SWEI sequence to show the accuracy of CSI speed reconstruction.