Double Profile Intersection (DoPIo) Ultrasound With Acoustic Radiation Force Tilting Interrogates Young's Modulus in...

This study evaluates the potential for interrogating the Young's elastic moduli in anisotropic media, including tissue, using Double Profile Intersection (DoPIo) ultrasound. DoPIo is an on-axis acoustic radiation force (ARF)-based elasticity imaging method that quantifies shear elasticity without relying on shear wave propagation. It is hypothesized that by applying a range of ARF excitations that are not perpendicular to the axis of symmetry (AoS) of transversely isotropic (TI) materials and monitoring the resultant variation in DoPIo-measured elasticity versus excitation angle, the Young's elastic modulus may be interrogated in addition to the shear elastic modulus. The hypothesis was tested in silico, and results suggested that while DoPIo outcomes measured at normal (90°) ARF-AoS incidence were related to the shear elastic modulus alone, variation in DoPIo-derived elasticity over ARF-AoS incidence angle (defined as Δ Elasticity) exhibited a strong linear correlation with the longitudinal Young's modulus ( $E_L$ ). The results suggest that $E_L$ evaluated by the rate of change of Δ Elasticity with ARF-AoS incidence angle may serve as a novel biomarker for characterizing elastically anisotropic tissues such as kidney, skeletal muscle, and breast.