  In vivo measurement of the mechanical properties of thin-walled soft tissues
(e.g., mitral valve, artery and bladder) and in situ mechanical
characterization of thin-walled artificial soft biomaterials in service are of
great challenge and difficult to address via commonly used testing methods.
Here we investigate the properties of guided waves generated by focused
acoustic radiation force in immersed pre-stressed plates and tubes, and show
that they can address this challenge. To this end, we carry out both (i) a
theoretical analysis based on incremental wave motion in finite deformation
theory and (ii) finite element simulations. Our analysis leads to a novel
method based on the ultrasound elastography to image the elastic properties of
pre-stressed thin-walled soft tissues and artificial soft materials in a
non-destructive and non-invasive manner. To validate the theoretical and
numerical solutions and demonstrate the usefulness of the corresponding method
in practical measurements, we perform (iii) experiments on polyvinyl alcohol
cryogel phantoms immersed in water, using the Verasonics V1 System equipped
with a L10-5 transducer. Finally, potential clinical applications of the method
have been discussed.
