title: The influence of the boundary conditions on longitudinal wave propagation in a viscoelastic medium.
abstract: In this paper, the effect of the boundary conditions and excitation dimensions on the speed of longitudinal waves in a medium is investigated. It is shown that with appropriate boundary conditions, a low-speed longitudinal wave can be generated in the medium which can be tracked by standard pulse-echo ultrasound motion tracking techniques. Three different cases of boundary conditions are explored in which the longitudinal wave speed in an incompressible material can be as high as the acoustic wave speed or as low as the shear wave speed. It is shown that the displacement spectrum can be used to estimate the wave speed in a viscoelastic medium. Numerical simulations with 3D viscoelastic finite element models and experiments on tissue-mimicking phantoms are performed to validate the theory.
authors.affiliation: Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Hani
authors.initials: H
authors.lastname: Eskandari
authors.forename: Ali
authors.initials: A
authors.lastname: Baghani
authors.forename: Septimiu E
authors.initials: SE
authors.lastname: Salcudean
authors.forename: Robert
authors.initials: R
authors.lastname: Rohling
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003238:Connective Tissue / Q000502:physiology*; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008954:Models, Biological; D012542:Scattering, Radiation; D013314:Stress, Mechanical; D014732:Vibration; D014783:Viscosity