Transient elastography in anisotropic medium: application to the measurement of slow and fast shear wave speeds in muscles.
From the measurement of a low frequency (50-150 Hz) shear wave speed, transient elastography evaluates the Young's modulus in isotropic soft tissues. In this paper, it is shown that a rod source can generate a low frequency polarized shear strain waves. Consequently this technique allows to study anisotropic medium such as muscle. The evidence of the polarization of low frequency shear strain waves is supported by both numeric simulations and experiments. The numeric simulations are based on theoretical Green's functions in isotropic and anisotropic media (hexagonal system). The experiments in vitro led on beef muscle proves the pertinent of this simple anisotropic pattern. Results in vivo on man biceps shows the existence of slow and fast shear waves as predicted by theory.
Gennisson
Jean-Luc
JL
Laboratoire Ondes et Acoustique, E.S.P.C.I., Université Paris VII, U.M.R. 7587 C.N.R.S. 1503, 10 rue Vauquelin, 75231 Paris cedex 05, France. jeanluc.gennisson@loa.espci.fr
Catheline
Stefan
S
Chaffaï
Sana
S
Fink
Mathias
M
D000161:Acoustic Stimulation; D000328:Adult; D000818:Animals; D016880:Anisotropy; D002417:Cattle; D003198:Computer Simulation; D004548:Elasticity; D006801:Humans; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009716:Numerical Analysis, Computer-Assisted; D019047:Phantoms, Imaging; D033081:Shear Strength; D013018:Sound Spectrography; D014159:Transducers; D014465:Ultrasonics