Résumé:
Pulsed elastography allows one to accurately achieve the young modulus of soft tissues from the measurement of the shear wave velocity. Because the low frequency shear wave can easily be polarized by using a rod source, one can extend this technique to measure the elastic parameters of anisotropic media like muscles. Moreover, as it is shown in a first part, the same technique used in an acoustoelasticity-like experiment allows one to measure the non-linear third order elastic Landau coefficients A , B, C in an agar-gelatin based phantom. In a second part, the behavior of a finite amplitude transverse wave is compared to a simulation based on the modified Burger’s equation. In both approaches, it appears that contrary to longitudinal wave for which even harmonics are created during the propagation, only odd harmonics are present on the displacement spectra of a finite amplitude transverse wave.

Mots-clés: elastography, acoustoelasticity, nonlinear, modified Burger's equation, Landau Coefficient