Bone properties determination from guided wave velocities: an in vitro test case study
Résumé
Ultrasonic guided mode propagation has been suggested as a mean for assessment of cortical bone properties such as porosity and thickness, through inverse procedure based on the identification of experimental guided wave spectrum (wavenumber as function of frequency) to a reference model. However, while a high number of unknowns (stiffnesses, density, thickness) must be determined, several factors inherent to measurement on bone such as absorption reduce the quantity of experimental data. Moreover, spatial variability of geometry and elasticity implies to develop dedicated measurement sequence to improve the robustness of stable experimental data. A feasibility study on an in vitro radius (forearm) is presented. Experimental signals were obtained using a probe dedicated to clinical use (broadband 1 MHz signals) associated with a dedicated signal processing efficient for dissipative materials. The reference model was a 2D transverse isotropic plate model with the bone material considered as a homogenized biphasic model (bone matrix/porosity) with elastic properties of the bone matrix a priori known. Estimated parameters were a thickness of 2.3 mm and stiffness coefficients (in GPa) of c11 = 29.4, c13 = 8.8, c33 = 18.3 and c55 = 5.4. Current works focus on the robustness and the accuracy of the technique.
Domaines
Acoustique [physics.class-ph]
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