3-D numerical simulation of wave propagation in porous media: Influence of the microstructure and of the material properties of trabecular bone

Abstract

Finite-difference time domain simulations coupled to 3-D microstructural models of 30 trabecular bones reconstructed from synchrotron radiation microtomography were employed herein to compare and quantify the effects of bone volume fraction, microstructure, and material properties of trabecular bone on QUS parameters. Scenarios of trabecular thinning and thickening using an iterative dedicated algorithm allowed the estimation of the sensitivity of QUS parameters to bone volume fraction. The sensitivity to bone material properties was assessed by considering independent variations of density and stiffness. The effect of microstructure was qualitatively assessed by producing virtual bone specimens of identical bone volume fraction (13%). Both BUA and SOS show a strong correlation with BV/TV (r2=0.94 p10−4) and vary quasi-linearly with BV/TV at an approximate rate of 2 dB/cm/MHz and 11 m/s per % increase of BV/TV, respectively. Bone alterations caused by variation in BV/TV (BUA: 40 dB/cm.MHz; SOS: 200 m/s) is much more detrimental to QUS variables than that caused by alterations of material properties or diversity in microarchitecture (BUA: 7.8 dB/cm.MHz; SOS: 36 m/s). QUS variables are changed more dramatically by BV/TV than by changes in material properties or microstructural diversity. However, material properties and structure also appear to play a role.