Variations of the Frequency-Dependent Attenuation Coefficient with the Bone Mineral Density and the Architectural Parameters in Bovine Trabecular Bone

초록

The present study aims to investigate the variations of the frequency-dependent attenuation coefficient with the bone mineral density (BMD) and two architectural parameters, the bone volume fraction (BV/TV) and the trabecular thickness (Tb.Th), in bovine trabecular bone in vitro. The attenuation coefficient was measured over a frequency range from 0.2 to 0.6 MHz in 22 bovine femoral trabecular bone samples. The frequency variation of the attenuation coefficient was characterized by using a nonlinear power law, alpha(f) = alpha(0) + alpha(1)f(n), at frequencies between 0.2 and 0.6 MHz. The parameters alpha (the attenuation coefficient at 0.4 MHz) and alpha(1) exhibited high correlations with the BMD and the BV/TV and relatively low correlations with the Tb.Th. The parameter alpha(1) was found to have weak correlations with the BMD and the Tb.Th and a very weak correlation with the BV/TV. In contrast, the exponent n showed no correlations with the BMD and the architectural parameters. These results suggest that measurements of the parameters alpha and alpha(1) in trabecular bone may be useful for the assessment of bone status and osteoporosis. A scattering model based on velocity fluctuations in a binary mixture (cortical matrix and marrow fat) was successfully applied to predict the variations of the frequency-dependent attenuation coefficient with the architectural parameters observed in the 22 bone samples.

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