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

Abstract

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, α(f) = α0 + α1fn, at frequencies between 0.2 and 0.6 MHz. The parameters α (the attenuation coefficient at 0.4 MHz) and α1 exhibited high correlations with the BMD and the BV/TV and relatively low correlations with the Tb.Th. The parameter α1 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 α and α1 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.