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Fabric dependence of bone ultrasound

Cowin S. C., Cardoso L.

Acta of Bioengineering and Biomechanics

2010

Vol. 12, no. 2

3-23

Current diagnosis of bone loss and osteoporosis is based on the measurement of the Bone Mineral Density (BMD) or the apparent mass density. Unfortunately, in most clinical ultrasound densitometers: 1) measurements are often performed in a single anatomical direction, 2) only the first wave arriving to the ultrasound probe is characterized, and 3) the analysis of bone status is based on empirical relationships between measurable quantities such as Speed of Sound (SOS) and Broadband Ultrasound Attenuation (BUA) and the density of the porous medium. However, the existence of a second wave in cancellous bone has been reported, which is an unequivocal signature of poroelastic media, as predicted by Biot’s poroelastic wave propagation theory. A fabric-dependent anisotropic poroelastic approach is empolyed as a theoretical framework to describe the microarchitectural-dependent relationship between measurable wave properties and the elastic constants of trabecular bone, and thus represents an alternative for bone quality assessment beyond BMD alone.

Adaptive Elasticity: A Review and Critique of a Bone Tissue Adaptation Model

Cowin S.C.

Engineering Transactions

2003

Vol. 51, iss.2-3

113-193

Living bone is continually undergoing processes of growth, reinforcement and resorption. These processes are termed collectively ``remodeling''. The remodeling processes in living bone are the mechanisms by which the bone adapts its histological structure to changes in long-term loading. The theory of adaptive elasticity was developed as a model for the mechanical load induced adaptation of bone. All three aspects of the theory of adaptive elasticity are reviewed here. These include internal adaptation, surface adaptation and architectural adaptation. The successes of the theory as well as the features of the theory that should now be revised are discussed.