Imaging Beyond Bone Mineral Density
Pp. 53-82 (30)
Bone is a composite tissue comprised of organic and inorganic phases. It
adapts itself to mechanical strains with an aim to maintain its mechanical competence
via modelling and remodeling. Such adaptation of bone can result in alteration of
material and structural properties including bone mineral density (BMD), microarchitecture,
mineralization, and morphology. Quantitative bone imaging enables the
evaluation of bone status in relation to diseases, mechanical and other interventions.
However, bone quantity measurement of BMD using dual-energy X-Ray
absorptiometry is limited because of its projection imaging approach and provides only
a scalar measurement. As an anisotropic material, other bone quality including the
architecture and spatial distribution of bone have to be considered in the evaluation of
bone status. Also collagen fiber orientation and degree of mineralization in this
composite tissue are important determinants of bone adaptation in response to
treatment interventions. Thus, synergized use of multi-imaging modalities may
decipher the interplay of material and structural properties in bone adaptation. Current
imaging techniques using peripheral quantitative computed tomography, microcomputed
tomography, magnetic resonance imaging, quantitative ultrasound and
circularly polarized light microscopic imaging have gone beyond the measurement of
bone quantity and to provide significant information of bone quality in the
understanding of bone status. The present chapter aims to discuss the contribution of
different imaging modalities in the evaluation of bone status.
Bone Quantity, Bone Quality, Bone Strength, Imaging.