Apport des ultrasons dans l'exploration du tissu osseux

The preferred assessment of bone biomechanical competence in vitro is by direct mechanical testing and in vivo by X-ray absorptiometry techniques. For more than 30 years investigators have been developing alternative techniques, by ultrasonic methods, aimed at providing (i) the elastic properties in vitro without the complications related the destructive character of mechanical testing and (ii) the evaluation of the fracture risk in vivo, taking benefit of the propagation of elastic wave which are inherently affected by both material and structural bone properties. The in vitro strategy includes the use of multiscale ultrasonic assessment for the combined evaluation of both the material (or intrinsic) and the structural elastic properties in various axes of symmetry. The in vivo approach involves the use of the different propagation modes (bulk wave, guided wave, surface wave) permitted by the ultrasonic approach. We will review the in vitro and clinical data on each ultrasonic approach and discuss potential areas of development in the field of quantitative bone assessment bone.