The estimation of structural anisotropy of trabecular and cortical bone tissues based on ultrasonic velocity and attenuation

Velocity of ultrasound and broad-band ultrasound attenuation (BUA) were measured in three perpendicular directions in anisotropic samples of cancellous and cortical bones. The aim was to study tte influence of microarchitecture of bone tissue on ultrasound propagation in bone. The pulse transmission method (1 MHz and 3.5 MHz) and the Fourier analysis of transmitted were applied. The dependence of both ultrasonic parameters on the orientation and the correlation between the degree of the anisotropy and bone density were stated. In cancellous bone samples, both velocity and BUA had extreme value in the direction of trabeculae alingment. In cortical bone, maximal velocity was in the axial direction, while BUA in this direction was minimal. The influence of the anisotropy of bone structure, both cancellous and cortical, on ultrasonic parameters is discussed.