Ultrasound velocity and attenuation in cancellous bone samples from lumbar vertebra and calcaneus

We report a study of ultrasound velocity and broadband ultrasound attenuation (BUA) in human cancellous bone samples. The influence of density and microarchitecture on ultrasound propagation in cancellous bone was examined. A total of 20 samples from vertebra L1 and 21 from calcanei were studied. The direction of ultrasound propagation was anteroposterior in the vertebra and lateromedial in the calcaneus. The relationships between ultrasonic parameters and density of bone samples, apparent ash density, trabecular bone volume (BV/TV) and trabecular thickness (Tb.Th) were analyzed using a simple linear model and a multiple regression model. Velocity of ultrasound and BUA were positively correlated with density and morphometric parameters, in both vertebra and calcaneus. The best correlation was found between velocity and bone sample density in vertebra (r = 0.961, p < 0.0001) and the worst between velocity and trabecular thickness in calcaneus (r = 0.632, p = 0.002). The best correlation for BUA was with BV/TV in vertebra (r = 0.960, p < 0.0001). Using the stepwise regression procedure, BV/TV only was selected as significant for BUA and apparent ash density with Tb.Th for velocity, in both vertebra and in calcaneus. The possible influence of trabecular configuration on ultrasonic parameters is discussed, emphasizing the different slopes of regression lines obtained for vertebra and calcaneus, sites with different architecture of trabecular bone.