Ultrasonic non destructive characterization of trabecular bone: estimation of the propagation velocity and attenuation

摘要

The non destructive characterization of porous structures with ultrasonic waves allows determining the propagation velocities and the attenuation for diagnosis of diseased bone (e.g., osteoporosis) by establishing correlations between ultrasonic parameters and their mineral density. Two compressional modes have been identified independently in bovine trabecular bone, a fast wave and a slow wave. The principal objective of this paper is to characterize the propagation velocity and ultrasonic attenuation as functions of frequency and porosity of bovine cancellous bone. The porosity of the used samples varies between 40 % and 75 %. A transmission technique is used. This method only requires the measurement of the specimen’s thickness and recording of two pulses: one without and one with the specimen inserted between the transmitting and receiving transducers. From the two pulses, the attenuation can be determined using spectral analysis. The attenuation coefficient increases nonlinearly over the frequency from 200 to 700 kHz. The experimental results show a strong correlation between the bone density, the measured propagation velocity and the attenuation. The measurement of these velocities allows determining the bone elastic parameters. This study confirms the sensitivity of the ultrasonic propagation velocity to the change of bone porosity. The potential of ultrasound in bone tissue characterization seems to provide interesting results and would lead to predict bone pathology and particularly permit better diagnosis of bone fragility.