Propagation of two longitudinal waves in human cancellous bone: An in vitro study

Abstract

The ultrasonic wave propagation of fast and slow waves was investigated in vitro in 35 cubic cancellous bone specimens extracted from human femoral heads. Measurements were performed in three orthogonal directions using home-made PVDF transducers excited by a single sinusoidal wave at 1 MHz. The apparent density of the specimens was measured. Two separated fast and slow waves were clearly observed in 16 specimens, mainly in the main load direction. The waveforms and the sound speeds of fast and slow waves were similar to the reported data in bovine bone. The group of specimens in which the two waves were observed did not exhibit statistically higher apparent density than the rest of the specimens, but did exhibit statistically higher acoustic anisotropy ratio. The speeds in the main load direction were higher than those in the other direction. The fast and slow wave speeds were in good agreement with Biot's model, showing an increase with bone volume fraction (BV/TV). The ratio of peak amplitudes of the fast and slow waves nonlinearly increased as a function of BV/TV. These results open interesting perspective for acoustic assessment of cancellous bone micro-architecture and especially anisotropy that might lead to an improved assessment of bone strength.

Determining attenuation properties of interfering fast and slow ultrasonic waves in cancellous bone

“…[4][5][6][7][8][9][10] In some experimental situations, the two waves are separated in the time-domain data, whereas in other circumstances the two waves substantially overlap and may appear as only a single wave. The degree to which the fast waves and slow waves overlap depends on a number of factors including porosity, structural anisotropy, ultrasonic path length, and the angle of insonification relative to the predominant trabecular orientation.…”

Local ultrasonic wave velocities in trabeculae measured by micro-Brillouin scattering

“…However, these parameters are affected by structure, heterogeneity, and material properties in the macroscopic area through which ultrasound waves pass. 6,7 Evaluating the material properties of bone without the effects due to structure remains difficult. Therefore measurements of microscopic elastic properties of bone have been made with in vitro measurement methods, such as nanoindentation and scanning acoustic microscopy (SAM).…”

Inverse problems in cancellous bone: Estimation of the ultrasonic properties of fast and slow waves using Bayesian probability theory

“…The complicated microstructure is known to support the propagation of multiple compressional ultrasonic wave modes, often referred to as fast waves and slow waves. [13][14][15][16][17][18][19] When cancellous bone samples are insonified in through-transmission studies, the two waves occasionally are separated and clearly distinct in the radiofrequency ͑rf͒ data. However, in some circumstances, the two waves can strongly overlap during the time period over which the rf data are acquired, resulting in interference and difficulties in distinguishing between the two waves.…”