Mizuno Katsunori, Matsukawa Mami, Otani Takahiko, Laugier Pascal, Padilla Frédéric
Laboratory of Ultrasonic Electronics, Doshisha University, Kyotanabe, 610-0321 Kyoto, Japan.
J Acoust Soc Am. 2009 May;125(5):3460-6. doi: 10.1121/1.3111107.
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.
在从人股骨头提取的35个立方体松质骨标本中，对快波和慢波的超声波传播进行了体外研究。使用由1 MHz单正弦波激发的自制聚偏二氟乙烯（PVDF）换能器，在三个正交方向上进行测量。测量了标本的表观密度。在16个标本中清晰地观察到两个分离的快波和慢波，主要出现在主载荷方向。快波和慢波的波形及声速与牛骨中报道的数据相似。观察到两个波的标本组，其表观密度在统计学上并不高于其余标本，但声学各向异性比在统计学上确实更高。主载荷方向的速度高于其他方向。快波和慢波速度与毕奥模型吻合良好，显示出随骨体积分数（BV/TV）增加。快波和慢波峰值振幅之比作为BV/TV的函数呈非线性增加。这些结果为松质骨微结构的声学评估，尤其是各向异性评估开辟了有趣的前景，这可能会改进对骨强度的评估。
