Moreschi H, Callé S, Guerard S, Mitton D, Renaud G, Defontaine M
Université F. Rabelais, Unité 'Imagerie et Cerveau', UMRS/CNRS, Tours, France.
Proc Inst Mech Eng H. 2011 Mar;225(3):282-95. doi: 10.1243/09544119JEIM846.
Dynamic acousto-elastic testing (DAET) is based on the coupling of a low-frequency (LF) acoustic wave and high-frequency ultrasound (US) pulses (probing wave). It was developed to measure US viscoelastic and dissipative non-linearity in trabecular bone. It is well known that this complex biphasic medium contains microdamage, even when tissues are healthy. The purpose of the present study was to assess the sensitivity of DAET to monitor microdamage in human calcanei. Three protocols were therefore performed to investigate the regional heterogeneity of the calcaneus, the correlation between DAET measurements and microdamage revealed by histology, and DAET sensitivity to mechanically induced fatigue microdamage. The non-linear elastic parameter beta was computed for all these protocols. The study demonstrated the presence of high viscoelastic and dissipative non-linearity only in the region of the calcaneus close to the anterior talocalcaneal articulation (region of high bone density). Protocols 1 and 2 also showed that most unsorted calcanei did not naturally exhibit high non-linearity, which is correlated with a low level of microcracks. Nevertheless, when microdamage was actually present, high levels of US non-linearity were always found, with characteristic non-linear signatures such as hysteresis and tension/compression asymmetry. Finally, protocol 3 demonstrated the high sensitivity of DAET measurement to fatigue-induced microdamage.
动态声弹性测试（DAET）基于低频（LF）声波与高频超声（US）脉冲（探测波）的耦合。它是为测量小梁骨中的超声粘弹性和耗散非线性而开发的。众所周知，即使组织健康，这种复杂的双相介质中也存在微损伤。本研究的目的是评估DAET监测人跟骨微损伤的敏感性。因此，进行了三个实验方案来研究跟骨的区域异质性、DAET测量值与组织学显示的微损伤之间的相关性以及DAET对机械诱导疲劳微损伤的敏感性。针对所有这些实验方案计算了非线性弹性参数β。研究表明，仅在跟骨靠近距下关节前部的区域（高骨密度区域）存在高粘弹性和耗散非线性。实验方案1和2还表明，大多数未分类的跟骨自然情况下不会表现出高非线性，这与低水平的微裂纹相关。然而，当实际存在微损伤时，总是会发现高水平的超声非线性，并伴有诸如滞后和拉伸/压缩不对称等特征性非线性特征。最后，实验方案3证明了DAET测量对疲劳诱导微损伤具有高敏感性。
