Gennisson Jean-Luc, Cloutier Guy
Laboratory of Biorheology and Medical Ultrasonics, University of Montréal Hospital, Montréal, Québec, Canada.
IEEE Trans Ultrason Ferroelectr Freq Control. 2006 Apr;53(4):716-23. doi: 10.1109/tuffc.2006.1621498.
Using the shear wave propagation in solids, the transient elastography technique has been developed to assess the elastic properties of soft tissues. Here, a new approach of transient elastography allows assessing the viscoelastic properties of soft tissues. In this paper, the method is used to follow-up the sol-gel transition of an agar-gelatin mixture noninvasively. The shear wave velocity and shear wave attenuation through the mixture were continuously monitored in the audible range of frequencies (from 50 Hz to 200 Hz). The observed changes in velocities and attenuations as a function of frequency confirmed the validity of the Voigt's model to describe the gel at its stable mechanical state. By a simple inverse problem approach, based on the one-dimensional (1-D) Helmholtz equation, the elasticity and the viscosity of such a mixture were recovered as a function of time. The results obtained are in good agreement with the literature and theoretical predictions. Overall, they demonstrate the high sensitivity of the transient elastography measurements to the rheological parameter changes in agar-gelatin mixtures during gelation.
利用固体中的剪切波传播，已经开发出瞬态弹性成像技术来评估软组织的弹性特性。在此，一种新的瞬态弹性成像方法能够评估软组织的粘弹性特性。在本文中，该方法被用于无创跟踪琼脂 - 明胶混合物的溶胶 - 凝胶转变。在可听频率范围（从50赫兹到200赫兹）内持续监测通过该混合物的剪切波速度和剪切波衰减。观察到的速度和衰减随频率的变化证实了Voigt模型在描述凝胶稳定力学状态时的有效性。通过基于一维（1 - D）亥姆霍兹方程的简单反问题方法，这种混合物的弹性和粘度作为时间的函数被恢复。所获得的结果与文献和理论预测高度一致。总体而言，它们证明了瞬态弹性成像测量对凝胶化过程中琼脂 - 明胶混合物流变学参数变化的高灵敏度。
