BACKGROUND Ultrasound elastography has been widely used to measure liver stiffness. However, the accuracy of liver viscoelasticity obtained by ultrasound elastography has not been well established. OBJECTIVE To assess the accuracy of ultrasound elastography for measuring liver viscoelasticity and compare to conventional rheometry methods. In addition, to determine if combining these two methods could delineate the rheological behavior of liver over a wide range of frequencies. METHODS The phase velocities of shear waves were measured in livers over a frequency range from 100 to 400 Hz using the ultrasound elastography method of shearwave dispersion ultrasound vibrometry (SDUV), while the complex shear moduli were obtained by rheometry over a frequency range of 1 to 30 Hz. Three rheological models, Maxwell, Voigt, and Zener, were fit to the measured data obtained from the two separate methods and from the combination of the two methods. RESULTS The elasticity measured by SDUV was in good agreement with that of rheometry. However, the viscosity measured by SDUV was significantly different from that of rheometry. CONCLUSIONS The results indicate that the high frequency components of the dispersive data play a much more important role in determining the dispersive pattern or the viscous value than the low frequency components. It was found that the Maxwell model is not as appropriate as the Voigt and Zener models for describing the rheological behavior of liver.

中文翻译：

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超声弹性成像法测量正常大鼠肝脏的粘弹性：与振荡流变法比较。

背景技术超声弹性成像已被广泛地用于测量肝硬度。然而，通过超声弹性成像获得的肝粘弹性的准确性尚未得到很好的确立。目的评估超声弹性成像技术测量肝粘弹性的准确性，并与常规流变学方法进行比较。另外，要确定这两种方法的结合是否可以在很宽的频率范围内描绘肝脏的流变行为。方法使用剪切波弥散超声振动法（SDUV）的超声弹性成像方法，在100至400 Hz频率范围内的肝脏中测量剪切波的相速度，而通过流变法在1至1 Hz的频率范围内获得复数剪切模量30赫兹。麦克斯韦（Maxwell），沃伊格（Voigt）和齐纳（Zener）三种流变模型 拟合从两种单独的方法以及两种方法的组合获得的测量数据。结果SDUV测得的弹性与流变测定的吻合良好。然而，通过SDUV测量的粘度与流变学的粘度显着不同。结论结果表明，色散数据的高频分量在确定色散模式或粘性值方面比低频分量起着更为重要的作用。已经发现，Maxwell模型不如Voigt和Zener模型适合描述肝脏的流变行为。SDUV测得的粘度与流变仪的粘度显着不同。结论结果表明，色散数据的高频分量在确定色散模式或粘性值方面比低频分量起着更为重要的作用。已经发现，Maxwell模型不如Voigt和Zener模型适合描述肝脏的流变行为。SDUV测得的粘度与流变仪的粘度显着不同。结论结果表明，色散数据的高频分量在确定色散模式或粘性值方面比低频分量起着更为重要的作用。已经发现，Maxwell模型不如Voigt和Zener模型适合描述肝脏的流变行为。