基于Zener模型的生物组织剪切模量测量

Shear modulus measurement of biological tissues based on Zener model

目的克服基于Voigt模型的超声振动检测方法的不足,使用Zener模型更加准确地测量生物组织剪切模量,为组织定征提供有效的手段。方法利用基于力学模型本构关系的剪切波传播速度公式,在获得剪切波在多个频率上速度的前提下,通过数学方法估计出介质的剪切模量。实验对象为不同浓度的凝胶模型和不同程度热力学损伤的猪肝脏,通过超声辐射力振动产生剪切波,获取剪切波在不同实验介质中的传播速度。结果分别用Voigt模型和Zener模型对速度值进行拟合,结果均显示Zener模型描述的准确性更高,并且所估计出的剪切模量能够很好地区分不同浓度的凝胶模型或不同损伤程度的猪肝。结论本方法为无创测量生物组织剪切模量提供了潜在的手段,对医学上的组织定征和疾病诊断有着重要的意义。

Objective To measure the shear modulus of biological tissues by using Zener model so as to over- come the limitation of Voigt model-based ultrasound vibrometry, and to provide effective approaches of tissue characterization. Methods The mechanical constitutive relation-based shear wave propagation velocity formula was utilized to estimate the shear modulus in terms of the velocities at multiple frequencies via mathematical methods. To obtain shear wave velocities in different objects, experiments were conducted by using different con- sistencies-based gelatin models and thermally damaged porcine livers as subjects, in which shear waves were in- duced by ultrasound radio forces. Results Voigt and Zener models were utilized to fit the velocities respectively. The Zener model exhibited higher fitting accuracy than the Voigt model, and the shear modulus could well distin- guish gelatin models with different consistencies or porcine livers of different damage degrees. Conclusions The method in this paper provides a potential means of measuring the shear modulus of biological tissues non-inva- sively, which is very promising for tissue characterization and disease diagnosis in medicine.