Chuong C J, Zhong P, Preminger G M
Joint Biomedical Engineering Program, University of Texas, Arlington.
J Endourol. 1993 Dec;7(6):437-44. doi: 10.1089/end.1993.7.437.
The acoustic and mechanical properties of renal calculi dictate how a stone interacts with the mechanical forces produced by shock wave lithotripsy; thus, these properties are directly related to the success of the treatment. Using an ultrasound pulse transmission technique, we measured both longitudinal and transverse (or shear) wave propagation speeds in nine groups of renal calculi with different chemical compositions. We also measured stone density using a pycnometer based on Archimedes' principle. From these measurements, we calculated wave impedance and dynamic mechanical properties of the renal stones. Calcium oxalate monohydrate and cystine stones had higher longitudinal and transverse wave speeds, wave impedances, and dynamic moduli (bulk modulus, Young's modulus, and shear modulus), suggesting that these stones are more difficult to fragment. Phosphate stones (carbonate apatite and magnesium ammonium phosphate hydrogen) were found to have lower values of these properties, suggesting they are more amenable to shock wave fragmentation. These data provide a physical explanation for the significant differences in stone fragility observed clinically.
肾结石的声学和力学特性决定了结石与冲击波碎石术产生的机械力之间的相互作用方式；因此，这些特性与治疗的成功率直接相关。我们使用超声脉冲传输技术，测量了九组不同化学成分的肾结石中的纵波和横波（或剪切波）传播速度。我们还基于阿基米德原理，使用比重瓶测量了结石密度。通过这些测量，我们计算了肾结石的波阻抗和动态力学特性。一水草酸钙结石和胱氨酸结石具有较高的纵波和横波速度、波阻抗以及动态模量（体积模量、杨氏模量和剪切模量），这表明这些结石更难破碎。发现磷酸盐结石（碳酸磷灰石和磷酸氢镁铵）的这些特性值较低，表明它们更易于被冲击波破碎。这些数据为临床上观察到的结石易碎性的显著差异提供了物理解释。
