A detailed investigation of the relationship between ultrasonic (US) properties and trabecular bone microstructure is difficult because of the great variability in the bone loss process. The aim of this work was twofold. First, to verify by compressive tests that the three-dimensional (3D)-printer is able to produce precisely and repeatedly “bone replica models” of different size and density. Following, replicas of the original specimens with two different polymers and thinned trabeculae models were used to investigate US properties (speed of sound, SOS, and backscatter coefficient), aiming to deconvolute the influence of material properties on ultrasound characteristics. The results revealed that matrix material properties influence only the magnitude of the backscatter coefficient, whereas the characteristic undulated patterns are related to the trabecular structure. Simulation of perforation and thinning of cancellous bone, associated with bone loss, showed that SOS and mechanical properties were reduced perfectly linearly with apparent density when structure deteriorated. The 3D-printed bone replicas have the potential to enable systematic investigations of the influence of structure on both acoustical and mechanical properties and evaluate changes caused by bone loss. The development of replicas from materials with properties close to those of bone will permit quantitative conclusions for trabecular bone.

中文翻译：

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用于解耦小梁骨特性对超声传播参数贡献的骨骼的三维打印副本模型

超声（US）特性与骨小梁的骨微结构之间的关系很难进行详细研究，因为骨丢失过程的变异性很大。这项工作的目的是双重的。首先，通过压缩测试来验证三维（3D）打印机能够精确且重复地生成不同大小和密度的“骨骼复制模型”。接下来，使用具有两种不同聚合物和细化的小梁模型的原始标本的副本来研究美国特性（声速，SOS和反向散射系数），以消除对材料特性对超声特性的影响。结果表明，基质材料的性质仅影响后向散射系数的大小，而起伏的特征与小梁结构有关。模拟松质骨的穿孔和变薄以及骨质流失，结果表明，当结构劣化时，SOS和机械性能会随着表观密度线性降低。3D打印的骨骼复制品具有潜力，可以对结构对声学和机械性能的影响进行系统研究，并评估由骨骼损失引起的变化。由性质接近骨骼的材料制成的复制品将为小梁骨提供定量结论。结果表明，当结构劣化时，SOS和力学性能随表观密度线性降低。3D打印的骨骼复制品具有潜力，可以对结构对声学和机械性能的影响进行系统研究，并评估由骨骼损失引起的变化。由性质接近骨骼的材料制成的复制品将为小梁骨提供定量结论。结果表明，当结构劣化时，SOS和力学性能随表观密度线性降低。3D打印的骨骼复制品具有潜力，可以对结构对声学和机械性能的影响进行系统研究，并评估由骨骼损失引起的变化。由性质接近骨骼的材料制成的复制品将为小梁骨提供定量结论。