Interrelationship of trabecular mechanical and microstructural properties in sheep trabecular bone
Interrelationship of trabecular mechanical and microstructural properties in sheep trabecular bone
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DOI：
10.1016/j.jbiomech.2004.06.007
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发表时间：
2005-06-01
影响因子：
2.4
通讯作者：
Qin, YX
中科院分区：
文献类型：
--
作者：
Mittra, E;Rubin, C;Qin, YX
在早期时间点评估骨折风险的能力对于改善骨密度以及在骨质疏松症等骨丢失病例中加强治疗至关重要。提高诊断能力是高分辨率非侵入性成像的内在要求，也是对结构和密度的衍生指数如何与其真实机械行为相关的透彻理解。采用不同强度的绵羊股骨松质骨，通过多方向力学测试和显微计算机断层扫描，分析了力学参数和微观结构参数之间的相互关系。从23只成年雌性绵羊中采集了45个立方骨小梁样本，其中一些绵羊在2年的时间内接受了后肢振动刺激，从而增强了机械性能。这些样本被合并到低，中，或高强度组进行进一步分析。研究结果表明，μ CT指数是结构性的，例如，结构模型指数（SMI）（r（2）= 0.85，p < 0.0001）在预测松质骨区域的极限强度方面与更密度导向的指数如骨体积/总体积（BV/TV）（r 2 = 0.81，p < 0.0001）一样好。此外，那些与骨小梁结构的整体变化更相关的指标，如连接密度（ConnD）或各向异性程度（DA），不太能够预测骨的力学性能。骨小梁指数（如骨小梁数量（TbN）、厚度（TbTh）和间距（TbSp））的相互关系为骨小梁如何重塑以最终实现表观机械性能差异提供了线索。例如，分析表明，骨丢失主要影响骨小梁的连通性和总数，而强度增加导致骨小梁的总厚度增加，而不改善连通性。当然，所研究的mu CT指数能够很好地预测骨小梁ROI的整体机械特性，仅留下约15-20%的固有可变性。在诊断上，这意味着未来关于骨折风险早期预测的工作应该继续探索骨质量作为关键因素或作为骨量辅助因素的作用（例如，表观密度）。(c)2004爱思唯尔有限公司保留所有权利。
The ability to evaluate fracture risk at an early time point is essential for improved prognostics as well as enhanced treatment in cases of bone loss such as from osteoporosis. Improving the diagnostic ability is inherent upon both high-resolution non-invasive imaging, and a thorough understanding of how the derived indices of structure and density relate to its true mechanical behavior. Using sheep femoral trabecular bone with a range of strength, the interrelationship of mechanical and microstructural parameters was analyzed using multi-directional mechanical testing and micro-computed tomography. Forty-five cubic trabecular bone samples were harvested from 23 adult female sheep, some of whom had received hind-limb vibratory stimuli over the course of 2 years with consequently enhanced mechanical properties. These samples were pooled into a low, medium, or high strength group for further analysis.The findings show that mu CT indices that are structural in nature, e.g., structural model index (SMI) (r(2) = 0.85, p < 0.0001) is as good as more density oriented indices like bone volume/total volume (BV/TV) (r2 = 0.81, p < 0.0001) in predicting the ultimate strength of a region of trabecular bone. Additionally, those indices more related to global changes in trabecular structure such as connectivity density (ConnD) or degree of anisotropy (DA) are less able to predict the mechanical poperties of bone. Interrelationships of trabecular indices such as trabecular number (TbN), thickness (TbTh), and spacing (TbSp) provide clues as to how the trabecular bone will remodel to ultimately achieve differences in the apparent mechanical properties. For instance, the analysis showed that a loss of bone primarily affects the connectedness and overall number of trabeculae, while increased strength results in an increase of the overall thickness of trabeculae while not improving the connectedness.Certainly, the mu CT indices Studied are able to predict the bulk mechanical properties of a trabecular ROI well, leaving unaccounted only about 15-20% of its inherent variability. Diagnostically, this implies that future work on the early prediction of fracture risk should continue to explore the role of bone quality as the key factors or as an adjuvant to bone quantity (e.g., apparent density). (c) 2004 Elsevier Ltd. All rights reserved.