Assessement of Trabecular Bone Strength & Damage

小梁骨强度评估

• 批准号: 6773893
• 负责人: Tony M Keaveny
• 金额: $ 17.04万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-30 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6773893
• 关键词: bioimaging /biomedical imaging; biomechanics; bone density; bone disorder; bone fracture; bone imaging /visualization /scanning; clinical research; computed axial tomography; computer simulation; computer system design /evaluation; human tissue; mathematics; model design /development; musculoskeletal disorder diagnosis; noninvasive diagnosis; skeletal stress; substantia spongiosa

DESCRIPTION (provided by applicant): The ability to non-destructively measure trabecular bone strength and microdamage would have a profound effect in bone biomechanics research. It would enable researchers to assess bone strength longitudinally in animal models, and determine the strength behavior of bone repeatedly in the same specimen for various different types of loading cases and under simulation of various types of treatment, including drug and exercise effects. It would also greatly facilitate the study of microdamage in bone since currently this is an extremely tedious process. We propose here a method to perform such non-invasive assessment of trabecular bone strength and microdamage. This method can also be used to measure the failure properties of trabecular hard tissue material, a unique indicator of trabecular quality. The basis of this technology is the "high-resolution" finite element computer modeling technique, in which the models are derived from micro-computed tomography (micro-CT) images having spatial resolutions on the order of microns. Specifically, we plan to incorporate into these models the physics of large deformations. This will enable us to simulate the correct deformation patterns that occur in individual trabeculae when loaded to failure. We have evidence that inclusion of such behavior is crucial to the ability of such models to properly capture the strength behavior of trabecular bone of any density, but particularly at low density. To validate the models, we will also develop an automated technique for the direct three-dimensional quantification of trabecular microdamage, itself a substantial technical innovation that will greatly impact research on bone microdamage. In achieving our goal, we will test two hypotheses. First, we hypothesize that the failure strains of trabecular tissue material are independent of anatomic site even though the failure strains of the whole specimen (apparent level) are not. The reason for this is the large deformation effect, which is manifested in some sites due to the low bone density. Second, we hypothesize that microdamage within trabecular bone can be predicted based on the magnitude of the strains within the trabecular tissue. This is based on the assumption that tissue level damage occurs when the site-independent tissue failure strains are exceeded. Should this be true, it will enable researchers to use these types of computer models to study both the development and biomechanical effects of microdamage in trabecular bone at a level of detail so far unthinkable. This R21 project represents an important technological foundation for improving understanding of the failure mechanisms in trabecular bone, with particular applications to aging and osteoporosis. Specifically, by addressing strength at the whole specimen and trabecular tissue levels, as well as microdamage and large deformation architectural effects, this work will provide a comprehensive and unique approach to assessment of trabecular bone strength and quality.

描述（由申请人提供）： 非破坏性测量骨小梁强度和微损伤的能力将对骨生物力学研究产生深远影响。它将使研究人员能够在动物模型中纵向评估骨强度，并在同一标本中针对各种不同类型的负载情况以及在模拟各种类型的治疗（包括药物和运动效果）下重复确定骨的强度行为。它还将极大地促进骨骼微损伤的研究，因为目前这是一个极其繁琐的过程。我们在这里提出了一种对骨小梁强度和微损伤进行非侵入性评估的方法。该方法还可用于测量小梁硬组织材料的失效特性，这是小梁质量的独特指标。该技术的基础是“高分辨率”有限元计算机建模技术，其中模型源自空间分辨率为微米量级的微计算机断层扫描（micro-CT）图像。具体来说，我们计划将大变形的物理原理纳入这些模型中。这将使我们能够模拟加载失败时单个小梁中发生的正确变形模式。我们有证据表明，包含此类行为对于此类模型正确捕获任何密度（尤其是低密度）骨小梁的强度行为的能力至关重要。为了验证模型，我们还将开发一种用于直接三维量化小梁微损伤的自动化技术，这本身就是一项重大技术创新，将极大地影响骨微损伤的研究。为了实现我们的目标，我们将检验两个假设。首先，我们假设小梁组织材料的失效应变与解剖部位无关，尽管整个样本的失效应变（表观水平）并非如此。其原因是由于骨密度低而在某些部位表现出较大的变形效应。其次，我们假设可以根据小梁组织内应变的大小来预测小梁骨内的微损伤。这是基于这样的假设：当超过与位点无关的组织失效应变时，就会发生组织水平损伤。如果这是真的，研究人员将能够使用这些类型的计算机模型来研究骨小梁微损伤的发展和生物力学效应，其详细程度迄今为止是不可想象的。该 R21 项目为提高对骨小梁失效机制的理解奠定了重要的技术基础，特别是在衰老和骨质疏松症方面的应用。具体来说，通过解决整个标本和小梁组织水平的强度以及微损伤和大变形结构效应，这项工作将为评估小梁骨强度和质量提供全面且独特的方法。