Osteoporotic biopsies assessed by microCT

描述（由申请人提供）： 骨质疏松症传统上被定义为多孔骨结构，其数量减少但具有正常的骨材料或质量。骨密度降低被认为是骨质疏松症的标志，但骨折是关键的临床结果。此外，虽然骨密度与骨的力学特性相关，但它不能完全解释骨的力学响应。越来越多的证据表明，骨转换不仅通过影响数量，而且通过影响结构、矿物质和基质质量来促进骨强度的变化。定量微计算机断层扫描（microCT）有可能在三维空间中表征松质骨的数量和质量，并探索骨质疏松症和骨转换的影响。这项探索性和发展性拨款提案（R21）的目标是使用定量microCT分析人类活检。将检查以正常、低转换骨质疏松和高转换骨质疏松为特征的髂嵴活检，以检验以下研究问题：正常、低转换和高转换骨质疏松骨之间的松质骨体积分数、小梁三维结构和材料不均匀性模式是否不同？将通过定量microCT将低转换或高转换骨质疏松症的人髂嵴活检与正常活检进行比较。将表征骨体积分数和骨小梁结构。定量CT X射线衰减值将用于提供小梁内的组织矿物质密度。通过距离转换方法，将组织矿物质密度的变化作为距离小梁表面的深度的函数进行评估。将在三组之间进行比较，以研究低转换骨和高转换骨之间以及骨化标本和对照标本之间是否存在实质性差异。主要目标是检测小梁结构和材料特性与周转状态的差异。这些结果应导致特定的假设，骨质疏松症的骨质量的影响，并可能在治疗干预的周转率。

DESCRIPTION (provided by applicant): Osteoporosis has been defined traditionally as porous bone structure that is reduced in quantity but has normal bone material or quality. A decrease in bone density is considered the hallmark of osteoporosis, but bone fracture is the critical clinical outcome. Moreover, although bone density is associated with the mechanical characteristics of bone, it does not fully account for bone mechanical response. There is a growing body of evidence that bone turnover contributes to changes in bone strength by affecting not only quantity but also architecture, mineral, and matrix quality. Quantitative micro-computed tomography (microCT) has the potential to characterize the quantity and quality of cancellous bone in three dimensions and to explore the effects of osteoporosis and bone turnover. The goal of this exploratory & developmental grant proposal (R21) is to analyze human biopsies using quantitative microCT. Iliac crest biopsies characterized as normal, low-turnover osteoporosis, and high-turnover osteoporosis will be examined to test the following research question: Do cancellous volume fraction, trabecular three-dimensional architecture, and patterns of material inhomogeneity differ among normal, low-turnover, and high-turnover osteoporotic bone? Human iliac crest biopsies of low-turnover or high-turnover osteoporosis will be compared with normal biopsies by quantitative microCT. Bone volume fraction and trabecular architecture will be characterized. Quantitative CT x-ray attenuation values will be used to provide tissue mineral density within trabeculae. The variation in tissue mineral density will be assessed as a function of depth from the trabecular surface by a distance transformation approach. Comparisons will be made among the three groups to investigate whether substantial differences exist between low- and high-turnover bone and between osteoporotic and control specimens. The main goal is to detect differences in trabecular architecture and material properties with turnover state. These results should lead to specific hypotheses about the effects of turnover rate on bone quality in osteoporosis and possibly under therapeutic interventions.