ANALYSIS OF DEXA SCANS FROM OSTEOPOROSIS STUDIES

髋部骨折率和骨密度（BMD）值不同 性别和种族群体之间的差异很大。 的价值 骨密度与骨折发生率有很强的统计学联系， 测量缺乏解释观察到的 协会. 对性别和种族差异的解释是 被BMD测量所显示的 对骨骼脆弱性的了解很少。 应该可以 通过应用工程原理来解决这个问题， 合适的数据。 一些大型人群研究获得了双重标准。 能量X射线吸收仪（DEXA）扫描髋关节，以研究 随着年龄、性别和种族的差异， rates. 可以从以下数据中获得有限的结构信息： 这些数据集用于工程模型的应用。 过程 涉及使用专门的交互式计算机程序， 产生（皮质等效）横截面积，横截面 整个股骨近端的惯性矩和骨宽度， 连续体，包括近端股骨干、转子间区域和 股骨颈 股骨颈长度、髋轴等尺寸 长度和颈干角也计算以及弯矩 具体的装载条件。 该方法已用于提取 从大约15，000次髋关节扫描中获得的结构信息， 第三次全国健康和营养调查（NHANES III） 以及骨质疏松性骨折研究（SOF）的子样本。 将该方法应用于整个SOF数据集以及数据 欧洲前瞻性骨质疏松症研究（EPOS）。 为了补充二维分析， 它也来自DEXA数据，但可以使用 复杂的结构有限元分析方法 分析. 将通过与以下方法进行比较来验证伪3D FEA方法： 通过尸体股骨计算机断层扫描获得的真实3D FEA数据。 如果 伪三维方法是可行的，它应该提供一种快速的方法 将先进的有限元分析方法应用于骨质疏松症的研究。 这些2D和3D分析应有助于更好地了解 与老龄化相关的结构变化的特定模式，以及 不同髋关节的种族群体中这些模式的差异 骨折率 它还应提供资料， 生物力学解释为什么某些尺寸，如髋关节轴， 与髋部骨折风险增加有关。

Hip fracture rates and bone mineral density (BMD) values differ significantly between the sexes and among ethnic groups. The value of BMD is due to its strong statistical links with fracture incidence but the measurement lacks theoretical underpinnings explaining the observed associations. The interpretation of sex and ethnic differences is confounded by the fact that exactly what a BMD measurement indicates about bone fragility is poorly understood. It should be possible to approach this problem by the application of engineering principles to suitable data. A number of large population studies have acquired dual energy x-ray absorptiometric (DEXA) scans of the hip to study rates of bone mass loss with age as well as sex and ethnic differences in those rates. It is possible to derive limited structural information from such data sets for the application of engineering models. The process involves the use of specialized interactive computer programs which yield the (cortical equivalent) cross-sectional areas, cross-sectional moments of inertia and bone widths of the entire proximal femur as a continuum including the proximal shaft, intertrochanteric region and femoral neck. Dimensions such as the femoral neck length, hip axis length and neck-shaft angle are also computed as well as bending moments for specific loading conditions. The method has been used to extract structural information from approximately 15,000 hip scans acquired in the third National Health and Nutrition Examination Survey (NHANES III) as well as a subsample of the Study of Osteoporotic Fracture (SOF). Application of the method to the entire SOF data set as well as data from the European Prospective Osteoporosis Study (EPOS) are planned. To supplement the two dimensional analysis a pseudo-3D method has been developed which is also derived from DEXA data but can employ sophisticated finite element analysis (FEA) methods for structural analysis. The pseudo-3D FEA method will be validated by comparison with true 3D FEA data derived by computed tomography on cadaver femora. If the pseudo-3D method proves feasible, it should provide a rapid method for employing sophisticated FEA methods to the study of osteoporosis. These 2D and 3D analyses should permit improved understanding of specific patterns of structural change associated with aging as well as the differences in those patterns in ethnic groups with disparate hip fracture rates. It should also provide information permitting a biomechanical explanation of why certain dimensions such as hip axis length, are associated with increased hip fracture risk.