HIP DEXA SCANS FROM OSTEOPOROSIS STUDIES

一些大型人口研究已经获得了双能X-射线成像技术， 髋关节X线吸收测量（DEXA）扫描，以研究 随着年龄的增长以及性别和种族的差异， 这些率。 越来越多的人意识到，除了骨骼 质量、结构细节是骨强度的重要指标。 它们的测量应该可以更好地理解 老年髋关节骨量减少的生物力学意义。 这些细节在传统的骨组织中是模糊的 测量，但DEXA扫描在这些大型人群中获得 研究被存档为髋关节的定量投影图像。 虽然没有设计的目的，这些图像可以重新- 分析以提取几何特性， 对衰老的生物医学适应和改变的洞察 髋关节，或可替代地，用于有限的（二维） 工程分析，以估计与 骨质减少该过程涉及使用 专门的交互式计算机程序，产生（皮层 等效）横截面积、横截力矩 整个股骨近端的惯性和骨宽度作为 连续体，包括近端股骨干、转子间区域 和股骨颈 股骨颈长度等尺寸， 髋轴长度和颈干角也被计算，以及 特定载荷条件下的弯矩。 该方法具有 被用来从大约15个， 在第三届全国健康和营养大会上获得了1，000次髋关节扫描 考试调查（NHANES III）以及 骨质疏松性骨折（SOF）的研究。 作为方法应用 整个SOF数据集以及来自欧洲的数据 计划进行前瞻性骨质疏松研究（EPOS）。 这些 分析应有助于更好地了解具体模式 与老龄化相关的结构变化以及 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， 轴长与髋部骨折风险增加相关。 因为结构几何学不像骨密度， 强烈的身体大小依赖，适当的大小缩放方法免疫 队列效应，脊椎塌陷和老年人的浪费 将必须设计，以便年龄趋势可以得出， 横截面样本数据。 粘结质量的结构分析 具有良好人体测量数据的研究数据也应该产生 更有生物力学意义的方法， 身体尺寸和形状的骨量测量数据， 改善临床管理。

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. There is a growing realization that in addition to bone mass, structural details are important indices of bone strength. Their measurement should permit a better understanding of biomechanical implications of reduced bone mass in the aging hip. Such details are obscured in the conventional bone mass measurement but DEXA scans acquired in these large population studies are archived as a quantitative projection image of the hip. Although not designed for the purpose, these images can be re- analyzed to extract geometric properties which should provide insight into biomedicanical adaptations and alterations of the aging hip, or alternatively, used in a limited (two dimensional) engineering analysis to estimate the strength loss associated with the reduced bone mass. 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 femoral 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. These 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. Because structural geometry is, unlike bone mineral density, strongly body size dependent, proper size scaling methods immune to cohort effects, vertebral collapse and wasting in the very old will have to be devised so that age trends can be elicited from cross-sectional sample data. A structural analysis of bond mass data in studies with good anthropometric data should also yield more biomechnically meaningful ways of scaling conventional bone mass measurement data for body size and shape for improved clinical management.