Griffith James F, Genant Harry K
Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong, Shatin, NT, Hong Kong.
Best Pract Res Clin Endocrinol Metab. 2008 Oct;22(5):737-64. doi: 10.1016/j.beem.2008.07.003.
Bone fracture occurs when the bone strength (i.e. the ability of the bone to resist a force) is less than the force applied to the bone. In the elderly, falls represent the more severe forces applied to bone. Bone density is a good marker of bone strength, and has been used widely in this respect. Nevertheless, many aspects of bone strength cannot be explained by bone density alone. For this reason there has been increasing interest in studying architectural parameters of bone, beyond bone density, which may affect bone strength. Macro-architectural parameters include e.g. bone size and geometry assessed with techniques such as radiography, dual-energy x-ray absorptiometry (DXA), peripheral quantitative computed tomography (QCT), computed tomography (CT) and magnetic resonance imaging (MRI). Micro-architectural parameters include fine cortical and trabecular structural detail which can be evaluated using high-resolution imaging techniques such as multidetector CT, MRI, and high-resolution peripheral QCT. These techniques are providing a great deal of new information on the physiological architectural responses of bone to aging, weightlessness, and treatment. This will ultimately lead to the prediction of fracture risk being improved through a combined assessment of bone density and architectural parameters.
当骨强度(即骨骼抵抗外力的能力)小于作用于骨骼的外力时,就会发生骨折。在老年人中,跌倒代表作用于骨骼的更严重外力。骨密度是骨强度的一个良好指标,并且在这方面已被广泛应用。然而,骨强度的许多方面不能仅由骨密度来解释。因此,人们越来越关注研究除骨密度之外可能影响骨强度的骨骼结构参数。宏观结构参数包括例如通过放射照相、双能X线吸收法(DXA)、外周定量计算机断层扫描(QCT)、计算机断层扫描(CT)和磁共振成像(MRI)等技术评估的骨骼大小和几何形状。微观结构参数包括精细的皮质和小梁结构细节,可使用多探测器CT、MRI和高分辨率外周QCT等高分辨率成像技术进行评估。这些技术正在提供大量关于骨骼对衰老、失重和治疗的生理结构反应的新信息。这最终将通过对骨密度和结构参数的综合评估来改善骨折风险的预测。