Ulrich D, Rietbergen B, Laib A, Rüegsegger P
Institute for Biomedical Engineering, University of Zurich and Swiss Federal Institute of Technology of Zurich.
Technol Health Care. 1998 Dec;6(5-6):421-7.
Prevention of osteoporotic fractures requires accurate methods to detect the increase in bone fragility at an early disease stage as well as effective therapies to reduce the risk of bone fractures. Presently the prediction of the patient-specific bone fracture risk is primarily based on bone density, since this is the only parameter which can routinely be measured in vivo. However, these predictions might not always be precise because the fracture risk is also determined by the bone microarchitecture and the bone's loading conditions. The aim of this paper is to introduce and evaluate new methods which could contribute to a better quantification of bone fracture risk. Recently, a new approach, combining computational engineering methods (finite element (FE) method) and 3D high-resolution imaging techniques, has been introduced which can account not only for bone density but also for microarchitecture and loading conditions. High-resolution imaging techniques allow acquisition of 3D images of the bone microarchitecture, whereas FE methods applied to these images allow very precise calculation of the mechanical properties of bone. However, such a detailed FE analysis was not feasible for bone in vivo mainly because the resolution was not sufficient to measure the bone microarchitecture. It is shown here, from preliminary results, that the FE approach based on high-resolution images from a new CT scanner now allows prediction of the mechanical behavior of peripheral bones in vivo. It is expected that, eventually, the FE approach will lead to a better patient-specific fracture risk prediction than earlier methods based on bone density alone. Hence, with this new approach, it might be possible to detect the increase in bone fragility at an early stage of osteoporosis and it might also be possible to evaluate treatments more accurately.
预防骨质疏松性骨折需要准确的方法来在疾病早期阶段检测骨脆性增加，以及有效的疗法来降低骨折风险。目前，针对特定患者的骨折风险预测主要基于骨密度，因为这是唯一可以在体内常规测量的参数。然而，这些预测可能并不总是精确的，因为骨折风险还由骨微结构和骨的负荷条件决定。本文的目的是介绍和评估有助于更好地量化骨折风险的新方法。最近，一种结合计算工程方法（有限元（FE）方法）和3D高分辨率成像技术的新方法被引入，该方法不仅可以考虑骨密度，还可以考虑微结构和负荷条件。高分辨率成像技术允许获取骨微结构的3D图像，而将FE方法应用于这些图像可以非常精确地计算骨的力学性能。然而，这种详细的FE分析在体内对骨来说并不可行，主要是因为分辨率不足以测量骨微结构。从初步结果可以看出，基于新型CT扫描仪的高分辨率图像的FE方法现在能够在体内预测外周骨的力学行为。预计最终，FE方法将比早期仅基于骨密度的方法带来更好的针对特定患者的骨折风险预测。因此，通过这种新方法，有可能在骨质疏松症的早期阶段检测到骨脆性增加，也有可能更准确地评估治疗效果。
