评估椎体骨质疏松性骨折风险的生物力学 CT 方法

骨质疏松症以骨强度下降和骨折风险增大为特征，其最严重的后果是引发骨折，且以椎体骨折最为常见。早期精准评估骨折风险是鉴别高风险人群进而预防骨质疏松性骨折的关键。目前临床评估椎体骨折风险主要依靠双能X射线吸收测定法(dual energy X-ray absorptiometry, DXA)或定量计算机断层扫描(quantitative computed tomography, QCT)检测骨密度，但其不能完全体现骨强度和抗骨折特性，存在评估不准确的问题。基于CT数字建模和有限元分析的生物力学CT(biomechanical CT, BCT)技术，以无创计算椎体骨强度为目标，架起了生物力学应用于临床评价骨折风险的桥梁。椎体离体力学实验已证实，BCT较骨密度可更准确地评估椎体骨折强度。临床研究也表明，BCT在鉴别既存骨折和预测新发骨折方面显著优于DXA骨密度。本文介绍BCT技术的实现流程，以及各环节中影响计算结果的关键参数，并总结BCT离体验证和在体评估椎体骨折风险的研究进展，以期推动BCT技术在临床评估中国人椎体骨折风险中的应用。

Biomechanical CT for Assessment of Osteoporotic Vertebral Fracture Risk

Osteoporosis is characterized by decreased bone strength and increased fracture risk. The most serious consequence of osteoporosis is fracture, which commonly occurs in vertebrae. Accurate assessment of fracture risk at an earlier stage is the key to identify high-risk population and further prevent osteoporotic fracture. Currently, clinical assessment of vertebral fracture risk mainly relies on measurement of bone mineral density (BMD) based on dual energy X-ray absorptiometry ( DXA) or quantitative computed tomography ( QCT). However, they cannot fully reflect bone strength and resistance to fracture, and it is hard to achieve an accurate assessment. Biomechanical CT (BCT) technology, based on CT digital modeling and finite element analysis, aims at non-invasive calculation of individual bone strength, bridging the gap between biomechanics and clinical evaluation of fracture risk. In vitro mechanical experiment of vertebrae has proved that BCT is more accurate than BMD in evaluating vertebral fracture strength. Clinical studies have also shown that BCT is superior to DXA inidentifying existing fractures and predicting new fractures. In this article, the implementation process of the BCT technology was introduced, as well as critical parameters during each step affecting its result . The research progress of the BCT technique for in vitro validation and in vivo assessment of vertebral fracture risk was also summarized, with the aim to promote the application of BCT technology in clinical assessment of vertebral fracture risk for the Chinese people.