Lang T F, Keyak J H, Heitz M W, Augat P, Lu Y, Mathur A, Genant H K
Department of Radiology, University of California, San Francisco 94143-1250, USA.
Bone. 1997 Jul;21(1):101-8. doi: 10.1016/s8756-3282(97)00072-0.
We have developed a three-dimensional computed tomography (CT) scanning and image analysis method for measurement of trabecular and integral bone mineral density (BMD) and geometry in automatically determined femoral-neck and trochanteric subregions of the proximal femur. We measured the correlation of the density and geometry variables to femoral strength assessed in vitro under loading simulating a single-limb condition and a fall to the side. While BMD alone accounted for 48%-77% of the variability in strength for the stance loading configuration, femoral neck cross-sectional area (minCSA) and femoral neck axis length (FNAL) also contributed independently to femoral strength, and a combination of BMD and geometry variables explained 87%-93% of the variance in the data. For the fall loading configuration, trochanteric trabecular BMD alone explained 87% of the variability of strength. The reproducibility in vivo of the technique was assessed in a group of seven postmenopausal women, who underwent repeat scans with repositioning. For trabecular BMD, the precision was 1.1% and 0.6% for the femoral neck and trochanteric subregions, respectively, compared to 3.3% and 1.6% for the corresponding integral envelopes. Thus, trabecular BMD measurements were reproducible and highly correlated to biomechanical strength measurements. These results support further exploration of quantitative CT for assessment of osteoporosis at the proximal femur.
我们开发了一种三维计算机断层扫描（CT）扫描和图像分析方法，用于测量股骨近端自动确定的股骨颈和转子亚区域的小梁骨和整体骨矿物质密度（BMD）以及几何形状。我们测量了密度和几何变量与在模拟单肢站立和向一侧跌倒的负荷条件下体外评估的股骨强度之间的相关性。对于站立负荷配置，单独的BMD占强度变异性的48%-77%，股骨颈横截面积（最小CSA）和股骨颈轴长（FNAL）也独立地对股骨强度有贡献，BMD和几何变量的组合解释了数据中87%-93%的方差。对于跌倒负荷配置，仅转子小梁BMD就解释了87%的强度变异性。在一组七名绝经后妇女中评估了该技术在体内的可重复性，她们重新定位后进行了重复扫描。对于小梁BMD，股骨颈和转子亚区域的精度分别为1.1%和0.6%，而相应整体包膜的精度分别为3.3%和1.6%。因此，小梁BMD测量具有可重复性，并且与生物力学强度测量高度相关。这些结果支持进一步探索定量CT用于评估股骨近端骨质疏松症。
