Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA.
J Bone Miner Res. 2013 Mar;28(3):524-36. doi: 10.1002/jbmr.1795.
High-resolution peripheral quantitative computed tomography (HR-pQCT) has recently been introduced as a clinical research tool for in vivo assessment of bone quality. The utility of this technology to address important skeletal health questions requires translation to standardized multicenter data pools. Our goal was to evaluate the feasibility of pooling data in multicenter HR-pQCT imaging trials. Reproducibility imaging experiments were performed using structure and composition-realistic phantoms constructed from cadaveric radii. Single-center precision was determined by repeat scanning over short-term (<72 hours), intermediate-term (3-5 months), and long-term intervals (28 months). Multicenter precision was determined by imaging the phantoms at nine different HR-pQCT centers. Least significant change (LSC) and root mean squared coefficient of variation (RMSCV) for each interval and across centers was calculated for bone density, geometry, microstructure, and biomechanical parameters. Single-center short-term RMSCVs were <1% for all parameters except cortical thickness (Ct.Th) (1.1%), spatial variability in cortical thickness (Ct.Th.SD) (2.6%), standard deviation of trabecular separation (Tb.Sp.SD) (1.8%), and porosity measures (6% to 8%). Intermediate-term RMSCVs were generally not statistically different from short-term values. Long-term variability was significantly greater for all density measures (0.7% to 2.0%; p < 0.05 versus short-term) and several structure measures: cortical thickness (Ct.Th) (3.4%; p < 0.01 versus short-term), cortical porosity (Ct.Po) (15.4%; p < 0.01 versus short-term), and trabecular thickness (Tb.Th) (2.2%; p < 0.01 versus short-term). Multicenter RMSCVs were also significantly higher than short-term values: 2% to 4% for density and micro-finite element analysis (µFE) measures (p < 0.0001), 2.6% to 5.3% for morphometric measures (p < 0.001), whereas Ct.Po was 16.2% (p < 0.001). In the absence of subject motion, multicenter precision errors for HR-pQCT parameters were generally less than 5%. Phantom-based multicenter precision was comparable to previously reported in in vivo single-center precision errors, although this was approximately two to five times worse than ex vivo short-term precision. The data generated from this study will contribute to the future design and validation of standardized procedures that are broadly translatable to multicenter study designs.
高分辨率外周定量计算机断层扫描（HR-pQCT）最近已被引入临床研究工具，用于评估活体骨骼质量。该技术解决重要骨骼健康问题的实用性需要转化为标准化的多中心数据池。我们的目标是评估多中心 HR-pQCT 成像试验中数据汇总的可行性。使用从尸体桡骨构建的具有结构和组成逼真的体模进行了重现性成像实验。通过在短期（<72 小时）、中期（3-5 个月）和长期（28 个月）间隔内重复扫描来确定单中心精度。通过在九个不同的 HR-pQCT 中心对体模进行成像来确定多中心精度。计算了每个间隔和各中心的骨密度、几何形状、微观结构和生物力学参数的最小有意义变化（LSC）和均方根变异系数（RMSCV）。短期单中心 RMSCV 除皮质厚度（Ct.Th）（1.1%）、皮质厚度空间变异性（Ct.Th.SD）（2.6%）、骨小梁间距标准差（Tb.Sp.SD）（1.8%）和孔隙度测量（6%至 8%）外，所有参数均低于 1%。中期 RMSCV 通常与短期值无统计学差异。长期变异性对于所有密度测量值（0.7%至 2.0%；与短期相比，p<0.05）和几个结构测量值（皮质厚度（Ct.Th）（3.4%；与短期相比，p<0.01）、皮质孔隙率（Ct.Po）（15.4%；与短期相比，p<0.01）和骨小梁厚度（Tb.Th）（2.2%；与短期相比，p<0.01））显著更高。多中心 RMSCV 也明显高于短期值：密度和微有限元分析（µFE）测量值为 2%至 4%（p<0.0001），形态计量测量值为 2.6%至 5.3%（p<0.001），而 Ct.Po 为 16.2%（p<0.001）。在没有受试者运动的情况下，HR-pQCT 参数的多中心精度误差通常小于 5%。基于体模的多中心精度与先前报道的体内单中心精度误差相当，尽管这大约是体外短期精度的两倍至五倍。本研究产生的数据将有助于未来设计和验证标准化程序，这些程序可以广泛转化为多中心研究设计。
