Comparison of pQCT-Based Measures of Radial Bone Geometry and Apparent Trabecular Bone Structure Using Manufacturer and In-House-Developed Algorithms
Comparison of pQCT-Based Measures of Radial Bone Geometry and Apparent Trabecular Bone Structure Using Manufacturer and In-House-Developed Algorithms
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DOI：
10.1016/j.jocd.2010.06.007
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发表时间：
2010-10-01
影响因子：
2.5
通讯作者：
MacIntyre, Norma J.
中科院分区：
文献类型：
--
作者：
Calder, Kristina M.;Inglis, Dean;MacIntyre, Norma J.
外周定量计算机断层扫描（pQCT）提供了无创密度和形态测量的总，小梁和皮质骨隔间。随着时间的推移，Skills的变化可以通过重复测量来确定。认为2.5 mm的图像厚度对于通过询问显著组织体积的重测可靠性是有利的。然而，与图像位置轻微偏移相关的误差尚不清楚。本研究的主要目的是确定4%部位周围位置变异性对桡骨测量的影响。次要目的是比较用于估计相同骨特征的不同软件算法。使用pQCT（10层;平面内分辨率：0.2 x 0.2 mm;厚度：2.5 mm; PDLC XCT 2000 L），以0.5 mm的间隔对8具左侧尸体前臂（年龄65 - 88岁）桡骨4%部位周围进行成像。我们使用制造商的软件（BMC v6.0B）从每张图像中确定总骨矿物质密度（BD_tot）、总骨矿物质含量（BMC_tot）、总骨面积（Area_tot）、骨小梁密度（BD_trab）、骨小梁矿物质含量（BMC_trab）和骨小梁面积（Area_trab）。为了进行比较，还使用内部开发的软件分析4%部位的Area_tot和Area_trab。内部软件还产生了表观小梁结构的测量值，包括数量（App. Tb. N）、厚度（App. Tb. Th）和间距（App. Tb. Sp），使用2种不同的体视学方法进行量化：使用小梁周长和平均截距长度分析的平行板法。使用单因素重复测量方差分析（ANOVA）评估切片位置的影响。使用组内相关系数（ICC）确定4%部位周围无意义切片距离的可靠性。使用单因素重复测量ANOVA比较4%部位相似骨特征的测量值。创建Bland-Altman图以评估量化可比表观小梁结构的算法对之间的一致性水平。Area_tot和Area_trab在4%部位近端大于或等于1.0 mm和远端大于或等于0.5 mm处存在显著差异。BMC_tot和BMC_trab的差异显著，近端（两者）大于或等于1.5 mm，远端分别大于或等于2.0 mm和1.0 mm。BD_tot在4%部位的近端和远端大于或等于1 mm处存在显著差异。BD_trab在10个切片之间没有差异。对于在4%部位和近端0.5 mm处采集的图像，可靠性极佳（ICC = 0.98至0.99）。尽管内部软件在4%位点产生的Area_tot和Area_trab值较高（p <0.05），但未观察到系统偏倚。平行板法得出的App. Tb. N值较高，App. Tb. Th值较低（p <0.05），无系统偏倚。采用平行板法测定的App. Tb. Sp值较小，方法间差异随App. Tb. Sp值的增加而增加。从统计学上讲，桡骨4%部位周围的重新定位公差对于骨面积测量值最小，而对于BD_trab最大。重复测量时，近端偏移0.5 mm不会影响结果。
Peripheral quantitative computed tomography (pQCT) provides noninvasive densitometric and morphometric measures of total, trabecular, and cortical bone compartments. Skeletal changes over time can be determined by repeated measurements. Image thickness of 2.5 mm is thought to be advantageous with respect to test-retest reliability through interrogation of a significant tissue volume. However, the error associated with slight shifts in image location is unknown. The primary purpose of this study was to determine the effects of positional variability around the 4% site on radial bone measures. The secondary objective was to compare different software algorithms for estimating the same bone characteristics. Eight left cadaveric forearms (aged 65-88 yr) were imaged at 0.5-mm intervals around the 4% site of the radial bone using pQCT (10 slices; in-plane resolution: 0.2 x 0.2 mm; thickness: 2.5 mm; Stratec XCT2000L. We used the manufacturer's software (Stratec v6.0B) to determine the total bone mineral density (BD_tot), total bone mineral content (BMC_tot), total bone area (Area_tot), trabecular bone mineral density (BD_trab), trabecular bone mineral content (BMC_trab), and trabecular bone area (Area_trab) from each image. For comparison, in-house-developed software was also used to analyze Area_tot and Area_trab at the 4% site. The in-house software also produced measures of apparent trabecular structure, including number (App.Tb.N), thickness (App.Tb.Th), and spacing (App.Tb.Sp), quantified using 2 different stereological approaches: the parallel-plate method using trabecular perimeter lengths and mean intercept length analysis. The effect of slice position was assessed using a 1-way repeated-measures analysis of variance (ANOVA). Reliability of nonsignificant slice distances around the 4% site was determined using intraclass correlation coefficients (ICCs). One-way repeated-measures ANOVA was used to compare measures of similar bone characteristics at the 4% site. Bland-Altman plots were created to assess the level of agreement between pairs of algorithms quantifying comparable apparent trabecular structure. Area_tot and Area_trab differed significantly at greater than or equal to 1.0 mm proximal and greater than or equal to 0.5 mm distal to the 4% site. BMC_tot and BMC_trab differ significantly greater than or equal to 1.5 mm proximally (for both) and greater than or equal to 2.0 and 1.0 mm distally, respectively. BD_tot differed significantly at greater than or equal to 1 mm proximal and distal to the 4% site. BD_trab did not differ among the 10 slices. For images acquired at the 4% site, and 0.5 mm more proximally, reliability was excellent (ICC = 0.98 to 0.99). Although the in-house software yielded a higher value for Area_tot and Area_trab at the 4% site (p < 0.05), no systematic bias was observed. The parallel-plate method yielded higher values for App.Tb.N and lower values for App.Tb.Th (p < 0.05), with no systematic bias. App.Tb.Sp values were smaller using the parallel-plate method, and the difference in methods increased as App.Tb.Sp values increased. Statistically, tolerance for repositioning around the 4% site of the radial bone is least for measures of bone area and greatest for BD_trab. On repeated measures, a proximal shift of 0.5 mm will not influence the results.