Differences in bone mineral density and morphometry measurements by fixed versus relative offset methods in high-resolution peripheral quantitative computed tomography
Differences in bone mineral density and morphometry measurements by fixed versus relative offset methods in high-resolution peripheral quantitative computed tomography
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DOI：
10.1016/j.bone.2021.115973
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发表时间：
2021-05-08
期刊：
影响因子：
4.1
通讯作者：
Osaki, Makoto
中科院分区：
文献类型：
--
作者：
Okazaki, Narihiro;Chiba, Ko;Osaki, Makoto
简介：高分辨率外周定量计算机断层扫描（HR-pQCT），使在体内分析骨形态，广泛用于骨质疏松症的研究。扫描位置通常由固定偏移方法确定;然而，如果肢体长度较短，则扫描位置可能变得相对近端。本研究比较了使用固定和相对偏移方法测量的骨矿物质密度和形态计量学，其中扫描位置是根据前臂和小腿的长度确定的，并调查了两种方法之间测量差异的因素。方法：本研究共入组了150例健康日本受试者，包括75例男性和75例女性，平均年龄为45.1岁。使用固定和相对偏心距方法扫描桡骨远端和胫骨;固定偏心距方法涉及分别在桡骨和胫骨远端关节面近端9 mm和22 mm处扫描桡骨和胫骨。相比之下，相对偏移方法需要扫描前臂长度的4%处的桡骨和小腿长度的7.3%处的胫骨，靠近其各自的远端关节面。使用定位视图测量两种方法的扫描位置之间的重叠百分比。比较了两种方法的测量值。检查两种方法之间的值差异与前臂长度、小腿长度和身高之间的相关性。受试者的平均身高为164.3 ± 14.3 cm，平均前臂长度为252.9 ± 17.3 mm，平均小腿长度为346.7 ± 22.3 mm。桡骨和胫骨的平均重叠百分比分别为85.0 ± 9.1%（59.2-99.6%）和79.8 ± 12.5%（48.3-99.8%）。固定偏移扫描产生更高的总体积骨矿物质密度（Tt.vBMD）和皮质vBMD（Ct.vBMD）以及更大的皮质厚度（Ct.Th）（所有p < 0.001）。两种方法在Tt.vBMD、Ct.vBMD和Ct.Th方面的差异在前臂长度、小腿长度和身高（半径：0.51 <0.55）较短的情况下显著更大。|R| < 0.63，胫骨：0.61 <|R|结论：使用固定偏移方法获得的骨矿物质密度和形态测量结果与使用相对偏移方法获得的结果不同，相对偏移方法考虑了身体尺寸。较短的身高，前臂长度和小腿长度与更大的测量差异。在身材较小的人群中，使用固定偏移方法会产生相对近端的图像;因此，在比较不同身高的人群时应谨慎。
Introduction: High-resolution peripheral quantitative computed tomography (HR-pQCT), which enables in vivo analysis of bone morphometry, is widely used in osteoporosis research. The scan position is usually determined by the fixed offset method; however, there are concerns that the scan position can become relatively proximal if limb length is short. The present study compared bone mineral density and morphometry measured using the fixed and relative offset methods, in which the scan position is determined based on the lengths of the forearm and lower leg, and investigated factors responsible for measurement differences between the two methods.Methods: A total of 150 healthy Japanese subjects, comprising 75 men and 75 women, with a mean age of 45.1 years, were enrolled in this study. The distal radius and tibia were scanned using the fixed and relative offset methods; the fixed offset method involved scanning the radius and tibia at 9 mm and 22 mm, respectively, proximal to their distal articular surfaces. By contrast, the relative offset method entailed scanning the radius at 4% of the forearm length and the tibia at 7.3% of the lower leg length, proximal to their respective distal articular surfaces. The percent overlap between the scan positions of the two methods was measured using the scout views. Measurement values obtained with the two methods were compared. The correlation between the differences in the values among the two methods and forearm length, lower leg length, and body height was examined.Results: The subjects had a mean height of 164.3 +/- 14.3 cm, mean forearm length of 252.9 +/- 17.3 mm, and mean lower leg length of 346.7 +/- 22.3 mm. The mean percent overlap was 85.0 +/- 9.1% (59.2-99.6%) for the radius and 79.8 +/- 12.5% (48.3-99.8%) for the tibia. Fixed offset scanning yielded higher total volumetric bone mineral density (Tt.vBMD) and cortical vBMD (Ct.vBMD) and greater cortical thickness (Ct.Th) (all p < 0.001). The differences between the two methods in terms of Tt.vBMD, Ct.vBMD and Ct.Th were significantly greater with shorter forearm length, lower leg length, and body height (radius: 0.51 < |r| < 0.63, tibia: 0.61 < |r| < 0.95).Conclusion: Measurements of bone mineral density and morphometry obtained using the fixed offset method differed from those obtained using the relative offset method, which takes body size into account. Shorter body height, forearm length, and lower leg length were found to correlate with greater measurement differences. In populations with smaller stature, use of the fixed offset method results in relatively proximal images; thus, caution should be exercised when comparing groups of different height.