Accuracy of peripheral quantitative computed tomography (pQCT) for assessing area and density of mouse cortical bone
Accuracy of peripheral quantitative computed tomography (pQCT) for assessing area and density of mouse cortical bone
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DOI：
10.1007/s00223-002-0006-0
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发表时间：
2003-10-01
影响因子：
4.2
通讯作者：
Silva, MJ
中科院分区：
文献类型：
--
作者：
Brodt, MD;Petz, GB;Silva, MJ
外周定量计算机断层扫描(PQCT)越来越多地用于测量小鼠的皮质骨几何形状和密度。我们评估了pQCT测量薄壁铝模体和小鼠股骨的面积和密度的准确性。用70或90微米分辨率扫描1-6月龄C3H/HeJ(C3H)和C57B1/6J(136)小鼠不同壁厚和股骨的铝管(平均皮质厚度0.14-0.29 mm)。PQCT面积值与切片后测定的光学值进行比较，pQCT密度(VBMD)与固体铝密度比较或与骨灰含量相关。对于铝模体，pQCT面积和密度的误差强烈依赖于壁厚，而密度始终被低估。对于小鼠股骨，尽管最佳阈值在不同的组之间有所不同，但对于每个应变和年龄组，阈值在骨面积方面产生了零误差。PQCT的vBMD与灰分含量有很强的相关性(r(2)=0.7)，尽管不同品系的回归方程不同，并且vBMD的品系间差异比灰分含量的差异大四倍。这一发现表明，pQCT可能高估了骨骼厚度不同的近交系小鼠之间的体积矿物质密度的差异(例如，C3Hvs.B6)。总之，pQCT得到的面积和密度值都强烈依赖于样品厚度，这与部分体积平均伪影一致。使用pQCT评估小鼠皮质骨的研究人员应该意识到皮质层厚度相关误差的可能性。
Peripheral quantitative computed tomography (pQCT) is increasingly used for measurement of cortical bone geometry and density in mice. We evaluated the accuracy of pQCT for area and density measurements of thin-walled aluminum phantoms and mouse femora. Aluminum tubes with varying wall thicknesses and femora from 1- to 6-month-old C3H/HeJ (C3H) and C57B1/6J (136) mice (average cortical thickness 0.14-0.29 mm) were scanned at 70- or 90-mum resolution. pQCT values of area were compared to optical values determined after sectioning, while pQCT density (vBMD) was compared to solid aluminum density or correlated to bone ash content. For the aluminum phantoms, the error in pQCT area and density depended strongly on wall thickness, and density was consistently underestimated. For mouse femora, threshold values were found that produced zero error in bone area for each strain and age group, although the optimal threshold differed between groups. pQCT vBMD correlated strongly with ash content (r(2) = 0.7), although the regression equations differed between strains and the magnitude of the inter-strain difference in vBMD was fourfold greater than the difference in ash content. This finding suggests that pQCT can overestimate the differences in volumetric mineral density between inbred mouse strains whose bones are of different thickness (e.g., C3H vs. B6). In conclusion, both area and density values obtained by pQCT depend strongly on specimen thickness, consistent with a partial volume averaging artifact. Investigators using pQCT to assess cortical bones in mice should be aware of the potential for cortical thickness-dependent errors.