University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
J Microsc. 2010 Oct;240(1):32-7. doi: 10.1111/j.1365-2818.2010.03381.x.
Although micro-computed tomography (micro-CT) has become the gold standard for assessing the 3D structure of trabecular bone, its extension to cortical bone microstructure has been relatively limited. Desktop micro-CT has been employed to assess cortical bone porosity of humans, whereas that of smaller animals, such as mice and rats, has thus far only been imaged using synchrotron-based micro-CT. The goal of this study was to determine if it is possible to visualize and quantify rat cortical porosity using desktop micro-CT. Tibiae (n = 10) from 30-week-old female Sprague-Dawley rats were imaged with micro-CT (3 μm nominal resolution) and sequential ground sections were then prepared. Bland-Altman plots were constructed to compare per cent porosity and mean canal diameter from micro-CT (3D) versus histology (2D). The mean difference or bias (histology-micro-CT; ±95% confidence interval) for per cent porosity was found to be -0.15% (±2.57%), which was not significantly different from zero (P= 0.720). Canal diameter had a bias (±95% confidence interval) of -5.73 μm (±4.02 μm) which was found to be significantly different from zero (P < 0.001). The results indicated that cortical porosity in rat bone can indeed be visualized by desktop micro-CT. Quantitative assessment of per cent porosity provided unbiased results, whereas direct analysis of mean canal diameter was overestimated by micro-CT. Thus, although higher resolution, such as that available from synchrotron micro-CT, may ultimately be required for precise geometric measurements, desktop micro-CT--which is far more accessible--is capable of yielding comparable measures of porosity and holds great promise for assessment of the 3D arrangement of cortical porosity in the rat.
虽然微计算机断层扫描（micro-CT）已成为评估小梁骨 3D 结构的金标准，但将其扩展到皮质骨微结构的应用相对有限。台式 micro-CT 已被用于评估人类皮质骨的多孔性，而对于较小的动物，如老鼠和大鼠，迄今为止仅使用基于同步加速器的 micro-CT 进行成像。本研究的目的是确定是否可以使用台式 micro-CT 可视化和量化大鼠皮质多孔性。对来自 30 周龄雌性 Sprague-Dawley 大鼠的胫骨（n = 10）进行 micro-CT（名义分辨率为 3μm）成像，然后制备连续的地面切片。构建 Bland-Altman 图，以比较 micro-CT（3D）与组织学（2D）的孔隙率和平均管腔直径。发现孔隙率的平均差值或偏差（组织学-micro-CT；±95%置信区间）为-0.15%（±2.57%），与零无显著差异（P=0.720）。管腔直径的偏差（±95%置信区间）为-5.73μm（±4.02μm），与零有显著差异（P < 0.001）。结果表明，台式 micro-CT 确实可以可视化大鼠骨的皮质多孔性。对孔隙率的定量评估提供了无偏差的结果，而直接分析平均管腔直径则被 micro-CT 高估。因此，尽管可能最终需要更高的分辨率，例如同步加速器 micro-CT 提供的分辨率，才能进行精确的几何测量，但台式 micro-CT（更易于获得）能够产生可比的孔隙率测量值，并为评估大鼠皮质多孔性的 3D 排列提供了很大的希望。
