3D assessment of cortical bone porosity and tissue mineral density using high-resolution µCT: effects of resolution and threshold method.
3D assessment of cortical bone porosity and tissue mineral density using high-resolution µCT: effects of resolution and threshold method.
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DOI：
10.1002/jbmr.2012
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发表时间：
2014-01
影响因子：
6.2
通讯作者：
Fritton, Susannah P.
中科院分区：
文献类型：
--
作者：
Palacio-Mancheno, Paolo E.;Larriera, Adriana I.;Doty, Stephen B.;Cardoso, Luis;Fritton, Susannah P.
目前的微型ct系统允许扫描骨骼的分辨率能够三维表征皮质内血管孔隙和骨细胞腔隙。然而，扫描和重建参数以及图像分割方法会影响测量的精度。本研究分析了扫描分辨率和图像阈值法对皮质骨小特征（血管孔隙度、血管管直径和分离、腔隙孔隙度和密度、组织矿物质密度）量化的影响。Sprague-Dawley大鼠胫骨皮质骨以1µm和4µm分辨率扫描，重建密度校准，并使用基于边缘检测或直方图分析的方法分割感兴趣的体积。通过1µm分辨率的扫描，可以看到骨细胞腔隙，并且可以将腔隙孔隙与血管孔隙区分开。在4µm分辨率下，血管孔隙度和血管管直径被低估，骨细胞腔隙无法有效检测，而与1µm分辨率相比，血管管分离和组织矿物质密度被高估。分辨率对测量结果的影响比阈值法大得多，在两个独立的分析中，分辨率大于2 μ m的部分体积效应得到了证明，其中一个分析评估了分辨率对已知尺寸的物体的影响，这些物体的结构与血管孔相似。尽管使用边缘检测与基于直方图的阈值方法差异不大，但在更精细的分辨率（1 - 2 μ m）下，边缘检测在描绘运河结构方面更有效。此外，在低分辨率（4µm）密度校准图像上使用高分辨率（1µm）密度阈值对提高低分辨率测量效果无效。总之，如果测量皮质血管微结构，特别是在小动物中，1 - 2微米的微ct分辨率是合适的，而在评估骨细胞腔隙孔隙度时，分辨率至少为1微米是必要的。
Current micro-CT systems allow scanning bone at resolutions capable of three-dimensional characterization of intracortical vascular porosity and osteocyte lacunae. However, the scanning and reconstruction parameters along with the image segmentation method affect the accuracy of the measurements. In this study, the effects of scanning resolution and image threshold method in quantifying small features of cortical bone (vascular porosity, vascular canal diameter and separation, lacunar porosity and density, and tissue mineral density) were analyzed. Cortical bone from the tibia of Sprague-Dawley rats was scanned at 1-µm and 4-µm resolutions, reconstructions were density-calibrated, and volumes of interest were segmented using approaches based on edge-detection or histogram analysis. With 1-µm resolution scans, the osteocyte lacunar spaces could be visualized, and it was possible to separate the lacunar porosity from the vascular porosity. At 4-µm resolution, the vascular porosity and vascular canal diameter were underestimated, and osteocyte lacunae were not effectively detected, whereas the vascular canal separation and tissue mineral density were overestimated compared to 1-µm resolution. Resolution had a much greater effect on the measurements than did threshold method, with partial volume effects at resolutions coarser than 2 µm demonstrated in two separate analyses, one of which assessed the effect of resolution on an object of known size with similar architecture to a vascular pore. Although there was little difference when using the edge-detection versus histogram-based threshold approaches, edge-detection was somewhat more effective in delineating canal architecture at finer resolutions (1 – 2 µm). In addition, use of a high-resolution (1-µm) density-based threshold on lower resolution (4-µm) density-calibrated images was not effective in improving the lower-resolution measurements. In conclusion, if measuring cortical vascular microarchitecture, especially in small animals, a micro-CT resolution of 1 – 2 µm is appropriate, while a resolution of at least 1 µm is necessary when assessing osteocyte lacunar porosity.
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影响因子：
2.4
作者：
Cardoso L;Fritton SP;Gailani G;Benalla M;Cowin SC
通讯作者：
Cowin SC
影响因子：
4.2
作者：
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Hallgrimsson, B
影响因子：
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作者：
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影响因子：
7
作者：
Gu, X. I.;Palacio-Mancheno, P. E.;Cardoso, L.
通讯作者：
Cardoso, L.