Palmquist Anders, Shah Furqan A, Emanuelsson Lena, Omar Omar, Suska Felicia
Department of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden.
Department of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden; BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, Göteborg, Sweden.
Micron. 2017 Mar;94:1-8. doi: 10.1016/j.micron.2016.11.009. Epub 2016 Nov 21.
This paper investigates the application of X-ray micro-computed tomography (micro-CT) to accurately evaluate bone formation within 3D printed, porous Ti6Al4V implants manufactured using Electron Beam Melting (EBM), retrieved after six months of healing in sheep femur and tibia. All samples were scanned twice (i.e., before and after resin embedding), using fast, low-resolution scans (Skyscan 1172; Bruker micro-CT, Kontich, Belgium), and were analysed by 2D and 3D morphometry. The main questions posed were: (i) Can low resolution, fast scans provide morphometric data of bone formed inside (and around) metal implants with a complex, open-pore architecture?, (ii) Can micro-CT be used to accurately quantify both the bone area (BA) and bone-implant contact (BIC)?, (iii) What degree of error is introduced in the quantitative data by varying the threshold values?, and (iv) Does resin embedding influence the accuracy of the analysis? To validate the accuracy of micro-CT measurements, each data set was correlated with a corresponding centrally cut histological section. The results show that quantitative histomorphometry corresponds strongly with 3D measurements made by micro-CT, where a high correlation exists between the two techniques for bone area/volume measurements around and inside the porous network. On the contrary, the direct bone-implant contact is challenging to estimate accurately or reproducibly. Large errors may be introduced in micro-CT measurements when segmentation is performed without calibrating the data set against a corresponding histological section. Generally, the bone area measurement is strongly influenced by the lower threshold limit, while the upper threshold limit has little or no effect. Resin embedding does not compromise the accuracy of micro-CT measurements, although there is a change in the contrast distributions and optimisation of the threshold ranges is required.
本文研究了X射线显微计算机断层扫描（显微CT）在准确评估电子束熔炼（EBM）制造的三维打印多孔Ti6Al4V植入物内骨形成情况中的应用。这些植入物在绵羊股骨和胫骨中愈合六个月后取出。所有样本均使用快速、低分辨率扫描（Skyscan 1172；布鲁克显微CT，比利时孔蒂奇）进行了两次扫描（即在树脂包埋前后），并通过二维和三维形态测量法进行分析。提出的主要问题包括：（i）低分辨率、快速扫描能否提供具有复杂开放孔结构的金属植入物内部（及周围）形成的骨的形态测量数据？（ii）显微CT能否用于准确量化骨面积（BA）和骨-植入物接触面积（BIC）？（iii）通过改变阈值，定量数据中会引入多大程度的误差？（iv）树脂包埋是否会影响分析的准确性？为验证显微CT测量的准确性，将每个数据集与相应的中心切割组织学切片进行关联。结果表明，定量组织形态计量学与显微CT进行的三维测量高度相关，在多孔网络周围和内部的骨面积/体积测量中，这两种技术之间存在高度相关性。相反，直接的骨-植入物接触难以准确或可重复地估计。在未根据相应组织学切片校准数据集的情况下进行分割时，显微CT测量可能会引入较大误差。一般来说，骨面积测量受较低阈值限制的影响较大，而较高阈值限制的影响很小或没有影响。树脂包埋不会影响显微CT测量的准确性，尽管对比度分布会发生变化，并且需要优化阈值范围。
