Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.
Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
Am J Biol Anthropol. 2024 Nov;185(3):e25023. doi: 10.1002/ajpa.25023. Epub 2024 Sep 5.
The "gold standard" for the assessment of trabecular bone structure is high-resolution micro-CT. In this technical note, we test the influence of initial scan resolution and post hoc downsampling on the quantitative and qualitative analysis of trabecular bone in a Gorilla tibia. We analyzed trabecular morphology in the right distal tibia of one Gorilla gorilla individual to investigate the impact of variation in voxel size on measured trabecular variables. For each version of the micro-CT volume, trabecular bone was segmented using the medical image analysis method. Holistic morphometric analysis was then used to analyze bone volume (BV/TV), anisotropy (DA), trabecular thickness (Tb.Th), spacing (Tb.Sp), and number (Tb.N). Increasing voxel size during initial scanning was found to have a strong impact on DA and Tb.Th measures, while BV/TV, Tb.Sp, and Tb.N were found to be less sensitive to variations in initial scan resolution. All tested parameters were not substantially influenced by downsampling up to 90 μm resolution. Color maps of BV/TV and DA also retained their distribution up to 90 μm. This study is the first to examine the effect of variation in micro-CT voxel size on the analysis of trabecular bone structure using whole epiphysis approaches. Our results indicate that microstructural variables may be measured for most trabecular parameters up to a voxel size of 90 μm for both scan and downsampled resolutions. Moreover, if only BV/TV, Tb.Sp or Tb.N is measured, even larger voxel sizes might be used without substantially affecting the results.
评估小梁骨结构的“金标准”是高分辨率微计算机断层扫描。在本技术说明中，我们测试了初始扫描分辨率和事后下采样对大猩猩胫骨中小梁骨定量和定性分析的影响。我们分析了一只大猩猩右胫骨远端的小梁形态，以研究体素大小变化对测量的小梁变量的影响。对于微计算机断层扫描体积的每个版本，使用医学图像分析方法对小梁骨进行分割。然后使用整体形态计量分析来分析骨体积（BV/TV）、各向异性（DA）、小梁厚度（Tb.Th）、间距（Tb.Sp）和数量（Tb.N）。研究发现，在初始扫描过程中增加体素大小对 DA 和 Tb.Th 测量有很大影响，而 BV/TV、Tb.Sp 和 Tb.N 对初始扫描分辨率的变化不太敏感。所有测试参数在分辨率降低至 90μm 之前都不会受到太大影响。BV/TV 和 DA 的彩色图谱在分辨率降低至 90μm 之前也保留了其分布。本研究首次检查了微计算机断层扫描体素大小变化对使用整个骺板方法分析小梁骨结构的影响。我们的结果表明，对于大多数小梁参数，在扫描和下采样分辨率下，微观结构变量可以在体素大小为 90μm 时进行测量。此外，如果仅测量 BV/TV、Tb.Sp 或 Tb.N，则甚至可以使用更大的体素大小，而不会对结果产生实质性影响。
