London Health Science Centre, Victoria Hospital, 800 Commissioners Rd E, E1-305, London, ON N6A 5W9, Canada; Westmead Hospital, Sydney, NSW, Australia.
London Health Science Centre, Victoria Hospital, 800 Commissioners Rd E, E1-305, London, ON N6A 5W9, Canada.
Acad Radiol. 2021 Jun;28(6):e172-e181. doi: 10.1016/j.acra.2020.05.027. Epub 2020 Jun 30.
Crucial to the process of three-dimensional (3D) printing is the knowledge of how the actual structure or organ relates dimensionally to its corresponding medical image. This study will examine the differences between human lumbar vertebrae, 3D scans of these bones, 3D models based on computed tomographic (CT) scans, and 3D-printed models.
CT scans were obtained for six human lumbar spines. The bones were cleaned, and 3D scanned. 3D mesh models were created from the CT data, and then 3D printed. Four models were analyzed: anatomic bones, 3D-scanned models, CT-models, and 3D-printed models. Manual measurements were performed for all model types, and segmentation metric comparisons were performed comparing the 3D-scanned models to the CT-models.
There was no statistical difference between manual measurements when comparing each parameter of all model types, except for vertebral width (p = 0.044). There was no statistical difference when comparing the average of all measurements between all model types (p = 0.247). The mean Hausdorff distance was 0.99 mm (SD 0.55 mm) when comparing 3D-scanned model to CT-model. The mean Dice coefficient was 0.90 (SD 0.07) when comparing 3D-scanned model to CT-model. The mean volume for 3D-scanned model and CT-model were 41.6 ml and 45.9 ml (p < 0.001), respectively.
This study clarifies the geometric and volumetric relationship between human lumbar vertebra and CT-based vertebral models. Segmentation metrics reveal a 1 mm difference between examined bones (using the 3D-scanned bone as a surrogate), and the CT measurements. This is confirmed by a volumetric difference of 4.3 ml, between the larger CT-based model and the smaller bone.
三维（3D）打印的关键在于了解实际结构或器官如何在尺寸上与其相应的医学图像相关联。本研究将检查人类腰椎、这些骨骼的 3D 扫描、基于计算机断层扫描（CT）的 3D 模型和 3D 打印模型之间的差异。
对 6 个人类腰椎进行 CT 扫描。对骨骼进行清洁和 3D 扫描。从 CT 数据创建 3D 网格模型，然后进行 3D 打印。对 4 种模型进行分析：解剖骨骼、3D 扫描模型、CT 模型和 3D 打印模型。对所有模型类型进行手动测量，并对 3D 扫描模型与 CT 模型进行分割度量比较。
除了椎体宽度（p=0.044）外，比较所有模型类型的每个参数时，手动测量没有统计学差异。比较所有模型类型之间所有测量值的平均值时，没有统计学差异（p=0.247）。比较 3D 扫描模型和 CT 模型时，Hausdorff 距离的平均值为 0.99 毫米（SD 0.55 毫米）。比较 3D 扫描模型和 CT 模型时，Dice 系数的平均值为 0.90（SD 0.07）。3D 扫描模型和 CT 模型的平均体积分别为 41.6 毫升和 45.9 毫升（p<0.001）。
本研究阐明了人类腰椎与基于 CT 的椎体模型之间的几何和体积关系。分割度量值显示检查骨骼（使用 3D 扫描骨骼作为替代物）与 CT 测量值之间存在 1 毫米的差异。这一点得到了较大的基于 CT 的模型和较小骨骼之间 4.3 毫升体积差异的证实。
