Summary Generalized Procrustes analysis and thin plate splines were employed to create an average 3D shape template of the proximal femur that was warped to the size and shape of a single 2D radiographic image of a subject. Mean absolute depth errors are comparable with previous approaches utilising multiple 2D input projections.ud udIntroduction Several approaches have been adopted to derive volumetric density (g cm-3) from a conventional 2D representation of areal bone mineral density (BMD, g cm-2). Such approaches have generally aimed at deriving an average depth across the areal projection rather than creating a formal 3D shape of the bone. ududMethods Generalized Procrustes analysis and thin plate splines were employed to create an average 3D shape template of the proximal femur that was subsequently warped to suit the size and shape of a single 2D radiographic image of a subject. CT scans of excised human femora, 18 and 24 scanned at pixel resolutions of 1.08 mm and 0.674 mm, respectively, were equally split into training (created 3D shape template) and test cohorts.ud udResults The mean absolute depth errors of 3.4 mm and 1.73 mm, respectively, for the two CT pixel sizes are comparable with previous approaches based upon multiple 2D input projections. ududConclusions This technique has the potential to derive volumetric density from BMD and to facilitate 3D finite element analysis for prediction of the mechanical integrity of the proximal femur. It may further be applied to other anatomical bone sites such as the distal radius and lumbar spine. ud
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机译:小结使用广义Procrustes分析和薄板样条来创建股骨近端的平均3D形状模板,该模板变形为对象的单个2D射线照相图像的大小和形状。平均绝对深度误差与使用多个2D输入投影的先前方法具有可比性。 2)。此类方法通常旨在得出整个面投影的平均深度,而不是创建骨骼的正式3D形状。 ud udMethods采用广义Procrustes分析和薄板样条曲线来创建股骨近端的平均3D形状模板,随后将其变形以适合对象的单个2D射线照相图像的大小和形状。分别以1.08 mm和0.674 mm的像素分辨率扫描切除的人股骨的CT扫描图18和24,将其平均分为训练(创建3D形状模板)和测试组。 ud ud结果平均绝对深度误差为3.4 mm对于两个CT像素大小,它们的最大宽度分别为1.73 mm和1.73 mm,与基于多个2D输入投影的先前方法相当。结论该技术具有从BMD推导体积密度并促进3D有限元分析以预测股骨近端机械完整性的潜力。它可以进一步应用于其他解剖骨骼部位,例如radius骨远端和腰椎。 ud
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