Abstract
Purpose: Accurate intraoperative X-ray/CT registration is essential for surgical navigation in orthopedic procedures. However, existing methods struggle with consistently achieving sub-millimeter accuracy, robustness under broad initial pose estimates or need manual key-point annotations. This work aims to address these challenges by proposing a novel multi-view X-ray/CT registration method for intraoperative bone registration. Methods: The proposed registration method consists of a multi-view, contour-based iterative closest point (ICP) optimization. Unlike previous methods, which attempt to match bone contours across the entire silhouette in both imaging modalities, we focus on matching specific subcategories of contours corresponding to bone substructures. This leads to reduced ambiguity in the ICP matches, resulting in a more robust and accurate registration solution. This approach requires only two X-ray images and operates fully automatically. Additionally, we contribute a dataset of 5 cadaveric specimens, including real X-ray images, X-ray image poses and the corresponding CT scans. Results: The proposed registration method is evaluated on real X-ray images using mean reprojection error (mRPD). The method consistently achieves sub-millimeter accuracy with a mRPD 0.67mm compared to 5.35mm by a commercial solution requiring manual intervention. Furthermore, the method offers improved practical applicability, being fully automatic. Conclusion: Our method offers a practical, accurate, and efficient solution for multi-view X-ray/CT registration in orthopedic surgeries, which can be easily combined with tracking systems. By improving registration accuracy and minimizing manual intervention, it enhances intraoperative navigation, contributing to more accurate and effective surgical outcomes in computer-assisted surgery (CAS).
Abstract (translated)
目的：在骨科手术中，术中X射线/CT配准对于手术导航至关重要。然而，现有方法难以持续实现亚毫米级精度、广泛初始姿态估计下的鲁棒性或需要手动关键点标注。本研究旨在通过提出一种新的多视角X射线/CT配准方法来解决这些问题，该方法适用于术中骨配准。 **方法：** 所提出的注册方法包括一个基于轮廓的多视图迭代最近点（ICP）优化过程。与以往试图在两种成像模式下在整个剪影范围内匹配骨骼轮廓的方法不同，我们专注于匹配特定子类别的对应于骨骼亚结构的轮廓。这减少了ICP匹配中的歧义，从而提高了配准解决方案的稳健性和准确性。这种方法仅需两张X射线图像，并且完全自动运行。 此外，我们贡献了一组包含5个解剖标本的真实数据集，包括X射线影像、X射线影像姿态和相应的CT扫描。 **结果：** 所提出的注册方法在使用均方根重投影误差（mRPD）评估真实X射线图像时表现出色。该方法持续实现亚毫米级精度，达到0.67mm的mRPD，而商业解决方案需手动干预且仅为5.35mm。此外，这种方法提供了更实用的应用性，因为它是完全自动化的。 **结论：** 我们的方法为多视角X射线/CT配准提供了一种实际、准确和有效的解决方案，在骨科手术中可以轻松与跟踪系统结合使用。通过提高注册精度并减少人工干预，该方法改善了术中的导航性能，有助于计算机辅助外科手术（CAS）实现更精确和有效的结果。
URL
https://arxiv.org/abs/2506.13292
