在固有校准扰动下椎体数字重建射线照片的投影域敏感性分析

中文摘要 AI 辅助

准确的几何校准对于荧光透视引导的脊柱成像、数字重建射线照片（DRR）生成和二维到三维椎体配准至关重要。虽然通常使用基于重建的指标（如重投影误差）来评估校准质量，但其对投影域一致性的影响仍知之甚少。本研究提出了一个综合框架，用于评估固有校准扰动如何影响椎体荧光透视投影和下游配准性能。利用CT衍生的椎体模型和可控锥束成像几何结构，在保持相同解剖结构和采集姿势的同时，生成具有真实和扰动固有校准参数的DRR。通过解剖标志位移、轮廓距离、轮廓重叠、图像相似度以及基于标志的前后（AP）和侧位（LAT）视图中的二维到三维配准精度来量化投影域变化。结果表明，即使是小的固有校准扰动也会在椎体投影几何、轮廓形态、标志定位和DRR外观上产生可测量的变化。敏感性强烈依赖于视图，LAT投影比AP投影表现出更大的变形和解剖位移。这些投影不一致也会降低下游二维到三维配准，特别是旋转对齐精度。研究结果表明，投影域一致性补充了传统的基于重建的校准指标，并提供了一个评估校准鲁棒性的实用框架。这种方法可能会提高图像引导脊柱应用中DRR生成和荧光透视引导椎体配准的可靠性。

英文摘要

Accurate geometric calibration is essential for fluoroscopy-guided spinal imaging, digitally reconstructed radiograph (DRR) generation, and 2D--3D vertebral registration. Although calibration quality is typically evaluated using reconstruction-based metrics such as reprojection error, its influence on projection-domain consistency remains poorly understood. This study presents a synthetic framework for evaluating how intrinsic calibration perturbations affect vertebral fluoroscopic projections and downstream registration performance. CT-derived vertebral models and controlled cone-beam imaging geometry were used to generate DRRs with both ground-truth and perturbed intrinsic calibration parameters while maintaining identical anatomy and acquisition pose. Projection-domain changes were quantified using anatomical landmark displacement, contour distance, silhouette overlap, image similarity, and landmark-based 2D--3D registration accuracy in anterior--posterior (AP) and lateral (LAT) views. Results show that even small intrinsic calibration perturbations produce measurable changes in vertebral projection geometry, contour morphology, landmark localization, and DRR appearance. Sensitivity is strongly view dependent, with LAT projections exhibiting substantially greater deformation and anatomical displacement than AP projections. These projection inconsistencies also degrade downstream 2D--3D registration, particularly rotational alignment accuracy. The findings demonstrate that projection-domain consistency complements conventional reconstruction-based calibration metrics and provides a practical framework for assessing calibration robustness. This approach may improve the reliability of DRR generation and fluoroscopy-guided vertebral registration in image-guided spinal applications.

发表机构

• Department of Mathematics, Tulane University（特伦特大学数学系）
• Department of Computer Science, University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校计算机科学系）
• EOS, EOS Imaging Inc.（EOS公司）
• Department of Electrical and Computer Engineering, Vanderbilt University（范德比大学电气与计算机工程系）
• Department of Computer Science, Vanderbilt University（范德比大学计算机科学系）

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