开发并优化5DCT成像模拟与重建方法

中文摘要 AI 辅助

目的：开发并优化一个5DCT（3D + 心脏相位 + 呼吸相位）成像模拟与重建流程，并比较两种正弦图空间插值方法，用于在任意心脏和呼吸相位组合下重建图像。方法：从4D XCAT体模模拟螺旋CT投影，覆盖一系列心脏和呼吸运动状态，并添加泊松噪声和电子噪声。在5个心脏相位和10个呼吸幅度下生成与真值匹配的体数据（共50种相位组合）。由于采集的投影在该联合相位空间中稀疏且不均匀分布，每个目标切片通过将重排后的正弦图行插值到目标心脏相位和呼吸幅度进行重建，使用二维散点重心插值或二维散点局部线性插值（对心脏相位采用圆形核）。重建体积与体模真值使用平均绝对误差（MAE）进行比较，并与从相同模拟数据重建的常规呼吸门控4DCT（r4DCT）进行比较。结果：两种插值方法均消除了在未进行相位空间插值的情况下重建螺旋投影时出现的严重轴向错位伪影。局部线性插值在大多数测试条件下实现了比重心插值更低的MAE，在低螺距下改善最大。5DCT流程还产生了呼吸-only体积，其残余心脏运动伪影少于从相同投影数据重建的常规r4DCT，包括在标准临床螺距（0.1）下。结论：使用正弦图空间插值的5DCT重建是可行的，并且能够以比常规4DCT重建更高的准确性联合解析心脏和呼吸运动。

英文摘要

Purpose: To develop and optimize a 5DCT (3D + cardiac phase + respiratory phase) imaging simulation and reconstruction pipeline, and to compare two sinogram-space interpolation methods for reconstructing images at arbitrary combinations of cardiac and respiratory phase. Methods: Helical CT projections were simulated from the 4D XCAT phantom across a range of cardiac and respiratory motion states, with Poisson and electronic noise added. Ground-truth-matched volumes were generated at 5 cardiac phases and 10 respiratory amplitudes (50 total phase combinations). Because acquired projections are sparsely and unevenly distributed across this joint phase space, each target slice was reconstructed by interpolating rebinned sinogram rows to the target cardiac phase and respiratory amplitude, using either 2D scattered barycentric interpolation or 2D scattered local linear interpolation with a circular kernel for cardiac phase. Reconstructed volumes were compared to phantom ground truth using mean absolute error (MAE), and to conventional respiratory-gated 4DCT (r4DCT) reconstructed from the same simulated data. Results: Both interpolation methods eliminated the severe axial misalignment artifacts present when helical projections were reconstructed without phase-space interpolation. Local linear interpolation achieved lower MAE than barycentric interpolation across most tested conditions, with the largest improvement at low pitch. The 5DCT pipeline also produced respiratory-only volumes with fewer residual cardiac-motion artifacts than conventional r4DCT reconstructed from the same projection data, including at standard clinical pitch (0.1). Conclusions: 5DCT reconstruction using sinogram-space interpolation is feasible and can jointly resolve cardiac and respiratory motion with better accuracy than conventional 4DCT reconstruction.

发表机构

• Duke University（杜克大学）
• Washington University in Saint Louis（圣路易斯华盛顿大学）

机构由 AI 辅助整理，请以论文原文为准。