Comprehensive evaluation of ten deformable image registration algorithms for contour propagation between CT and cone-beam CT images in adaptive head & neck radiotherapy.
Comprehensive evaluation of ten deformable image registration algorithms for contour propagation between CT and cone-beam CT images in adaptive head & neck radiotherapy.
复制标题
自适应头中CT与锥束CT图像之间轮廓传播的10种变形图像配准算法的综合评价
DOI：
10.1371/journal.pone.0175906
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Zhou L
中科院分区：
文献类型：
--
作者：
Li X;Zhang Y;Shi Y;Wu S;Xiao Y;Gu X;Zhen X;Zhou L
可变形图像配准 (DIR) 是自适应放射治疗 (ART) 中的一项关键技术，用于在规划计算机断层扫描 (CT) 图像和治疗 CT/锥形束 CT (CBCT) 图像之间传播轮廓，以考虑器官变形以进行治疗重新规划。为了验证 DIR 算法在危及器官 (OAR) 轮廓绘制中的能力和准确性，我们对 21 名接受 6~7 周调强放射治疗 (IMRT) 的头颈 (H&N) 癌症患者采集的计划 CT 和分数 CBCT 图像进行了测试，测试了 10 种基于强度的 DIR 策略，分为基于光流、基于恶魔、基于水平集和基于样条的四类。采用三个相似性度量，即 Dice 相似性系数 (DSC)、百分比误差 (PE) 和 Hausdorff 距离 (HD)，用于测量四个 OAR（包括椎骨 (VTB)、椎孔 (VF)、腮腺 (PG) 和下颌下腺 (SMG)）的传播轮廓与医生描绘的基本事实之间的一致性。结果发现，这项工作中评估的 DIR 不一定优于严格注册。 DIR 对于骨结构的表现优于软组织器官，并且随着治疗的进行，对于具有不同变形程度的不同 ROI，DIR 的表现往往会有所不同。一般来说，基于光流的 DIR 表现最好，而基于恶魔的 DIR 通常排名最后，除了用于 CT-CBCT DIR 的改进的基于恶魔的 DISC 之外。这些实验结果表明，特定 DIR 算法的选择取决于图像模态、解剖部位、变形幅度和应用。因此，在接受自动传播的轮廓之前，需要仔细检查和修改，特别是对于自动重新规划 ART 系统。
Deformable image registration (DIR) is a critical technic in adaptive radiotherapy (ART) for propagating contours between planning computerized tomography (CT) images and treatment CT/cone-beam CT (CBCT) images to account for organ deformation for treatment re-planning. To validate the ability and accuracy of DIR algorithms in organ at risk (OAR) contour mapping, ten intensity-based DIR strategies, which were classified into four categories—optical flow-based, demons-based, level-set-based and spline-based—were tested on planning CT and fractional CBCT images acquired from twenty-one head & neck (H&N) cancer patients who underwent 6~7-week intensity-modulated radiation therapy (IMRT). Three similarity metrics, i.e., the Dice similarity coefficient (DSC), the percentage error (PE) and the Hausdorff distance (HD), were employed to measure the agreement between the propagated contours and the physician-delineated ground truths of four OARs, including the vertebra (VTB), the vertebral foramen (VF), the parotid gland (PG) and the submandibular gland (SMG). It was found that the evaluated DIRs in this work did not necessarily outperform rigid registration. DIR performed better for bony structures than soft-tissue organs, and the DIR performance tended to vary for different ROIs with different degrees of deformation as the treatment proceeded. Generally, the optical flow-based DIR performed best, while the demons-based DIR usually ranked last except for a modified demons-based DISC used for CT-CBCT DIR. These experimental results suggest that the choice of a specific DIR algorithm depends on the image modality, anatomic site, magnitude of deformation and application. Therefore, careful examinations and modifications are required before accepting the auto-propagated contours, especially for automatic re-planning ART systems.