用于吞咽运动估计的 2D MR 电影图像的自动配准。
Automatic registration of 2D MR cine images for swallowing motion estimation.
机构信息
Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America.
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America.
出版信息
PLoS One. 2020 Feb 11;15(2):e0228652. doi: 10.1371/journal.pone.0228652. eCollection 2020.
PURPOSE
To automate the estimation of swallowing motion from 2D MR cine images using deformable registration for future applications of personalized margin reduction in head and neck radiotherapy and outcome assessment of radiation-associated dysphagia.
METHODS
Twenty-one patients with serial 2D FSPGR-MR cine scans of the head and neck conducted through the course of definitive radiotherapy for oropharyngeal cancer. Included patients had at least one cine scan before, during, or after radiotherapy, with a total of 52 cine scans. Contours of 7 swallowing related regions-of-interest (ROIs), including pharyngeal constrictor, epiglottis, base of tongue, geniohyoid, hyoid, soft palate, and larynx, were manually delineated from consecutive frames of the cine scan covering at least one swallowing cycle. We applied a modified thin-plate-spline robust-point-matching algorithm to register the point sets of each ROI automatically over frames. The deformation vector fields from the registration were then used to estimate the motion during swallowing for each ROI. Registration errors were estimated by comparing the deformed contours with the manual contours.
RESULTS
On average 22 frames of each cine scan were contoured. The registration for one cine scan (7 ROIs over 22 frames) on average took roughly 22 minutes. A number of 8018 registrations were successfully batch processed without human interaction after the contours were drawn. The average registration error for all ROIs and all patients was 0.36 mm (range: 0.06 mm- 2.06 mm). Larynx had the average largest motion in superior direction of all structures under consideration (range: 0.0 mm- 58.7 mm). Geniohyoid had the smallest overall motion of all ROIs under consideration and the superior-inferior motion was larger than the anterior-posterior motion for all ROIs.
CONCLUSION
We developed and validated a deformable registration framework to automate the estimation of swallowing motion from 2D MR cine scans.
目的
通过变形配准从 2D MR 电影图像中自动估计吞咽运动，以便将来在头颈放疗中进行个性化边缘减少和评估与辐射相关的吞咽困难的应用。
方法
对 21 例接受口咽癌根治性放疗的患者进行了头颈部 2D FSPGR-MR 电影扫描。纳入的患者在放疗前、放疗中和放疗后至少有一次电影扫描，共有 52 次电影扫描。从至少一个吞咽周期的连续电影扫描帧中手动勾画 7 个与吞咽相关的感兴趣区域（ROI）的轮廓，包括咽缩肌、会厌、舌根、颏舌肌、舌骨、软腭和喉。我们应用一种改进的薄板样条鲁棒点匹配算法自动在各帧之间配准各 ROI 的点集。然后，使用配准的变形向量场来估计各 ROI 在吞咽过程中的运动。通过比较变形轮廓和手动轮廓来估计配准误差。
结果
平均对每一电影扫描的 22 个帧进行了勾画。对一电影扫描（22 帧 7 个 ROI）的配准平均耗时约 22 分钟。在绘制完轮廓后，无需人工干预即可成功批量处理 8018 次配准。所有 ROI 和所有患者的平均配准误差为 0.36mm（范围：0.06mm-2.06mm）。在所有考虑的结构中，喉的平均运动最大，向上方向为 0.0mm-58.7mm。颏舌肌是所有 ROI 中运动最小的，所有 ROI 的上下运动均大于前后运动。
结论
我们开发并验证了一种变形配准框架，用于从 2D MR 电影扫描中自动估计吞咽运动。
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