The influence of non‐rigid anatomy and patient positioning on endoscopy‐CT image registration in the head and neck
The influence of non‐rigid anatomy and patient positioning on endoscopy‐CT image registration in the head and neck
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非刚性解剖和患者体位对头颈部内窥镜-CT 图像配准的影响
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
L. Court
中科院分区：
文献类型：
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作者：
S. Ingram;Jinzhong Yang;R. Wendt;B. Beadle;A. Rao;Xin A. Wang;L. Court
目的：评估非刚性解剖结构以及 CT 采集和内窥镜检查之间患者体位差异对头颈部内窥镜 CT 图像配准的影响。方法：获取 19 名患者的放射治疗计划 CT 和每日 31-35 次治疗室 CT。为 13 名患者获取了诊断 CT。在所有扫描中对气道表面进行分割，并创建三角形网格，以使用内窥镜的校准针孔模型渲染虚拟内窥镜图像。虚拟图像用于在整个网格中进行投影测量，参考测量定义为在计划 CT 上进行的测量，测试测量定义为在日常或诊断 CT 上进行的测量。非刚性解剖结构的影响通过日常 CT 上的参考测量值和测试测量值之间的 3D 距离误差来量化，并且通过诊断 CT 上的参考测量值和测试测量值之间的 3D 距离误差来量化患者体位的影响。每日 CT 测量还用于研究相机到表面距离、表面角度和扫描时间间隔的影响。结果：鼻腔每日 CT 平均误差为 0.36 ± 0.61 cm，鼻和口咽为 0.58 ± 0.83 cm，下咽和喉为 0.47 ± 0.73 cm。这些区域诊断 CT 的平均误差分别为 0.52 ± 0.69 cm、0.65 ± 0.84 cm 和 0.69 ± 0.90 cm。尽管存在较大的异常值，但所有 CT 的误差都严重偏向 0。研究发现，相机到表面的距离较大会增加误差，但相机观察表面的角度没有影响。第 1 天和第 15 天 CT 的误差明显小于第 30 天 CT 的误差（P < 0.05）。结论：患者体位的不一致对投影测量误差的影响比非刚性解剖结构更大。一般来说，当相机位于上咽部时，这些误差最大，因为它可以看到很远的距离和大量的肌肉运动。 CT采集的时间间隔越长，误差越大，这表明CT采集和内镜检查之间的时间间隔应保持较短。本研究中发现的中值误差与可变形 CT 配准中可接受的不确定性水平相当。即使图像对准非常好，也可能出现较大误差，这表明必须仔细进行投影测量以避免这些异常值。
Purpose: To assess the influence of non‐rigid anatomy and differences in patient positioning between CT acquisition and endoscopic examination on endoscopy‐CT image registration in the head and neck. Methods: Radiotherapy planning CTs and 31–35 daily treatment‐room CTs were acquired for nineteen patients. Diagnostic CTs were acquired for thirteen of the patients. The surfaces of the airways were segmented on all scans and triangular meshes were created to render virtual endoscopic images with a calibrated pinhole model of an endoscope. The virtual images were used to take projective measurements throughout the meshes, with reference measurements defined as those taken on the planning CTs and test measurements defined as those taken on the daily or diagnostic CTs. The influence of non‐rigid anatomy was quantified by 3D distance errors between reference and test measurements on the daily CTs, and the influence of patient positioning was quantified by 3D distance errors between reference and test measurements on the diagnostic CTs. The daily CT measurements were also used to investigate the influences of camera‐to‐surface distance, surface angle, and the interval of time between scans. Results: Average errors in the daily CTs were 0.36 ± 0.61 cm in the nasal cavity, 0.58 ± 0.83 cm in the naso‐ and oropharynx, and 0.47 ± 0.73 cm in the hypopharynx and larynx. Average errors in the diagnostic CTs in those regions were 0.52 ± 0.69 cm, 0.65 ± 0.84 cm, and 0.69 ± 0.90 cm, respectively. All CTs had errors heavily skewed towards 0, albeit with large outliers. Large camera‐to‐surface distances were found to increase the errors, but the angle at which the camera viewed the surface had no effect. The errors in the Day 1 and Day 15 CTs were found to be significantly smaller than those in the Day 30 CTs (P < 0.05). Conclusions: Inconsistencies of patient positioning have a larger influence than non‐rigid anatomy on projective measurement errors. In general, these errors are largest when the camera is in the superior pharynx, where it sees large distances and a lot of muscle motion. The errors are larger when the interval of time between CT acquisitions is longer, which suggests that the interval of time between the CT acquisition and the endoscopic examination should be kept short. The median errors found in this study are comparable to acceptable levels of uncertainty in deformable CT registration. Large errors are possible even when image alignment is very good, indicating that projective measurements must be made carefully to avoid these outliers.
影响因子：
19.7
作者：
Mohamed AS;Ruangskul MN;Awan MJ;Baron CA;Kalpathy-Cramer J;Castillo R;Castillo E;Guerrero TM;Kocak-Uzel E;Yang J;Court LE;Kantor ME;Gunn GB;Colen RR;Frank SJ;Garden AS;Rosenthal DI;Fuller CD
通讯作者：
Fuller CD