4D-CT lung motion estimation with deformable registration: Quantification of motion nonlinearity and hysteresis
4D-CT lung motion estimation with deformable registration: Quantification of motion nonlinearity and hysteresis
复制标题
DOI：
10.1118/1.2839103
复制
发表时间：
2008-03-01
期刊：
影响因子：
3.8
通讯作者：
Sarrut, David
中科院分区：
文献类型：
--
作者：
Boldea, Vlad;Sharp, Gregory C.;Sarrut, David
在本文中，我们的目标是双重的。首先，我们提出并比较了两种方法，处理变形登记估计患者特定的肺和肿瘤的位移和变形，在自由呼吸的四维计算机断层扫描（4D-CT）数据。其次，我们提出了技术来量化运动非线性和滞后的生理参数。一个基于Frechet距离的标准被引入到测量的运动滞后。实验采用5例接受放疗的非小细胞肺癌患者的4D-CT数据。根据专家选择的标志评估的变形场的准确性被发现在图像体素公差范围内。第二种方法在准确性和一致性方面的结果略好，尽管两种方法之间的差异在统计学上并不显著。肺运动非线性和滞后是患者特异性的，并且在呼吸期间在肺内的区域上变化。对于所有患者，呼气末和吸气末之间的运动很好地近似于大多数肺点的直线轨迹。滞后被认为是全球相关的轨迹长度。所提出的方法的主要限制是，基于强度的可变形配准是依赖于图像质量和图像分辨率。另一个限制是缺乏金标准，这使得计算的运动的验证困难。然而，所提出的工具提供了患者特定的运动信息，例如在放射治疗中，可以简化精确内部边缘的定义。在未来，来自多个患者的生理信息的整合可以帮助创建具有不同临床应用的通用肺图谱。(c)2008年美国医学物理学家协会。
In this article, our goal is twofold. First, we propose and compare two methods which process deformable registration to estimate patient specific lung and tumor displacements and deformation during free breathing from four-dimensional computed tomography (4D-CT) data. Second, we propose techniques to quantify the physiological parameters of motion nonlinearity and hysteresis. A Frechet distance-based criterion is introduced to measure the motion hysteresis. Experiments were conducted with 4D-CT data of five patients treated in radiotherapy for non-small cell lung cancer. The accuracy of deformation fields assessed against expert-selected landmarks was found to be within image voxel tolerance. The second method gave slightly better results in terms of accuracy and consistency, although the differences were not statistically significant between the two methods. Lung motion nonlinearity and hysteresis are patient specific, and vary across regions within the lung during respiration. For all patients, motion between end-exhale and end-inhale was well approximated with a straight line trajectory for the majority of lung points. Hysteresis was found to be globally correlated with trajectory length. The main limitation to the proposed method is that intensity-based deformable registration is dependent on image quality and image resolution. Another limitation is the absence of gold standard which makes the validation of the computed motion difficult. However, the proposed tools provide patient specific motion information which, in radiotherapy for example, can ease the definition of precise internal margins. In the future, the integration of physiological information from multiple patients could help to create a general lung atlas with different clinical applications. (c) 2008 American Association of Physicists in Medicine.