Division of Radiation Oncology, The University of Texas M D Anderson Cancer Center, Houston, TX, USA.
Phys Med Biol. 2010 Jan 7;55(1):305-27. doi: 10.1088/0031-9155/55/1/018.
A four-dimensional deformable image registration (4D DIR) algorithm, referred to as 4D local trajectory modeling (4DLTM), is presented and applied to thoracic 4D computed tomography (4DCT) image sets. The theoretical framework on which this algorithm is built exploits the incremental continuity present in 4DCT component images to calculate a dense set of parameterized voxel trajectories through space as functions of time. The spatial accuracy of the 4DLTM algorithm is compared with an alternative registration approach in which component phase to phase (CPP) DIR is utilized to determine the full displacement between maximum inhale and exhale images. A publically available DIR reference database (http://www.dir-lab.com) is utilized for the spatial accuracy assessment. The database consists of ten 4DCT image sets and corresponding manually identified landmark points between the maximum phases. A subset of points are propagated through the expiratory 4DCT component images. Cubic polynomials were found to provide sufficient flexibility and spatial accuracy for describing the point trajectories through the expiratory phases. The resulting average spatial error between the maximum phases was 1.25 mm for the 4DLTM and 1.44 mm for the CPP. The 4DLTM method captures the long-range motion between 4DCT extremes with high spatial accuracy.
提出并应用于胸部 4DCT 图像集的一种四维形变图像配准（4D DIR）算法，称为 4D 局部轨迹建模（4DLTM）。该算法所基于的理论框架利用 4DCT 分量图像中的增量连续性，计算出一组密集的参数化体素轨迹，这些轨迹作为时间的函数通过空间。4DLTM 算法的空间精度与另一种配准方法进行了比较，该方法利用相位到相位（CPP）DIR 来确定最大吸气和呼气图像之间的完全位移。利用一个公共的 DIR 参考数据库（http://www.dir-lab.com）进行空间精度评估。该数据库包含十个 4DCT 图像集和最大相位之间的手动识别地标点。将一部分点传播到呼气 4DCT 分量图像中。发现三次多项式可以提供足够的灵活性和空间精度来描述通过呼气阶段的点轨迹。4DLTM 和 CPP 的最大相位之间的平均空间误差分别为 1.25mm 和 1.44mm。4DLTM 方法以高精度捕捉 4DCT 极值之间的长程运动。
