基于4D—CT和变形图像配准获取肺通气功能的三维分布

目的获取基于4D—CT和变形图像配准方法，建立肺通气功能的三维分布阿像。方法在患者自由呼吸状态下进行肺部4D—CT图像采集和重建；用B样条三维变形配准算法，对4D—CT中不同相位的两个CT图像系列进行配准，获得三维变形场文件，再将该文件转换为雅可比行列式矩阵，根据其物理含义进行量化分析，得到任意横断面的通气分布图像。将此图像伪彩化后与CT图像融合，再进行任意冠状面、矢状面重建，从而得到直观的横断面、冠状面、矢状面三维方向的通气功能分布。将自动勾画并计算出的不同功能肺的体积，与吸气末和呼气末肺体积之差进行相关分析。结果实现了快速获得直观的肺通气功能的三维分布。结果表明，不同功能肺体积与呼吸过程中肺体积的最大变化显著相关（P〈0．05）。结论基于4D—CT和变形图像配准来获取肺通气功能的i维分布图像简便、快捷，具有可行性。

Study on 3D Distribution of Pulmonary Ventilation Based on 4D-CT and Deformation Image Registration

Objective To obtain 3D distribution images of pulmonary ventilation based on 4D-CT and deformation image registration （DIR）. Methods The 4D-CT data sets were acquired with patients in flee- breathing. 3D displacement vector field （DVF） of two different phase 4D-CT image pairs was calculated out by using 3D B-spline DIR algorithms, which was converted to Jacobian determinant. Then, the axial section of grayseale ventilation was obtained by quantitative analysis of the determinant. The pseudo-color was put on the axial grayseale ventilation before fused with the reference CT images. And based on the axial ventilation, the coronal and sagittal sections of venfflations can be reconstructed. Thus, 3D visualization ventilations have been implemented. The contours of the ventilation regions with different Jacobian values were delineated and the volumes of them were calculated. Results Based on 4D-CT images of patients in free-breathing and multi- resolution 3D B-spline DIP,, the 3D visualization ventilation can be easily obtained and quantified, The volume change of lung is significantly related with the volume of different ventilation regions at level 0.05 （bilateral）. Conclusion It is simple, convenient and feasible to obtain the 3D distribution of pulmonary ventilation based on the 4D-CT images and 3D B-spline DIR.