Accurate estimation of pulmonary nodule's growth rate in CT images with nonrigid registration and precise nodule detection and segmentation

We propose a new tumor growth measure for pulmonary nodules in CT images, which can account for the tumor deformation caused by the inspiration level's difference. It is accomplished with a new nonrigid lung registration process, which can handle the tumor expanding/shrinking problem occurring in many conventional nonrigid registration methods. The accurate nonrigid registration is performed by weighting the matching cost of each voxel, based on the result of a new nodule detection approach and a powerful nodule segmentation algorithm. Comprehensive experiments show the high accuracy of our algorithms and the promising results of our new tumor growth measure.