Abstract

Info

Title:: A preprocessing-based method for deformation registration of planned CT and online CT

Author(s):: LIU Huan; YU Gang; LU Yukun; LI Dengwang; School of Physics and Electronics, Shandong Normal University; Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Ji’nan 250000, China

Keywords:: planned CT; online CT; image registration; Demons algorithm; preprocessing; segmentation

Abstract:: During CT scanning, the existence of water-soluble iodine contrast agent makes the HU values of the blood vessels on planned CT images and online CT images deviate greatly, which leads to the mismatch between planned CT images and online CT images. Herein we propose a preprocessing-based method for the deformation registration between planned CT and online CT in order to solve the problem caused by water-soluble iodine contrast agent. Firstly, according to the information of tissues and structures on CT images, the blood vessels are segmented using threshold segmentation method, and the largest communicating region in all segmentations is taken as an initial segmented reinforcing blood vessel. Secondly, the segmented reinforcing blood vessel region is externally expanded by 5 mm as an expanded reinforcing blood vessel, and the blood vessel is filled with a fixed HU value. Finally, deformation registration of the filled image is carried out with the use of Demons algorithm. The results reveal that the deformation registration method with preprocessing can solve the problem of CT mismatch due to water-soluble iodine contrast agent.