title: Cardiac Image Reconstruction via Nonlinear Motion Correction Based on Partial Angle Reconstructed Images.
abstract: Even though the X-ray Computed Tomography (CT) scan is considered suitable for fast imaging, motion-artifact-free cardiac imaging is still an important issue, because the gantry rotation speed is not fast enough compared with the heart motion. To obtain a heart image with less motion artifacts, a motion estimation (ME) and motion compensation (MC) approach is usually adopted. In this paper, we propose an ME/MC algorithm that can estimate a nonlinear heart motion model from a sinogram with a rotation angle of less than 360°. In this algorithm, we first assume the heart motion to be nonrigid but linear, and thereby estimate an initial 4-D motion vector field (MVF) during a half rotation by using conjugate partial angle reconstructed images, as in our previous ME/MC algorithm. We then refine the MVF to determine a more accurate nonlinear MVF by maximizing the information potential of a motion-compensated image. Finally, MC is performed by incorporating the determined MVF into the image reconstruction process, and a time-resolved heart image is obtained. By using a numerical phantom, a physical cardiac phantom, and an animal data set, we demonstrate that the proposed algorithm can noticeably improve the image quality by reducing motion artifacts throughout the image.
authors.forename: Seungeon
authors.initials: S
authors.lastname: Kim
authors.forename: Yongjin
authors.initials: Y
authors.lastname: Chang
authors.forename: Jong Beom
authors.initials: JB
authors.lastname: Ra
mesh_terms: D000465:Algorithms; D000818:Animals; D016477:Artifacts; D006321:Heart; D007091:Image Processing, Computer-Assisted; D009038:Motion; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed