MSCT Lung Perfusion Imaging Based on Multi-stage Registration

摘要

We propose a novel subtraction-based method for visualizing segmental and subsegmental pulmonary embolism. For the registration of a pair of CT angiography, a proper geometrical transformation is found through the following steps: First, point-based rough registration is performed for correcting the gross translational mismatch. The center of inertia (COI), apex and hilar point of each unilateral lung are proposed as the reference point. Second, the initial alignment is refined by iterative surface registration. Third, thin-plate spline warping is used to accurately align inner region of lung parenchyma. Finally, enhanced vessels are visualized by subtracting registered pre-contrast images from post-contrast images. To facilitate visualization of parenchymal enhancement, color-coded mapping and image fusion is used. Our method has been successfully applied to four pairs of CT angiography.