Free-Breath DCE MRI for Solitary Pulmonary Nodule with Motion Correction Based on Non-Rigid Image Registration

Introduction Dynamic contrast-enhanced (DCE) MRI has proven valuable to characterize tissue of interest in solitary pulmonary nodule (SPN) [1], especially for delineating malignant from benign tumor. In DCE MRI studies, the kinetics of signal variation at lesions following the administration of the contrast agent is analyzed from time-intensity curve. Thus, it is crucial to measure the signal intensity at the corresponding regions in each frame in the time-series of images for accurate signal intensity curve analysis. However, the respiratory motion of the subjects during scans causes misalignment of anatomical regions among the frames resulting inaccuracy of time-intensity curve. Furthermore, the misalignment makes it impossible to perform pixel-by-pixel analysis to obtain distribution of kinetic parameters. To overcome the issue, several studies have demonstrated free-breath lung DCE MRI incorporating motion correction based on rigid image registration techniques [2,3]. We examined a free-breath lung perfusion analysis of patients with SPN using motion compensation technique based on deformable registration.