Motion Correction for Liver DCE-MRI with Time-Intensity Curve Constraint

Motion correction is a fundamental preprocessing step for liver dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), which can help accurate diagnosis of benign and malignant tumors. Previous studies have difficulty in aligning small structures, e.g., tumors and vessels, due to the remarkable intensity changes over different images. Except for measuring physiologic parameters in DCE-MRI, the time-intensity curves (TICs) can also be used to constrain the alignment of small anatomical structures such as small tumors and vessels. In this work, we propose a coarse-to-fine motion correction scheme with smoothness constraint of TICs to correct the motion in liver DCE-MRI. Specifically, the proposed motion correction scheme consists of two major stages. First, different time point images are registered to the selected fixed image pairwisely via a fully convolutional network (FCN), which outputs their corresponding coarse displacement vector fields (DVFs). Second, all of the coarse DVFs are further refined simultaneously under the group similarity of the warped time points and the fixed image, together with the smoothness constraint of TICs at a fine level. To our knowledge, our work is the first in constraining the motion correction using TICs for better alignment of small structures. Experimental results on liver DCE-MRI demonstrate that our proposed method can obtain a more accurate alignment of small structures (e.g., tumors and vessels) than state-of-the-art methods.