Unlocking 2D/3D+T myocardial mechanics from cine MRI: a mechanically regularized space-time finite element correlation framework

Accurate and biomechanically consistent quantification of cardiac motion remains a major challenge in cine MRI analysis. While classical feature tracking and recent deep learning methods have improved frame wise strain estimation, they often lack biomechanical interpretability and tem poral coherence. In this study, we propose a spacetime regularized finite element digital image/volume correlation (FE DIC/DVC) framework that enables 2D 3D+T myocardial motion tracking and strain analysis using only routine cine MRI. The method unifies Mu ltiview alignment and 2D/3D+T motion estimation into a coherent pipeline, combining region specific biomechanical regularization with data driven based temporal decomposition to promote spatial fidelity and temporal consistency . A correlation based Multiv i ew alignment module further enhances anatomical consistency across short and long axis views. We evaluate the approach on one synthetic dataset (with ground truth motion and strain fields), three public datasets (with ground truth landmarks or myocardial masks), and a clinical dataset (with ground truth myocardial masks). 2D+T motion and strain are evaluated across all datasets, whereas Multiview alignment and 3D+T motion estimation is assessed only on the clinical dataset. Compared with two classical feat ure tracking methods and four state of the art deep learning baselines, the proposed method improves 2D+T motion and strain estimation accuracy as well as temporal consistency on the synthetic data, achieving a displacement RMSE of 0.35 pixel (vs. 0.73 pixel), an equivalent strain RMSE of 0.05 (vs. 0.097), and a temporal consistency of 0.97 (vs. 0.91). On public and clinical data, it achieves superior performance in terms of a landmark error of 1.96 mm (vs. 3.15 mm), a boundary tracking Dice of 0.80 0.87 (a 2 4% improvement over the best performing baseline), and overall registration quality that consistently ranks among the top two methods By leveraging only standard cine MRI, this work enables 2D/3D+T myocardial mechanics and provides a practical route toward 4D cardiac function assessment.