Magnetic Resonance Imaging is a reference tool to assess myocardial function and viability, the two key measurements in clinics. However, several technical challenges remain. This thesis focuses on the development of new strategies to provide an efficient characterization of the myocardium. Using tools provided by MR physics and image processing a translational "bench-to-bedside" approach was adopted. Concerning the "bench", Manganese was studied as a contrast agent for myocardial viability assessment. A new cine sequence, "interleaved cine", was also developed to increase the time resolution and opens up the possibility of stress studies in mice on clinical scanners. In parallel, spiral imaging was applied to the "bedside". In the context of real-time imaging, the proposed reconstruction method, k-t SPIRE, takes into account the temporal information of data which helps to resolve the undersampling artifacts and showed important improvements compared to the classical method both in numerical simulations and in-vivo.