Acute heart allograft rejection is a common complication after orthotopic heart transplantation. It can lead to multiple cardiac injuries and sometimes to patient's death. Currently, acute heart graft rejection screening is based on invasive strategies. Gold standard is represented by endomyocardial biopsies which provide side effects risk, rare but potentially fatal for the recipient. Cardiac MRI is an imaging tool recently used in cardiology. It is a non-invasive without any X-Ray exposition method well adapted to assess cardiac function and cardiac muscle composition. Cardiac MRI is probably a great tool to help the screening of acute heart allograft rejection, by detecting changes in myocardium structure. MRI validation as a screening tool for heart allograft rejection detection could help to reduce endomyocardial biopsies realised after orthotopic heart transplantation.