Cardiac mr usually refers to MRI, the imaging principle is more complex so the information obtained is richer. MRI can clarify the relationship of the mass to the surrounding tissue and the nature of the mass. MRI is a non-invasive technique used in people of all ages, and cardiac MRI can show good soft tissue contrast resolution. The scanning field of view is relatively large and oblique cross-sectional images can be obtained from all angles. Cardiac mr is a complex and comprehensive examination, observing the morphology and motion of the heart in turn allows myocardial perfusion. The examination is performed with an understanding of the anatomical relationships of the heart, knowledge of common cardiac disorders and clinical knowledge, and relevant procedures and parameters. Indications include myocardial infarction, vascular disease, identifying and analyzing the anatomy and condition of congenital heart disease.