Magnetic resonance imaging (MRI) is an imaging technique that uses signals generated by the collection of magnetic resonance phenomena to reconstruct images. MRI is another major development in the field of medical imaging as it can visualize certain lesions that cannot be shown by CT. It is a new diagnostic imaging technology that was applied to clinical practice only in the early 1980s. Compared with CT, it has the unique advantages of no radiological damage, no bony artifacts, multifaceted and multiparametric imaging, high soft tissue resolution, and the ability to show vascular structures without the use of contrast. It is suitable for the examination of different diseases in almost all systems of the body, such as tumors, inflammation, trauma, degenerative lesions and various congenital diseases. It can show the structure of blood vessels without the use of angiographic contrast, so it is unique for the mutual identification of blood vessels, masses, lymph nodes and vascular structures. MRI can clearly and comprehensively display the heart chambers, myocardium, pericardium and other small structures within the heart, and is a reliable method for diagnosing various heart diseases as well as cardiac function tests.