The most commonly used clinical examination of the heart is an ultrasound or coronary CTA. Magnetic resonance imaging can also be used for cardiac examinations to understand the size of the heart, the condition of the heart valves, and the presence of regurgitation or insufficiency of closure. MRI can also determine whether there is ischemia in the heart muscle or the degree and extent of myocardial infarction based on myocardial perfusion. However, the determination of myocardial ischemia is not as good as ECT or PET-CT cardiac perfusion. Although MRI can be used for cardiac examination, it is relatively not used much in clinical practice at present because of the very long examination time of MRI and the fact that the heart beat will affect the accuracy of the examination. However, MRI can do cardiac coronary imaging without contrast, and it is a good choice for patients with iodine allergy when they need to check their cardiac coronary arteries.