MRI is an abbreviation for magnetic resonance imaging, a medical imaging technique that uses hydrogen protons in the human body to produce magnetic resonance phenomena under the action of specific radiofrequency pulses, and can be used to examine various systems throughout the body. It is more widely used clinically and has the advantages of no harmful radiation, high soft tissue resolution, multi-parameter and multi-sequence imaging, and no contrast agent. Compared to X-rays, MRI has the advantage of multi-parametric, multi-sequence, which helps in the detection, diagnosis and identification of diseases. MRI also has the advantage of being able to display fluid-containing duct systems, such as the gastrointestinal tract, without the use of any contrast agents, so MRI can clearly reflect the state of blood perfusion, which can be useful for some precise Therefore, MRI can clearly reflect the state of blood perfusion and accurately reflect the congestion and ischemia in some precise areas. In addition, MRI does not cause radioactive damage to the body and is safer than traditional CT and X-ray imaging. However, MRI is more expensive than X-rays and CT, and the examination time is longer, usually 10-30 minutes for one part of the body, so it requires a high degree of patient cooperation. In addition, patients with metal implants in their bodies, such as pacemakers, and patients who need to carry monitors for long periods of time should avoid MRI examinations, so it is not completely universal.