Magnetic resonance imaging, referred to as nuclear magnetic resonance, magnetic resonance or nuclear magnetic resonance, is a brand-new imaging technology developed in the 1980s. Its full name is: Magnetic Resonance Computed Tomography (MRl) is a new medical imaging technology that uses magnetic resonance imaging technology for medical diagnosis. Nuclear magnetic resonance is a physical phenomenon, which was discovered by Blauch and Xiangsel in the United States as early as 1946. As an analytical method, it is widely used in physics, chemistry and other fields to study the molecular structure of substances. It was not until 197 1 year that an American, Damandian, proposed to use nuclear magnetic resonance in medical diagnosis. At that time, the scientific community did not accept it. However, it only took 10 years, and by 198 1 year, the whole body NMR image was obtained. So that people's long-standing dream, not only to obtain detailed diagnostic images of living organs and tissues, but also to monitor chemical components and reactions in living organs and tissues, has finally come true. Nuclear magnetic resonance is completely different from traditional X-ray and CT. This is a biological magnetic spin imaging technology. Hydrogen atoms in all parts of the human body are excited by radio frequency pulses in an external strong magnetic field, resulting in nuclear magnetic resonance. After space coding technology, the detector detects and receives the nuclear magnetic resonance signal released in electromagnetic form and inputs it into the computer. After data processing and conversion, the morphology of human tissue is finally imaged for diagnosis. The images obtained by nuclear magnetic resonance are unusually clear, fine, high in resolution, good in contrast and rich in information, especially at the soft tissue level. It makes doctors as clear as directly seeing the internal tissues of human body, and greatly improves the diagnostic efficiency. It avoids exploratory diagnostic operations such as craniotomy, thoracotomy, laparotomy and so on, which were carried out many times before because of unclear preoperative diagnosis, so that patients can avoid unnecessary surgical pain and side injuries and complications caused by exploratory operations. Therefore, it has been welcomed by imaging workers and clinicians as soon as it appeared, and has been widely used in clinic. The diagnosis of some diseases has become an indispensable means of examination. The information provided by nuclear magnetic resonance is not only greater than many other imaging technologies in medical images, but also different from the existing imaging technologies. This is a revolutionary imaging diagnosis technology. Therefore, it has great potential advantages in disease diagnosis. In 1980s, the American government began to approve the commercial production of nuclear magnetic resonance machines and began its clinical application. Since China introduced the 1 NMR machine from 1985, more than 1000 NMR machines have been put into operation. At present, doctors are more and more aware of its important role in diagnosing various diseases, and its application scope is becoming more and more extensive. Modern MRI has developed to more than 3.0, and three-dimensional MRI has also appeared, which greatly improves the diagnostic level.