Magnetic Resonance Imaging (MRI) is also called MRI technology. It is another major advancement in medical imaging after CT. Since its application in the 1980s, it has been developed at a very fast pace. Its basic principle: it is to place the human body in a special magnetic field and excite the nucleus of hydrogen atoms in the human body with radio frequency pulses, causing the nucleus of hydrogen atoms to resonate and absorb energy. After stopping the radio frequency pulse, the hydrogen nucleus emits radio signals at a specific frequency and releases the absorbed energy, which is collected by the receiver outside the body and processed by an electronic computer to obtain an image, which is called MRI. Nuclear magnetic resonance is a physical phenomenon that is widely used as a means of analysis in the fields of physics, chemistry and biology, and it was only in 1973 that it was used in medical clinical testing. To avoid confusion with radiography in nuclear medicine, it is referred to as magnetic resonance imaging (MRI). It has great potential superiority for the diagnosis of diseases. Free of ionizing radiation and without adverse effects on the organism, MRI is very effective in detecting common cranio-cerebral diseases such as intracerebral hematomas, extracerebral hematomas, brain tumors, intracranial aneurysms, arteriovenous malformations, cerebral ischemia, intravertebral tumors, spinal cord cavernosity and spinal fluid, as well as in the diagnosis of posterior lumbar disc protrusion and primary liver cancer. MRI also has shortcomings. The spatial resolution of MRI is not as good as that of CT, and MRI cannot be performed in patients with pacemakers or in areas with certain metallic foreign bodies, and it is more expensive. Indications Neurological lesions including tumors, infarcts, hemorrhages, degeneration, congenital malformations, and infections are almost always the means of confirming the diagnosis. In particular, lesions of the spinal cord spine such as tumors, atrophy, degeneration, and traumatic disc lesions of the spine have become the preferred method of examination. Lesions of the large blood vessels of the heart; lesions of the mediastinum within the lungs. The examination of abdominal pelvic organs; biliary system, urinary system, etc. is significantly better than CT; for soft tissue lesions of joints; very sensitive to bone marrow, aseptic necrosis of bone, lesions are detected earlier than X-rays and CT. because of its large range of tissue density contrast. In the diagnosis of bone, joint and soft tissue lesions, magnetic resonance imaging has several times more imaging parameters and high soft tissue resolution than CT, which makes its contrast of soft tissue significantly higher than CT.