MRI is sensitive to changes in the water content of tissue components and can show changes in physiological and biochemical information such as function and metabolic processes. It has enabled the development of the body’s tissues from a purely anatomical image to a “chemical image” combining anatomy with changes in biochemical and physical properties of tissues, providing a diagnostic basis for some early lesions. It is often more effective and earlier than CT in detecting lesions. MRI can show the gray and white matter of the brain and spinal cord very clearly, so it is better than CT in the diagnosis of neurological diseases, and better than CT for cranial, spinal and spinal cord diseases, which is incomparable to CT; MRI, like the current spiral CT, can directly display any angle of the human body as needed, and can directly make cross-sectional, sagittal, coronal and various oblique images of the body MRI has several times higher soft tissue resolution than CT, and the pictures taken by high-powered MRI machines are so clear that even the tiny blood vessels in the tissues can be seen; MRI does not produce ionizing radiation that is damaging to the human body like CT, so there is no adverse effect on the body, and even when pregnant women receive MRI examinations, there is no adverse effect on the fetus; MRI has three characteristic parameters, while MRI has three characteristic parameters, while CT has only one physical parameter, the attenuation of X-ray beam through biological tissues, so the MRI leakage rate is lower than CT; MRI can obtain good soft tissue contrast without contrast agent, and can show the structure of blood vessels, so it is unique in the mutual identification of blood vessels, masses, lymph nodes and vascular structures, and it also avoids allergic reactions that may be caused by contrast agent; MRI does not produce the bone artifacts in CT detection. MRI does not produce the bony artifacts in CT, and can clearly visualize the spinal cord and nerve roots in the spine, and may detect tissue damage due to ischemia. MRI is suitable for almost all systems of different diseases, such as tumors, inflammation, trauma, degenerative diseases and various congenital diseases. MRI also has shortcomings, compared with CT, the main shortcomings include: the scanning and imaging time is long, and it takes more than 10 minutes to scan one part of the spine. It takes more than 10 minutes to image a part of the body, which requires the patient to lie motionless in the examination machine for such a long time, making it difficult to complete the examination successfully for patients with severe pain or severe limb twitching due to spinal cord damage. Due to the long scanning and imaging time, it is easy to affect the imaging quality when the patient is slightly moving during the examination. It is the same as when we take ordinary pictures, the image is fuzzy because of the shaking of the object being photographed. The spatial resolution of MRI is low, only 2 mm, and the activity makes the resolution even lower, so the diagnosis of active organs such as the heart is less effective; the ability to display bone tissue is worse than CT, and it is not as clear as CT when observing the degeneration of bone tissue such as cervical spine spurs, ligament calcification and spinal stenosis, but it is better than CT in showing the compression of spinal nerve roots after the change of these bone tissue degeneration; due to the ferrous metal Because of the magnetic field reaction of ferrous metals, patients with pacemakers or parts of the body with certain metals cannot be examined by MRI, such as after internal fixation of the spine and other parts, after artificial joint surgery, after surgery. After surgery with sutures, women with metal contraceptive rings, women with dentures, and other cases where there are metal foreign bodies in the body. However, since titanium metal has no magnetic field reaction, titanium metal internal fixation, which is being gradually promoted in orthopedic internal fixation surgery, can be subjected to MRI; there must be a special room for MRI installation, which must be anti-magnetic and anti-electric interference, and there are special requirements for the temperature, humidity and cooling system in the room, requiring the temperature to be 20-25℃, and the difference between the upper and lower cannot exceed 1℃. The acquisition and maintenance cost of MRI machine is much higher than that of CT, resulting in the cost of MRI examination is much higher than that of CT examination, the cost of one part of MRI examination is 800-1300 yuan, while CT is only 180-600 yuan; the operation and maintenance cost is high, about 400,000 degrees of electricity is consumed in a year, only the electricity cost is several tens of thousands of RMB. It also requires liquid helium, liquid nitrogen, heavy water and other materials. When MRI is performed, the patient needs to lie in a long and narrow space for a long time, and the noise is so loud that some people who are “claustrophobic” may have a sense of fear and have difficulty in completing the examination. In summary, although MRI has many advantages, there are also limitations of varying degrees. Therefore, MRI should not be overly dependent and superstitious, but should be used reasonably according to the characteristics of MRI, clinical requirements and different conditions of the patient, and each MRI image should be carefully analyzed objectively and comprehensively in relation to anatomical pathology and clinical conditions.