MRI refers to magnetic resonance imaging. MRI not only provides more information than many other imaging techniques in medical imaging, but also differs from existing imaging techniques, so it has the following potential advantages for disease diagnosis: 1. MRI has good soft tissue resolution, especially in the nervous system and bone and joint system, and the bone and joint, cartilage, and ligament levels are clearly defined, which is significantly better than CT; 2. Very accurate localization It can be multi-planar and multi-parametric imaging. Multi-planar imaging can clearly show where the disease is located, its scope and the relationship with the surrounding organs. Multi-parametric imaging can better determine the lesion and tissue composition, which helps to diagnose the lesion; 3, no contrast agent can be used for vascular imaging, especially for patients with poor heart and kidney function, which can avoid contrast agent side effects; 4, MRI does not have ionizing radiation, so it can be repeatedly examined for many times.