The Chinese name of MRI examination is Magnetic Resonance Imaging (MRI). The basic principle of MRI is to place the human body in a special magnetic field and to excite the hydrogen nucleus of the human body with radio frequency pulses, causing the nucleus to resonate and absorb energy. After special processing by a computer, the magnetic resonance images normally obtained for diagnosis are produced. Magnetic resonance imaging provides a large amount of information to the patient and can be used to diagnose diseases from coronal, sagittal and axial multi-directional imaging, which has more superiority than other examinations and facilitates clinical observation. In addition, it has no artifacts of bone or metal in CT scans, and there is no radiation to the patient, making the examination safe. Magnetic resonance examination is suitable for the neurological system, bone and muscle system, and also to see if there is any obstruction in the bile duct system, all are suitable for this examination of magnetic resonance.