The basic principle of MRI is that a signal is generated when hydrogen protons in the body resonate within a static magnetic field by magnetic field interference. Abnormal signals represent changes in the original composition or ratio within the cellular tissue, suggesting the occurrence of inflammation, ischemia, infarction, necrosis, edema and hemorrhage. If a tumor is detected, a comparative analysis is performed on each sequence according to the hint of abnormal signals, comparing the signal changes after scanning and enhancement examinations to clarify whether the disease is caused by physiological changes or other factors.