Magnetic resonance examination is a tomographic examination that divides the human body into layers of images from sagittal, coronal or axial imaging. The imaging principle is to place the human body in a special magnetic field and produce images through resonance of hydrogen atomic nuclei, but PET-CT is different, it is a nuclear medicine imaging method that injects nuclear radioactive nuclear elements into the human body and collects images through the emission of rays from the human body, so PET-CT is a coarse image that reflects the body at the metabolic level. It is generally used clinically nowadays to check tumor diseases or whether tumors have metastases throughout the body, and is more widely used. Magnetic resonance imaging and PET-CT imaging, two imaging methods are completely different, imaging methods, image analysis are different, so in the clinical application of the scope is different, do not confuse these two examination methods.