Whether CT requires fasting needs to be judged according to the type of examination and the part of the examination, generally cranial brain, chest, limbs CT does not require fasting, abdominal CT, CT enhancement, CT imaging, etc. requires fasting. Usually in clinical examination, CT of the central system, eyes, ears, nose and sinuses, pharynx, larynx and other parts of the CT and limbs of the skeletal muscle CT does not need fasting. While abdominal CT mainly observes the organs in the abdominal cavity, enhanced CT requires intravascular injection of contrast agent before scanning, CT contrast refers to the imaging of an organ or structure before scanning, and these CT examinations often need to be performed on an empty stomach. It is recommended that patients undergo a detailed physical examination before the CT, choose the appropriate modality according to their actual situation under the guidance of the doctor, and inquire about the details of the examination in advance.