Whether or not you need to fast for a 64-row CT depends on the site of the exam and the requirements of the exam. Fasting is required if the examination is performed on the upper abdomen, such as the stomach or gallbladder. Fasting is also required before an enhanced CT or angiogram. Fasting is required for upper abdominal examinations because if there is still food residue in the stomach, it is not easy to visualize the structure of the stomach wall, and it is easy to confuse the food residue with the stomach wall, making it difficult to detect underlying disease and miss the diagnosis; the gallbladder shrinks after eating, and the structure of the gallbladder is not easy to visualize in the imaging, which is also prone to miss the diagnosis. Enhanced CT and angiography both require injection of contrast medium, which can cause nausea and vomiting. Fasting can prevent the reflux of vomitus into the trachea caused by the contrast medium, which can lead to lung infection or even choking. 64-row CT belongs to the energy spectrum CT, the basic configuration of 64 rows of detector array, scanner scanning week the shortest time of 0.35 seconds, and has a spectrum of imaging function, belongs to the more advanced one CT.