Enhanced CT involves injecting a large dose of iodine-containing contrast agent from a vein for a short period of time, followed by a CT scan. The non-ionic iodinated contrast agent used is safe and adverse drug reactions are rare. However, a small number of patients may have allergic reactions due to their special physical condition or certain unpredictable factors. Most of them are mild allergic reactions, but a very small number of them may have severe allergic reactions, which may even be life-threatening. Therefore, before doing the enhanced CT examination, patients or their families need to sign an informed consent form to understand the contraindications to the use of contrast media and possible allergic reactions. Inform the doctor in time if there are special circumstances. The preparations needed before the examination include firstly, to avoid nausea and vomiting in a few people who are allergic to it, and asphyxiation caused by inhalation of vomitus into the airway. In order to avoid nausea and vomiting in a few people who are allergic and suffocation caused by inhalation of vomit into the airway, it is necessary to fast for at least 4 hours before the enhanced scan. Most hospitals now require an indwelling needle to be tied up in advance before an enhanced examination. Usually a family member needs to accompany the enhanced CT, so that the doctor can be informed in time in case of allergic reactions or accidents such as running needles. When doing the examination, the indwelling needle is first connected to the high-pressure syringe, and a flat scan is done first. After the flat scan, the medication and scanning will be completed according to a set program. Depending on the different requirements of the diagnosis the enhancement scan may be done in multiple phases, where multiple scans are done at different points in time to obtain images in different phases. For example, images of arterial phase, venous phase, and delayed phase. Drink plenty of water after an enhanced CT exam. Those who are unable to eat may be hydrated with an infusion of fluids for the purpose of facilitating the elimination of the contrast agent from the body.