• Patient should fast for about four hours if intravenous contrast (a medication that enhances and better define blood vessels and accentuate the appearance between normal and abnormal tissue in organs and helps detection of abnormalities) injection is required. Most studies do require this injection.
• Please inform staff if you have any history of drug or other allergies.
• Please be punctual for your appointment.

• You will be asked if you have any history of allergies or impaired kidney functions.
• Informed consent will be obtained if intravenous contrast is required.
• If the CT is to examine your abdomen, you will be asked to drink a liquid contrast material that will enable better visualisation of the stomach and bowels.  Usually it will be necessary for you to wait up to one hour while the contrast material reaches the bowels. If the lower bowels are to be studied, we may require to administer contrast material by enema.
• An intravenous injection line may be set up in preparation for the injection of contrast. 
• You will be positioned on a padded table and moved into the scanner.
• The radiographer will be able to see and hear you at all times.
• You may be asked to hold your breath, a few times, during the scan. It is important to follow the instructions given to ensure that the examination is successful.
• If the intravenous injection is given, a warm sensation will be felt as the injection goes through the body. Some people report feeling a flush of heat or a metallic taste at the back of the mouth. These sensations usually disappear within a minute or two.
• Depending on the parts to be examined, the total examination from preparation could be from 15 minutes to 90 minutes.

BENEFITS

• Unlike other imaging methods, CT scanning offers detailed views of many types of tissue, including the lungs, bones, soft tissues and blood vessels.
• CT scanning is painless, non-invasive and accurate.
• CT examinations are fast and simple. For example, in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.
• CT scanning can identity both normal and abnormal structures, making it a useful tool to guide radiotherapy, needle biopsies and other minimally invasive procedures.
• CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.

RISKS

• CT does involve exposure to radiation in the form of x-ray, but the benefit of an accurate diagnosis far outweighs the risk. The effective radiation dose from this procedure is small and varies with the type of examination but generally is about the same as what the average person receives from background radiation from the sun and atmosphere every year.

• Women should always inform their doctor or nurse or radiographer if there is any possibility that they are pregnant.

• Nursing mothers should wait for 24 hours after contrast material injection before resuming breast feeding.

• The risk of severe allergic reaction is 1 in 10,000.

• ACR and RSNA Radiology Info