CT Scan Risks

 

What are the risks of a CT scan?

CT scan is a very low-risk procedure.

• The patient will be exposed to radiation when undergoing a CT scan. However, it is a safe level.
• The biggest potential risk is with a contrast (also called dye) injection that is sometimes used in CT scanning. This contrast can help distinguish normal tissues from abnormal tissues. It also helps to help distinguish blood vessels from other structures such as lymph nodes. Like any medication, some people can have a serious allergic reaction to the contrast. The chance of a fatal reaction to the contrast is about 1 in 100,000. Those at increased risk may require special pretreatment and should have the test in a hospital setting. Anyone who has had a prior contrast reaction or severe allergic reaction to other medications, has asthma or emphysema, or has severe heart disease is at increased risk for a contrast reaction and is referred to a hospital X-ray department for the exam. Besides an allergic reaction, the intravenous dye can damage the kidneys, particularly if an individual already has marginal kidney disease. Usually, the patient is advised to drink plenty of fluids to help flush the dye out of their system.
• Any time an injection is done into a vein, there is a risk of the contrast leaking outside of the vein under the skin. If a large amount of contrast leaks under the skin, in rare cases, this can cause the skin to break down.

CT Scan Preparation

If a patient is going to have a contrast injection, he or she should not have anything to eat or drink for a few hours before the CT scan because the injection may cause stomach upset. To receive the contrast injection, an IV is inserted into the arm just prior to the scan. The contrast then enters the body through the IV.

Prior to most CT scans of the abdomen and pelvis, it is important to drink an oral contrast agent that contains dilute barium. This contrast agent helps the radiologist identify the gastrointestinal tract (stomach, small and large bowel), detect abnormalities of these organs, and to separate these structures from other structures within the abdomen. The patient will be asked to drink slightly less than a quart spread out over 1.5 to 2 hours.