Why is a contrast agent used?
You are scheduled for an imaging test that might require us to inject a contrast agent into a vein in your arm.
Imaging tests such as X-rays, computed tomography (CT) scans, or magnetic resonance (MR) scans take pictures of what is inside you. The contrast agent (also called contrast media, contrast material, X-ray dye, or gadolinium contrast) shows up white on X-ray, CT, and MR images. This makes your organs, blood vessels, and tissues more visible, which helps us interpret these imaging studies.
What risks are involved in getting a contrast injection?
Contrast injections are considered to be very safe. But, any injection carries a small risk.
The risks include injury to a nerve, artery, or vein; infection; or an allergic reaction to the contrast agent.
Some people have mild allergic-like reactions to contrast, such as sneezing or hives. Rarely (1 time in 2,500), a serious reaction occurs. The doctors and staff of Imaging Services are trained to treat these reactions. Very rarely (1 time in 170,000), death has occurred after a contrast injection.
Some people are also at risk of kidney injury from a contrast injection. This is true mainly for people whose kidneys are already working poorly. We might not give a contrast agent to people who are already on dialysis.
A contrast agent may be recommended when you have your imaging study. This handout explains why the agent might be used, what reactions might occur, and who may be at higher risk for these reactions.
Be Sure to Tell Us
You are at higher risk for a problem from the contrast if you are on dialysis or you have:
- Had a moderate or severe allergic reaction to contrast in the past that required treatment
- Severe or many allergies to food or drugs
- Unstable asthma that currently needs treatment
- Severe heart disease
- Multiple myeloma, sickle cell disease, or polycythemia
- Severe kidney disease, especially if it is caused by diabetes
If you believe you have any of these conditions, be sure to tell your imaging technologist or radiologist. This will help us plan your scan to reduce the chance of a problem.
If you have any questions or concerns, please talk with your imaging technologist or radiologist.
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