Certain exams require a special dye, called contrast, to be delivered into your body before the test starts. Contrast helps certain areas show up better on the x-rays.
Let your doctor know if you have ever had a reaction to contrast. You may need to take medicines before the test in order to avoid another reaction.
Contrast can be given several ways, depending on the type of CT being performed.
- It may be delivered through a vein (IV) in your hand or forearm.
- It may be given into your rectum using an enema.
- You might drink the contrast before your scan. When you drink the contrast depends on the type of exam being done. The contrast liquid may taste chalky, although some are flavored. The contrast passes out of your body through your stools.
If contrast is used, you may also be asked not to eat or drink anything for 4 to 6 hours before the test.
Before receiving the contrast, tell your health care provider if you take the diabetes medication metformin (Glucophage). People taking this medicine may need to stop temporarily. Also let your provider know if you have any problems with your kidneys. The IV contrast can worsen kidney function.
Find out if the CT machine has a weight limit if you weigh more than 300 pounds. Too much weight can damage the scanner.
You will need to remove jewelry and wear a hospital gown during the study.