Using Contrast Dyes in CT

To get clearer pictures for some imaging tests, we give patients a special dye called contrast. Contrast dye can make specific organs, tissues or blood vessels stand out in imaging scans, helping doctors see them more clearly.

Patients who are pregnant or who believe they could be pregnant should talk to their doctors before having a CT exam. Information discussed with a doctor is confidential.  In addition, parents or caregivers who are pregnant or believe they might be pregnant shouldn’t be in the room during a CT exam.  

Female patients who are 12 and older must have a urine or blood pregnancy test before receiving IV contrast. 

We use many different types of contrast dye. We give some types into a vein through an intravenous (IV) line. We give other types by mouth.

When we give contrast dye into a vein, we place an IV line in the hand, arm or foot, depending on the patient’s age. Immediately after the dye goes into the IV line, the patient might feel a flush of warmth and notice a funny taste in the back of the mouth. Both sensations are common and will go away in a few minutes.

Guideline for IV Contrast Exams: Eating and Drinking

Do not eat or drink anything during the four hours leading up to the exam. That includes any solids or liquids by mouth and/or feeding tube.

When we give contrast dye by mouth, the amount varies by the size of the patient and the procedure being done.  The contrast can be chalky and thick, or thin and bitter. We can sweeten the mixture to make it easier to drink.

Guideline for Oral Contrast Exams: Eating and Drinking

• Under age 5:  Do not eat or drink anything during the 4 hours leading up to the exam.  That includes any solids or liquids by mouth and/or feeding tube, unless approved by the fluoroscopy staff.
• Age 5 and up:  Do not eat or drink anything during the 8 hours leading up to the exam.  That includes any solids or liquids by mouth and/or feeding tube, unless approved by the fluoroscopy staff.

We might collect a blood or urine sample before giving contrast dye to make sure that a patient’s kidneys are working well. In general, it’s important to stay well-hydrated before and after having contrast dye. Patients who have a type of contrast dye called barium will have white stool for a day or two after the test. These patients might also notice constipation (hard stool or difficulty passing stool). Mild laxatives or stool softeners can help with this. Contact the doctor if the constipation continues or is an ongoing problem.

For more information about imaging tests at Gillette, please call the Advanced Imaging Center at 651-229-3995.