Radiology - Iodine Contrast Injection

This leaflet contains information on Iodine, which is a contrast (dye) used during Computerised Tomography (CT) scans.

What is Iodine?

Iodine is a mineral. In this instance it is a clear colourless fluid that shows up white on the CT scan images. The referring Consultant or the supervising Radiologist (xray doctor) will make the decision on whether iodine is needed for your scan. The iodine is used to make the images clearer during a CT scan and help with diagnosis.

How is it given?

A cannula (a soft, hollow, plastic tube) will be inserted into a vein in your arm. The iodine will be given to you through this cannula. The cannula will remain in place until the scan is finished. We will remove it once we are happy that you are well enough to leave the department.

Are there any side effects?

Iodine is not suitable for everybody and the radiographer/ radiologist will decide if it is appropriate for you. Please let us know if you have had a previous allergic reaction to a contrast agent.

Iodine may on occasion cause side effects. Whilst uncommon, these are usually mild and short lasting.

Some of the more common side effects include:

Injection site pain, nausea, vomiting, itching, rash, headache and paraesthesia (abnormal skin sensation, such as prickling, burning or tingling).
 
If you have any concerns about side effects, please speak to the staff caring for you.

Patients with severe kidney failure should not be given Iodine unless their Kidney Doctor (Nephrologist) agrees it is important for them to have this contrast injection.

Occasionally the injection may leak out from the vein to the tissues under the skin – this is known as extravasation. If this has happened, you will experience a stinging sensation where the contrast has gone into the tissue and it can be painful.

Allergic reactions to Iodine contrast agents are uncommon but do occur. Most occur during the injection or within the first 30 minutes following administration; however, some can occur up to several days after.

Serious allergic reactions have been rarely reported.

Please seek immediate medical attention if you have any of the following:

• Swelling of face, mouth, hands, feet or throat
• Coughing/wheezing/sneezing
• Difficulty in breathing, swallowing or eye irritation

Rarely the contrast can cause problems with your kidneys. You can minimise this risk by drinking plenty of fluid (water, tea, coffee or fruit juice) following your scan. If you notice a reduction in your urine output over the days following your scan please seek medical advice.

If you experience any of the symptoms, please c ontact your GP or go to your local Accident and Emergency (A&E) Department for advice.