.: intravenous injection of contrast medium for a ct scan

Your doctor has requested that you have an examination that may include an injection of a liquid known as intravenous contrast. This contrast is used to outline blood vessels and other parts of the body and is removed by your kidneys. The contrast or ‘dyes’ (although the fluid is colourless) are in daily use in all x-ray and CT scanning departments throughout the world.

As you have the contrast injected you may notice:

• A sensation of warmth.
• A sensation of having ‘wet’ oneself.
• Mild nausea.
• Metallic taste.

These are normal and are not ‘reactions’.

Very occasionally, a person may ‘react’ to the injection of contrast.  Such reactions are mostly very mild and also rare, less than 4 per 10,000 cases.

These include chills, fever, shortness of breath and wheezing or changes in blood pressure.  A severe reaction is unlikely to be life-threatening.  A severe reaction usually occurs immediately and is treatable.

All staff involved are fully trained to deal with any reactions which might occur.

There is no way of predicting who might have such a reaction – a history of allergies’ to other drugs, foods, iodine or even a history of a reaction to contrast medium for a previous x-ray study is often not helpful in predicting the likelihood of a reaction.  Most reactions are not true ‘allergies’.