CT Scans with Intravenous (IV) Contrast

What is a CT scan?

A CT scan is an examination of any part of your body using a Computed Tomography scanner (CT scanner), which provides accurate pictures of the structures inside your body using x-rays. The scan taken builds up many images of the body, rather like the slices of a loaf of bread. It helps the doctor investigate your symptoms.

How do I get ready for a CT scan with IV contrast?

Yes, please do not eat solid foods for 4 hours prior to your appointment time. You can drink fluids and take medication as normal. Diabetic patients may have a light snack if necessary but should avoid eating a large meal beforehand.
You will be asked to change into a gown for the scan which will be provided. You will also be asked to remove any metal items like jewellery from the area being scanned.
You will be given an injection of contrast (X-ray dye) via a cannula placed in your arm or hand. This helps to make certain parts of the picture clearer by highlighting internal structures on the images. You may also be asked to drink water before the scan for the same reason.
You should drink plenty of water/ fluids before and after the examination. This is particularly important if you have had any recent episodes of vomiting or diarrhoea.

Are there any risks?

This is a safe examination, however, as with all medical procedures there is some associated risk:

  • There is a small risk from the exposure to radiation as with any X-ray examination
  • There is a small risk of having an allergic reaction to the contrast (X-ray dye) if given in some people.

Please talk to your doctor or radiographer if you have any concerns about the risks. You can also access more information about radiation doses on the gov.uk site by clicking here
Please telephone the CT department on 020 7288 5888 and ask to speak to a CT radiographer if:
  • You are allergic to iodine based IV contrast (or have had an allergic reaction in the past during an X-ray procedure)
  • You are pregnant

What happens during a CT scan with IV contrast?

The radiographer (who operates the scanner) will take you into the scanning room where you will lie on a scan couch. This moves slowly through the scanner, which is shaped like a large ring. You can talk to the radiographer via a microphone and they can talk back to you and see you throughout. It is very important to lie still throughout your scan so that the pictures are not blurred.
You may be asked to hold your breath for approximately 5-10 seconds whilst pictures are taken. A CT scan is not a painful examination. The scan will take around 10 minutes in the scan room but you can expect to be in the department for up to an hour.
You may experience a metallic taste, hot flush or a sensation of passing urine during the injection, this is normal and will pass quickly.

Occasionally some people experience a mild rash, itchiness or nausea. Inform a radiographer if this happens on the day of the scan.

What happens after a CT scan with IV contrast?

You will be asked to take a seat in the waiting area for approximately 10 minutes to ensure that you are feeling well before you get changed and leave the department.
The scan is reported by a radiologist and the report will be sent to the doctor in clinic who requested the scan. The report will only go to your GP if they directly requested the scan. Typically you will receive the results of the scan the next time you visit the doctor looking after you. Your doctor will be able to discuss what future tests or treatment you may need.
Page last updated: 17 Feb 2021
Working on it!