Introduction
Computerised tomography, or CT scans, are used to see the inside of the body in detail.
They are used to look at:
- bones
- organs
- muscles
- blood vessels.
Before the test
You will get instructions from the hospital or your child's doctor before the CT scan.
Instructions can be different depending on what part of the body is being scanned. Some CT scans do not need any preparation.
Let your child's treatment team know if they have:
Parents and carers are encouraged to stay and support their child during the scan. If a parent or carer is pregnant, they will not be able to stay in the scan room due to the radiation.
Fasting
Some children might need to fast before a CT scan if they are:
- having a general anaesthetic – medicine that puts your child to sleep so they don't feel stress or pain
- being sedated – medicine that relaxes your child but is not as intense as a general anaesthetic.
Fasting means no eating or drinking, usually 2 hours before the scan. This is to stop your child from aspirating, which is when food or water is brought up into the lungs during a procedure.
Contrast
Some children may need to drink a liquid or inject a dye before their scan. This is called contrast. Contrast is a liquid that helps parts of the body to show up on a scan as it goes through the digestive system or the bloodstream.
Contrast dye can make your child feel sick, so they usually need to fast beforehand.
During the test
A CT scan is done in a big X-ray machine shaped like a doughnut. The machine will make a soft noise like a fan. It will also make some clicking noises as the pictures are taken. Your child will be exposed to some X-ray radiation during the scan.
A CT scan should only take a few minutes and should not be painful.
Your child will need to stay very still for the scan. They might also be asked to hold their breath for a few seconds if they are having chest and abdominal scans.
Speak to your child's doctor if you have questions or concerns about the CT scan.
Management
About contrast
Contrast is a clear liquid that shows up on images taken by a CT scan. Contrast helps to show things like blood vessels and organs clearly.
Contrast is commonly given as:
- oral contrast – a drink
- contrast dye – an injection.
If your child needs to have contrast dye, they will be given an intravenous (IV) cannula. An IV cannula is a thin plastic tube inserted into a vein in the arm.
Contrast dye, fluids, and medication can be pushed through the cannula, meaning your child will not need more than one needle.
Some children can have a severe allergic reaction to contrast dye called anaphylaxis. You will need to let your child's doctor know if they have any allergies or have had a reaction to contrast dye before.
Children who have a CT scan with contrast dye will need to wait in the hospital for 15 minutes after their scan to make sure there is no reaction.