This page explains about contrast enemas and what to expect when your child comes to Great Ormond Street Hospital (GOSH) for the scan.
What is a contrast enema?
Contrast enema scans usually use a thick, white liquid (barium) that shows up well on X-rays.
Sometimes, we use a clear liquid instead that also shows up well on X-rays. This liquid is introduced to your child’s digestive system to show how well it is working. It is used to diagnose all types of abnormalities of the lower digestive system.
Are there any alternatives?
When you receive your appointment letter
If you are unable to keep this appointment, please inform the department at least two weeks beforehand. Sometimes, we can offer the appointment to another child on the waiting list. As so many children and young people need to use our services, we have had to introduce a policy where if a child cancels or does not attend two appointments in a row, we will close their referral and inform their GOSH consultant.
The day before the scan
To make sure that the images are of good quality, we ask that your child avoid foods with lots of fibre on the day before the test. This includes foods such as wholemeal bread, wholemeal pasta, beans, or excessive amounts of fruit or vegetables.
The day of the scan
Your child should not have breakfast on the day of the scan and should only drink clear fluids, such as weak squash or water, until one hour before the test. Children who are bottle feeding or breast feeding should not be fed for at least an hour before the test. Again, this ensures that the images taken are of good quality.
Please arrive at the Radiology department at the time stated in your child’s appointment letter.
Many of the studies we perform involve the use of X-rays. Legally, we are obliged to ask any girls over the age of 12 whether there is any chance they might be pregnant. This is to protect babies in the womb from receiving unnecessary radiation.
We will also ask mothers or other female carers if they could be pregnant, especially if they are planning to come into the scanning room with their child. If you are pregnant, we suggest you bring another member of the family with you, to be with your child during the scan instead.
Your child will need to wear a hospital gown for this test, but can keep a vest or t-shirt on underneath. Any metal on their everyday clothing, such as zips or buttons, will show up on the scan, giving a misleading result. All other underwear and nappies need to be removed once they are in the room, just before the scan starts.
You will be able to stay with your child throughout the scan. They will need to get onto the bed and lie on one side. The doctor will pass a thin, soft, plastic tube into your child’s anus (back passage), which is then taped in position. This is not painful but may be slightly uncomfortable just while the tube is going in. Once it is in place, that feeling should go away.
The contrast liquid is then slowly introduced into the tube, so that it flows into the large intestine. Your child will not usually be able to feel the liquid being passed into the tube but may feel a bit full such as after a big meal.
X-ray pictures are taken while the liquid moves through the large intestine as far as the appendix. While the pictures are taken, we might ask your child to turn over, lie on their back or the other side. You and your child will be able to see the pictures on the screen.
The scan usually lasts 30 minutes.
After the scan
When enough pictures have been taken, your child will be able to get off the scanning bed, get dressed and go home. Older children may want to go to the toilet straightaway and there is a toilet cubicle they can use in the corner of the room. The radiology doctor will send a report about the scan to your child’s doctor.
Are there any risks?
The contrast will not interfere with any medicines your child is taking. However, it may cause some constipation in the days that follow the test, so your child should drink plenty of fluids. Your child’s faeces (poo) may appear white as the contrast is passing out of their body, but this is quite normal.
While X-rays use radiation, the amount in an individual set of pictures is low compared with the background radiation we get from the environment. Each X-ray is calculated so that the best picture can be taken using the minimum amount of radiation.
When you get home
Your child should drink plenty of fluids for the next couple of days to flush the contrast out of their digestive system and prevent any constipation.