A CT – or computerised tomography – scan is used to create detailed images of the inside of your body using X-rays and a computer screen.
They can be used to diagnose conditions or take small tissue samples (biopsies) using a needle. They are also used to drain abscesses or monitor ongoing conditions. CT scans are not suitable if you are pregnant as they could harm your baby.
You will be asked to avoid eating for a few hours before your scan to give the clearest possible images.
If you are wearing jewellery or anything with zips, you will be asked to remove these, as they will interfere with the scanning equipment. You will be given a gown to change into.
Just before the scan, you may be given a harmless dye to help improve the quality of the images. This may be given as a drink or passed into your bottom as an enema or injected.
If you feel anxious about the scan, you may be given a sedative to help you to relax. During the scan you will lie on your back on a flat bed that goes inside the CT scanner. The scanner rotates around your body as you pass through it. Unlike MRI scanners, CT scanners do not surround the whole of your body. The radiographer who is doing the scan will sit in an adjacent room but will be able to talk to you via an intercom. You will be able to respond.
It is best to lie as still as possible to ensure that the images are clear. Try not to hold your breath. At various points you may be asked to breathe in or out or to hold your breath.
The scan will normally take around 20 minutes. If you were given a dye, you will normally be asked to stay in the hospital for around an hour after the scan to ensure there are no after effects. Normally it will just pass out of your body when you wee.
Your results may take a few days or weeks. You will be asked to make a follow-up appointment with your doctor to review them.
