CT Scan

A range of diagnostic techniques are used to determine the cause of your symptoms. These techniques are highly sophisticated and can accurately diagnose most gastroenterological conditions.

You will be given detailed information about whichever procedure you are having before you attend for your appointment.

The person carrying out the procedure will endeavour to put you at your ease and to answer any questions that you may have.

Although you may feel a little apprehensive about undergoing one of these investigations, please be assured they are routine procedures that should help to get to the bottom of whatever is causing your symptoms. This is the first step towards feeling better.

CT Scan


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.

What to expect before, during and after

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.

CT Scan

No. The scan is very quick and the scanner does not surround your body unlike an MRI scan so you won’t feel any anxieties associated with being in a confined space.

A CT scan exposes you to radiation. The levels are low however any exposure to radiation increases your risk of developing cancer.

CT scans can be used to detect cancer, to find out where the cancer is, whether it has spread and if it is interfering with your normal body function.

CT (Virtual) colonoscopy


During CT – or virtual – colonoscopy a CT scanner is used to produce 3D images of your large bowel and rectum.

What to expect before, during and after

For a few days prior to your appointment you will be asked to follow a special diet and on the morning of your appointment you should take a laxative to make sure your bowels are empty.

Just before the procedure you may also be asked to take a liquid called gastrograffin.

During the procedure, the doctor will insert a thin flexible tube into your bottom. Gas is then pumped into your bowel to inflate it, giving a clearer view of what is going on inside, and CT scans are taken from different angles.

This is a less invasive procedure than a colonoscopy and is normally offered to people who are not suitable for a colonoscopy due to a medical condition.

CT (Virtual) colonoscopy

A virtual colonoscopy uses a CT scan that produce X-ray images of the inside of your bowel. With a conventional colonoscopy a narrow flexible tube containing a camera is inserted into your anus and gently fed into your bowel.

With a virtual colonoscopy a tube is inserted just a short way into your anus to allow air to be pumped into your bowel. A conventional colonoscopy enables your doctor to take biopsies or remove polyps, whereas this is not possible with a virtual colonoscopy. Virtual colonoscopies may be safer if you are elderly and frail or your bowel is blocked.

A virtual colonoscopy can be used to identify ulcers or polyps or to show swollen or irritated tissue. It is used to diagnose conditions such as bowel cancer.

You will be able to go back to your normal activities immediately after having a virtual colonoscopy. You may feel a bit bloated and have trapped wind due to the air that was pumped into your bowel but these symptoms should quickly pass.

Experienced bowel doctor, here to help you

The sooner you seek help, the sooner your chances of returning to health and getting your life back on track.

There really is nothing to feel embarrassed about and everything to be gained by coming to talk to a specialist.

Browse the site to find more information about bowel health.