CT colonography

Your consultant may recommend a CT colonography to examine your large bowel (colon) and back passage (rectum).

A CT colonography may be suggested if a standard colonoscopy is not suitable for you, or if you’d already had a standard colonoscopy, but your consultant was unable to examine your large bowel fully.

As opposed to a colonoscopy, a CT colonography offers the following benefits:

• The procedure less invasive
• It's faster than a standard colonoscopy
• The risk of harming the large intestine is lower
• It can be used for people who have problems with swelling, bleeding or breathing problems, and therefore may not be suitable for a standard colonoscopy
• It can show areas of the large intestine that a standard colonoscopy can't reach, especially if part of the intestine is narrowed or blocked
• It screens your entire colon, and can detect other issues in your abdomen
• You don't need to be sedated for the procedure

CT colonography vs colonoscopy

CT colonography	Colonoscopy
15-30 minutes	45 minutes-1 hour
5-7-centimetre-long probe	160-180-centimetre-long probe
No sedation	Usually requires sedation
Low dose of radiation	No radiation
Entire colon and abdomen screened	Entire colon screened, although can be obscured if part of your intestine is narrowed or blocked

The cost of a private CT colonography depends on your individual circumstances. At the time of your appointment your consultant will discuss all options with you and ensure all your questions are answered.

Our fixed-price packages include the cost of your surgery and all appropriate aftercare appointments. However, any pre-surgery diagnostic tests and your consultant's outpatient appointment consultation fee are charged separately.

Our flexible payment options help you spread the cost of your payment across a time period that suits you.

At your first consultation, you will be seen by a consultant gastroenterologist or colorectal surgeon, a doctor specialising in conditions affecting the digestive system.

Your consultant will ask you about your symptoms, general health, medical and family history, and any medications you take regularly before performing a physical examination.

Your consultant may ask to see the results of any previous tests or scans you've had, or they may arrange them on the day. These may include:

• Blood and/or stool tests: To check your general health and rule out any underlying medical conditions
• An abdominal ultrasound: Uses high-frequency sound waves to produce images of your abdominal organs and blood vessels

Your first appointment is important as it's where you'll meet your consultant, the doctor responsible for your care. Your consultant will take time to get to know you, discuss your expectations for treatment and encourage you to ask any questions you may have.

At Circle Health Group, we want you to be as well-informed and comfortable as possible during your time with us, so please discuss any questions or concerns with your consultant during your appointment.

Your consultant will tell you everything you need to do to prepare for your CT colonography. Instructions on how to prepare will also be in your appointment letter. 

You should not have a CT colonography if you are pregnant, so if you think you're pregnant, tell your consultant.

Tell your consultant about any medications you are taking, including over-the-counter medicines and supplements before your procedure, and any medical conditions, such as diabetes, or allergies you have.

Your consultant may tell you to stop taking some medications such as iron tablets, blood thinners or any medication that can cause constipation for around a week before your CT colonography.

Bowel prep

Before your CT colonography, you'll need to follow specific instructions to clear your bowels and ensure they are empty for the procedure. This is to allow the radiographer (the person conducting the procedure) to see your colon and rectum clearly.

You'll be given instructions on how to prepare your bowels by your healthcare team. Please call the hospital if you are not sure about anything regarding bowel prep. If your bowels are not empty before the procedure, your colonography will likely be postponed.

Bowel prep may involve:

• Following a special diet known as a low-residue diet for one or two days before your procedure. You'll be given written instructions on what you can and cannot eat during this time.
• Taking medications (laxatives) to empty your bowel
• Drinking a liquid contrast medium (dye) to make the images clearer on the CT scan
• Drinking plenty of clear fluids such as water, black coffee, black tea, clear soup and some clear fruit juices (without pulp) to prevent dehydration

During bowel prep, the medications you are given will make you open your bowels frequently. This can be very sudden, so make sure you are near a toilet while undergoing bowel prep. You may also experience some abdominal discomfort and cramping during your bowel prep.

When you arrive for your appointment at the CT department, you'll be met by a member of the radiography staff. They will explain the procedure to you and answer any questions you may have. You may need to fill out a short health questionnaire before your procedure.

Before your virtual colonoscopy, you'll need to sign a consent form to say that you agree to have the procedure and are aware of what it entails and the possible risks and complications.

You'll be asked to change into a hospital gown before your CT colonography and will have a small plastic tube called a cannula inserted into your hand before the procedure. You may be given medication to relax your bowels and reduce abdominal cramping during your CT colonography. 

The CT scan is painless and normally lasts around 30 minutes. It's important to keep as still as possible during your scan as this will allow your radiographer to get the clearest images of your bowel.

During your CT colonography:

1. You'll be asked to lie on the CT examination table on your left side.
2. Your radiographer will insert a small, flexible tube a few centimetres into your rectum.
3. They will pump carbon dioxide gas gently into your colon to open your large bowel so that your rectum and colon can be examined fully.
4. You will then be asked to lie on your front and the scanning table moves through the CT scanner. You may be asked to hold your breath for about five seconds during the scan.
5. You will then be asked to lie on your back and the CT scan will be repeated.
6. You may be given an injection of contrast medium (dye) through your cannula during your CT colonography. This helps produce clearer images of your bowel.
7. At the end of your CT scan the tube will be removed, and you can get down from the examination table.

Following your scan, you'll be scheduled in for a follow-up appointment one to two weeks after your CT colonography to discuss your results and any necessary treatment options.

After your CT scan, you'll need to stay in the CT department for around 15 minutes to check you don't have an allergic reaction to the medications you were given during the scan. Your cannula will then be removed, and you will be allowed to go home.

You may feel discomfort and bloating for a while after your virtual colonoscopy due to the gas that was pumped into your bowel. This should ease within a few hours.

Blurred vision can occur as a side effect of the medication used to relax your bowels. This normally resolves after about 30 minutes. Please do not drive until your vision has returned to normal.

You can return to work and normal activities and eat and drink normally as soon as you feel able after your CT colonography.

A CT colonography is a very safe procedure, but as with any type of medical procedure, there is a small risk that complications may occur.

Your consultant will explain all the possible risks and complications of a colonography before your procedure and answer any questions you may have. It’s important that you are fully aware of any possible risks and complications before your procedure to make an informed decision.

Possible complications of CT colonography include:

• Dehydration: bowel prep can lead to dehydration, so make sure you drink plenty of fluids before and after your CT colonography
• Abdominal pain or bloating: this is caused by the gas being pumped into your bowel during the test and normally resolves within a few hours
• Blurred vision: this can be a side effect of the medication used to relax your bowels and normally lasts around 30 minutes
• Side effects of contrast medium: you may feel hot and flushed, have a metallic taste in your mouth, feel a warm sensation and a need to pass urine for a few minutes after your injection of contrast medium
• Severe allergic reactions to the contrast medium: while this is rare, tell your radiographer immediately if you feel unwell or have difficulty breathing during your procedure.
• Bowel perforation (tear in your bowel): this is very rare and would be corrected with surgery
• Radiation exposure: CT scanners emit a small amount of radiation which can slightly increase your risk of developing cancer in the future, although the risk is very small and the benefits of having your CT colonography far outweigh the risk

At Circle Health Group, we have the experience and expertise to ensure the best possible care and outcome for our patients. As a patient with Circle Health Group, you can expect the highest standards of care including:

• Flexible appointment times and locations that are convenient for you
• The freedom to choose which hospital and consultant suit your needs
• Personalised, consultant-led treatment plans tailored to your individual needs
• Comfortable and safe private facilities maintained by expert multidisciplinary teams
• Private ensuite rooms as standard
• A range of delicious healthy meals
• Affordable, fixed-price packages with aftercare included
• Flexible payment options to help you spread the cost of your care

If you would like to see a consultant or learn more about a CT colonography, book your appointment online or call a member of our team today.

1. CT colonography, Cancer Research UK
2. Virtual colonoscopy, Macmillan Cancer Support
3. Virtual Colonoscopy, Johns Hopkins Medicine
4. CT colonography (CT pneumocolon or virtual colonoscopy), Cambridge University Hospitals NHS Trust