CT Colonography with Gastrografin

Radiology

Your consultant has requested that you attend for a CT colonogram. This leaflet is designed to explain what the examination involves. The examination will be carried out in the X-ray department at The James Cook University Hospital.

If you are unable to attend, please contact us immediately to rearrange. This will allow us to use the appointment for another patient.

What is a CT Colonography?

This is an examination using a type of scan called computed tomography (CT) to produce images of the large bowel (rectum and colon).

You have been prescribed Gastrografin, which is a ‘contrast medium’ (a dye) which contains iodine. Gastrografin does have a side effect of causing diarrhoea, so its role is to help clear out your bowels and stick to the remaining faeces, so that it can be identified on the scan. It is an important part of the test to ensure the safety and effectiveness of the examination.

The test is performed as an outpatient and takes approximately 30 minutes. You will not be given sedation for this procedure.

Medication

One week before your examination:

• Stop iron medication
  For example: Ferrous Sulphate, Sanatogen.
• Stop bulking agents
  Such as: Fybogel, Regulan, Isaghula husk or Normacol.

If you have not received specific advice regarding your regular medications, then you should continue to take them as normal. However, you may need to amend the timing as it is preferable to avoid taking them less than one hour either side of any dose of oral bowel cleansing agent.

Patients taking the oral contraceptive pill should take alternative precautions during the week following taking the oral bowel cleansing agent.

Diabetic patients – tablet and insulin controlled

Morning appointments – bring your medication with you to take after the test. Please consult your doctor or diabetes nurse before starting this diet. If you do not have a morning appointment, please ring to re-arrange.

Is there anything I need to tell the staff?

For all patients between the ages of 12 and 55 who have ovaries, the x-ray department has a legal responsibility to ensure that this examination is performed within ten days of the first day of your menstrual period.

The preparation

• Your bowel must be empty before the examination!
• You must follow a special diet and take the Gastrografin (bowel prep) provided
• You must drink clear fluids frequently during this preparation, to stop you becoming dehydrated.

Two days before your examination

You must follow this low-residue diet:

• Breakfast
  • Fruit juice or
  • Tea or coffee, skimmed milk, sugar
  • White bread, butter or margarine
  • Honey, clear jam or marmalade (with no seeds, fruit or peel)
• Mid-morning
  • Tea or coffee, skimmed milk, sugar
• Lunch
  • Grilled or poached fish or chicken with boiled, mashed potatoes or white rice
  • Thin gravy, tomato or brown sauce or
  • Poached egg and toast
• Afternoon
  • Tea or coffee, skimmed milk, sugar
• Evening meal
  Choice of:
  • Omelette (plain or cheese)
  • Kedgeree
  • Grilled or poached fish or chicken
  • Chicken sandwiches
  • Clear soups
• Supper
  • Cheddar cheese and cream crackers or biscuits for example, Rich tea, Nice
  • Tea or coffee, skimmed milk, sugar
• Desserts
  • Plain cakes, jelly, custard, rice pudding, tinned fruit, poached or stewed fruits
• Suitable snacks
  • Plain biscuits or cakes, white bread, plain crackers and cheese, yoghurt

The day before your examination

You must follow this low-residue diet and that the Gastrografin with each meal.

• Breakfast
  33mls Gastrografin with:
  • Fruit juice, tea or coffee, skimmed milk, sugar
  • White bread, butter or margarine
  • Honey, clear jam or marmalade (with no seeds, fruit or peel)
• Mid-morning
  • Tea or coffee, skimmed milk, sugar
• Lunch
  33mls Gastrografin with:
  • Grilled or poached fish or chicken with boiled, mashed potatoes or white rice
  • Thin gravy, tomato or brown sauce or
  • Poached egg and toast
• Afternoon
  • Tea or coffee, skimmed milk, sugar
• Evening meal
  33mls Gastrografin with a choice of:
  • Omelette (plain or cheese)
  • Kedgeree
  • Grilled or poached fish or chicken
  • Chicken sandwiches
  • Clear soups
• Supper
  • Cheddar cheese and cream crackers or biscuits for example, Rich tea, Nice
  • Tea or coffee, skimmed milk, sugar
• Desserts
  • Plain cakes, jelly, custard, rice pudding, tinned fruit, poached or stewed fruits
• Suitable snacks
  • Plain biscuits or cakes, white bread, plain crackers and cheese, yoghurt

You must drink whenever you feel thirsty. Fluids allowed:

• Tea and coffee with skimmed milk
• Water
• Squash
• Still orange
• Lemonade, coca cola etc.
• Lucozade

You will need to remain near a toilet as Gastrografin is a laxative. We suggest you remain at home today. The Gastrografin does not always work immediately; do not worry if this happens.

Drink plenty of clear fluids throughout the treatment with Gastrografin. Try to drink at least a full glass every hour during the treatment day.

The day of your examination

• Morning appointments
  Have a light breakfast, for example, tea and toast with butter and jam (normal milk is allowed today).
• Afternoon appointments
  Clear fluids only in the morning. Two hours before your appointment have a light lunch for example, tea and toast. Take any medication as normal.

During the test

You may bring your own dressing gown and slippers to wear, however you will be asked to change into a hospital gown. The radiographer performing your test will talk to you, making sure you fully understand the procedure before the examination starts.

A small plastic tube called a cannula will be placed into your arm so that an injection of a medicine, to relax the muscles in your bowel wall, can be given. This may cause blurred vision, and you are advised not to drive home. This cannula may also be used to give an injection of x-ray dye during the scan.

Once in the scan room, a small, soft tube will be placed into your back passage (rectum), and then carbon dioxide will be put through this tube to help distend your bowel.
Whilst the carbon dioxide enters your bowel you may get a little discomfort similar to wind and also have the sensation of needing to go to the toilet.

Once your bowel is full of carbon dioxide, a scan will be taken of your tummy whilst you are laid on your back, you will be given breathing instructions to follow during the scan. You will then be asked to turn to lie on your tummy and another scan will be taken of your tummy.

If these scans provide good images of the bowel this will be the end of the test, if however, we need some more images, you may be asked to lie on your side for some more scans to be taken. Do not worry if you cannot manage to lie on your tummy, we will give as much assistance as possible and work around any difficulties we encounter.

Aftercare

Your tummy may be bloated and uncomfortable; this will be relieved by visiting the toilet and drinking warm fluids. We suggest wearing clothes that are loose fitting around the waist. Your normal diet may be resumed as soon as you wish.

When will I get the result?

You will not be given the result straight away. The radiologist (consultant) will examine your x-rays and send a report to the referring doctor, which normally takes less than 14 days.

Radiation dosage and risk

X-rays use ionising radiation which can cause cell damage that may, after many years or decades, turn cancerous. The risk of this happening is very small compared to the normal lifetime risk of developing cancer which is 1 in 2. We are also all exposed to background radiation every day.

The risk of long-term effects is considered when the healthcare team decide whether someone needs an x-ray examination and radiation doses are kept as low as possible. For this examination radiation dose levels are typically equivalent to around 1 to 4 years of background radiation. The associated risk is less than 1 in 1000 – Low.

What about transport to the hospital?

Transport has not been arranged for this appointment. If you require a patient transport ambulance, please contact your GP at least 48 hours before the appointment date.
There is a charge to use the car parks. For details of costs, visit: www.southtees.nhs.uk

Patient experience

South Tees Hospitals NHS Foundation Trust would like your feedback. If you wish to share your experience about your care and treatment or on behalf of a patient, please contact The Patient Experience Department who will advise you on how best to do this.

This service is based at The James Cook University Hospital but also covers the Friarage Hospital in Northallerton, our community hospitals and community health services.

To ensure we meet your communication needs please inform the Patient Experience Department of any special requirements, for example; braille or large print.

T: 01642 835964
E: [email protected]

The James Cook University Hospital, Marton Road, Middlesbrough, TS4 3BW.
Telephone: 01642 850850

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