Information for Patients

A contrast enema is a lower gastrointestinal exam that uses x-rays to view the large intestine.  There are two types of tests: the single contrast technique, where contrast is injected into the rectum to gain a profile view of the large intestine, and the double-contrast technique, where both air and contrast media are inserted into the rectum.

One reason for this examination is to help in the diagnosis of colon and rectal cancer and inflammatory disease.  Detection of polyps, diverticula and structural changes may also be confirmed by using this examination.

The decision to perform a contrast enema is based upon your history of altered bowel habits.

To conduct the most accurate contrast enema examination, you must follow the prescribed diet and bowel preparation prior to your visit at the clinic.  This commonly includes restricted intake of dairy products and a liquid diet for 24 hours prior to the test.  Clear liquids should be ingested 12-24 hours before the exam.  You may also be given a laxative and asked to give yourself a cleansing enema.

Complications that may arise include perforation of the colon, water intoxication and allergic reactions.  These conditions, however, are all extremely rare.

The investigation involves exposure to x-rays.  X-rays consist of a type of radiation known as ionising radiation.  The doses that are used in medical x-rays are very low and the associated risks are minimal.  We keep the doses as low as possible and make sure that the benefits of having the x-ray outweigh any risk. 

Also, x-rays can be harmful for an unborn baby and should be avoided by women who are or who may be pregnant.  It is recommended that the examination is performed within 10 days of the first day of the onset of your menstrual period. 

When you arrive, report to X-ray Central Reception (Area 4) or X-ray North.  You will be asked to change into a hospital gown and to remove jewellery, dentures, glasses and any metal objects or clothing that might interfere with the x-ray images.  You will then be called into the x-ray room and will be asked to lie down on the x-ray table.  An image of your abdomen will be taken, and the radiologist will assess if the colon is adequately cleansed of stool.  A well-lubricated tube is inserted into the rectum, and the bowels will be filled with contrast media.  During this process, you must squeeze your buttocks together as much as you can, to prevent leakage. 

After the intestines are filled, x-rays of the abdomen are taken, and this may be done in various table positions. 

After the images are reviewed by the radiologist, you will be able to get dressed.

You should follow several steps after having a contrast enema:

• Drink plenty of fluids to counteract the dehydrating effects of the preparation.

• Take time to rest!  The preparation can be exhausting and cause some degree of discomfort.

• If your stools are lighter in colour after the examination, do not worry, as this is normal.  This may persist up to 72 hours after the examination. 

• Do not worry if your bowel movements are not present the following day.  The ingested food needs time to transverse the gastrointestinal tract.

The results of your examination will not be given to you on the same day. To receive these results you will need an appointment see either the consultant who referred you, or your own GP. You will be told after the examination which of these doctors you need to see.