CT Contrast Enema

Why do I need a contrast enema?

A CT contrast enema or rectal contrast examination is often used to enhance images of the large intestines, but if indicated by the reporting radiologist we may also scan the entire abdomen and pelvis. Common pathologies requiring rectal contrast include fistulas between the rectum and bladder or vagina, rectal or perirectal abscesses, diverticulosis/diverticulitis and rectal or sigmoid carcinoma.

CT scans of the abdomen and pelvis require 1-1.5 litre of water to be gradually consumed over the 90 minutes before the scan appointment time. By drinking the water, the reporting radiologist can see your bowel more clearly. Sometimes a positive oral contrast solution may be needed to be given in preference over water. This can only be consumed in the CT department. The required oral preparation will be indicated to you at the time of making your appointment. You are allowed to go toilet at any time once beginning the oral preparation.

You may also require intravenous contrast. Therefore, patients are required to fast for two hours prior to the examination. Please continue to drink water and also take medications with water during this period as necessary.

Depending on the scans required it will take approximately 25 – 45 minutes.

A volume between 100 mls – 300 mls is commonly given under radiologist instruction. Patients may be asked to try and clench their pelvic muscles in order to hold onto the catheter and contrast solution. In doing so, the best quality imaging can be obtained.
CT – Contrast Enema (Rectal Contrast)Rectal contrast helps to greatly increase the sensitivity of the CT exam. It is important to relax as much as possible until the CT scan is complete. Once the desired amount of contrast has been delivered into the rectum intravenous contrast will then be given at this point if it is also required. It is very important that you lie still for this test and hold your breath when requested. After the exam is complete, the rectal contrast will be drained and the patient may go to the bathroom.What is an iodinated contrast injection? Sometimes an Intravenous (IV) contrast agent may be required to help the radiologist provide a more comprehensive diagnosis. If IV contrast is required for your test you will be asked to complete a questionnaire to assess your suitability. The contrast will only be given once your consent has been obtained and information will be provided detailing the benefits and risks. The contrast is injected through a small cannula (plastic tube) inserted into a vein in your arm

If you have an injection of iodinated contrast, you may experience a sensation of warmth and a strange taste. These usually go away within a few minutes. In rare cases, some people may be allergic to the iodinated contrast.If you have any concerns, please contact the department and speak with one of our staff.

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