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Your doctor has scheduled a defecography for you. This handout will tell you how to prepare and what will happen during the exam. 

If you have questions, you may call Radiology at (608) 263-9729 press #2.

Let us know if:

  • There is any chance you may be pregnant.

  • You have had rectal surgery in the past.

  • You have a history of chronic colitis.

  • You have any renal (kidney) disease.

  • You have heart problems.

  • You have diabetes.

If you have any of these, you may need more instructions.

If you have other tests scheduled before this exam, ask your doctor if you need to change your pre-exam schedule.

If you are taking medicines, ask the doctor about taking them in the 24 hours before the exam. 

What is a defecography?

A defecography is an x-ray of the rectum and sigmoid (lower) portion of the colon while you are emptying contrast from your bowel. In order to see parts of the rectum, it will be filled with contrast. For woman, the vagina will also be filled with a small amount of contrast. You will need a clean and empty colon.

To Prepare for the Exam

To clean out the bowel, you will need to follow a clear liquid diet. Clear liquids include:

  • Clear broth

  • Consommé (such as Campbell’s beef consommé)

  • Coffee or tea (no cream, sugar is fine)

  • Clear Jell-O® (do not add fresh or canned fruit)

  • Clear fruit juices or drinks – cranberry, grape, or apple (Hi-C®, Kool-Aid®).

  • Popsicles®

  • Clear hard candy

  • Ice made from cranberry, apple, or grape juice

  • Sodas such as ginger ale, 7-Up®, Sprite®

Getting Ready 

Please follow the schedule below unless your doctor gave you other instructions.

Day Before the Exam

Start your clear liquid diet at breakfast. Do not drink cola, milk, orange juice, or tomato juice.

Starting at 12:00 Noon

Between noon and 11 pm, drink eight (8-ounce) glasses of water, unless your fluid intake is restricted. Be sure to have a clear liquid lunch as well.

At 5:00 p.m.

Have a clear liquid dinner.

At 5:30 p.m.

Drink a bottle (10 ounces) of magnesium citrate. You can purchase this laxative without a prescription from any drugstore.

At 8:00 p.m.

Take 20 milligrams of bisacodyl tablets. Four tablets of 5 mg each or two tablets of 10 mg each. You can purchase bisacodyl without a prescription from any drugstore. Swallow the tablets whole, do not chew or crush.

After Midnight

Do not eat or drink anything.

Morning of the Exam

No breakfast or liquids. If you have been told to take medicine, take with a small sip of water.

Day of the Exam

If you are an inpatient, you will be taken to Radiology.

If you are an outpatient, go to the place where the exam is scheduled. It will either be Digestive Health Center Radiology or UW Hospital Radiology. (G3/3Atrium elevators to the 3rd floor). Arrive at the time scheduled. 

When you we arrive will ask you to drink two cups of contrast before the exam. This will help show your small bowel.

We will give you a robe and gown to put on.

The Procedure

We will place a lubricated tube into your rectum. We will use contrast paste to fill the rectum. Using a special screen, the radiologist will watch your rectum empty while you sit on a commode. The lights will be dim so the doctor can see the screen clearly. You will hear the x-ray machine make a humming noise.

We will take pictures and video images during the exam and elimination process. This part of the exam takes only a few minutes. You may then expel any remaining contrast in a nearby bathroom. We will ask you to wait while the radiologist checks the films. Please allow 1½-2 hours for the entire exam

After the Exam

The radiologist will talk with your doctor about the findings. Your doctor will then talk with you and suggest further treatment, if needed. 

Ask the doctor if you should take two tablespoons of milk of magnesia to help you expel any extra contrast in your bowel.

Your bowel movements may be whitish in color for a day or two. This is normal. This color is caused by traces of contrast still in your bowel. Drink plenty of fluids to help wash the contrast out.

You may go back to your usual diet unless your doctor tells you otherwise.