General Information Radiological images are created by passing small, highly controlled amounts of radiation through the body and capturing the resulting shadows and reflections on film. Most people are familiar with x-ray images, which produce a still picture of the body’s internal organs. A similar imaging method, fluoroscopy, uses x-rays to capture a moving image of an organ while it is functioning. Though still x-ray images can be useful in examining the colon, and rectum, dynamic fluoroscopy is often the most effective way to view abnormal or blocked movement of waste through the body’s lower gastrointestinal tract.
Common uses of this procedure A physician may order a lower GI examination to look for ulcers, benign tumors (polyps, for example), cancer, or signs of certain other intestinal illnesses. The procedure is frequently performed on individuals suffering from chronic diarrhea, blood in stools, constipation, irritable bowel syndrome, unexplained weight loss, a change in bowel habits, or to detect a source of suspected blood loss. Images of the bowel and colon are also used to diagnose inflammatory bowel disease, a group of disorders that include Chron’s disease and ulcerative colitis.
Patient Preparation You should tell your doctor about any recent illnesses or other medical conditions, as well as any allergies you might have to medications. Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.
Your doctor will give you detailed instructions on how to prepare for your lower GI imaging. During the day before the procedure, you will likely be asked not to eat, and to drink only clear liquids like juice, tea, black coffee, cola, or broth, and avoid dairy products. After midnight, you should take nothing by mouth. You may also be instructed to take a laxative (in either pill or liquid form) and to use an over-the-counter enema preparation the evening, or even a few hours before the procedure. It is permissible to take usual prescribed oral medication with limited amounts of water.
Once you arrive at the imaging center, you will be asked to change into a gown before your examination. You may also be asked to remove jewelry, eyeglasses, or any metal objects that could obscure the images.
Procedure A lower GI radiological examination is usually done on an outpatient basis. The radiologist or technologist will discuss details of the examination. You will be positioned on the table, and a preliminary film is obtained to check for adequacy of the bowel preparation. The radiologist or technologist will then make the contrast material introduction through a small tube inserted into the rectum. A mixture of barium and water is passed into the patient’s colon through the tube. To help the barium thoroughly coat the lining of the colon, air may also be injected through the tube. In some circumstances, the radiologist or referring physician may prefer a water and iodine solution rather than barium to opacify the colon. Then a series of images is captured.
You may be repositioned frequently to enable the radiologist or technologist to capture views of your color from several angles. Some equipment allows patients to remain in the same position throughout the exam. During the study, the radiologist will monitor the delivery of barium and take or request special views or close-ups.
Once the x-ray images are completed, most of the barium is drawn back into a bag and you are directed to the washroom to expel the remaining barium and air. In some cases, the technologist may then take additional images to help the doctor see how well the colon has cleared.
As the barium fills your colon, you may feel the need to move your bowel. You may feel abdominal pressure, or even minor cramping. These are common sensations and most people tolerate the mild discomfort easily. The tip of the enema tube is specially designed to help you hold in the barium. If you have trouble, let the technologist know.
During the imaging process you will be asked to turn from side to side and to hold several different positions. At times pressure may be applied to your abdomen. With air contrast studies of the bowel, the table may be turned into an upright position.
You are able to return to a normal diet and activities immediately after the exam. Your stools may appear white for a day or so as your body clears the metallic liquid from your system. You will be encouraged to drink additional water for 24 hours after the examination. After a barium enema, some people experience constipation. If you do not have a bowel movement for more than two days after your exam, or are unable to pass gas rectally, call your doctor promptly. You may need an enema or laxative to assist in eliminating the barium and your doctor will prescribe the right solution for you.
Benefits
- With the use of the barium contrast material, lower GI imaging provides valuable detailed information to assist physicians in diagnosing and treating conditions from normal to ulcers to cancer
- X-ray imaging of the lower GI tract is a minimally invasive procedure with rare complications
- You may return to normal activity following the examination
- The imaging process is fast and well tolerated
- Radiology examination can often provide enough information to avoid more invasive procedures such as colonoscopy
Risks
- In rare cases, the barium suspension could leak through an undetected perforation in the lower GI tract, producing inflammation in surrounding tissues
- Even more rarely, the barium can cause an obstruction in the gastrointestinal tract, called barium impaction
- The effective radiation dose from this procedure is about 4 mSv which is about the same as the average person receives from background radiation in 16 months
- Women should always inform the doctor or x-ray technologist if there is any possibility that they may be pregnant
Risks are further minimized by:
- Special care that is taken during x-ray examinations to ensure maximum safety for the patient by prudent targeted application of fluoroscopic radiation
- The use of high-speed x-ray film that does not require much radiation to produce an optimal image;
- Technique standards established by national and international guidelines that have been designed and are continually reviewed by national and international radiology protection councils
- Modern, state-of-the-art x-ray systems that have very tightly controlled x-ray beams with significant filtration and x-ray dose control methods. Thus, scatter or stray radiation is minimized and those parts of a patient’s body not being imaged receive minimal exposure
A barium enema is usually not indicated for someone who is in extreme abdominal pain or had a recent colonic biopsy. If perforation is suspected, the enema should be performed with the iodinated solution. X-ray imaging is not usually indicated for pregnant women.
