What is Lower Gastrointestinal (GI) Tract Radiography?
This is a dynamic fluoroscopic x-ray evaluation of the large intestine, also known as the colon. This includes the right or ascending colon, the transverse colon, and the left or descending colon and the rectum. The appendix may be seen if it is present and a portion of the small intestine may be visualized as well. 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 an 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 used to obtain optimal images of the colon with the patient in a variety of positions during a barium enema examination.
What are some common uses of the procedure?
A physician may request a lower GI examination to look for diverticula (small outpouchings of the bowel wall), benign tumours (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 includes Crohn’s disease and ulcerative colitis.
How should I prepare for the procedure?
Women should always inform their doctor, radiologist, and x-ray technologist if there is any possibility that they are pregnant.
You will be given detailed instructions on how to prepare for your lower GI imaging. During the day before the procedure, you will 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 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. Just follow the instructions. It is permissible to take usual prescribed oral medication with limited amounts of water.
Once you arrive at Annex Medical Imaging, 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.
What does the x-ray equipment look like?
How does the procedure work?
The tissues of the lower GI tract are similar in density, so a contrast material is needed to provide exquisite detail of the inside of the colon. Liquid barium, a dense, non-absorbable metallic solution, is introduced into the colon through a rectal tube. The barium coats the inside of the rectum, colon, and a part of the lower small intestine, and produces a sharp, well-defined image.
How is the procedure performed?
Sometimes spasm of the colon prevents a good examination. The radiologist may give you an injection of Buscopan or Glucagon to relax the colon so as to obtain good quality images.
The patient may be repositioned frequently to enable the radiologist or technologist to capture views of their colon from several angles. 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 the patient is directed to the washroom to expel the remaining barium and air. In some cases, the technologist may then take additional images to help the radiologist see how well the colon has cleared.
A lower GI study typically takes 30 to 60 minutes.
What will I experience during the procedure?
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.
Who interprets the results and how do I get them?
What are the benefits vs. risks?
- With the use of the barium contrast material, lower GI imaging provides valuable, detailed information to assist physicians in diagnosing and treating conditions from diverticular disease to inflammation to polyps 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, or may show polyps or other conditions that may need colonoscopy to further investigate or treat them.
- 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. See the Safety page for more information about radiation dose.
- Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.
What are the limitations of Lower GI Tract Radiography?
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