| Radiography - Lower GI Tract (Barium Enema "BE")
What is Lower Gastrointestinal (GI) Tract Radiography? Back to Top
This
is an x-ray evaluation of the large intestine, also known as the colon.
This includes the right or ascending colon, the transverse colon, 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. 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
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
often the most effective way to view abnormal or blocked movement of
waste through the body's lower gastrointestinal (GI) tract.
What are some common uses of the procedure? Back to Top
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 includes Crohn's disease and
ulcerative colitis.
How should I prepare for the procedure? Back to Top
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 to 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. Just follow your doctor's instructions. 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.
What does the x-ray equipment look like? Back to Top
The
equipment used for most lower GI examinations consists of a large, flat
table. A moveable apparatus extends over a portion of the table and
sends real-time images to a television monitor. Multiple static images
are obtained by the radiologist and technologist for later review. The
table can move and tilt and contains a drawer with a fluorescent plate
that captures the image and sends it to a nearby television monitor for
viewing.
Examples of the radiography equipment that may be used are shown at the top of this page.
How does the procedure work? Back to Top
Very
small, physician-controlled amounts of x-ray radiation are passed
through the body. Different tissues—such as bone, blood vessels,
muscles and other soft tissues—absorb x-ray radiation at different
rates. When a special film plate is exposed to the absorbed x-rays, a
detailed image of the inside of the abdomen is captured.
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? Back to Top
A
lower GI radiological examination is often done on an outpatient basis.
The radiologist or technologist will discuss details of the examination
and can review rare contraindications (circumstances that need special
consideration). The patient is 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. Air may also be injected through the tube to
help the barium thoroughly coat the lining of the colon. 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.
The patient may be
repositioned frequently to enable the radiologist or technologist to
capture views of their colon 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 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 doctor see how well the colon has cleared. The patient is then
released.
A lower GI study typically takes 30 to 60 minutes.
What will I experience during the procedure? Back to Top
As
the barium fills your colon, you will 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 are having 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. Some people experience constipation
after a barium enema. 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? Back to Top
A
radiologist, a physician experienced in GI studies and other radiology
examinations, will analyze the images and send a signed report with his
or her interpretation to your primary care or referring physician, who
will inform you on your test results. New technology also allows for
distribution of diagnostic reports and referral images over the
Internet at many facilities.
What are the benefits vs. risks? Back to Top
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.
- 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. 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.
- Radiation 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 (including mammography systems,
angiographic labs and CT scanners) 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.
What are the limitations of Lower GI Tract Radiography? Back to Top
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.
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