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test may be done in a hospital or clinic radiology department. The
patient lies on the X-ray table and a preliminary X-ray is taken.
The patient is then asked to lie on the side while a well lubricated
enema tube is inserted into the rectum. As the enema enters the
body, the patient might have the sensation that their stomach is
being filled. The barium, a radiopaque (shows up on X-ray) contrast
medium, is then allowed to flow into the colon. A small balloon
at the tip of the enema tube may be inflated to help keep the barium
inside. The flow of the barium is monitored by the health care provider
on an X-ray fluoroscope screen (like a TV monitor). Air may be puffed
into the colon to distend it and provide better images (often called
a "double-contrast" exam). If air is used, the enema tube
will be reinserted (if it had been removed; whether it is depends
on who does the exam) and a small amount of air will be introduced
into the colon, and more X-ray pictures are taken. [1]
The
patient is usually asked to move to different positions and the
table is slightly tipped to get different views. [1]
If
there is a suspected bowel perforation, a water-soluble contrast
is used instead of barium. The study is otherwise very similar,
although the images are not quite as good. (The concern with existing
perforation is that contrast will leak from the bowel to the peritoneal
cavity, and water-soluble material is safer than barium, which must
be removed.) [1]
[1] Lower gastrointestinal series, (last visited Nov. 25, 2007). |