A barium enema is a medical imaging technique used to visualize the large intestine or colon
. It is used to identify anomalies in the terminal part of the digestive tract. A contrast agent, barium, is injected through the natural channels of the patient and makes the colon opaque, and is then X-rayed. X-rays
allow a study of the large intestine and a search for inflammation
, the presence of polyps
. Barium is also used to opacify other organs, including the ones in the digestive tract: this is the case in a barium meal or upper gastrointestinal series, where barium is ingested by the patient and allows the study of the upper gastrointestinal tract.