Upper gastrointestinal series tract in addition to barium, and this procedure is called double-contrast imaging. In this case the gas is referred to as the negative contrast medium. Traditionally the images produced with barium contrast are made with plain-film radiography, but computed tomography is also used in combination with barium contrast, in which case the procedure is called CT enterography. Various types of barium X-ray examinations are used to examine different parts of the gastrointestinal tract. These include barium swallow, barium meal, barium follow-through, and barium enema. The barium swallow, barium meal, and barium follow-through are together also called an upper gastrointestinal series
Gastrointestinal bleeding risk about fourfold. SSRIs, corticosteroids, and anticoagulants may also increase the risk. The risk with dabigatran is 30% greater than that with warfarin. Lower gastrointestinal bleeding is typically from the colon, rectum or anus. Common causes of lower gastrointestinal bleeding include hemorrhoids, cancer, angiodysplasia, ulcerative colitis, Crohn's disease, and aortoenteric fistula. It may be indicated by the passage of fresh red blood rectally, especially in the absence of bloody vomiting. Isolated melena may originate from anywhere between the stomach and the proximal colon. A number of foods and medications can turn the stool either red or black. Bismuth found in