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Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract


Jonathan Gotfried

, MD, Lewis Katz School of Medicine at Temple University

Last full review/revision Apr 2021| Content last modified Apr 2021
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For CT and MRI of the digestive tract, doctors may give people substances that can be seen on the imaging test (contrast agents) to help distinguish one tissue or structure from its surroundings. Contrast agents may be given by mouth, by vein, by enema, or in combination.

CT enterography and MR enterography

Regular CT does not show the lining of the intestines well. A variation of the test, called CT enterography, allows doctors to clearly see the lining of the small intestine and look for tumors or narrowing of the intestines resulting from inflammation (strictures). For this test, people drink a large volume (about 1.6 quarts [1.5 liters]) of a liquid contrast agent such as barium. The contrast agent distends the small intestine so that doctors can see it better.

Magnetic resonance (MR) enterography is similar to CT enterography in that people drink a contrast agent before pictures are taken of their small intestine. It helps doctors see inflammation, bleeding, and other problems. This test is typically reserved for younger people, especially those with inflammatory bowel disease, so they are not exposed to radiation.

CT colonography

This test generates two-dimensional and three-dimensional images of the colon that may show tumors or other problems.

For this test, people drink a contrast agent, and their colon is inflated with gas from a tube inserted in the rectum. Before the test, people are given laxatives or enemas similar to those required for a regular colonoscopy to thoroughly remove stool. Although CT colonography is able to detect abnormal growths (intestinal polyps Polyps of the Colon and Rectum A polyp is a projecting growth of tissue from the wall of a hollow space, such as the intestines. Some polyps are caused by hereditary conditions. Bleeding from the rectum is the most common... read more Polyps of the Colon and Rectum ) or even colon cancer Colorectal Cancer Family history and some dietary factors (low fiber, high fat) increase a person’s risk of colorectal cancer. Typical symptoms include bleeding during a bowel movement, fatigue, and weakness... read more Colorectal Cancer , people still need to have a colonoscopy to remove any polyps or abnormalities detected during the test.

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