Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract

By

Jonathan Gotfried

, MD, Lewis Katz School of Medicine at Temple University

Last full review/revision Apr 2021| Content last modified Apr 2021
Click here for the Professional Version

Computed tomography (CT—see also Computed Tomography (CT)) and magnetic resonance imaging (MRI—see also Magnetic Resonance Imaging (MRI)) scans are good tools for assessing the size and location of abdominal organs. Additionally, cancerous (malignant) or noncancerous (benign) tumors are often detected by these tests. Changes in blood vessels can be detected as well. Inflammation, such as that of the appendix (appendicitis) or diverticula (diverticulitis), usually can also be detected. Sometimes, these tests are used to help guide x-ray or surgical procedures.

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) or even colon cancer, people still need to have a colonoscopy to remove any polyps or abnormalities detected during the test.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
Others also read

Test your knowledge

Anorectal Fistula
An anorectal fistula is an abnormal channel from the anus or rectum to the skin, usually near the anus, but occasionally near another organ, such as the vagina. Anorectal fistulas are common among patients with each of the following medical conditions EXCEPT:
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
TOP