Crohn disease (CD) is a chronic condition caused by inflammation of the bowel. The small bowel, the colon, or both can be involved. Individuals may have periods with frequent flare-ups and periods of remission. CD is usually diagnosed by colonoscopy along with clinical symptoms, laboratory tests, and imaging. Imaging is helpful to evaluate the extent of involvement on initial diagnosis, to evaluate for residual inflammation, or to monitor response to treatment.
For individuals without a prior diagnosis of CD or individuals with known CD with a suspected flare-up, CT abdomen and pelvis with intravenous (IV) contrast, CT enterography, or MR enterography is usually appropriate. For enterography, whether done under CT or MR, the individual has to consume approximately 1 to 1.5 L of a special liquid to help fill the small bowel. For individuals with known CD under surveillance or monitoring for treatment, MR enterography is preferred because of its lack of radiation dose.
Other imaging tests may be appropriate including MRI abdomen and pelvis without and with IV contrast when an individual is acutely ill and cannot tolerate a large volume of liquid to drink. CT abdomen and pelvis without IV contrast, fluoroscopy small-bowel follow-through, and MRI abdomen and pelvis without IV contrast can be performed in different situations but yield less information than CT enterography or MR enterography.
For more information, see the Crohn’s Disease page.
This page was reviewed on December 15, 2021