What Are the Radiological Signs of Crohn’s Disease?

An MRI is the gold standard imaging technique for viewing patches of inflammation that indicate Crohn’s disease. They can also help a doctor notice complications and the extent of your disease activity.

Features of Crohn’s disease that may show up on an MRI include:

• thickened bowel walls
• strictures
• ulcerations
• creeping fat
• skip lesions

Crohn’s disease often requires repeated scans of your intestines to track how your disease changes over time. Unlike CT scans and X-rays, an MRI doesn’t expose your body to radiation.

The MRI techniques doctors use to visualize Crohn’s include:

• MR enteroclysis: During this procedure, you receive a tube through your nose that leads to your small intestines. A healthcare professional then injects a contrast solution through this tube.
• MR enterography: During this procedure, you drink a fluid that fills your bowel. This can help your doctor monitor disease activity and the effectiveness of treatments such as immune-modulating agents.

In a 2018 study, researchers compared the accuracy of MR enterography and ultrasound for identifying Crohn’s gut changes to a panel of tests used as the reference standard. The researchers found that MR enterography was better than ultrasound in:

• diagnosing small bowel disease extent (80% versus 70%)
• detecting disease presence (97% versus 92%)
• correctly ruling out small bowel disease extent (95% versus 81%)
• correctly ruling out disease presence (96% versus 84%)

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A CT scan uses a series of X-rays to create a detailed image of your abdomen. Doctors use them to assess Crohn’s disease:

• activity
• extent
• complications

Features of Crohn’s disease that show up on a CT scan include:

• thickened bowel walls
• creeping fat
• “comb sign” showing the swelling of blood vessels in one of the bowel layers

A doctor may recommend a conventional CT scan with or without a contrast dye injection if you have a sudden onset of Crohn’s disease with no prior diagnosis. They may also recommend a conventional CT scan to check for complications of Crohn’s, such as:

• bowel blockage
• abdominal abscesses
• bowel perforation

CT enterography is a type of CT scan that can better visualize your small intestines than a conventional scan. This procedure involves drinking a special contrast liquid that shows up in the scanner. CT scans can accurately identify or rule out Crohn’s disease in more than 90% of cases.

Ultrasound is a radiation-free type of imaging that uses sound waves to produce an image of your gastrointestinal tract. It can also help identify health complications of other organs, such as your:

• liver
• bladder
• gallbladder

Abdominal ultrasounds are quick and widely available. They may help doctors identify:

• whether your disease is in remission
• potential complications
• disease severity

Ultrasounds can correctly identify Crohn’s inflammation around 93% of the time. They’re better at visualizing certain areas, such as the area between your large and small intestines and the lower part of your large intestines.

X-rays have a limited function in the diagnosis of Crohn’s disease. However, they can help identify complications such as:

• ulcers
• blockages
• fistulae

A barium enema involves putting a contrast dye into your anus with a tube so your doctors can better visualize your bowel on an X-ray.

Doctors don’t frequently use barium enemas. They more often perform CT scans or colonoscopies to identify changes to your colon.

Imaging can help your doctor understand the extent of your Crohn’s disease and screen you for complications. Many experts consider an MRI the most accurate imaging tool for assessing Crohn’s, but CT scans and ultrasounds can make quicker and cheaper alternatives.