A CT scan is a painless, noninvasive imaging test that doctors use to better view internal structures, such as the intestines. A doctor may order a CT scan to help diagnose and assess Crohn’s disease.

Crohn’s disease is one of the types of inflammatory bowel disease (IBD). The condition can affect any part of the gastrointestinal (GI) tract, from the anus to the mouth. However, it commonly affects the end of the bowel and the beginning of the colon.

Doctors characterize the types of Crohn’s disease by what part of the digestive tract they affect. The most common type, ileocolitis, often causes symptoms such as:

Learn more about ileocolitis here.

A doctor who suspects a person has Crohn’s disease will likely:

  • conduct a physical examination
  • review personal and family medical history
  • order tests, such as a CT scan, to examine the digestive tract better.

This article reviews when a doctor may use a CT scan, what to expect during the procedure, results, and more.

A person lying in a CT scan machineShare on Pinterest
Tom Werner/Getty Images

CT scans can help doctors in several ways, including as a diagnostic tool and for disease monitoring.

In a 2021 review, researchers evaluated the different imaging techniques used in Crohn’s disease. They noted that CT scans are highly accurate for both diagnoses and detecting possible complications.

However, they also noted it is best when used to evaluate the colon and ileum — the last part of the small intestine. It is not as effective when evaluating the jejunal — another part of the small intestine.


Doctors can use a CT scan to help diagnose Crohn’s disease. A medical professional can view the digestive tract to check for signs of inflammation and damage that may indicate Crohn’s disease.

Learn more about diagnosing Crohn’s disease here.


Doctors can also use CT scans to help determine if Crohn’s disease caused any additional complications. Possible complications a doctor may find using a CT scan can include the following:

  • Fistulas: These are abnormal tunnels that go through the intestinal walls.
  • Abscesses: These are pus-filled areas of infection.
  • Intestinal obstruction: This causes narrowed intestines and can create a blockage.
  • Ulcers: These are open sores that may appear anywhere in the digestive tract.

A CT scan can also help assess the following:

  • disease activity
  • progression of the disease
  • response to treatment

Learn more about IBD in our dedicated hub.

A CT scan does not typically require any special preparation.

However, a person should talk with their doctor about whether to temporarily stop taking certain medications or make other adjustments to their routine. They should also tell them about any other conditions they may have.

Before the scan, a healthcare professional may ask the person to swallow a special dye. The dye helps to create a sharper image of structures in the abdomen.

The procedure itself is painless and should not take long. People will not need any recovery time and can usually return to regular activities immediately.

Learn more about how a CT scan works here.

After the scan, a doctor will review the images. They will look for abnormalities in the intestines and other structures of the gastrointestinal tract.

Combined with other test results, CT images can help doctors diagnose Crohn’s disease.

A doctor may also order additional CT scans periodically. They can use the scans to check for complications or if a person develops new symptoms.

Learn whether Crohn’s is genetic here.

CT scans can help show clinical signs of Crohn’s. Compared to a normal intestine, a doctor will check for the following findings on the CT image:

  • swelling
  • thickening intestinal wall
  • areas of narrowing intestines
  • ulcers
  • inflammation
  • presence of abscesses
  • fistulas

A healthy intestine will appear intact with no abnormal thickening, inflammation, or other features that indicate an underlying condition, such as Crohn’s disease.

Learn more about how the intestines work here.

CT scans provide a detailed image of the intestines and other structures that can help with diagnosis. However, doctors do not rely solely on a CT scan for diagnosis.

To make a diagnosis, they will typically use a variety of tests and exams. They can include:

  • Colonoscopy: A doctor inserts a tube into the rectum to examine the intestines.
  • Endoscopy: A healthcare professional insert a tube into the throat to examine the upper gastrointestinal (GI) tract.
  • Upper GI series: These tests use X-rays and dyes to examine the GI tract.
  • Blood tests: These test the blood for inflammation markers.
  • Stool samples: Doctors will assess these samples for signs of inflammation
  • Physical examination: A doctor will examine the abdomen and surrounding area.
  • Medical history: A doctor will take a personal and family history to identify any existing health issues that may help with diagnosis.

Learn more about other tests for Crohn’s disease here.

CT scans provide a clear image of the GI tract. A doctor can use the image to look for signs of Crohn’s disease, such as inflammation, ulcers, and thickening intestinal walls.

A CT scan is noninvasive and requires no recovery time or specialized preparation.

After the scan, a doctor will examine the results of the CT scan and any other tests and make a diagnosis based on any clinical features of Crohn’s they find.