What is the recommended initial abdominal imaging test for a patient with Crohn's disease (CD)?

From the Guidelines

The recommended initial abdominal imaging test for a patient with Crohn's disease is magnetic resonance enterography (MRE) or computed tomography enterography (CTE). These cross-sectional imaging techniques provide detailed visualization of the small bowel and can detect inflammation, strictures, fistulas, and abscesses that are common complications of Crohn's disease 1. MRE is particularly advantageous for patients who require repeated imaging over time as it does not expose patients to ionizing radiation, making it preferable for younger patients or those needing frequent monitoring 1. CTE offers slightly better spatial resolution but involves radiation exposure. Both techniques require oral contrast to distend the bowel for optimal visualization.

Key Considerations

• Ultrasound may be used as an alternative in some settings, particularly for focused assessment of specific areas or in pediatric patients, though it is operator-dependent and may not visualize deep structures as effectively 1.
• Endoscopic procedures like colonoscopy with ileoscopy remain essential for direct mucosal assessment and tissue sampling but are complementary to cross-sectional imaging rather than alternatives 1.
• The choice between MRE and CTE should be based on the individual patient's needs and preferences, as well as the availability of these modalities at the institution 1.

Imaging Modalities

• MRE: provides detailed visualization of the small bowel without exposing patients to ionizing radiation, making it a preferred choice for patients who require repeated imaging 1.
• CTE: offers slightly better spatial resolution than MRE but involves radiation exposure, making it a less preferred choice for patients who require repeated imaging 1.
• Ultrasound: may be used as an alternative in some settings, particularly for focused assessment of specific areas or in pediatric patients, though it is operator-dependent and may not visualize deep structures as effectively 1.

From the Research

Initial Abdominal Imaging Test for Crohn's Disease

The recommended initial abdominal imaging test for a patient with Crohn's disease (CD) is a topic of discussion among medical professionals.

• CT enterography (CTE) is a common examination for patients with Crohn's disease, as it provides detailed images of the small bowel and can help diagnose the disease 2.
• CTE has been shown to be an accurate preoperative diagnostic imaging study for small-bowel Crohn's disease, with high sensitivity and specificity for detecting stricture, fistula, inflammatory mass, and abscess 3.
• Other imaging techniques, such as MR enterography and small-bowel follow-through, can also be used to diagnose Crohn's disease, but CTE is often preferred due to its high diagnostic yield and ability to detect both luminal and extraluminal pathology 4, 5.
• A recent study published in 2020 provides a comprehensive imaging atlas and glossary of terms for small bowel Crohn disease at CT and MR enterography, which can help standardize the interpretation and reporting of imaging findings 6.

Comparison of Imaging Techniques

• CT enterography, MR enterography, and small-bowel follow-through are all effective imaging techniques for diagnosing Crohn's disease, but they have different strengths and weaknesses.
• CT enterography is highly sensitive and specific for detecting active terminal ileitis and extraenteric complications, but it involves radiation exposure 5.
• MR enterography is a radiation-free alternative to CT enterography and has comparable diagnostic effectiveness, making it a promising option for patients with Crohn's disease 5.
• Small-bowel follow-through is less sensitive than CT and MR enterography for detecting extraenteric complications, but it can still be useful in certain cases 4, 5.

Imaging Findings and Reporting

• The Society of Abdominal Radiology Crohn's Disease-Focused Panel has developed consensus recommendations for standardized nomenclature for the interpretation and reporting of CT enterography and MR enterography findings of small bowel Crohn disease 6.
• These recommendations include guidelines for reporting bowel wall findings, penetrating Crohn disease, and changes in the mesentery related to Crohn disease, as well as recommended radiology report impression statements that summarize the findings of small bowel Crohn disease at CT enterography and MR enterography 6.