Radiologic Examination: Small-Bowel Follow-Through, Computed Tomography Enterography, and Magnetic Resonance Enterography

Radiologic examination is effective and useful to diagnose and evaluate small bowel involvement in Crohn’s disease. Three modalities-small bowel follow-through (SBFT); CT enterography, and MR enterography-are currently used in clinical practice. Although the sensitivity and specificity of SBFT are relatively lower than those of capsule endoscopy or CT enterography, it is still a useful method in cases of difficulty in evaluating fine mucosal changes, contraindicated capsule endoscopy, and high risk of intravenous contrast agents. CT enterography has high sensitivity and specificity for detecting small bowel involvement of Crohn’s disease and is also useful to diagnose obstructions, penetrating disease, and extraintestinal manifestations. MR enterography can be used to distinguish between active inflammation and stricture caused by fibrosis because of the excellent soft tissue contrast. Since there is no radiation risk, MR enterography can be useful as an imaging technique that complements the limitations of CT enterography. Considering the advantages and disadvantages of each method, the appropriate modality should be selected according to the patient’s situation and the purpose of the test.