Comparison of small bowel follow through and abdominal CT for detecting recurrent Crohn's disease in neoterminal ileum

Purpose: To assess the findings of recurrent Crohn's disease in the neoterminal ileum on small bowel follow through (SBFT) and computed tomography (CT) as well as the overall diagnostic performance of these imaging tests.

Methods: Our radiology database yielded 52 patients with an ileocolic anastomosis for Crohn's disease who underwent SBFT and CT. The images were reviewed to determine the sensitivity, specificity, PPV, and NPV for individual findings of recurrent Crohn's disease in the neoterminal ileum. The overall sensitivity, specificity, PPV, and NPV of these tests for recurrent Crohn's disease were determined by comparing imaging reports to endoscopic and surgical findings in 45 patients (87%) and clinical response to treatment in seven (13%).

Results: SBFT had a sensitivity of 90%, specificity of 85%, PPV of 95%, and NPV of 73% for detecting recurrent Crohn's disease, and CT had a sensitivity of 77%, specificity of 69%, PPV of 88%, and NPV of 50%. These tests combined had a sensitivity of 95%, specificity of 69%, PPV of 90%, and NPV of 82%. The most common findings were luminal narrowing, thickened folds, and ulcers (especially aphthoid lesions) on SBFT and bowel wall thickening on CT. CT also revealed extraenteric collections not visualized on SBFT in three patients (8%).

Conclusions: Our experience suggests that SBFT is more sensitive and specific than CT for detecting recurrent Crohn's disease in the neoterminal ileum, mainly because of the ability of barium studies to depict aphthoid lesions not visualized on CT. Conversely, CT is better for detecting extraenteric findings such as abscesses. When combined, these tests have a higher sensitivity for detecting recurrent Crohn's disease than either test alone.