Appendiceal involvement in Crohn's disease: gray-scale sonography and color Doppler flow features

OBJECTIVE: The objective of our study was to evaluate appendiceal involvement in Crohn's disease with gray-scale and color Doppler sonography and differentiate it from acute appendicitis. MATERIALS AND METHODS: Analysis of the sonographic examinations was performed over 5 years in 190 patients with an established diagnosis of Crohn's disease. Data analyzed were as follows: visualization of the appendix; thickness and color Doppler signal (grade 0, 1, or 2) of the appendix and adjacent intestinal loop (cecum, terminal ileum, or both); involvement of other intestinal segments; and abscesses. The findings were compared with those of 49 consecutive patients with sonographic findings of acute appendicitis. RESULTS: Thirty-nine patients with Crohn's disease (21%) had appendicular involvement. All but one patient showed thickening of the terminal ileum, and 46% of patients also showed thickening of the cecum. The thickness of the ileum was more than 5 mm (only the anterior wall) in 64% of patients. Appendicular hyperemia was seen in 72% of patients. Involvement of other segments was seen in 23 patients (59%) and adjacent abscesses in six (15%). Irregular thickness of the submucosa was seen in nine cases (23%) and fibrofatty proliferation in 19 (49%). In patients with ileocecal regional disease, ileum thickness of more than 5 mm and visible color in the ileum were the most valuable signs, both for the diagnosis of Crohn's disease and to differentiate it from acute appendicitis (positive predictive value, 96%; negative predictive value, 74%). CONCLUSION: Appendicular involvement in Crohn's disease is a relatively frequent event (21%). Sonography and color Doppler sonography may be useful for differentiating Crohn's disease with appendicular involvement from acute appendicitis.