Background and objective: Radiation exposure increases cancer risk in children with Crohn disease (CD). Magnetic resonance enterography (MRE) can image the gastrointestinal tract without exposure to radiation. The aim of the present study was to determine whether our MRE protocol could diagnose terminal ileitis and the degree of inflammatory activity in children with CD.
Methods: Retrospective review of patients 18 years of age or younger who underwent MRE for known or suspected CD from June 15, 2007 to April 1, 2010. MRE was performed with Volumen and water as oral contrast and gadolinium-based intravenous contrast. No antiperistaltic agent was used. Each MRE was compared with ileal biopsies obtained within 90 days. Severity of inflammation on MRE was scored and compared with the Pediatric Crohn Disease Activity Index (PCDAI).
Results: Seventy-two patients underwent 80 MREs during the study period. Forty-two of the 72 patients (58.3%) underwent colonoscopy within 90 days of MRE, and the terminal ileum was intubated in 33. Compared with histology, MRE had a sensitivity of 71.4% and a specificity of 100% for terminal ileitis. The positive and negative predictive values were 100% and 70%, respectively. PCDAI was calculated in 39 of the 72 patients (54.2%) and had a statistically significant positive correlation with MRE score of 0.37 (P = 0.020426).
Conclusions: In children with known or suspected CD, our MRE protocol has a high specificity and positive predictive value for terminal ileitis. Severity of inflammation on MRE had a statistically significant positive correlation with PCDAI.