Magnetic resonance imaging in Crohn's disease

To evaluate the value of gadolinium enhanced MRI with oral opacification using a 5% mannitol solution (CE-Mannitol-MRI) to reveal bowel inflammation in pediatric patients with known or suspected Crohn's disease (CD).

Sixty-two consecutive children (median age 13.9 years) with known or suspected CD underwent ileocolonoscopy with biopsy, ultrasonography and CE-Mannitol-MRI. CD activity was measured with the Pediatric Crohn's Disease Activity Index (PCDAI). Image quality, wall thickness, bowel wall enhancement and complications identified on CE-Mannitol-MRI were evaluated by two blinded radiologists.

The sensitivity and specificity of CE-Mannitol-MRI for the diagnosis of CD were 83% and 100%, respectively. Bowel wall enhancement was higher in the group of patients with abnormal small bowel loops versus control group (P = 0.001). In patients with known CD, there was a positive correlation between wall thickness and PCDAI (P = 0.003). However, no significant correlation was demonstrated between parietal contrast enhancement and PCDAI (P = 0.497). CE-Mannitol-MRI enabled identification of complications in 18 patients (9 fistulae, 8 strictures and 1 intussusception).

In pediatric patients with CD, CE-Mannitol-MRI contributes significantly to the identification of disease extension, severity and intestinal complications with adequate diagnostic accuracy. This technique could also be useful as the first line diagnostic exploration in young patients with suspected CD.