MR enterography-histology comparison in resected pediatric small bowel Crohn disease strictures: can imaging predict fibrosis?

Crohn disease is a chronic inflammatory condition that can lead to intestinal strictures. The presence of fibrosis within strictures alters optimal management but is not reliably detected by current imaging methods. To correlate the MRI features of surgically resected small-bowel strictures in pediatric Crohn disease with histological inflammation and fibrosis scoring. We included children with Crohn disease who had symptomatic small-bowel strictures requiring surgical resection and had preoperative MR enterography (MRE) within 3 months of surgery (n = 20). Two blinded radiologists reviewed MRE examinations to document stricture-related findings. A pediatric pathologist scored stricture histological specimens for fibrosis (0-4) and inflammation (0-4). MRE findings were correlated with histological data using Spearman correlation (rho) and exact logistic regression analysis. There was significant positive correlation between histological bowel wall fibrosis and inflammation in resected strictures (rho = 0.55; P = 0.01). Confluent transmural histological fibrosis was associated with pre-stricture upstream small-bowel dilatation > 3 cm at univariate (odds ratio [OR] = 51.7; 95% confidence interval [CI]: 7.6-aEuro parts per thousand > 999.9; P = 0.0002) and multivariate (OR = 43.4; 95% CI: 6.1-aEuro parts per thousand > 999.9; P = 0.0006, adjusted for age) analysis. The degree of bowel wall T2-weighted signal intensity failed to correlate with histological bowel wall fibrosis or inflammation (P-values > 0.05). There were significant negative correlations between histological fibrosis score and patient age at resection (rho = -0.48, P = 0.03), and time from diagnosis to surgery (rho = -0.73, P = 0.0002). Histological fibrosis and inflammation co-exist in symptomatic pediatric Crohn disease small-bowel strictures and are positively correlated. Pre-stenotic upstream small-bowel dilatation greater than 3 cm is significantly associated with confluent transmural fibrosis.