Performance of Surveillance MR Enterography (MRE) in Asymptomatic Children and Adolescents With Crohn's Disease

Background: MR enterography (MRE) is the primary modality for evaluating small bowel disease in pediatric Crohn's patients. Standard clinical practice includes imaging patients at diagnosis and during symptomatic recurrence. The role for MRE in surveillance of asymptomatic Crohn's patients has not yet been established.

Purpose: To determine whether MRE imaging features are associated with clinical recurrence.

Study type: Retrospective.

Populations: Pediatric Crohn's patients who underwent MRE while asymptomatic, defined by pediatric gastroenterologists using a physician global assessment; 35 MREs were identified.

Field strength/sequence: 1.5T including T₂ -weighted single-shot fast spin echo, balanced steady-state free precession, diffusion-weighted, and contrast-enhanced multiphase T₁ -weighted gradient recalled echo sequences.

Assessment: MREs were reviewed by three radiologists independently for mural thickening, T₂ -weighted hyperintensity, diffusion restriction, hyperenhancement, vasa recta engorgement, and overall assessment of disease activity. Two pediatric gastroenterologists reviewed patient medical records for 6 months following MRE to evaluate for recurrence, defined as Crohn's-related treatment escalation, surgery, or hospitalization.

Statistical tests: Fisher's exact test, Wald chi-square test, and model selection by Akaike information criterion minimization were used to assess statistical significance of MRE imaging features.

Results: Of 35 MREs identified, seven cases demonstrated clinical recurrence at 6 months (20%); 28 cases remained in remission (80%). Imaging features of active disease were present in 86% of patients with recurrence compared to 29% of patients in remission (P = 0.01). Wall thickening, T₂ -weighted hyperintensity, hyperenhancement, and diffusion restriction were significantly associated with recurrence. Multivariate regression analysis determined diffusion restriction to be the best predictor of recurrence within 6 months (P = 0.001, area under the curve 0.786).

Data conclusion: MRE performed on young asymptomatic Crohn's patients can identify patients who have a high probability of developing clinical recurrence in a 6-month period, indicating a potential role for surveillance imaging to assess for subclinical active disease.

Level of evidence: 3 Technical Efficacy Stage 5 J. Magn. Reson. Imaging 2019;50:1955-1963.