Baseline Magnetic Resonance Enterography Stratifies Persistence Risk of Crohn's Disease Strictures

Crohn's disease (CD) strictures are clinically important, but persistence after advanced therapy remains difficult to assess. We developed and temporally validated a magnetic resonance enterography (MRE)-based framework integrating activity-related and structural imaging severity to stratify stricture non-improvement.

This two-stage study included patients with CD who initiated advanced therapy and underwent baseline and follow-up MRE. An activity-related score (A-score) and a persistence-associated structural score (P-score) were derived in a development cohort (2012-2020) and applied to a temporally separated validation cohort (2021-2024). The primary endpoint was stricture-level non-improvement on follow-up MRE; intestinal surgery was also evaluated.

The development cohort included 115 patients with 161 strictures, and the validation cohort included 72 patients with 104 strictures. The A-score comprised bowel wall thickness >6 mm, ulceration, and comb sign; the P-score comprised stricture length >3 cm, prestenotic bowel diameter >3 cm, and lack of intramural edema. A-score and P-score positivity were each associated with stricture non-improvement after multivariable adjustment (adjusted odds ratios, 18.68 and 19.75, respectively; P<.01 for both). The summed A+P score showed an area under the curve of 0.90 and higher discrimination than either score, segmental MaRIA, or segmental sMaRIA alone. Improvement rates decreased with increasing A-scores and remained low at higher P-scores. Baseline A/P strata also differed in surgery-free survival (P<.01).

Baseline MRE integrating activity-related and structural imaging severity stratified stricture persistence and was associated with subsequent surgery. This framework should be interpreted as a baseline imaging severity and risk-stratification tool rather than an inflammatory-fibrotic phenotype classifier.