Utility of T2* and DWI-IVIM to distinguish inflammatory and noninflammatory strictures in Crohn’s disease: a prospective cross-sectional cohort study

OBJECTIVE: In Crohn's disease (CD), noninflammatory strictures benefit from surgical resection or endoscopic dilatation, whereas inflammatory strictures might still respond to anti-inflammatory treatment. Therefore, it is crucial to determine whether a stricture is inflammatory or noninflammatory. We investigated whether magnetic resonance imaging (MRI) T2* and intravoxel incoherent motion (IVIM) parameters can distinguish inflammatory from noninflammatory strictures, using histopathology of location-matched surgical resection specimens as reference. MATERIALS AND METHODS: CD patients scheduled for small bowel segment resection were included. MRI scans were acquired in 32 patients, including conventional anatomical T2*-weighted and DWI-IVIM sequences. The field of view was centred on the most significant small bowel stricture. T2* and IVIM parameters were compared with location-matched surgical resection specimens on histopathological sections, scored as inflammatory or noninflammatory. A Mann-Whitney U test (α = 0.01) was used to assess differences in MRI parameters between inflammatory and noninflammatory sections. RESULTS: Thirty-one patients (55% females) were analysed. Median T2*-value was significantly higher in inflammatory sections (25.4 ms [interquartile range 19.0‒33.1], n = 33) versus noninflammatory sections (18.6 ms [14.5‒27.8], n = 26) (p = 0.010). Diffusion coefficient was lower in inflammatory sections (0.0012 mm²/s [0.0010‒0.0014], n = 35) versus noninflammatory sections (0.0014 mm²/s [0.0011‒0.0019], n = 24) (p = 0.039). No significant differences were found in pseudodiffusion coefficient and pseudodiffusion signal fraction (0.06 mm²/s [0.03‒0.08] versus 0.06 mm²/s [0.03‒0.11], p = 0.926; 0.15 [0.09‒0.20] versus 0.18 [0.11‒0.24], p = 0.327). CONCLUSION: A significantly higher T2*-value and a trend towards a lower diffusion coefficient were observed in inflammatory sections compared to noninflammatory sections in CD. External validation is needed. RELEVANCE STATEMENT: Higher T2*-value and lower IVIM diffusion coefficient could potentially serve as a biomarker in inflammatory stricture sections compared to noninflammatory sections in Crohn's disease. TRAIL REGISTRATION: Dutch trial register NL9105: https://trialsearch.who.int/Trial2.aspx?TrialID=NL-OMON54948 . KEY POINTS: T2* could serve as a biomarker for distinguishing inflammatory from noninflammatory strictures in Crohn's disease. Diffusion measured by IVIM can distinguish inflammatory from noninflammatory strictures in Crohn's disease. Muscularisation was more prominent than fibrosis in strictures due to Crohn's disease.