Abbreviated magnetic resonance (MR) enterography for Crohn's disease: is intravenous contrast enhancement always necessary?

Aim

The aim of the study is to evaluate the diagnostic performance and noninferiority of an abbreviated, nonintravenous contrast-enhanced magnetic resonance enterography (MRE) protocol compared with a standard gadolinium-enhanced protocol for the assessment of Crohn's disease activity, extent and complications.

Materials And Methods

This retrospective, single-centre study included 50 consecutive patients (mean age 42.7 ± 16.9 years) with suspected or established Crohn's disease who underwent standard MRE. Two radiologists, blinded to clinical data and reference reports, independently evaluated abbreviated protocol sequences (balanced turbo field echo [BTFE], T2-weighted spectral attenuated inversion recovery [SPAIR] and turbo spin echo [TSE], diffusion-weighted imaging [DWI]/apparent diffusion coefficient [ADC]). Diagnostic performance was assessed against the report as the reference standard. Interobserver agreement for categorical variables was analysed using Cohen's and Fleiss' kappa coefficients, while continuous variables were evaluated using intraclass correlation coefficients (ICCs), with 95% confidence intervals. Bland-Altman analysis was performed.

Results

Agreement for disease activity was almost perfect (κ = 0.83, 95% confidence interval [CI]: 0.64-0.96). (Reader A: sensitivity 93.5% (95% CI: 78.6-99.2), specificity 84.2% (60.4-96.6); reader B: sensitivity 90.3% (74.2-98.0), specificity 94.7% (74.0-99.9)). Agreement for anatomical location was also almost perfect. Substantial agreement was observed for stenosis detection (κ from 0.66 (95% CI: 0.29-0.89) to 0.73 (0.44-0.92)), whereas agreement for ulceration and penetrating complications was lower and heterogeneous. Quantitative measurements demonstrated excellent reproducibility (ICC > 0.87, 95% CI: 0.79-0.93).

Conclusion

The abbreviated, nonintravenous contrast-enhanced MRE protocol demonstrates noninferior diagnostic performance for the evaluation of disease activity, extent and stenosis in Crohn's disease. Its implementation may reduce examination time and contrast exposure, although contrast-enhanced imaging remains indicated for the assessment of ulcerations and penetrating complications.