Feasibility of Terminal Ileal Crohn's Disease Volume Measurement by MRE

Overview

This study demonstrates the technical feasibility of volumetric assessment of terminal ileal Crohn's disease (CD) using magnetic resonance enterography (MRE). Volumetric measurements showed good interobserver agreement and correlated with established disease activity indices, suggesting potential utility in monitoring treatment response.

Background

Endoscopic evaluation remains the gold standard for assessing Crohn's disease activity but is invasive and limited in scope. Cross-sectional imaging modalities such as MRE are widely used for diagnosis and monitoring, with established activity scores based on 2D measurements. However, these scores are subjective and do not capture the full disease volume. Volumetric assessment, common in oncology imaging, may provide a more comprehensive and sensitive biomarker of disease burden and treatment response in CD.

Data Highlights

The study retrospectively included 30 patients with suspected or known Crohn's disease who underwent MRE and ileocolonoscopy within 2 weeks. Two experienced radiologists independently performed manual volumetric segmentations of the terminal ileum disease using centrelines placed on T2-weighted sequences. The first reader also calculated the simplified magnetic resonance index of activity (sMARIA) and recorded segmentation times. Interobserver agreement and correlations with endoscopic scores were assessed.

Key Findings

• Volumetric measurement of terminal ileal Crohn's disease on MRE is technically feasible using manual segmentation guided by centrelines.
• Interobserver agreement between two radiologists for volumetric assessment was good, indicating reproducibility.
• Volumetric disease burden correlated with endoscopic Crohn’s disease endoscopic index of severity (CDEIS) and the sMARIA score, supporting its validity as a biomarker.
• Volumetric assessment may better capture the full extent of disease compared to traditional single-slice bowel wall thickness measurements.
• Preliminary analysis suggests volumetric changes could reflect treatment response to biologic therapy.

Clinical Implications

Volumetric MRE assessment offers a promising, reproducible imaging biomarker for evaluating terminal ileal Crohn's disease activity and treatment response. This approach may enhance monitoring by providing a more comprehensive measure of disease burden beyond conventional 2D metrics. Incorporation of volumetric analysis into clinical practice could improve objective assessment of transmural healing and guide therapeutic decisions.

Conclusion

Volumetric measurement of terminal ileal Crohn's disease using MRE is feasible and correlates with established disease activity indices. This method holds potential as a sensitive imaging biomarker for monitoring disease burden and response to therapy.

References

1. Pariente et al. 2011 -- Development of the Crohn’s Disease Endoscopic Index of Severity (CDEIS)
2. Rimola et al. 2016 -- Magnetic Resonance Imaging for Crohn's Disease Activity Assessment
3. Orlando et al. 2020 -- Simplified Magnetic Resonance Index of Activity (sMARIA) Validation
4. Taylor et al. 2018 -- Cross-sectional Imaging in Crohn’s Disease