MRI in Perianal Fistulizing Crohn’s Disease: Inter-Reader Agreement of MAGNIFI-CD and 3D Volume Measurements
Author Block: K. Johnson1, I. De Kock2, K. J. H. Bengtsson3, B. Janssens1, A. Menys4, G. Bislenghi1, C. W. P. Greer4, G. Bhatnagar4, B. Verstockt1; 1Leuven/BE, 2Ghent/BE, 3Lund/SE, 4London/UK
Purpose: The Magnetic Resonance Novel Index for Fistula Imaging in Crohn's Disease (MAGNIFI-CD) and 3D volumetry are emerging metrics for quantifying and visualizing perianal Crohn’s disease (pCD). The purpose of the study was to assess inter-reader agreement for both metrics in different pCD TOpClass categories among radiologists with varying levels of expertise in inflammatory bowel disease (IBD).
Methods or Background: Fifty pelvic MRIs from 50 unique pCD patients were retrospectively and randomly selected from a single-center IBD database: 25 represented minimal disease (suitable for repair; TOpClass 1–2a), while 25 represented disease requiring symptom control interventions/proctectomy (TOpClass 2b–3). Six radiologists independently assessed each MRI using a commercial MAGNIFI-CD module (Entrolytics by Motilent), blinded to clinical data. Three were IBD experts (>50 fistula MRI reads/year), three were non-IBD experts (<10/year). MAGNIFI-CD (0–25) was scored, and contrast-enhancing fistula volumes were manually segmented on T1 post-contrast axial images. Inter-reader agreement was analyzed through intraclass correlation coefficient (ICC).
Results or Findings: Inter-reader agreement for MAGNIFI-CD was ICC = 0.747 (95% CI: 0.640–0.835), among experts 0.786 (0.681–0.865) and non-experts 0.780 (0.610–0.877). Agreement for 3D volume was 0.887 (0.830–0.929), among experts 0.872 (0.792–0.923) and non-experts 0.893 (0.796–0.942). In TOpClass 1–2a, agreement for MAGNIFI-CD was 0.706 (0.561–0.834) and volume 0.537 (0.367–0.715). In TOpClass 2b–3, agreement was 0.664 (0.482–0.816) for MAGNIFI-CD and 0.885 (0.800–0.943) for volume.
Conclusion: MAGNIFI-CD and 3D fistula volume measurements showed substantial to almost perfect inter-reader agreement with comparable performance between experts and non-experts, underscoring their reliability for research and clinical use. Agreement for volume was, however, only moderate in mild disease (TOpClass 1–2a), indicating greater assessment difficulty in this subgroup.
Limitations: Single-center, small sub-groups.
Funding for this study: Swedish governmental funding of clinical research ALF, Maggie Stephens foundation, Gastroenterological Research Fund Sweden, the Royal Physiographic Society of Lund, Medical Society in Lund, Olle Olsson foundation, Nils-Magnus and Irma Ohlsson Foundation, Swedish Society of Radiology
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Local ethics committee approval (S69002)