BMC Medical Imaging (Sep 2017)

Computer-aided evaluation of inflammatory changes over time on MRI of the spine in patients with suspected axial spondyloarthritis: a feasibility study

  • Evgeni Aizenberg,
  • Rosaline van den Berg,
  • Zineb Ez-Zaitouni,
  • Désirée van der Heijde,
  • Monique Reijnierse,
  • Oleh Dzyubachyk,
  • Boudewijn P.F. Lelieveldt

DOI
https://doi.org/10.1186/s12880-017-0226-4
Journal volume & issue
Vol. 17, no. 1
pp. 1 – 9

Abstract

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Abstract Background Evaluating inflammatory changes over time on MR images of the spine in patients with suspected axial Spondyloarthritis (axSpA) can be a labor-intensive task, requiring readers to manually search for and perceptually align a set of vertebrae between two scans. The purpose of this study was to assess the feasibility of computer-aided (CA) evaluation of such inflammatory changes in a framework where scans from two time points are fused into a single color-encoded image integrated into an interactive scoring tool. Methods For 30 patients from the SPondyloArthritis Caught Early (SPACE) cohort (back pain ≥ 3 months, ≤ 2 years, onset < 45 years), baseline and follow-up MR scans acquired 9–12 months apart were fused into a single color-encoded image through locally-rigid image registration to evaluate inflammatory changes in 23 vertebral units (VUs). Scoring was performed by two expert readers on a (−2, 2) scale using an interactive scoring tool. For comparison of direction of change (increase/decrease) indicated by an existing reference, Berlin method scores ((−3, 3) scale) of the same MR scans from a different ongoing study were used. The distributions of VU-level differences between CA readers and between the CA and Berlin methods (sign of change scores) across patients were analyzed descriptively. Patient-level agreement between CA readers was assessed by intraclass correlation coefficient (ICC). Results Five patients were excluded from evaluation due to failed vertebrae segmentation. Patient-level inter-reader agreement ICC was 0.56 (95% CI: 0.22 to 0.78). Mean VU-level inter-reader differences across 25 patients ranged (−0.04, 0.12) with SD range (0, 0.45). Across all VUs, inter-reader differences ranged (−1, 1) in 573/575 VUs (99.7%). Mean VU-level inter-method differences across patients ranged (−0.04, 0.08) with SD range (0, 0.61). Across all VUs, inter-method differences ranged (−1, 1) in 572/575 VUs (99.5%). Conclusions Fusion of MR scans of the spine from two time points into a single color-encoded image allows for direct visualization and measurement of inflammatory changes over time in patients with suspected axSpA.

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