Correlation between computer-aided dynamic gadolinium-enhanced MRI assessment of inflammation and semi-quantitative synovitis and bone marrow oedema scores of the wrist in patients with rheumatoid arthritis-a cohort study

Objective. To test the correlation between assessment of inflammation using dynamic contrast-enhanced MRI (DCE-MRI) analysed by a novel computer-aided approach and semi-quantitative scores of synovitis and bone marrow oedema (BME) using the OMERACT-RA MRI Scoring (RAMRIS) system, in the wrist of patients with RA. Methods. Fifty-four RA patients had conventional and DCE-MRI of a symptomatic wrist using a low-field 0.2T extremity scanner. RAMRIS synovitis and BME of the wrist joint were done. DCE-MRI data were analysed in three ways: (i) in all images (fully automated approach), (ii) within a large extended region of interest (ROI) placed around the wrist joint (semi-automated approach) and (iii) within a small ROI placed in the area with most visual enhancement (semi-automated approach). Time spent on each procedure was noted. Spearman's rank correlation test was applied to assess the correlation between RAMRIS and the computer-generated dynamic parameters. Results. RAMRIS synovitis (range 2-9), BME (range 0-39) and the dynamic parameters reflecting the number of enhancing voxels were significantly correlated, especially when an extended ROI around the wrist was used (rho = 0.74; P<0.01 for synovitis and rho = 0.82; P<0.01 for BME). The observer spent on average 20 min (range 12-25 min) to perform RAMRIS, including acquisition of the results in the database, and 8 min (range 7-10 min) to perform all above-mentioned computer-aided analyses. Conclusion. Computer-aided analysis of DCE-MRI data correlated with RAMRIS synovitis and BME and was twice as fast to perform. This technique may be useful for quick semi-automated assessment of joint inflammation, but needs further validation.