Validating MRI and the OMERACT RAMRIS for assessing joint damage in RA
Original article
Møller Døhn U et al. (2007) Rheumatoid arthritis bone erosion volumes on CT and MRI: reliability and correlations with erosion scores on CT, MRI and radiography. Ann Rheum Dis 66: 1388–1392 PubMed
Documenting joint damage in rheumatoid arthritis (RA) is important for monitoring the course of the disease and for evaluating new treatments. MRI can be used for quantitative assessment of bone erosion volumes in the wrists and metacarpophalangeal (MCP) joints of RA patients. A semiquantitative scoring system, the Outcome Measures in Rheumatology Clinical Trials/Rheumatoid Arthritis Magnetic Resonance Imaging Score (OMERACT RAMRIS) has also been developed to assess bone erosions in these joints.
Neither scoring method has been sufficiently validated against any external reference, something that Møller Døhn et al. sought to rectify. They investigated agreement within and between methods when measuring erosion volumes of MCP joints on CT and MRI in 17 patients with RA and 4 healthy controls. They then compared the volumes with erosion scores for CT, MRI and radiography.
CT, MRI and radiography detected 77, 62 and 12 erosions, respectively. The mean erosion volume seen on CT compared to MRI was very similar (26 mm3 vs 30 mm3). Total mean erosion volumes (per person, including controls) were 97 mm3 on CT and 90 mm3 on MRI. MRI erosion volumes correlated strongly with OMERACT RAMRIS erosion scores and with the Sharp/van der Heijde erosion score.
The authors say that their data support the reliability of MRI in estimating bone erosion size in RA, and demonstrate that the OMERACT RAMRIS erosion score is a valid measure of joint destruction.
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Subject areas under which this article appears: Rheumatoid arthritis | Diagnosis, imaging and screening
