Magnetic Resonance Imaging of Bilateral Hands Is More Optimal Than MRI of Unilateral Hands for Rheumatoid Arthritis.

Objective: To explore the advantages of magnetic resonance imaging (MRI) of bilateral hands in rheumatoid arthritis (RA).

Methods: Consecutive patients with active RA were recruited for clinical assessments, radiographs, and MRI of bilateral hands. Bilateral hands were scanned simultaneously on 3.0 T whole-body MRI system and were scored on synovitis, osteitis, and bone erosion according to the RA MRI scoring (RAMRIS) system.

Results: Among 120 patients included, wrist bones and metacarpophalangeal joint (MCPJ) 2 proximal showed bone erosion in early RA. The second to fifth metacarpal bases and the second to fourth MCPJ distal showed more bone erosion in mid-stage or late-stage RA. When MRI of dominant unilateral hand was analyzed, MRI synovitis and osteitis in 5% of wrists and 3 MRI features in 5-14% of MCPJ were misdiagnosed (McNemar test, all p < 0.05). There were 46% wrist synovitis, 29-52% MCPJ2-5 synovitis, 45% wrist osteitis, and 20%-34% MCPJ2-5 osteitis not detected by joint tenderness and/or swelling. When the clinically more severe hand was selected for MRI of unilateral hand according to physical examination, MRI synovitis in 5% of wrists and 3 MRI features in 7-15% of MCPJ were misdiagnosed (all p < 0.05). Scatter plots and linear regression analyses were used to illustrate RAMRIS between dominant or selected hand (Y values) and nondominant or nonselected hand (X values). All linear models were markedly different from a Y = X linear model, indicating the dominant or clinically more severe hand could not represent the contralateral hand to evaluate RAMRIS.

Conclusion: MRI of bilateral hands is more optimal than MRI of the unilateral hand in RA.