Caveat on the Interpretation of Metacarpal Head Erosions Seen by Magnetic Resonance Imaging

To the Editor: Olech, et al 1 recently used extremity-dedicated magnetic resonance imaging (MRI) to highlight hand lesions in patients with rheumatoid arthritis (RA) in comparison with controls. They noted that the second and third metacarpal heads were more often eroded in RA. Bone lesions, morphologically identical with erosions, were also common in controls at the same locations. A similar observation was made by Tan, et al , who linked it to anatomical causes2. The term “lesion” in MRI studies of the joints encompasses bone edema, erosions, and cysts3. According to the OMERACT definition4, an erosion is a sharply marginated bone lesion, of typical juxtaarticular localization and specific signal characteristics, which is … Address correspondence to Prof. M.A. Cimmino; E-mail: cimmino{at}unige.it