To assess the practicability of magnetic resonance imaging (MRI) in confirming the diagnosis of clinically suspected rheumatoid arthritis (RA), when anti-cyclic citrullinated peptide antibody and radiographic erosions are absent.
We prospectively involved 31 treatment-naive patients with early inflammatory arthritis. At the initial visit, X-rays and gadolinium-enhanced MRI of both hands, as well as serological examinations and acute phase reactants were performed. The scores of synovitis, bone edema, bone erosion and tenosynovitis of metacarpophalangeal and wrist joints were evaluated using the RA-MRI scoring system. For all the patients, radiographs at baseline were normal and anti-cyclic citrullinated peptide antibodies were negative.
At the end of follow-up(median 15 months, range 12-20 months), 22 patients were diagnosed as having RA according to 1987 American College of Rheumatology criteria. Bone edema, erosions, synovitis and tenosynovitis were observed in all the patients. However, the frequency of symmetric synovitis in wrists was significantly higher in the RA group. Moreover this group turned out to have significantly higher MRI bone erosion score in wrists. Further, receiver operating characteristic curve analysis revealed a positive wrist bone erosion score at 5, with a specificity of 78% and a sensitivity of 68%. There was no significant difference between the two groups with respect to metacarpophalangeal synovitis, metacarpophalangeal bone erosion, bone edema or tenosynovitis.
MRI evidence of symmetric synovitis at wrist and a high bone erosion score at that site may assist in making an early diagnosis of RA in those patients who are negative for anti-cyclic citrullinated peptide antibody.