Magnetic resonance imaging of the wrist in defining remission of rheumatoid arthritis

Objective. To assess the efficacy of magnetic resonance imaging (MRI) in objectively defining a state of remission in rheumatoid arthritis (RA) after treatment. Methods. Ten patients with RA involving the wrist were evaluated before treatment with methotrexate and hydroxychloroquine, and then mean 14 mo later with a followup evaluation. Clinical variables, laboratory measurements, and MRI using various techniques (TI weighted image, T2 weighted image, fat suppression T2 weighted image, postcontrast T1 weighted image, postcontrast dynamic image, postcontrast 3 dimensional image) were observed. Remission was defined by ACR crite ria. MRI changes were observed using 3 variables: extent of synovial proliferation; extent of bone marrow edema; and development of new erosion. In 6 of 10 patients, synovial signal intensity time curve changes at 30 s (E-30 ratio) were determined for quantitative assessment of synovitis. Results. Four patients achieved remission and 6 did not. All patients in remission showed decrease in extent of synovial proliferation and bone marrow edema with no newly developed erosion after treatment, compared to baseline. Five of 6 patients in nonremission showed newly developed erosions with variable changes in extent of synovial proliferation and bone marrow edema. E-30 ratio was determined in 3 patients in the remission group and 3 in the nonremission group, with 48% reduction in the former compared to 9% reduction in the latter. Conclusion. MRI is feasible for objectively defining remission and assessing the therapeutic effect of antirheumatic drugs; utility of MRI measures in clinical remission criteria remains to be verified.