USE OF MAGNETIC-RESONANCE-IMAGING AND POSITRON EMISSION TOMOGRAPHY INTHE ASSESSMENT OF SYNOVIAL VOLUME AND GLUCOSE-METABOLISM IN PATIENTS WITH RHEUMATOID-ARTHRITIS

Objective. To measure the anatomic and physiologic changes in the syno vium of patients with active rheumatoid arthritis (RA) before and afte r the initiation of treatment with low-dose systemic glucocorticoids a nd methotrexate (MTX), Methods, Two patients with RA with active synov itis-involving the carpus we're evaluated by imaging parameters at bas eline and again after 14 weeks (of treatment with low-dose prednisone and MTX), Standard clinical parameters, laboratory measurements, and c ontrast-enhanced magnetic resonance imaging (MRI) (synovial volume est imate) and positron emission tomography (PET) with F-18-fluoro-2-deoxy glucose (18-FDG) (synovial metabolism estimate) were performed, Result s, Compared with baseline, standard clinical parameters (i,e,, joint c ount, joint index, morning stiffness, global assessments of arthritis activity, and erythrocyte sedimentation rate) improved dramatically in both patients after treatment with low-dose prednisone and MTX, In co ncert with this trend, the synovial volume of the affected wrist was r educed by 60%, and 76% and the metabolism of 18-FDG was reduced by 66% and 69% in the 2 patients, Conclusion, These preliminary observations indicate that a volumetric estimate of inflamed synovium (using contr ast-enhanced MRI) and quantification of synovial deoxyglucose metaboli sm (using PET) are technically feasible and, in the 2 reported casts, correlate well with standard outcome measures; These imaging modalitie s may provide new objective parameters to determine RA disease activit y and effectiveness of antirheumatic medications; however, the potenti al clinical utility of these measures remains to be defined.