Bone oedema predicts erosive progression on wrist MRI in early RA--a 2-yr observational MRI and NC scintigraphy study.

Objectives: To investigate if disease assessment by contrast-enhanced dynamic and static magnetic resonance imaging (MRI) and quantitative nanocolloid (NC) scintigraphy gives useful additional information in early rheumatoid arthritis (RA).

Methods: Twenty-seven patients with early RA (disease duration < or =12 months) were followed up for 1 yr and 24 of them for 2 yrs with contrast-enhanced MRI and NC scintigraphy of the wrist joint. Synovial inflammation was assessed by measuring time-dependent enhancement rates (E-rate) from dynamic MRI scans and technetium(99m)-labelled nanocolloid ((99m)Tc-NC) uptake from scintigraphy scans. Synovial membrane hypertrophy, bone oedema and erosions were semiquantitatively scored according to the Outcome Measures in Rheumatology Clinical Trials RA-MRI scoring system from static MR images. Response to the treatment was evaluated based on whether or not > or = 50% improvement was achieved in the tender and swollen joint scores and the Health Assessment Questionnaire score, with normal C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) levels. Progression of the erosion score on wrist MRI was evaluated as the outcome.

Results: The baseline MRI bone oedema score (rho= 0.67), MRI synovitis score (rho= 0.57), ESR (rho= 0.56), CRP (rho= 0.48), E-rate (rho= 0.47) and (99m)Tc-NC uptake (rho= 0.45) were related with the change in the MRI erosion score from baseline to 2 yrs (rho= Spearman's correlation). In the multivariate logistic regression model, the bone marrow oedema score was the only baseline variable that predicted erosive progression at 2 yrs' follow-up (OR 4.2, 95% CI 1.3-13.8). The median (interquartile range) change in the erosion score from baseline to 2 yrs was 0 (0, 0) and 4 (2, 5) in the patients with (n= 9) and without (n= 15) a persistent clinical response over the 2 yrs, respectively (P= 0.001). The non-responders who presented with erosive progression from 1 yr to 2 yrs had higher MRI synovitis scores, bone oedema scores, E-rate and (99m)Tc-NC uptake at 1-yr follow-up than the non-responders without progressive bone damage.

Conclusion: The degree of local synovial inflammation at baseline, evaluated by dynamic and static MRI and quantitative NC scintigraphy, is closely related to the progression of wrist joint erosions during the first 2 yrs of the disease. Furthermore, at follow-up, if no persistent clinical response is achieved, these imaging methods may help to predict future erosiveness and help in clinical therapeutic decision making.