Role of the inflamed synovial volume of the wrist in defining remission of rheumatoid arthritis with gadolinium-enhanced 3D-SPGR MR imaging

The purpose of this study was to assess the role of inflamed synovial volume (ISV) in defining a state of remission in rheumatoid arthritis (RA) with contrast-enhanced, fatsuppression, three-dimensional (3D) gradient-recalled acquisition in the steady state with radiofrequency spoiling (SPGR) magnetic resonance (MR) imaging. Sixteen patients with RA (5 remission and 11 non-remission patients) were enrolled in this study. Contrast-enhanced, fat-suppression, 3D-SPGR MR imaging was performed before (n 5 12) and after (n 5 16) a mean 17 months of disease-modifying antirheumatic drugs (DMARDs). ISV was calculated by using a segmentation method. Statistical analysis of changes in ISVs and residual ISVs between the remission and the non-remission groups was performed. Intra- and interobserver reproducibility was tested. Residual ISVs and relative changes in ISVs were 3.23 6 1.84 cm3 and 51.4% (range 47.6‐55.2%) in the remission group and 6.26 6 2.03 cm 3 and 31.4% (range -73.5‐53.5%) in the non-remission group. Both values were significantly different between the two groups (P F 0.05 and 0.05, respectively). Volume measurement showed high reproducibility: Intra- and interobserver mean percentage errors were 5.04, 7.06, and 5.09%, respectively. Residual ISVs and relative changes in ISVs measured by MR imaging may provide objective and quantitative parameters in defining a state of remission in RA after therapy; however, the clinical utility of these measurements remains to be verified. J. Magn. Reson. Imaging 1999;10:202‐208. r 1999 Wiley-Liss, Inc.