Reliability and agreement of proton density-weighted vs. gadolinium-enhanced T1-weighted MRI in hand osteoarthritis. An OMERACT MRI special interest group reliability exercise.

OBJECTIVES: To compare reliabilities of assessing synovitis in hand osteoarthritis (OA) using Magnetic Resonance Imaging (MRI) with/without gadolinium (Gd). METHODS: Three readers scored synovitis on non-enhanced two-dimensional (2D) proton density (PD)-weighted MRI and Gd-enhanced (3D) MRI of hand joints in 20 patients. Inter-reader reliabilities were examined. RESULTS: Reliability was good for Gd-enhanced MRI, but poor for non-enhanced PD-weighted MRI (intraclass correlation coefficient 0.83 and 0.21, respectively). Agreement between the two sequences was poor (weighted kappa 0.18). CONCLUSION: Gd-enhanced MRI was more reliable than PD-weighted MRI for assessing synovitis. Gd-enhancement, but also resolution and tissue contrast, might have contributed to this.

Evaluation of three scoring methods for Fluorescence Optical Imaging in erosive hand osteoarthritis and rheumatoid arthritis.

Objective: Fluorescence Optical Imaging (FOI) demonstrates indocyanine green (ICG)-enhanced microcirculation in wrist and finger joints, as a sign of inflammation. We wanted to assess the reliability of three FOI scoring methods from Berlin, Stockholm, and Copenhagen, to assess the validity of FOI with MRI as reference and to compare enhancement in hand joints in erosive hand osteoarthritis (OA) vs. rheumatoid arthritis (RA). Design: Five readers scored all finger and wrist joints of 26 patients with erosive hand OA and RA on semi-quantitative 0-3 scales using three different FOI scoring methods. To evaluate inter-reader reliability, we calculated the intraclass correlation coefficients (ICC) for sum scores and prevalence and bias adjusted kappa values for ordinal scales (Pabak-OS) on joint level. Enhancement in joint groups in erosive hand OA vs. RA was compared using Mann-Whitney test. Sensitivities and specificities of FOI was calculated with MRI as reference for hand OA patients only. Results: We found moderate to good inter-reader reliability for all FOI scoring methods (Pabak-OS: 0.50-0.78, ICC: 0.43-0.85) and different patterns of enhancement in erosive hand OA vs. RA with significantly more FOI enhancement in DIP joints in erosive hand OA across all methods. With MRI as reference the different FOI scoring methods reached similar sensitivities (63-65%) and specificities (76-91%). Conclusion: FOI enhancement can be measured reliably in erosive hand OA and RA using three different scoring methods. More DIP enhancement in erosive hand OA patients and good agreement with MRI support the diagnostic performance of FOI.