Discrimination between fluid, synovium, and cartilage in patients with rheumatoid arthritis: Contrast enhanced spin echo versus non-contrast-enhancedfat-suppressed gradient echo MR imaging

PURPOSE: The aim of this study was to compare fat-suppressed T1-weighted 3D -Gradient Echo (GE)-images and conventional T1-weighted contrast-enhanced S E images in the assessment of patients with rheumatoid arthritis in an atte mpt to improve discrimination of inflamed synovium, joint fluid, and cartil age, PATIENTS AND METHODS: 28 knee joints in 20 patients with rheumatoid arthrit is were examined with a 3 D-GE-T1 weighted sequence with frequency-selectiv e fat suppression (Flash 3D fat sat) and T1-weighted SE-sequences after int ravenous gadolinium-containing contrast agent administration using a 1.5T s ystem. Differentiation of cartilage, synovium, and joint effusion was asses sed on both sequences qualitatively by two observers and quantitatively by signal intensity measurements. RESULTS: Qualititative analysis revealed higher grading rates for cartilage /fluid differentiation with fat-suppressed T1-weighted GE images than contr ast enhanced T1-SE images, Quantitative analysis by measurements of contras t-to-noise ratios revealed significantly higher rates for the Flash 3D fat sat with regard to cartilage/fluid discrimination, significantly higher rat es for T1-SE postcontrast for cartilage/synovium discrimination, and signif icantly higher rates for T1-SE post-contrast for synovium/fluid discriminat ion, CONCLUSION: 3D-GE-imaging with fat-suppressed T1 weighted sequences allows sufficient differentiation of cartilage and joint fluid in patients with rh eumatoid arthritis without application of contrast agents and may assist in monitoring disease progression and response to therapy. The higher contras t to noise ratios of cartilage/synovium and synovium/fluid on T1-SE images following administration of gadolinium-containing contrast agents may impro ve detection of disease activity.