Objectives: To compare the ability of 2 different dedicated extremity magnetic resonance imaging (E-MRI) units and conventional radiography (CR) for identifying bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) and wrist joints.
Methods: CR and 2 MRI-examinations (on 0.2T Esaote Artoscan and 0.2T portable MagneVu MV1000 units) of 418 bones in the dominant wrist and 2.-5. MCP-joints of 15 RA patients and 4 healthy controls were performed and blindedly evaluated for bones being visible and for erosions.
Results: In MCP-joints, MagneVu visualized 18.5% of bones entirely and 71.1% were 67-99% visualized. In wrists, MagneVu visualized 1.5% of bones entirely, 39.8% were 67-99% visualized and 19% were not visualized at all. Artoscan and CR visualized all bones entirely. Artoscan/MagneVu/CR found 22/19/15 bones with erosions in MCP-joints and 66/40/13 in wrist joints. With the previously validated Artoscan-unit as standard reference, MagneVu and CR had sensitivities of 0.82 and 0.55, respectively, in MCP-joint bones and 0.41 and 0.14 in wrist bones. Specificities of CR and MagneVu were comparable (0.82-0.99). MagneVu was particularly more sensitive than CR in metacarpal heads and carpal bones. MagneVu and CR detected 100% and 89%, respectively, of large erosions (OMERACT-RAMRIS-score > 1 on Artoscan) in MCP-joints, and 69% and 15.8% of large erosions in wrists.
Conclusions: Both E-MRI units detected more erosions than CR, particularly due to a higher sensitivity in metacarpal heads and carpal bones. The MagneVu detected fewer erosions than the Artoscan, due to a lower average image quality and a smaller proportion of bones being visualized.
- Magnetic Resonance Imaging
- rheumatoid arthritis