Assessing Synovitis and Bone Erosion With Apparent Diffusion Coefficient in Early Stage of Rheumatoid Arthritis.

PURPOSE: The aim of this study was to assess the value of apparent diffusion coefficient (ADC) in distinguishing synovitis from joint fluid and bone erosion from cysts.

METHODS

Twenty-eight patients with suspected rheumatoid arthritis underwent diffusion-weighted imaging and pre- and post-contrast-enhanced magnetic resonance imaging. The mean ADC values were compared between synovitis and joint effusion and between bone erosion and cyst.

RESULTS

Mean ADC value of synovitis was significantly lower than that of the joint effusion (2.6 ± 0.37 × 10 vs 1.63 ± 0.37 × 10 mm/s, P < 0.001; cutoff value 2.10 × 10 mm/s). Mean ADC value of bone erosion was significantly lower than that of the cysts (1.61 ± 0.39 × 10 vs 2.39 ± 0.34 × 10 mm/s, P < 0.001; cutoff value 2.04 × 10 mm/s).

CONCLUSION

Apparent diffusion coefficient can be used in differentiating between synovitis and joint effusion and between bone erosion and cysts.