Objective: MRI is an important tool for assessing activity and structural progression in patients with juvenile idiopathic arthritis (JIA). Assessment of erosions on the wrist is difficult given the presence of normal variations in healthy children. We aimed to compare bone depressions in JIA patients and differentiate them in healthy children and to validate the RAMRIS erosions, synovitis and bone edema score in JIA.

Patients and Methods: MRI of the wrist was performed in healthy children and those with JIA aged between 5 and 18 years. We evaluated the number of bone depressions in the carpal bones using coronal T1 and fat-saturated T2 sequences.

Results: A total of 13 patients with JIA were included and 22 healthy children. The number of bone depressions was significantly higher in the JIA group compared with healthy children in both age groups; for the age group 5-9 years 6.55 ± 2.25 (n = 7) of bone depressions were found in the JIA group vs. 2.15 ± 1.12 (n = 10) in the control group (p = 0,03). In the group aged 10-18 years the number of bone depressions in the JIA group and the healthy children group were respectively 9.08 ± 4.36 (n=6) and 5.35 ± 2.06 (n = 12) (p = 0.02).

Conclusions: Our study suggests that bone erosions on MRI of the wrist are more common in JIA unlike healthy children, and synovitis on MRI is highly correlated with disease activity and functional impact.