Development and preliminary validation of a paediatric-targeted MRI scoring system for the assessment of disease activity and damage in juvenile idiopathic arthritis.
Objectives To develop and validate a paediatric-targeted
MRI scoring system for the assessment of disease
activity and damage in juvenile idiopathic arthritis (JIA).
To compare the paediatric MRI score with the adultdesigned. Outcome Measures in Rheumatology Clinical
Trials\u2014Rheumatoid Arthritis MRI Score (RAMRIS),
whose suitability for assessing growing joints was tested.
Methods In 66 patients with JIA the clinically more
affected wrist was studied. Thirty-nine patients had
a 1-year MRI follow-up. Two readers independently
assigned the paediatric score and the RAMRIS to all
studies. Validation procedures included analysis of
reliability, construct validity and responsiveness to
change. A reduced version of the bone erosion score was
also developed and tested.
Results The paediatric score showed an excellent
reproducibility (interclass correlation coeffi cient >0.9).
The interobserver agreement of RAMRIS was moderate
for bone erosions and excellent for bone marrow oedema
(BMO). The paediatric score and RAMRIS provided similar
results for construct validity. The responsiveness to
change of the paediatric score was moderate for synovitis
and bone erosion, and poor for BMO and did not improve
when RAMRIS was applied. The reduced version of the
bone erosion was valuable for the assessment of joint
damage, and provided time-saving advantages.
Conclusion The results demonstrate that the paediatric
MRI score is a reliable and valid method for assessing
disease activity and damage in JIA. Unexpectedly,
the RAMRIS provides acceptable suitability for use in
the paediatric age group. Further work, especially in a
longitudinal setting, is required before defi ning the most
suitable MRI scale for assessing growing joints