Development and preliminary validation of a paediatric-targeted MRI scoring system for the assessment of disease activity and damage in juvenile idiopathic arthritis.
OBJECTIVE
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 adult-designed. Outcome Measures in Rheumatology Clinical Trials-Rheumatoid 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 coefficient >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.


CONCLUSIONS
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 defining the most suitable MRI scale for assessing growing joints.
Correspondence to Dr Clara Malattia, Pediatria II, irccs G Gaslini, Largo G Gaslini 5, 16147 Genova, Italy. claramalattia@ospedale-gaslini.ge.it
Clara
C
Malattia
Maria Beatrice
MB
Damasio
Angela
A
Pistorio
Maka
M
Ioseliani
Iris
I
Vilca
Maura
M
Valle
Nicolino
N
Ruperto
Stefania
S
Viola
Antonella
A
Buoncompagni
Gian Michele
GM
Magnano
Angelo
A
Ravelli
Paolo
P
Tomà
Alberto
A
Martini
D000293:Adolescent; D001171:Arthritis, Juvenile / Q000175:diagnosis*; D001855:Bone Marrow Diseases / Q000175:diagnosis / Q000209:etiology; D002648:Child; D018450:Disease Progression; D004487:Edema / Q000175:diagnosis / Q000209:etiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013585:Synovitis / Q000175:diagnosis / Q000209:etiology; D014955:Wrist Joint / Q000473:pathology