Major Finding: A novel system for scoring MRIs in children with juvenile idiopathic arthritis showed significant, moderate correlation (0.47) with the Juvenile Arthritis Damage Index Articular score (P less than .0001), as well as a moderate (0.55) significant correlation with the Sharp/van der Heijde score for reading radiographs (P less than .0001).
Data Source: A total of 66 consecutively recruited patients with JIA from a single center in Italy.
Disclosures: The authors stated that they had no competing interests in relation to this study.
A new magnetic resonance imaging scoring system is a reliable method for assessing joint damage in patients with juvenile idiopathic arthritis.
The adult-targeted Rheumatoid Arthritis MRI Score, previously considered unusable in children because of the “peculiarities of the growing skeleton,” was also moderately well correlated with clinical indicators of disease, wrote Dr. Clara Malattia and her colleagues.
Dr. Malattia, of the Istituto G Gaslini in Genoa, Italy, and her colleagues looked at 66 patients, of whom 51 were females, who had juvenile idiopathic arthritis involving the wrist.
The patient's clinically more affected wrist was assessed with MRI, radiography, and clinical assessment (Ann Rheum Dis. 2010 [doi:10.1136/ard.2009.126862]).
Bone erosions were scored at 15 sites within the carpus according to a 0-4 scale.
Bone marrow edema was evaluated using a 0-2 scale. Finally, synovitis was assessed using the standard Rheumatoid Arthritis MRI Scoring System.
At baseline, 55 out of the total 66 patients (83.3%) patients had erosions detected by MRI (only 23 of which were detected on radiography). Bone marrow edema was also seen in 55 of the 66 patients (83.3%), and synovitis was detected in 60 of the 66 patients (90.9%).
The pediatric MRI erosion score registered significant, moderate correlation (0.47) with the Juvenile Arthritis Damage Index Articular score (P less than .0001), as well as a moderate (0.55) significant correlation with the Sharp/van der Heijde score for reading radiographs (P less than .0001). The pediatric MRI bone edema score correlated highly (0.66) with the Sharp/van der Heijde score (P less than 0.0001), and registered moderate correlation (0.40) with the JADI-A (P = .001).
On the other hand, there was also high correlation (0.66) between the RAMRIS bone marrow edema score and the Sharp/van der Heijde score (P less than .0001), as well as between the RAMRIS bone erosion score and the Sharp/van der Heijde score (0.60, P less than .0001).
The synovitis score correlated moderately but significantly with the physician's global assessment, the swollen joint count, and the Juvenile Arthritis Disease Activity Score for 71 joints.
Assessment of 39 follow-up MRIs completed a median of 1.2 years after the index scan showed that of the 22 who had improved according to the ACR Pediatric 30 criteria, there was a significant decrease on the pediatric bone marrow edema score, a non-significant decrease in the RAMRIS bone marrow edema score, and a significant, small decrease on the synovitis score.