Background In chronic inflammatory conditions, the need for a more objective measurement of disease activity has been identified. Imaging biomarkers based on the automated quantification of dynamic contrast enhanced magnetic resonance images (DCE-MRI) have been studied in adult patients with rheumatoid arthritis (RA)¹. In children with juvenile idiopathic arthritis (JIA) similar knowledge is very limited.

Objectives To compare treatment changes of clinical scores in patients with JIA and automated DCE-MRI quantitative parameters analysed with a dedicated software - Dynamika^tm.

Methods In 8 Caucasian patients (7 girls, median age 13,6 years) with polyarticular JIA, who underwent standardized DMARD treatment, DCE-MRI of the metacarpophaleangeal (MCP) 2–5 joints in the most affected hand were performed at 3 time points: baseline (BL), month 3 and 6 of treatment using 0.2 Tesla Esaote C-Scan. Clinical scores included active joints (AJ), swollen joints (SJ), tender joints (TJ) and joints with limited range of motion (LJ) divided into 3 levels: joint level (the MCP), region level (the hand) and global level (all joints). DCE-MRI were analyzed using a region of interest covering synovium of MCP 2–5. Output parameters included DEMRIQ-ME (Maximum Enhancement) and -IRE (Initial Rate of Enhancement). DEMRIQ is a perfusion/inflammation imaging biomarker and combines the volume of synovial inflammation (GD-map based statistics) and the degree of perfusion (ME-map or IRE-map based statistics), either as volume (classified pixels) or intensity (ME/IRE) or a combination of both (DEMRIQ score).

Differences in DEMRIQ scores between visits, were analyzed using the t-test (p<0.05 = statistically significant, p<0.25 = clinically meaningful). Correlations were also assessed using the Pearson's Correlation Coefficient.

Results At 3 months all patients showed statistically significant and/or clinically meaningful changes mainly in DEMRIQ-ME, 6 patients in parallel with clinical improvement. Two patients worsened in DEMRIQ-ME despite clinical improvement. At 6 months, six patients continued clinical improvement. In all but one, DEMRIQ-ME persisted or worsened (compared to previous examinations) and patients had a clinical flare within 2 to 6 months after last DCE-MRI. One patient had persistent clinical activity with corresponding DEMRIQ-ME score. Another patient showed clinical worsening and improvement in DEMRIQ-ME, where clinical improvement followed later during disease course. Thus a persistent/rising DEMRIQ-ME compared to previous examinations predicted clinical flare in a timeframe between 2 and 6 months after last DCE-MRI, despite of global clinical improvement.

Conclusions Dynamika based scores (mainly DEMRIQ-ME) show to be useful for depicting disease activity in JIA. In particular, the DEMRIQ-ME correlated with clinical activity over time especially after 3 months. Moreover, persistence or worsening of Dynamika based scores could predict clinical flares (in this study within 2–6 months) despite of global clinical improvement. Dynamika based DCE-MRI calculations could be of high importance for disease management and a supportive tool in treatment decisions in pediatric rheumatology.

1. Eur J Radiol. 2010 Jun;74(3):e67–72.

Disclosure of Interest N. Tzaribachev Grant/research support from: UCB, Janssen, Pfizer, Roche, R. Hagoug Employee of: Image Analysis Ltd, P. Louka Employee of: Image Analysis Ltd, C. Trentin Employee of: Image Analysis Ltd, O. Kubassova Employee of: Image Analysis Ltd, M. Hinton Employee of: Image Analysis Ltd, M. Boesen: None declared