Background Clinical examination of juvenile idiopathic arthritis (JIA) patients does not always adequately reflect disease activity, whereas quantitative Dynamic Contrast Enhanced (DCE)-MRI based biomarkers extracted from images of multiple joints have been shown to reliably predict the course of the disease 1.
Objectives To investigate the association between DCE-MRI measures of inflammation in a single and in multiple joints and the treatment related clinical changes.
Methods 18 patients (12 girls, med. age 12.6 years, med. disease 1.2 years) with polyarticular JIA with more than 3 affected joints or intolerance to more than 3 months of MTX were given Etanercept. Their most clinically affected hand was imaged with DCE-MRI (0.2T Esaote C-Scan) at baseline, 3 and 6 months following the treatment. DCE-MRI was analysed using dedicated software package (DYNAMIKA, IAG). Dynamic Enhanced MRI Quantification (DEMRIQ-V) was calculated as the volume of enhancing voxels within Region of Interest placed around a single or multiple MCPJs. DEMRIQ-V was also weighted by the mean of Maximum Enhancement (ME) and Initial Rate of Enhancement (IRE), the parameters corresponding to the height and slope of the signal intensity vs time curves extracted from the enhancing voxels.2 Clinical scores included active joint (AJ) count. Involvement of less than 3 AJ was considered a clinical response. The differences in DEMRIQ-V between the visits were analysed using t-test, assuming p<0.05* to be statistically significant and p<0.25** to be clinically meaningful.
Results In all patients, in clinically unaffected joints, MRI was able to detect subclinical disease, and in all but 3 patients, significant and/or clinically meaningful changes were documented for DEMRIQ-ME. In 4 patients, DEMRIQ-V scores showed corresponding clinical changes whereas all other patients these markers were non-concordant. DEMRIQ-V score was predictive of clinical outcome:
- · in 5 patients, improvement of DEMRIQ-V at month 3 predicted response to treatment at month 6;
- · in 4 patients, increase or persistence of a high DEMRIQ-V at month 3 predicted non-response to treatment at month 6;
- ·DEMRIQ-V measured in a single most affected joint was as predictive as when it was measured in all MCPJs.
Conclusions We conclude that DCE-MRI’s ability to detect early disease can reliably support clinical examination. Use of DEMRIQ-V and DEMRIQ-ME scores, which either followed clinical response (DEMRIQ-ME) or predicted clinical outcomes at 6 months (DEMRIQ-V) in most patients can support early clinical and research decisions.
References  Kubassova O, et al. Arthritis Rheumatol2017;69(suppl 10).
 Kubassova O, et al. Eur J Radiol2010Jun;74(3):e67–72.
Acknowledgements Support by Pfizer
Disclosure of Interest None declared
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