Charlotte M. Nusman MSc, Presenter: Nothing to Disclose

Robert Hemke MD,PhD, Abstract Co-Author: Nothing to Disclose

Marc Benninga MD, PhD, Abstract Co-Author: Nothing to Disclose

Angelika Kindermann MD, PhD, Abstract Co-Author: Nothing to Disclose

Marion Van Rossum MD, PhD, Abstract Co-Author: Nothing to Disclose

Taco Kuijpers MD, PhD, Abstract Co-Author: Nothing to Disclose

Mario Maas MD, PhD, Abstract Co-Author: Nothing to Disclose

The primary target of disease in juvenile idiopathic arthritis (JIA) is inflamed synovium, which can be objectified with magnetic resonance imaging (MRI) with administration of intravenous (IV) contrast. Adequate differentiation between pathologic from physiologic extent of synovial enhancement has important implications for (dis)continuation of therapy. The purpose of this study was to assess the enhancing synovium on MRI of the knee in asymptomatic children compared to JIA patients. 

An axial fat-saturated T1-weighted MRI sequence of the knee of 25 asymptomatic controls and 25 JIA patients was collected, blinded and randomized. The asymptomatic controls were children who underwent MR enterography with IV contrast, had no (history of) joint complaints or signs of joint inflammation and gave permission for an additional sequence of the knee. JIA patients were age/sex-matched and divided in three clinical subgroups: new-active, relapse and inactive. Two readers independently measured enhancing synovium and scored synovial thickening (ST) on a scale from 0-2 (none, mild, moderate/severe) at six locations. Afterwards agreement on incongruent cases was obtained. Differences in ST score and thickness of enhancing synovium between the controls and (subgroups) of JIA patients were assessed. 

Mean age of all subjects (42% female) was 13.5 years (SD 2.5). Enhanced thickened synovium was present on knee MRI in 36% of the controls (ST score range 1-3) and 80% of the patients. A significant difference (p=0.000) in the ST score was found between controls and JIA children. ST score could differentiate controls from all JIA subgroups (p=0.003-0.028) (Figure 1). Synovial thickness differed between controls (mean 1.4-1.9mm) and patients with clinically active arthritis (mean 1.8-2.6mm) on 4 out of 6 locations (p=0.020-0.049). 

This study is the first to objectively quantify enhanced synovial thickening in an asymptomatic population compared to JIA patients. ST score on MRI can adequately differentiate asymptomatic controls from (subgroups of) JIA patients. These findings further establish MRI as diagnostic and disease activity monitoring tool in JIA patients.  

Synovial thickening on contrast-enhanced MRI can distinguish between asymptomatic controls and JIA patients in all disease activity stages.

Nusman, C, Hemke, R, Benninga, M, Kindermann, A, Van Rossum, M, Kuijpers, T, Maas, M, Appearance of the Synovium on Contrast-enhanced MRI of the Knee in Asymptomatic Controls Compared to Juvenile Idiopathic Arthritis Patients.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013159.html