Magnetic resonance imaging findings in juvenile spondyloarthropathy and effects of treatment observed on subsequent imaging

Abstract

BackgroundMagnetic resonance imaging (MRI) is often used to diagnose and monitor treatment effects of juvenile spondyloarthropathy (SpA). Our objective was to describe MRI findings in juvenile SpA and determine predictors of active sacroiliitis and response to treatment.MethodsChildren who had MRI of the sacroiliac (SI) joints and were referred to the pediatric rheumatology clinic from 2009 to 2012 were retrospectively studied. The clinical parameters, laboratory studies and findings on MRI were collected and a composite score ratio (CR) was calculated for both SI joints on each MRI study based on a semi-quantitative scale that included evaluation of bone marrow edema (BME), synovial enhancement (SE), and erosions (ER). The findings on MRI were correlated with clinical and laboratory values.Results50 subjects who underwent 76 MRI for suspected or known SpA were included in the study. Sacroiliitis was seen in 48 MRIs in 32 subjects. Of the subjects with sacroiliitis, mean age ± standard deviation was 13.7 ± 2.6 years, 71% were male and 41% were HLA B27 positive. SE without BME was seen in 31% cases of sacroiliitis. In subjects with sacroiliitis, 79% also had hip arthritis and 41% had enthesitis of the pelvic region on MRI. In 38% of subjects with sacroiliitis, physical exam was not indicative of sacroiliitis or hip arthritis. Longitudinal data were available for 13 subjects. Sacroiliitis on MRI improved in 9 subjects with the greatest improvement in MRI composite score ratio after initiation of etanercept therapy. CR improvement was due to improvement of BME and SE components, while the ER score remained the same or worsened in all but 1 subject.ConclusionHistory, physical exam or laboratory data may not predict sacroiliitis in children. Magnetic resonance imaging plays a valuable role in the initial evaluation and later treatment monitoring of children with spondyloarthropathy. Synovial enhancement is significantly reduced after treatment, and unlike adults, synovial enhancement may be detected without accompanying bone marrow edema, which suggests gadolinium contrast may be an important component in the assessment of children with spondyloarthropathy.

Limited role of gadolinium to detect active sacroiliitis on MRI in juvenile spondyloarthritis

“…The unique MRI features specific to children they described should be carefully addressed since arthropathies other than SpA may result in similar changes. They concluded that contrast administration does have an added benefit, since synovial enhancement can be detected without accompanying BME; however, no comparison between STIR and T1/Gd was made, nor was a global impression assessed [11].…”

“…MRI may show clear sacroiliitis in patients that cannot be classified according to the current ILAR criteria, but the significance of these findings in terms of diagnosis and prognosis has not yet been well assessed in children. Review of the literature shows limited numbers of papers addressing sacroiliitis in children [5,[9][10][11][12]. It is clear that Fig.…”

“…Studies on spinal inflammation in adult ankylosing spondylitis to date have shown good agreement between STIR and T1/Gd, suggesting STIR sequences alone are sufficient for the assessment of acute spinal inflammation [17,18]. However, most published studies related to MRI in SpA concern adult patients, other than the small pediatric studies of Lin et al and Bollow et al [10][11][12]. Unlike adults [8], the diagnostic value of MRI assessment of sacroiliitis in children is not well studied.…”

“…Limited studies concerning this topic have been published. Some recommend contrast administration [10,11], while some do not favour contrast-enhanced imaging [14][15][16]. Studies on spinal inflammation in adult ankylosing spondylitis to date have shown good agreement between STIR and T1/Gd, suggesting STIR sequences alone are sufficient for the assessment of acute spinal inflammation [17,18].…”

“…In adults, active sacroiliitis on MRI is even a key criterion for disease classification according to the Assessment of SpondyloArthritis international Society (ASAS) criteria [8]. Recently, some studies emphasized the usefulness of MRI in juvenile arthritides [9][10][11][12][13].…”