Authors: Derk F M Avenarius LilSofie Ording Müller Karen Rosendahl
Publish Date: 2015/12/04
Volume: 46, Issue: 3, Pages: 322-330
Abstract
74 of the initial cohort of 89 healthy children 83 had a rescan of their wrists using the same protocol including coronal T1 and fatsaturated T2 sequences A cartilageselective sequence was added for this study We registered number and location of bony depressions and presence of overlying cartilageThe total number of carpal depressions increased by age group and over time their location was unchanged in 370 of 487 76 carpal sites and 91 of 117 78 metacarpal sites In total 426 of the 1087 392 bony depressions were covered by cartilage with a decreasing percentage by age P = 0001Juvenile idiopathic arthritis is a heterogeneous condition that includes all forms of chronic arthritis of unknown origin with onset before 16 years of age It is characterised by chronic synovial inflammation with a potential risk of progressive joint damage and serious functional disability 1 2 3 4 Juvenile idiopathic arthritis affects 1–2 in 1000 children 5 6 7 8 There is increasing evidence that many if not most children with juvenile idiopathic arthritis have ongoing disease into adulthood particularly if they are HLAB27positive 9 Moreover research has shown there might be a therapeutic window of opportunity during early disease and that early initiation of therapy is associated with slower progression of joint damage and higher rates of remission 10 This highlights the need for more sensitive disease markers because many of the existing markers based on clinical laboratory and conventional imaging are imprecise and inaccurateJoint damage evaluation in juvenile idiopathic arthritis has traditionally been performed by radiographic scoring methods these methods however are not sensitive particularly for disease in early stages 11 12 13 14 MRI on the other hand can be used to image synovitis and bone oedema/inflammation as well as damage to cartilage and bone and is believed to detect erosive changes with greater sensitivity than radiography particularly in early disease 15 The value of MRI as an advanced method to evaluate disease activity and disease damage in adults with rheumatoid arthritis is under active investigation by a research consortium called Outcome Measures in Rheumatology Clinical Trials OMERACT 16 17 However the results from OMERACT studies are not directly applicable to children because adult rheumatoid arthritis is different from JIA and because the growing skeleton of a child has different appearances on imaging and reacts differently to disease processes than does the mature skeleton This has fueled paediatric imaging groups such as the HealtheChild Radiology Group and the OMERACT special interest group “MRI in Juvenile Idiopathic Arthritis” to join efforts however no internationally validated and accepted scoring system for MRI in juvenile idiopathic arthritis exists for any joint 18We have previously shown that on MRI a large proportion of healthy children have changes similar to those described in children with juvenile idiopathic arthritis namely carpal depressions boneoedemalike changes and joint fluid ≥2 mm 19 20 21 To further characterise normal growth of the wrist we performed a 4year followup of this cohort and included a cartilagespecific sequence to examine the relationship between bony depressions and cartilage coverage
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