Purpose or Case Report: Background:

Juvenile idiopathic arthritis (JIA) is the most common rheumatic condition in the pediatric population, with a prevalence of up to 150 cases per 100,000 children. Although the diagnosis of JIA is clinical, imaging plays a crucial role in the monitoring and stratification of disease, such as detecting growth disturbances, chronic joint structural changes, or treatment response. Conventional radiography has low accuracy for detection of acute synovitis or enthesitis, whereas ultrasound provides real-time assessment of inflammatory changes. Magnetic resonance imaging (MRI) is the most sensitive modality to discern early inflammatory or destructive changes in JIA, with the potential to visualize soft tissue and osteochondral abnormalities.

Education goals:

1) To describe the diagnostic criteria for the 7 subtypes of JIA.
2) To illustrate the more common imaging findings in JIA (e.g. swelling, bone mineral density, loss of joint space, erosions, growth disturbances, joint malalignment, ankylosis, enthesitis) using conventional radiography, ultrasound, and MRI.
3) To highlight the importance of early imaging changes that can support the clinical diagnosis of JIA.
4) To present the role of multimodality imaging in the evaluation of complex joint involvement (e.g. atlanto-occipital, atlanto-axial, temporomandibular, spinal, sacroiliac) in JIA.
5) To emphasize the role of imaging in characterizing conditions that can mimic JIA.
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