<p>This article provides an overview of juvenile spondyloarthritis and important differences in the classification criteria, clinical presentation, outcomes, and pathology in juvenile versus adult-onset disease. Key differences in classification criteria between children and adults with spondyloarthritis are important to understand, as they can make transition from pediatric to adult care challenging. MRI and ultrasonography are increasingly relied on for the assessment of adult-onset disease activity and change over time in the pediatric population. The unique features of the maturing axial and peripheral skeleton are described for each modality, as they are key to understand for accurate interpretation of pathology in the pediatric population.</p>

<p><strong>PURPOSE OF REVIEW: </strong>This review aims to provide an update on the use of imaging in the assessment of juvenile spondyloarthritis (JSpA) disease manifestations.</p>

<p><strong>RECENT FINDINGS: </strong>Recent studies have demonstrated superior reliability and specificity of MRI for assessment of sacroiliac joint inflammation compared with radiography. The use of gadolinium contrast may not add incremental value to the assessment of inflammatory sacroiliitis. Sacroiliitis is common at diagnosis of spondyloarthritis. Inflammatory changes of the lumbar spine are not uncommon, and changes over time in the sacroiliac and apophyseal joints may not be concordant. Ultrasonography (US) in turn has been recognized as an excellent imaging technique to visualize the peripheral manifestations of JSpA. US does not only add important information to the clinical assessment but also helps to understand the complexity of the enthesis. Recognition of specific aspects in children is important though. The standardization of image acquisition as well as the establishment of the evidence base are underway. MRI and ultrasonography are recognized as increasingly important tools in the diagnosis and management of juvenile spondyloarthritis.</p>