Musculoskeletal Ultrasound in Juvenile Idiopathic Arthritis: Advances in Imaging and Clinical Practice.

Musculoskeletal ultrasound (MSUS) has become a cornerstone imaging modality in pediatric rheumatology, providing a safe, non-invasive, and highly sensitive method for assessing musculoskeletal pathology. Reliable interpretation of MSUS requires awareness of developmental anatomy, optimization of technical parameters, and recognition of common artifacts. These considerations are especially important in children, where physiological vascularization and age-related changes in cartilage or bone can mimic pathology. MSUS enables the detailed visualization of synovitis, tenosynovitis, enthesitis, and early structural abnormalities, often detecting both overt and subclinical inflammation that may be missed on clinical examination. These subclinical observations can offer additional context during follow-up and support more informed decisions in disease monitoring and management. In addition to its diagnostic and prognostic roles, MSUS also enhances interventional approaches. Ultrasound-guided intra-articular corticosteroid injections improve precision, safety, and patient comfort compared with landmark-based techniques, while also expanding therapeutic access to joints that are otherwise difficult to inject. Altogether, MSUS is increasingly recognized not only as a complementary tool but as an integral component of juvenile idiopathic arthritis (JIA) management. This review will provide an updated overview of MSUS in the context of JIA, with a particular focus on practical aspects of scanning in children, the differentiation between physiological and pathological findings, the main disease-related sonographic features, and the expanding role of ultrasound in guiding intra-articular procedures. Current challenges, limitations, and future perspectives regarding standardization and integration into clinical care will also be discussed.