Imaging Findings of Pediatric Rheumatic Disorders: JIA in the PRINTO Era and Autoimmune Interferonopathies.

Treatment strategies for pediatric rheumatic diseases have changed substantially over the past two decades, driven by the development of biologics and cytokine-targeted molecular therapy. Therapeutic approaches that modulate both innate and adaptive immune responses have improved prognosis in these immune-mediated disorders, and early diagnosis with timely intervention is associated with better outcomes. However, affected children often present with non-specific symptoms, and reliable biomarkers remain limited in juvenile idiopathic arthritis (JIA); thus, the diagnostic delay remains common. Imaging is an important adjunct in pediatric rheumatology; in selected scenarios, it can be pivotal for establishing a definitive diagnosis and for assessing disease subtype, complications, and treatment response. This review presents an imaging-focused overview of pediatric rheumatic diseases. We begin with a brief review of current immunologic concepts, including the autoinflammatory-autoimmune continuum, then illustrate typical imaging findings, discuss key differential diagnoses, and summarize the diagnostic strengths and limitations of major imaging modalities. We discuss in detail the major JIA subtypes based on the PRINTO classification, which aims to improve clinical coherence, facilitate risk stratification, and clarify relationships between pediatric and adult rheumatic entities. We also highlight interferonopathies-disorders characterized by a type I interferon signature-which provide a useful framework for understanding the mechanistic links between autoinflammation and autoimmunity along the continuum and for contextualizing selected autoimmune diseases, including systemic lupus erythematosus, juvenile dermatomyositis, and Sjögren's syndrome.