The joints in juvenile idiopathic arthritis

Juvenile idiopathic arthritis is the most common rheumatic entity in childhood. Imaging has become an important supplement to the clinical assessment of children with JIA. Radiographs still play an important role in the workup, and long-term follow-up in children with JIA, but are not sensitive to findings in the early disease stage. Both ultrasound and MRI are more sensitive to inflammatory changes than clinical assessment alone. However, the differentiation between normal findings and pathology can be challenging, particularly in early disease. The objective of this review is to discuss the role of imaging in JIA, describe the typical findings on different modalities and highlight the challenges we face regarding the reliability and accuracy of the different methods for imaging the joints in children with JIA.

• Imaging is an important supplement to the clinical examination in JIA. • Ultrasound is more sensitive for detecting synovitis than clinical examination alone. • MRI can depict all relevant structures in joint inflammation. • The differentiation between normal variants and pathology is difficult in children.