Imaging assessment of children presenting with suspected or known juvenile idiopathic arthritis: ESSR-ESPR points to consider

Abstract

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatic disease. It represents a group of heterogenous inflammatory disorders with unknown origin and is a diagnosis of exclusion in which imaging plays an important role. JIA is defined as arthritis of one or more joints that begins before the age of 16 years, persists for more than 6 weeks and is of unknown aetiology and pathophysiology. The clinical goal is early suppression of inflammation to prevent irreversible joint damage which has shifted the emphasis from detecting established joint damage to proactively detecting inflammatory change. This drives the need for imaging techniques that are more sensitive than conventional radiography in the evaluation of inflammatory processes as well as early osteochondral change. Physical examination has limited reliability, even if performed by an experienced clinician, emphasising the importance of imaging to aid in clinical decision-making. On behalf of the European Society of Musculoskeletal Radiology (ESSR) arthritis subcommittee and the European Society of Paediatric Radiology (ESPR) musculoskeletal imaging taskforce, based on literature review and/or expert opinion, we discuss paediatric-specific imaging characteristics of the most commonly involved, in literature best documented and clinically important joints in JIA, namely the temporomandibular joints (TMJs), spine, sacroiliac (SI) joints, wrists, hips and knees, followed by a clinically applicable point to consider for each joint. We will also touch upon controversies in the current literature that remain to be resolved with ongoing research. KEY POINTS: • Juvenile idiopathic arthritis (JIA) is the most common chronic paediatric rheumatic disease and, in JIA imaging, is increasingly important to aid in clinical decision-making. • Conventional radiographs have a lower sensitivity and specificity for detection of disease activity and early destructive change, as compared to MRI or ultrasound. Nonetheless, radiography remains important, particularly in narrowing the differential diagnosis and evaluating growth disturbances. • Mainly in peripheral joints, ultrasound can be helpful for assessment of inflammation and guiding joint injections. In JIA, MRI is the most validated technique. MRI should be considered as the modality of choice to assess the axial skeleton or where the clinical presentation overlaps with JIA.

Keywords: Conventional radiography; Diagnostic imaging; Juvenile idiopathic arthritis; Magnetic resonance imaging; Ultrasound computed tomography.

Fig. 1

An 18-year-old girl with long-standing TMJ arthritis showing chronic condylar bony abnormalities of the left temporomandibular joint including flattening of the temporal fossa and the mandibular condyle (arrows) on (a) coronal and (b) sagittal CT images

Fig. 2

A 13-year-old girl with JIA and active TMJ arthritis. MRI of the TMJ with (a) a sagittal oblique T2-weighted fat-saturated image showing bone marrow oedema (hyper-intense signal on T2-weighted images (arrow)) in the TMJ condyle, (b) a sagittal oblique T1-weigted image showing bone marrow oedema (hypo-intense signal on T1-weighted images) and condylar flattening (arrow) and (c) a sagittal oblique T1-weighted fat-saturated post-Gd image showing joint and condylar enhancement (arrow)

Fig. 3

A 16-year-old boy with JIA, active sacroiliitis and an MRI showing (a) a coronal oblique STIR image showing bone marrow oedema (arrow) in, predominantly, the iliac side of the sacroiliac joints and capsulitis and (b) a coronal oblique T1-weigted fat-saturated post-Gd image showing bone marrow enhancement, joint enhancement and capsulitis (arrow). In this case, capsulitis can be seen as hyper-intense T2-weighted signal with enhancement at the T1-weighted fat-saturated post-Gd image at the cranial site of the sacroiliac joints

Fig. 4

A 10-year-old healthy girl with a coronal T1-weighted image showing a bony depression on the radial side of the capitate (arrow). This is a normal depression that can be seen in the carpal bones of growing children and should not be mistaken for pathology (erosive disease)

Fig. 5

A 15-year-old boy with juvenile idiopathic arthritis and hip involvement with (a) a coronal T2-weighted fat-saturated image showing synovial thickening (arrow heads) in the left hip with extensive bone marrow oedema in the femoral head (arrow), (b) a coronal T1-weigted image showing irregular cortical linings in the scope of erosive changes (arrow) and (c) the corresponding X-ray showing joint space narrowing and cortical irregularities/erosive change in the femoral head (arrow)

Fig. 6

A 14-year-old boy with oligo-articular JIA and knee arthritis. MRI of the knee with (a) an axial T2-weighted fat-saturated image, (b) an axial T1-weigted fat-saturated post-Gd image showing an enhancing thickened synovial membrane retro-patellar (arrow) and posterior of the condyles (arrow) and (c) an axial double inversion recovery (DIR)–weighted Gd-free image showing a similar picture (arrows)