Associations between power Doppler ultrasound findings and B-mode synovitis and clinical arthritis in juvenile idiopathic arthritis using a standardised scanning approach and scoring system

Best practice in rheumatology new developments in ultrasound and MRI imaging of pediatric rheumatic diseases

The evidence base for ultrasound and MRI imaging in pediatric rheumatic diseases continues to grow, enabling the routine clinical use of the two techniques that complement each other. Ultrasound imaging has a superior spatial resolution, the ability to assess several joints at the same time without sedation and provides very detailed assessments of important structures like the entheses. MRI has advantages in the assessment of osteochondral damage and certain anatomic regions like the temporomandibular joint (TMJ) and the axial skeleton. Significant progress in the standardization of image acquisition and quantification of findings allows the utilisation of both techniques as an outcome measure. This will improve the standard of care in pediatric rheumatic diseases where objective measurements of disease activity are urgently needed. Finally, the integration of artificial intelligence (AI) represents a groundbreaking development in the field and potential applications will be discussed.

A clinical perspective on imaging in juvenile idiopathic arthritis

In recent years, imaging has become increasingly important to confirm diagnosis, monitor disease activity, and predict disease course and outcome in children with juvenile idiopathic arthritis (JIA). Over the past few decades, great efforts have been made to improve the quality of diagnostic imaging and to reach a consensus on which methods and scoring systems to use. However, there are still some critical issues, and the diagnosis, course, and management of JIA are closely related to clinical assessment. This review discusses the main indications for conventional radiography (XR), musculoskeletal ultrasound (US), and magnetic resonance imaging (MRI), while trying to maintain a clinical perspective. The diagnostic-therapeutic timing at which one or the other method should be used, depending on the disease/patient phenotype, will be assessed, considering the main advantages and disadvantages of each imaging modality according to the currently available literature. Some brief clinical case scenarios on the most frequently and severely involved joints in JIA are also presented.

Validity of an ultrasonographic joint-specific scoring system in juvenile idiopathic arthritis: a cross-sectional study comparing ultrasound findings of synovitis with whole-body magnetic resonance imaging and clinical assessment

OBJECTIVE

To assess the validity of an ultrasonographic scoring system in juvenile idiopathic arthritis (JIA) by comparing ultrasound detected synovitis with whole-body MRI and clinical assessment of disease activity.

METHODS

In a cross-sectional study, 27 patients with active JIA underwent clinical 71-joints examination, non-contrast enhanced whole-body MRI and ultrasound evaluation of 28 joints (elbow, radiocarpal, midcarpal, metacarpophalangeal 2-3, proximal interphalangeal 2-3, hip, knee, tibiotalar, talonavicular, subtalar and metatarsophalangeal 2-3). One rheumatologist, blinded to clinical findings, performed ultrasound and scored synovitis (B-mode and power Doppler) findings using a semiquantitative joint-specific scoring system for synovitis in JIA. A radiologist scored effusion/synovial thickening on whole-body MRI using a scoring system for whole-body MRI in JIA. At patient level, associations between ultrasound synovitis sum scores, whole-body MRI effusion/synovial thickening sum scores, clinical arthritis sum scores, and the 71-joints Juvenile Arthritis Disease Activity Score (JADAS71) were calculated using Spearman's correlation coefficients (rs). To explore associations at joint level, sensitivity and specificity were calculated for ultrasound using whole-body MRI or clinical joint examination as reference.

RESULTS

Ultrasound synovitis sum scores strongly correlated with whole-body MRI effusion/synovial thickening sum scores (rs=0.74,p<0.01) and the JADAS71 (rs=0.71,p<0.01), and moderately with clinical arthritis sum scores (rs=0.57,p<0.01). Sensitivity/specificity of ultrasound in detecting synovitis were 0.57/0.96 and 0.55/0.96 using whole-body MRI or clinical joint examination as reference, respectively.

CONCLUSION

Our findings suggest that ultrasound is a valid instrument to detect synovitis, and that ultrasound synovitis sum scores can reflect disease activity and may be an outcome measure in JIA.