Imaging of Juvenile Idiopathic Arthritis

Magnetic resonance imaging of the musculoskeletal system in the diagnosis of rheumatic diseases in the pediatric population

Magnetic resonance imaging (MRI) of the musculoskeletal system is an examination increasingly performed for suspected juvenile idiopathic arthritis, chronic nonbacterial osteomyelitis and juvenile idiopathic inflammatory myopathies, as well as other rheumatic diseases of developmental age. T1-, T2- and PD-weighted with or without fat suppression or short tau inversion recovery/turbo inversion recovery magnitude (STIR/TIRM) sequences and post-contrast sequences are evaluated to diagnose pathological changes in the synovial membrane, subchondral bone marrow and surrounding soft tissues. Magnetic resonance imaging allows detection of synovitis, tenosynovitis, bursitis, and enthesitis as well as bone marrow edema and soft tissue edema. Several pediatric-specific MRI scoring systems have been developed and validated to standardize and facilitate the assessment of the extent of the inflammatory process and disease activity in MRI. Early detection of inflammatory changes allows the inclusion of comprehensive pharmacotherapy giving the possibility of permanent remission and objective measurement of the effectiveness of treatment.

Multicentric Carpo-Tarsal Osteolysis

MCTO is a rare autosomal-dominant inherited disorder that causes bone destruction and deformity of the appendicular bones in children, with the carpal and tarsal bones severely affected. Imaging can narrow the differential diagnosis between MTCO and other diseases that cause osteolysis of the joints in children. The MCTO diagnosis is confirmed by a mutation of the MAFB gene.

Teaching Point

Multicentric carpo-tarsal osteolysis (MTCO) in childhood must be considered in the differential diagnosis of severe osteolysis on radiographs.

Reliability of ultrasonography to detect inflammatory lesions and structural damage in juvenile idiopathic arthritis

BACKGROUND

Musculoskeletal Ultrasonography (MSUS) is an important tool for the clinical assessment in Juvenile Idiopathic Arthritis (JIA). The objective of this study was to evaluate the reliability of MSUS to detect elementary lesions: synovitis, tenosynovitis, cartilage damage and bone erosions in the wrist and metacarpal (MCP) joints of patients with JIA.

METHODS

Thirty children in various subgroups of JIA according to ILAR criteria, were included in this cross-sectional study. Clinical data including painful, swollen and limited joints were recorded. Five rheumatologist ultrasonographers, blinded to the clinical evaluation, evaluated the presence of elementary lesions in the wrist and MCP 2 and 3 joints bilaterally. The synovitis was graded in B-Mode and Power Doppler (PD). In addition to descriptive statistics intra- and inter-observer reliability was calculated using Cohen's kappa according to Landis and Koch.

RESULTS

US detected more synovitis than the clinical examination (62% vs 28%, 30% vs 23% and 22% vs 17% in the wrist, second and third MCP joints respectively). The intra-observer concordance for synovitis in all joints was excellent in B-Mode (k 0.84 .63-1.0 p = 0.001), except for MCP 2, where it was good (0.61, IC 95% .34-89, p = 0.001). For both modalities (PD, B-Mode) tenosynovitis, cartilage damage and bone erosions it was also excellent. Regarding synovitis grading the concordance was excellent for all grades (0.83-1.0, IC 95% 0.51.1.0, p = 0.001), except for grade 1 where it was good (0.61, IC 95% 0.43-.83, p = 0.001). Reliability inter-observer for grayscale synovitis (0.67-0.95, IC 95% 0.67-1.0, p = 0.001), tenosynovitis grayscale (0.89, IC 95% 0.78-0.99, p.001), damage cartilage (0.89, IC 95% 0.78-0.99, p = 0.001), PD (0.66, IC 95% 0.39-1.0, p = 0.001). The concordance for grading synovitis was excellent, but for grayscale grade 1 and 2 (.66, IC 95% .53-.74, p = 0.007) and PD grade 1 and 2 (0.63, IC 95% .58-.91, p = 004) was good.

CONCLUSIONS

The intra- and inter-observer reliability of MSUS for inflammatory and structural lesions is good to excellent for the wrist and MCP in patients with JIA.

Peptide-based electrochemical biosensor for juvenile idiopathic arthritis detection

Juvenile idiopathic arthritis (JIA) is a wide group of diseases, characterized by synovial inflammation and joint tissue damage. Due to the delay in the implementation of biomarkers into clinical practice and the association with severe sequels, there is an imperative need for new JIA diagnosis strategies. Electrochemical biosensors based on screen-printed electrodes and peptides are promising alternatives for molecular diagnosis. In this work, a novel biosensor for detecting juvenile idiopathic arthritis (JIA) was developed based on the immobilization of the PRF+1 mimetic peptide, as recognition biological element, on the surface of screen-printed carbon electrode. This biosensor was able to discriminate the JIA positive and negative serum samples from different individuals using differential pulse voltammetry, presenting limits of detection and quantification in diluted samples of 1:784 (v/v) and 1:235 (v/v), respectively. Evaluation by electrochemical impedance spectroscopy showed R_CT 3 times higher for JIA positive sample than for a pool of human serum samples from healthy individuals. Surface analysis of the biosensor by atomic force microscopy, after contact with JIA positive serum, presented great globular clusters irregularly distributed. The long-term stability of the biosensor was evaluated, remaining functional for over 40 days of storage (after storage at 8°C). Therefore, a simple, miniaturized and selective biosensor was developed, being the first one based on mimetic peptide and screen-printed carbon electrode, aiming at the diagnosis of the juvenile idiopathic arthritis in real serum samples.