Clinical assessment and core outcome variables are poor predictors of hip arthritis diagnosed by MRI in juvenile idiopathic arthritis

A novel magnetic resonance imaging scoring system for active and chronic changes in children and adolescents with juvenile idiopathic arthritis of the hip

BACKGROUND

Hip involvement predicts severe disease in juvenile idiopathic arthritis (JIA) and is accurately assessed by MRI. However, a child-specific hip MRI scoring system has not been validated.

OBJECTIVE

To test the intra- and interobserver agreement of several MRI markers for active and chronic hip changes in children and young adults with JIA and to examine the precision of measurements commonly used for the assessment of growth abnormalities.

MATERIALS AND METHODS

Hip MRIs from 60 consecutive children, adolescents and young adults with JIA were scored independently by two sets of radiologists. One set scored the same MRIs twice. Features of active and chronic changes, growth abnormalities and secondary post-inflammatory changes were scored. We used kappa statistics to analyze inter- and intraobserver agreement for categorical variables and a Bland-Altman approach to test the precision of continuous variables.

RESULTS

Among active changes, there was good intra- and interobserver agreement for grading overall inflammation (kappa 0.6-0.7). Synovial enhancement showed a good intraobserver agreement (kappa 0.7-0.8), while the interobserver agreement was moderate (kappa 0.4-0.5). Regarding acetabular erosions on a 0-3 scale, the intraobserver agreement was 0.6 for the right hip and 0.7 for the left hip, while the interobserver agreement was 0.6 for both hips. Measurements of joint space width, caput-collum-diaphyseal angle, femoral neck-head length, femoral width and trochanteric distance were imprecise.

CONCLUSION

We identified a set of MRI markers for active and chronic changes in JIA and suggest that the more robust markers be included in future studies addressing clinical validity and long-term patient outcomes.

The reliability of Juvenile Arthritis Magnetic Resonance Imaging Scoring system in the evaluation of the shoulder joint in juvenile idiopathic arthritis

Objectives

We aimed to evaluate shoulder joint by magnetic resonance imaging (MRI) using the Juvenile Arthritis Magnetic Resonance Imaging Scoring (JAMRIS) system in children with juvenile idiopathic arthritis (JIA) and to compare clinical, laboratory parameters and disease activity scores with MRI parameters.

Patients and methods

A total of 32 shoulder joints of 20 patients (16 males, 4 females; mean age: 8.9±3.5 years; range, 2.5 to 14 years) with a known diagnosis of JIA and a clinical suspicion of shoulder joint involvement and underwent MRI were included. Reliability was determined by inter- and intra-observer correlation coefficients. Correlation of the clinical and laboratory parameters with JAMRIS scores was done using the non-parametric tests. Sensitivity of clinical examination to detect shoulder joint arthritis was also determined.

Results

Of the 32 joints, 27 joints in 17 patients showed MRI changes. Seven joints in five patients fulfilled the definition of clinical arthritis, all revealed MRI changes. In 25 joints without clinical arthritis, early and late MRI changes were seen in 19 (67%) and 12 (48%) joints, respectively. The inter- and intra-observer correlation coefficients for JAMRIS system were excellent. No correlation was found between MRI parameters, clinical, laboratory, and disease activity scores. The sensitivity of clinical examination to detect shoulder joint arthritis was 25.9%.

Conclusion

The JAMRIS system is reliable and reproducible to determine shoulder joint inflammation in JIA. Detection of shoulder joint arthritis by clinical examination has a poor sensitivity.

MRI Findings in Hip in Juvenile Idiopathic Arthritis

The aim of this study was to evaluate if magnetic resonance imaging allows hip arthritis in JIA to be differentiated from hip arthralgia of unknown etiology in juveniles clinically suspected for hip arthritis. This was a retrospective observational study which included 97 children with clinically suspected hip arthritis. Each hip was assessed and scored in MRI for signs of active and destructive inflammatory lesions and developmental lesions. MRI findings between JIA-confirmed patients and without final diagnosis of JIA were compared and the MRI summarized score was calculated, as the sum of scorings of all 24 hip lesions in an individual patient (i.a., effusion, synovitis, bone marrow edema, enthesitis). MRI showed at least one lesion in the majority of patients (95 patients; 98%). Effusion was the most common feature, followed by bone marrow oedema and synovitis. All lesions were more common in patients with a final diagnosis of JIA, especially synovitis and enthesitis (p = 0.037 and p = 0.047). The MRI summarized score was significantly higher in the JIA group than the non-JIA group: 3 (2–5) vs. 2 (2–2), respectively, p = 0.002. Using a cut-off score of 6, the MRI summarized score showed 25% sensitivity and 100% specificity indicating a good ability in discriminating hip arthritis during JIA from non-JIA patients. MRI allows hip arthritis in JIA to be differentiated from hip arthralgia of unknown etiology with good specificity, thus, may be helpful in confirming the diagnosis of JIA.

[Inflammatory changes of the hip joint]

Die Osteoarthrose ist die häufigste Ursache für den Hüftschmerz des Erwachsenen. Daher wird anderen Ursachen wie z. B. Entzündungen weniger Beachtung für den Gelenkschmerz in der Erstdiagnose geschenkt. Dieser Artikel gibt eine Übersicht von unterschiedlichen rheumatologischen Erkrankungen der Hüfte und deren Interpretation in der Bildgebung. Die Vor- und Nachteile der einzelnen bildgebenden Verfahren werden anhand der pathologischen Befunde für die rheumatologischen Erkrankungen erläutert.

Toward Developing a Semiquantitative Whole Body-MRI Scoring for Juvenile Idiopathic Arthritis: Critical Appraisal of the State of the Art, Challenges, and Opportunities

With powerful new therapies available for management of juvenile idiopathic arthritis (JIA), early diagnosis leading to appropriate treatment may prevent long-term structural joint damage. Although magnetic resonance imaging (MRI) is typically used to assess individual body parts, indications for whole body (WB) MRI are increasing. Its utility as a diagnostic and monitoring tool has already been widely investigated in adult rheumatology patients, but less so in pediatric rheumatologic patients. This paper is a comprehensive review of scoring systems and a proposal for the conceptual development of a WB-MRI scoring system for the evaluation of JIA. In this review we identify, summarize, and critically appraise the available literature on the use of WB-MRI in inflammatory arthritis, addressing relevant considerations on components of a classification system that can lead to the development of a future pediatric WB-MRI scoring system for use in children with JIA. We also discuss advantages and challenges of developing such a WB-MRI scoring system for assessment of JIA and outline next steps toward the conceptual development of this scoring system.

Magnetic resonance imaging findings in the sternoclavicular joint in juvenile idiopathic arthritis and comparison with clinical examination

OBJECTIVE

The sternoclavicular joint (SCJ), an important link between the appendicular and axial skeleton, though involved in 41% of rheumatoid arthritis patients, has not been studied in juvenile idiopathic arthritis (JIA). Hence, this cross-sectional study was done to delineate the magnetic resonance imaging (MRI) findings in SCJ in JIA and compare with the clinical examination to diagnose SCJ arthritis.

METHODS

Of the 116 JIA patients attending the pediatric rheumatology clinic, twenty-one patients (42 SC joints) were evaluated by 1.5 T MRI using the four components of early and late inflammatory changes-synovial hypertrophy, bone marrow edema (BME), cartilage lesions, and bone erosions. Results were compared with clinical assessment of SCJ arthritis.

RESULTS

Of the 42 SCJ evaluated (21/116 patients), MRI changes were seen in 27 SCJs (15 patients, 12.9% of 116 JIA patients). Early MRI changes were seen in 60% of joints found normal on clinical examination, with as much as 1/4th of them revealing late destructive changes. Synovial hypertrophy, BME, cartilage lesions, and bone erosions were seen in 5, 15, 4, and 10 patients, respectively. Sensitivity and specificity of clinical examinations to evaluate SC joint involvement were 55.5% and 53.3%, respectively.

CONCLUSION

MRI evaluation of the SCJ in JIA revealed findings in 15/21 enrolled patients. BME, bone erosions, synovial hypertrophy, and cartilage lesions were seen in 15, 10, 5, and 4 enrolled patients, respectively. Clinical examination was found to be neither sensitive nor specific. Key Points • MRI could delineate both early and late inflammatory changes in SCJ in JIA. BME, bone erosions, synovial hypertrophy, and cartilage lesions were seen in 15, 10, 5, and 4 enrolled patients, respectively. • The frequency of SC joint involvement in JIA was at least 12.9% of patients in our study. • Clinical examination for evaluating SC joint arthritis has low sensitivity (55.5%) and specificity (53.3%).

Prevalence and course of lower limb disease activity and walking disability over the first 5 years of juvenile idiopathic arthritis: results from the childhood arthritis prospective study

Objective

The aim was to investigate the time course of lower limb disease activity and walking disability in children with JIA over a 5-year course.

Methods

The Childhood Arthritis Prospective Study is a longitudinal study of children with a new JIA diagnosis. Childhood Arthritis Prospective Study data include demographics and core outcome variables at baseline, 6 months and yearly thereafter. Prevalence and transition rates from baseline to 5 years were obtained for active and limited joint counts at the hip, knee, ankle and foot joints; and walking disability, measured using the Childhood Health Assessment Questionnaire walking subscale. Missing data were accounted for using multiple imputation.

Results

A total of 1041 children (64% female), with a median age of 7.7 years at first visit, were included. Baseline knee and ankle synovitis prevalence was 71 and 34%, respectively, decreasing to 8–20 and 6–12%, respectively, after 1 year. Baseline hip and foot synovitis prevalence was <11%, decreasing to <5% after 6 months. At least mild walking disability was present in 52% at baseline, stabilizing at 25–30% after 1 year.

Conclusion

Lower limb synovitis and walking disability are relatively common around the time of initial presentation in children and young people with JIA. Mild to moderate walking disability persisted in ∼25% of patients for the duration of the study, despite a significant reduction in the frequency of lower limb synovitis. This suggests that there is an unmet need for non-medical strategies designed to prevent and/or resolve persistent walking disability in JIA.

Imaging of the hip in juvenile idiopathic arthritis

Hip involvement is common and estimated to occur in approximately 35-63% of children with juvenile idiopathic arthritis (JIA). It is more prevalent in the aggressive systemic subtypes, with irreversible changes occurring as early as within 5 years of diagnosis. Whilst clinical parameters and joint examination can be useful for assessing disease severity, subclinical disease is known to exist and delayed treatment may herald a lifetime of disability and pain. Early recognition of JIA changes is therefore crucial in determining treatment options. Validated scoring systems in the radiologic assessment of the hip for clinical drug trials may inform treatment outcomes, although robust tools for analysis are still lacking. This review article details the modalities utilised for imaging the hip in children with JIA with particular efforts focused upon reliability and validity in their assessment of joint disease. We conclude with a short literature review on the potential future techniques being developed for hip joint imaging in JIA.

Establishing percentile charts for hip joint capsule and synovial cavity thickness in apparently healthy children

BACKGROUND

The usefulness of musculoskeletal ultrasonography (MSUS) in paediatric population is limited by lack of reference values. One of such parameters is hip joint capsule thickness, postulated as an early measure for synovitis. However, the joint capsule is hardly a distinguished structure from slit synovial cavity in patients with little or no fluid collection. Therefore, in patients without effusion, it is more convenient to measure hip joint capsule thickness together with synovial cavity. The aim of the study was to establish percentile chart for hip joint capsule and synovial cavity thickness (HJC&SCT) in apparently healthy children.

MATERIAL AND METHODS

The analysis included 816 US of hip joint in 408 children without musculoskeletal disorders, distributed equally throughout the whole developmental period in 18 one-year subgroups. Hip joints US was performed according to standard protocol including measurement of HJC&SCT in a single rheumatology centre by three investigators.

RESULTS

The 3rd, 10th, 25th, 50th, 75th, 90th, and 97th HJC&SCT percentile curves were depicted in the age and height charts for the combined group of girls and boys. The median HJC&SCT values were increasing with age from 3.7 (C10 - C90: 3.3 - 4.2) mm in the first year of life up to 6.7 (5.8 - 7.3) in 16 years old, and above. In a similar way the increase was seen with height from 3.9 (3.5 - 4.7) mm in shorter than 95 cm to 6.9 (6.2 - 7.4) mm in taller than 169 cm subjects. Intra-observer and inter-observer mean precision was less than 1.8 and 12.5%, respectively.

CONCLUSION

The developed centile chart for hip joint capsule and synovial cavity thickness in the paediatric population is expected to improve detection of hip joint capsule disorders, including synovitis in juvenile idiopathic arthritis.

Juvenile Idiopathic Arthritis: Diagnosis and Treatment

Juvenile idiopathic arthritis is a broad term that describes a clinically heterogeneous group of arthritides of unknown cause, which begin before 16 years of age. This term encompasses several disease categories, each of which has distinct presentation, clinical manifestations, and, presumably, genetic background and etiopathogenesis. Although none of the available drugs has curative potential, prognosis has greatly improved as a result of substantial progresses in disease management. The most important new development has been the introduction of the biologic medications, which constitute a valuable treatment option for patients who are resistant to conventional antirheumatic agents. Further insights into the disease pathogenesis and treatment will be provided by the continuous advances in understanding of the mechanisms related to the immune response and inflammatory process, and by the development of new drugs that are capable of selectively inhibiting single molecules or pathways.

Management of Children with Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) comprises a group of heterogeneous disorders of chronic arthritis in childhood and remains the commonest pediatric rheumatic disease associated with significant long-term morbidity. Advances in understanding of the pathogenesis, better definition of disease control/remission measures, and the arrival of biological agents have improved the outcomes remarkably. Methotrexate (Mtx) remains the first-line disease modifying (DMARD) therapy for most children with JIA due to its proven efficacy and safety. Sulphosalazine (SSz) (especially for enthesitis) and leflunomide may also have a secondary role. Tumor necrosis factor inhibitors (TNF-I), alone or in combination with Mtx have shown tremendous benefit in children with polyarticular JIA, enthesitis related arthritis (ERA) and psoriatic arthritis. Tocilizumab appears very efficacious in systemic arthritis and abatacept and tocilizumab also appear to benefit polyarticular JIA; the role of rituximab remains unclear, though clearly beneficial in adult RA. TNF-I with Mtx is also effective in uveitis associated with JIA. Biologicals have demonstrated an impressive safety record in children with JIA, although close monitoring for rare but potentially dangerous adverse events, such as tuberculosis and other infections; paradoxical development of additional autoimmune diseases; and possibly an increased risk of cancers is warranted.

EULAR-PReS points to consider for the use of imaging in the diagnosis and management of juvenile idiopathic arthritis in clinical practice

To develop evidence based points to consider the use of imaging in the diagnosis and management of juvenile idiopathic arthritis (JIA) in clinical practice. The task force comprised a group of paediatric rheumatologists, rheumatologists experienced in imaging, radiologists, methodologists and patients from nine countries. Eleven questions on imaging in JIA were generated using a process of discussion and consensus. Research evidence was searched systematically for each question using MEDLINE, EMBASE and Cochrane CENTRAL. Imaging modalities included were conventional radiography, ultrasound, MRI, CT, scintigraphy and positron emission tomography. The experts used the evidence obtained from the relevant studies to develop a set of points to consider. The level of agreement with each point to consider was assessed using a numerical rating scale. A total of 13 277 references were identified from the search process, from which 204 studies were included in the systematic review. Nine points to consider were produced, taking into account the heterogeneity of JIA, the lack of normative data and consequent difficulty identifying pathology. These encompassed the role of imaging in making a diagnosis of JIA, detecting and monitoring inflammation and damage, predicting outcome and response to treatment, use of guided therapies, progression and remission. Level of agreement for each proposition varied according to the research evidence and expert opinion. Nine points to consider and a related research agenda for the role of imaging in the management of JIA were developed using published evidence and expert opinion.

Contrast-enhanced MRI features in the early diagnosis of Juvenile Idiopathic Arthritis

Objectives

To determine whether clinical, laboratory or Magnetic Resonance Imaging (MRI) measures differentiate Juvenile Idiopathic Arthritis (JIA) from other forms of active childhood arthritis.

Materials and methods

We prospectively collected data of 80 treatment-naïve patients clinically suspected of JIA with active non-infectious arthritis of (at least) one knee for <12 months duration. Upon presentation patients underwent clinical and laboratory assessments and contrast-enhanced MRI. MRI was not used as a diagnostic criterion.

Results

Forty-four (55 %) patients were clinically diagnosed with JIA, whereas in 36 (45 %) patients the diagnosis of JIA was discarded on clinical or laboratory findings. MRI-based synovitis was present in 27 (61.4 %) JIA patients and in 7 (19.4 %) non-JIA patients (P < 0.001).

Five factors (male gender, physician’s global assessment of overall disease activity, joints with limited range of motion, HLA-B27, MRI-based synovitis) were associated with the onset of JIA. In multivariate analysis MRI-based synovitis proved to be independently associated with JIA (OR 6.58, 95 % CI 2.36-18.33). In patients with MRI-based synovitis, the RR of having JIA was 3.16 (95 % CI 1.6-6.4).

Conclusions

The presence of MRI-based synovitis is associated with the clinical onset of JIA. Physical examination could be supported by MRI, particularly to contribute in the early differentiation of different forms of non-infectious childhood arthritis.

Key points

• Juvenile Idiopathic Arthritis (JIA) is a diagnosis of exclusion.

• Differentiating JIA and other forms of childhood arthritis can be difficult.

• MRI-techniques have substantially improved evaluation of joint abnormalities in JIA patients.

• MRI-based synovitis is significantly associated with the clinical onset of JIA.

• MRI could support physical examination in the early differentiation of childhood arthritis.

Polish Medical Society of Radiology and Polish Society of Rheumatology Recommendations for Magnetic Resonance Imaging of Musculoskeletal Disorders in Rheumatology

This document presents the recommendations of the Polish Medical Society of Radiology (PLTR) and the Polish Society of Polish Society of Rheumatology (PTR) regarding the standards of collaboration between radiologists and rheumatologists so as to optimize the diagnostics and treatment of patients with rheumatic diseases of the musculoskeletal system, including rheumatoid arthritis and spondyloarthropathies.

Definitions for the sonographic features of joints in healthy children

OBJECTIVE

Musculoskeletal ultrasonography (US) has potential in the assessment of disease activity and structural damage in childhood arthritides. In order to assess pathology, the US characteristics of joints in healthy children need to be defined first. The aim of this study was to develop definitions for the various components of the normal pediatric joint.

METHODS

The definitions were developed by an expert group and applicability was assessed on a collection of standardized scans of the knee and ankle joints by scoring the scans on a Likert scale. The definitions were then modified and applicability was reassessed before sending the definitions for approval to a larger panel of experts. A final scoring on stored images of all relevant joints at different ages followed.

RESULTS

Five definitions were developed addressing the articular bone, cartilage, joint capsule, epiphyseal ossification center, and synovial membrane. In total, 224 US images of knees and ankles were acquired, of which 172 were selected for scoring. An agreement of ≥80% was not met for any of the definitions, but after modifications, 81-97% agreement was reached. This version of the definitions was approved by 15 US experts. In the final validation exercise, all definitions reached an agreement of ≥80% for the shoulder, elbow, wrist, metacarpophalangeal hip, knee, ankle and metatarsophalangeal joint.

CONCLUSION

US definitions for the normal pediatric joint were successfully developed through a Delphi process and validated in a practical exercise. These results provide the basis to develop definitions for pathology and to support the standardized use of US in pediatric rheumatology.

One-year Followup Study on Clinical Findings and Changes in Magnetic Resonance Imaging-based Disease Activity Scores in Juvenile Idiopathic Arthritis

Objective.

To evaluate whether clinical disease activity findings during 1-year followup of patients with juvenile idiopathic arthritis (JIA) is associated with changes of magnetic resonance imaging (MRI)-based disease activity scores.

Methods.

Patients with JIA who had active knee involvement were studied using an open-bore MRI. After followup of a median of 1.3 years, patients were re-evaluated and classified as improved or unimproved according to the American College of Rheumatology Pediatric-50 (ACR-Ped50) criteria. Baseline and followup MRI features were scored by 2 readers using the Juvenile Arthritis MRI Scoring (JAMRIS) system, comprising validated scores for synovial hypertrophy, bone marrow changes, cartilage lesions, and bone erosions.

Results.

Data of 40 patients were analyzed (62.5% female, mean age 12.2 yrs). After followup, 27 patients (67.5%) were classified as clinically improved, whereas 13 patients (32.5%) showed no clinical improvement. The clinically improved patients showed a significant reduction in synovial hypertrophy scores during followup (p < 0.001), with substantial effects (standardized response mean −0.70). No such changes were observed for any of the other MRI features. Significant differences were detected regarding a change in synovial hypertrophy scores comparing clinically improved and unimproved patients (p = 0.004), without statistically significant differences for changes in scores for bone marrow changes (p = 0.079), cartilage lesions (p = 0.165), and bone erosions (p = 0.078).

Conclusion.

This is one of the first studies to provide evidence for MRI-based improvement upon followup in JIA patients with knee involvement. There is a strong association with clinical improvement according to the ACR-Ped50 criteria and changes in MRI-based synovial hypertrophy scores, supporting the role of MRI as a responsive outcome measure to evaluate disease activity with antiinflammatory treatment strategies.

Imaging in juvenile idiopathic arthritis (JIA): an update with particular emphasis on MRI

Juvenile idiopathic arthritis (JIA) is a heterogeneous condition encompassing all forms of chronic arthritis of unknown origin and with onset before 16 years of age. During the last decade new, potent therapeutic agents have become available, underscoring the need for accurate monitoring of therapeutic response on both disease activity and structural damage to the joint. However, so far, treatment efficacy is based on clinical ground only, although clinical parameters are poor markers for disease activity and progression of structural damage. Not so for rheumatoid arthritis patients where the inclusion of radiographic assessment has been required by FDA to test the disease-modifying potential of new anti-rheumatic drugs. In imaging of children with JIA there has been a shift from traditional radiography towards newer techniques such as ultrasound and MRI, however without proper evaluation of their accuracy and validity. We here summarize present knowledge and discuss future challenges in imaging children with JIA.

Selecting magnetic resonance imaging (MRI) outcome measures for juvenile idiopathic arthritis (JIA) clinical trials: first report of the MRI in JIA special interest group

Recent advances in magnetic resonance imaging (MRI) techniques have substantially improved the evaluation of joint pathologies in juvenile idiopathic arthritis (JIA). Because of the current availability of highly effective antirheumatic therapies and the unique and useful features of MRI, there is a growing need for an accurate and reproducible MRI assessment scoring system for JIA, such as the rheumatoid arthritis MRI Scoring (RAMRIS) for patients with rheumatoid arthritis (RA). To effectively evaluate the efficacy of treatment in clinical research trials, we need to develop and validate scoring methods to accurately measure joint outcomes, standardize imaging protocols for data acquisition and interpretation, and create imaging atlases to differentiate physiologic and pathologic joint findings in childhood and adolescence. Such a standardized, validated, JIA-MRI scoring method could be used as an outcome measure in clinical trials.

Clinical trial of etanercept tapering in juvenile idiopathic arthritis during remission

To explore the possibility of step-down method and low dose of etanercept for long-term stable remission of patients with juvenile idiopathic arthritis (JIA). Patients with JIA were enrolled into this study between February 2008 and March 2010 and then followed up for 2 years. The inclusion criteria were clinical remission and use of etanercept for therapy. On the first year of the study, the dose of etanercept was kept at 0.4 mg/kg per week, the half dose of what those patients had been used. On the second year, the dose of etanercept was further lowered to 0.4 mg/kg per month. DMARDs were allowed in this study. MR images were performed to observe joint changes. The primary end point was disease flare defined according to clinical and/or radiological data. The flare rate curve was analyzed by Kaplan-Meier, and logistic regression model was used to find factors associating with disease flare. MRI was performed to prove no active changes or progressions of bone erosions on joints. Thirty-one patients were enrolled in this study. There were 4 patients experiencing disease flare during the first 12th month. During the second year, disease flare was not occurred. Thus, the cumulative flare rate was 12.9 % on 12th month and then unchanged on the second year. Logistic regression model indicates there are no differences in sex, age of disease initiation, disease duration, subtypes, DMARDs, HLA-B27, months of etanercept duration and scores on MRI between patients with remission and those experiencing flares. At the end of the study, MRI found no progressions of joints to the patients keeping stable remission. Step-down method can be used for etanercept tapering. Long-term remission and low flare rate can be got by this method.

The diagnostic accuracy of unenhanced MRI in the assessment of joint abnormalities in juvenile idiopathic arthritis

OBJECTIVES

To assess the diagnostic accuracy and reliability of MRI without contrast enhancement in the evaluation of JIA knee joint abnormalities.

METHODS

JIA patients with clinically active knee involvement were prospectively studied using an 1-T open-bore magnet. MRI features were independently evaluated by two readers using the JAMRIS system. The first reading included unenhanced images, whereas complete image sets were available for the second reading.

RESULTS

Imaging findings from 73 patients were analysed. Agreement between Gd-enhanced (+Gd) and Gd-unenhanced (-Gd) MRI scores of bone marrow changes, cartilage lesions and bone erosions was good concerning sensitivity, specificity, negative predictive value and positive predictive value. Inter-observer agreement was good for both -Gd and +Gd scores (ICC = 0.91-1.00, 0.93-1.00, respectively). Regarding the assessment of synovial hypertrophy, specificity of -Gd was high (0.97), but the sensitivity of unenhanced MRI was only 0.62. Inter-reader agreement for +Gd MRI was ICC = 0.94; however, omitting post-Gd acquisitions increased inter-reader variation (ICC = 0.86).

CONCLUSIONS

If Gd-enhanced MRI is the reference standard, omitting Gd contrast medium is irrelevant for the assessment of bone marrow changes, cartilage lesions and bone erosions as joint abnormalities in JIA. Omitting intravenous Gd in the MRI assessment of joints in JIA is inadvisable, because it decreases the reliability of detecting synovial disease.

KEY POINTS

• Magnetic resonance imaging is increasingly used to assess juvenile idiopathic arthritis. • Synovial hypertrophy, a marker of JIA activity, is well shown by MRI. • Omitting intravenous contrast medium decreases the reliability of synovial hypertrophy scores. • Bone marrow, cartilage and erosions can be reliably evaluated without contrast enhancement. • In the evaluation of JIA disease activity, unenhanced MRI is inadvisable.

MRI of the wrist in juvenile idiopathic arthritis: proposal of a paediatric synovitis score by a consensus of an international working group. Results of a multicentre reliability study

BACKGROUND

MRI is a sensitive tool for the evaluation of synovitis in juvenile idiopathic arthritis (JIA).

OBJECTIVE

The purpose of this study was to introduce a novel MRI-based score for synovitis in children and to examine its inter- and intraobserver variability in a multi-centre study.

MATERIALS AND METHODS

Wrist MRI was performed in 76 children with JIA. On postcontrast 3-D spoiled gradient-echo and fat-suppressed T2-weighted spin-echo images, joint recesses were scored for the degree of synovial enhancement, effusion and overall inflammation independently by two paediatric radiologists. Total-enhancement and inflammation-synovitis scores were calculated.

RESULTS

Interobserver agreement was poor to moderate for enhancement and inflammation in all recesses, except in the radioulnar and radiocarpal joints. Intraobserver agreement was good to excellent. For enhancement and inflammation scores, mean differences (95 % CI) between observers were -1.18 (-4.79 to 2.42) and -2.11 (-6.06 to 1.83). Intraobserver variability (reader 1) was 0 (-1.65 to 1.65) and 0.02 (-1.39 to 1.44).

CONCLUSION

Intraobserver agreement was good. Except for the radioulnar and radiocarpal joints, interobserver agreement was not acceptable. Therefore, the proposed scoring system requires further refinement.

Advances and challenges in imaging in juvenile idiopathic arthritis

Imaging assessments of the joints of children with juvenile idiopathic arthritis (JIA) are challenging, owing to the unique features of the growing skeleton. Traditionally, imaging studies in childhood arthritis have been based on conventional radiography. However, in the past few years, interest in the use of MRI and ultrasonography has increased. As a result, imaging has become a main area of clinical and research investigation in paediatric rheumatology. The chief advance in the field of conventional radiography has been the development and validation of paediatric scoring systems for the assessment of radiographic progression. Several studies have shown that MRI provides a precise quantification of synovitis in children with JIA. Furthermore, a high frequency of bone marrow oedema and bone erosions has been found early in the disease course. Ultrasonography has been proven to be superior to clinical examination in detecting synovitis, tenosynovitis and enthesitis. A high frequency of subclinical synovitis has been demonstrated in patients with JIA who have clinically inactive disease using both MRI and ultrasonography. However, more information from healthy children is needed to enable differentiation of the bone and cartilage abnormalities that reflect damage from those that are part of normal development using MRI or ultrasonography. This Review provides a summary of the current information on conventional radiography, ultrasonography and MRI in JIA and highlights the advantages and limitations of each imaging modality.

T2 relaxation time changes in distal femoral articular cartilage in children with juvenile idiopathic arthritis: a 3-year longitudinal study

OBJECTIVE

Increased cartilage T2 relaxation time is thought to be an early marker of disease progression in juvenile idiopathic arthritis, because it can identify microstructural changes before damage becomes visible. The purpose of this study was to investigate longitudinal changes in T2 relaxation time mapping (i.e., T2 map) in children with early juvenile idiopathic arthritis and to compare with changes in clinical assessments.

SUBJECTS AND METHODS

Twenty children (age range, 6.4-16 years) with early juvenile idiopathic arthritis completed at least four evaluations with T2 maps and clinical assessments: at enrollment, at 3 months, and at 1, 2, and 3 years. Sagittal T2 maps of distal femoral cartilage were generated, a region of interest was selected, and a T2 relaxation time profile was generated. The area under the curve from the T2 profile (i.e., T2 value) was correlated with patient age and sex and the following clinical assessments: total knee score, Childhood Health Assessment Questionnaire, physician global assessment, parent global assessment, and total number of active joints.

RESULTS

There was a significant increase in mean T2 values from 3 months to 2 years (p < 0.05). There was a significant decrease in mean Childhood Health Assessment Questionnaire values between enrollment and 2 years (p < 0.05) and a significant decrease in parent global assessment, physician global assessment, total number of active joints, and total knee score values between enrollment and 1 year (p < 0.05). There were no statistically significant correlations between T2 values and patient age, sex, or clinical assessments.

CONCLUSION

In patients with early juvenile idiopathic arthritis, T2 maps showed increased T2 values from the 3-month to 2-year follow-up, during which time the clinical assessments improved. This increase likely represents progressive microstructural changes, even though clinical symptoms improved with treatment.

Synovial and inflammatory diseases in childhood: role of new imaging modalities in the assessment of patients with juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) represents a group of heterogeneous diseases characterized by a chronic inflammatory process primarily targeting the synovial membrane. A persistent synovitis is associated with an increased risk of osteocartilaginous damage.With the advent of effective structure-modifying treatment for JIA, it may be possible to significantly reduce or even completely prevent structural damage and associated functional disability. The trend towards early suppression of inflammation, in order to prevent erosive disease, shifts the emphasis away from conventional radiographic detectable structural damage to the slightest traces of early joint damage, and drives the need for alternative imaging techniques more sensitive in detecting early signs of disease activity and damage. In this regard MRI and US are playing an increasing role in the evaluation of arthritic joints.This article will review the key aspects of the current status and recent important advances of imaging techniques available to investigate the child with rheumatic disease, briefly discussing conventional radiography, and particularly focusing on MRI and US. In this era of advancing imaging technology, knowledge of the relative values of available imaging techniques is necessary to optimize the management of children with JIA.

Comparison of clinical versus ultrasound-determined synovitis in juvenile idiopathic arthritis

OBJECTIVE

To compare clinical evaluation and ultrasonography (US) in the assessment of joint synovitis in children with juvenile idiopathic arthritis (JIA).

METHODS

Thirty-two patients underwent clinical evaluation of 52 joints by 2 pediatric rheumatologists. Joints were assessed for swelling, tenderness/pain on motion, and restricted motion. The same joints were scanned independently by an experienced sonographer for synovial hyperplasia, joint effusion, and power Doppler (PD) signal.

RESULTS

In total, 1,664 joints were assessed both clinically and with US. On clinical examination, 98 joints (5.9%) were swollen, 59 joints (3.5%) were tender, and 40 joints (2.4%) had restricted motion. On US evaluation, 125 joints (7.5%) had synovial hyperplasia, 153 joints (9.2%) had joint effusion, and 53 joints (3.2%) had PD signal. A total of 104 (6.3%) and 167 (10%) joints had clinical and US synovitis, respectively. Of the 1,560 clinically normal joints, 86 (5.5%) had subclinical synovitis (i.e., had synovitis on US). US led to classifying 5 patients as having polyarthritis who were classified as having oligoarthritis or were found to have no synovitis on clinical evaluation. US variables were moderately correlated with clinical measures of joint swelling, but poorly correlated with those of joint tenderness/pain on motion and restricted motion. Overall, correlations were lower for PD signal than for synovial hyperplasia and joint effusion.

CONCLUSION

We found that subclinical synovitis as detected by US is common in children with JIA. This finding may have important implications for patient classification and may affect the choice of the optimal therapeutic strategy in individual patients.

Juvenile idiopathic arthritis of peripheral joints: quality of reporting of diagnostic accuracy of conventional MRI

RATIONALE AND OBJECTIVES

The aim of this study was to systematically review the quality of papers on the clinimetric properties of magnetic resonance imaging for the diagnosis of juvenile idiopathic arthritis in peripheral joints.

MATERIALS AND METHODS

A review of Medline, EMBASE, the Database of Abstracts of Reviews of Effects, and the Cochrane Library was performed by using a systematic search strategy. Two independent reviewers evaluated selected articles by using Standards for Reporting of Diagnostic Accuracy (STARD) and Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tools. Items were reported independently for STARD and QUADAS.

RESULTS

Eighteen studies (validity, n = 18; reliability, n = 3; responsiveness, n = 3) were included. Their overall quality of reporting of methods was fair. Methodological problems with the STARD system included a lack of reporting of exclusion criteria (n = 14), partial or no information on operators' expertise (n = 14) or blinding (n = 18), and deficient information on study time frames (n = 12), treatments (n = 10), or indeterminate results (n = 18). The distribution of QUADAS scores was heterogeneous, with overall scores ranging between 3.5 (poor) and 16.5 (excellent) (maximum score, 17.5).

CONCLUSIONS

The quality of reporting of methods in studies on the magnetic resonance imaging assessment of juvenile idiopathic arthritis is heterogeneous and fair overall. Further methodological refinement of research design should be sought in future studies to provide stronger evidence for the value of novel techniques in clinical settings.

MRI in juvenile idiopathic arthritis and juvenile dermatomyositis

The use of MRI in the assessment of the musculoskeletal system in children has important differences from its use in adults. Growth in children has significant impact on the epiphysis and growth plate, which are important structures in the growing child, and there are radiological features that differ from those in adults: disease may alter structures during a period of growth; the pathologies themselves are a distinct group of diseases at variance with adult arthritis and myositis, with a different spectrum of differential diagnoses; and many technical issues are different when imaging a child. These are important considerations in choosing the appropriate imaging. MRI is a powerful and valuable imaging technique in pediatric musculoskeletal pathologies, with considerable potential for future developments to enhance its role in diagnosis, management, and therapeutic intervention for these children.

Quantitative MR characterization of disease activity in the knee in children with juvenile idiopathic arthritis: a longitudinal pilot study

BACKGROUND

The development of a quantifiable and noninvasive method of monitoring disease activity and response to therapy is vital for arthritis management.

OBJECTIVE

The purpose of this study was to investigate the utility of quantitative dynamic contrast-enhanced MRI (DCE-MRI) based on pharmacokinetic (PK) modeling to evaluate disease activity in the knee and correlate the results with the clinical assessment in children with juvenile idiopathic arthritis (JIA).

MATERIALS AND METHODS

A group of 17 children with JIA underwent longitudinal clinical and laboratory assessment and DCE-MRI of the knee at enrollment, 3 months, and 12 months. A PK model was employed using MRI signal enhancement data to give three parameters, K(trans') (min(-1)), k(ep) (min(-1)), and V(p) (') and to calculate synovial volume.

RESULTS

The PK parameters, synovial volumes, and clinical and laboratory assessments in most children were significantly decreased (P < 0.05) at 12 months when compared to the enrollment values. There was excellent correlation between the PK and synovial volume and the clinical and laboratory assessments. Differences in MR and clinical parameter values in individual subjects illustrate persistent synovitis when in clinical remission.

CONCLUSION

A decrease in PK parameter values obtained from DCE-MRI in children with JIA likely reflects diminution of disease activity. This technique may be used as an objective follow-up measure of therapeutic efficacy in patients with JIA. MR imaging can detect persistent synovitis in patients considered to be in clinical remission.