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

Developing standards for MRI evaluation of joints in children with juvenile idiopathic arthritis utilizing the temporomandibular joint as a model

The treatment of a patient with juvenile idiopathic arthritis (JIA) is best monitored with standardized and validated tools to measure joint changes over time. Treatment approaches are best indicated if the clinicians are aware of the structural status of the joint at a given time, especially in anatomically deep joints for which clinical assessment is limited. Magnetic resonance imaging (MRI) is of utmost importance for assessment of deep joints and extra-articular soft tissue of the entire body for which ultrasound may be suboptimal. Because the distinction between pathologic and physiologic joint changes on MRI is key for proper diagnosis and treatment of patients with arthropathies, a comprehensive standardized approach is needed to effectively measure outcomes of growing joints of children with JIA. Such an approach is essential for both clinical assessment and to conduct clinical trials in patients with JIA treated in different centers around the world. To meet this need, several international imaging collaborative research groups have been developing MRI scales over the past years, including the MRI in JIA (JAMRI) special interest group within the Outcome Measures in Rheumatology (OMERACT) research network. This manuscript reviews the efforts of the OMERACT JAMRI working group to generate and validate pediatric MRI scoring systems for different joints in children with JIA that can have ubiquitous utilization anywhere in the world. In particular, it describes the different steps of development and validation of an MRI scale using the TMJ as a model.

Comparison of contrast-enhanced MRI features of the (teno)synovium in the wrist of patients with juvenile idiopathic arthritis and pediatric controls

To directly compare and describe the differences between juvenile idiopathic arthritis (JIA) patients and pediatric controls regarding features of the synovial and tenosynovial membrane on contrast-enhanced magnetic resonance imaging (MRI) of the wrist. T1-weighted contrast-enhanced MRI scans of 25 JIA patients with clinically active wrist arthritis and 25 children without a history of joint complaints nor any clinical signs of joint inflammation were evaluated by two readers blinded to clinical data. The synovium was scored at five anatomical sites based on thickening of the synovium (0–3 scale) and synovial enhancement (0–2 scale). Thickening and/or enhancement of the tenosynovium was scored at four anatomical sites using a 0–3 scale. Significantly higher scores for synovial thickening (median 4 vs. 1, p < 0.001) and synovial enhancement (median 4 vs. 1, p < 0.001) are found in the wrist of JIA patients as compared to controls. JIA patients experienced the highest synovial scores at the mid-/inter-carpal, 2nd –5th carpometacarpal, and radiocarpal joints. No significant difference in tenosynovial scores is found between both groups (median 0 vs. 0, p = 0.220). This study highlights the higher synovial thickening/enhancement scores on contrast-enhanced MRI of the wrist in JIA patients compared to pediatric controls. Tenosynovial thickening and/or enhancement was rarely present in both groups. In JIA patients, synovial thickening and enhancement were particularly present at three anatomical sites. These results substantially support rheumatologists and radiologists when navigating through MRI of the wrist in search for JIA disease activity.

Consensus-driven conceptual development of a standardized whole body-MRI scoring system for assessment of disease activity in juvenile idiopathic arthritis: MRI in JIA OMERACT working group

OBJECTIVES

Whole body-MRI is helpful in directing diagnostic and treatment approaches, and as a research outcome measure. We describe our initial consensus-driven phase towards developing a whole body-MRI scoring system for juvenile idiopathic arthritis.

METHODS

An iterative approach using three rounds of anonymous Delphi surveys followed by a consensus meeting was used to draft the structure of the whole body-MRI scoring system, including the relevant anatomic joints and entheses for assessment, diagnostic item selection, definition and grading, and selection of appropriate MRI planes and sequences. The surveys were completed independently by an international expert group consisting of pediatric radiologists and rheumatologists.

RESULTS

Twenty-two experts participated in at least one of three rounds of Delphi surveys and a concluding consensus meeting. A first iteration scoring system was developed which ultimately included the assessment of 100 peripheral, 23 chest, and 76 axial joints, and 64 entheses, with 2-4 diagnostic items graded in each of the items, using binary (presence/absence) and 2-3-level ordinal scores. Recommendations on anatomic MRI planes and sequences were specified as the minimally necessary imaging protocol for the scoring system.

CONCLUSION

A novel whole body-MRI scoring system for juvenile idiopathic arthritis was developed by consensus among members of MRI in JIA OMERACT working group. Further iterative refinements, reliability testing, and responsiveness are warranted in upcoming studies.

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 of the knee joint in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is an umbrella term for a group of diseases in children younger than 16 years old lasting six weeks or longer. Synovitis may lead to destructive and irreversible joint changes with subsequent functional impairment. Prompt diagnosis is essential to prevent permanent joint damage and preserve joint functionality. In the course of JIA both the axial and peripheral skeleton may be involved in the inflammatory process, but the knee joint is most frequently affected. New drugs and treatment protocols have forced the need for diagnosis at the earliest possible stage. Magnetic resonance imaging (MRI) allows early detection of lesions and constitutes a superior diagnostic imaging method. Synovitis, tenosynovitis, enthesitis, bursitis, osteitis, cartilage loss, bone cysts, and erosions are lesions diagnosed in JIA, and they can be precisely imaged in MRI. This article aims to present MRI inflammatory features of the knee in children with JIA based on the literature.

Current status of MR imaging of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy in the pediatric population. Although the diagnosis is essentially clinical for many affected joints, MR imaging has become an important tool for the assessment of joints that are difficult to evaluate clinically, such as temporomandibular and sacroiliac joints, and for screening of inflammatory changes in the entire body by whole body MRI (WBMRI) assessment. The utilization of MR imaging is challenging in the pediatric population given the need for discrimination between pathological and physiological changes in the growing skeleton. Several multicentric multidisciplinary organizations have made major efforts over the past decades to standardize, quantify, and validate scoring systems to measure joint changes both cross-sectionally and longitudinally according to rigorous methodological standards. In this paper, we (1) discuss current trends for the diagnosis and management of JIA, (2) review challenges for detecting real pathological changes in growing joints, (3) summarize the current status of standardization of MRI protocols for data acquisition and the quantification of joint pathology in JIA by means of scoring systems, and (4) outline novel MR imaging techniques for the evaluation of anatomy and function of joints in JIA. Optimizing the role of MRI as a robust biomarker and outcome measure remains a priority of future research in this field.

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

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.

Exploring contrast-enhanced MRI findings of the clinically non-inflamed symptomatic pediatric wrist

BACKGROUND

Knowledge of the synovial and tenosynovial appearance of the clinically non-arthritic symptomatic juvenile wrist using contrast-enhanced magnetic resonance imaging (MRI) is sparse.

OBJECTIVES

To analyze contrast-enhanced MRI findings of the clinically non-inflamed symptomatic pediatric wrist, focusing on the enhancing synovial and tenosynovial membrane. To evaluate the coexistent presence of (teno)synovial enhancement, joint fluid, bony depressions and medullary changes suggestive of bone marrow edema.

MATERIALS AND METHODS

We included 20 children (15 girls; age range: 7.5-17.6 years) who underwent contrast-enhanced MRI of the wrist, based on initial clinical indication, and eventually turned out to be unaffected by arthritic or orthopedic disorders. Various imaging characteristics of the synovium, tenosynovium, joint fluid, bone tissue and bone marrow were evaluated using existing MRI scoring systems.

RESULTS

In 3/20 (15%) children, mild or moderate-severe synovial enhancement was observed and 2/20 (10%) children showed mild tenosynovial enhancement/thickening. Joint fluid (11/20 children; 55%), bony depressions (20/20 children; 100%) and medullary changes suggestive of bone marrow edema (6/20; 30%) were found in a substantial percentage of children. The most frequently observed combination of coexisting imaging characteristics was bony depressions with ≥2 mm joint fluid, which was found in 7/20 (35%) children. Simultaneous presence of synovial and tenosynovial enhancement/thickening, bony depressions and medullary changes suggestive of bone marrow edema was observed in one child.

CONCLUSION

Several juvenile idiopathic arthritis-relevant MRI characteristics can be observed in the clinically non-inflamed symptomatic pediatric wrist.

Linking Joint Impairment and Gait Biomechanics in Patients with Juvenile Idiopathic Arthritis

Juvenile Idiopathic Arthritis (JIA) is a paediatric musculoskeletal disease of unknown aetiology, leading to walking alterations when the lower-limb joints are involved. Diagnosis of JIA is mostly clinical. Imaging can quantify impairments associated to inflammation and joint damage. However, treatment planning could be better supported using dynamic information, such as joint contact forces (JCFs). To this purpose, we used a musculoskeletal model to predict JCFs and investigate how JCFs varied as a result of joint impairment in eighteen children with JIA. Gait analysis data and magnetic resonance images (MRI) were used to develop patient-specific lower-limb musculoskeletal models, which were evaluated for operator-dependent variability (< 3.6°, 0.05 N kg-1 and 0.5 BW for joint angles, moments, and JCFs, respectively). Gait alterations and JCF patterns showed high between-subjects variability reflecting the pathology heterogeneity in the cohort. Higher joint impairment, assessed with MRI-based evaluation, was weakly associated to overall joint overloading. A stronger correlation was observed between impairment of one limb and overload of the contralateral limb, suggesting risky compensatory strategies being adopted, especially at the knee level. This suggests that knee overloading during gait might be a good predictor of disease progression and gait biomechanics should be used to inform treatment planning.

Consider the wrist: a retrospective study on pediatric connective tissue disease with MRI

The aim of this study is to describe the clinical characteristics and MRI findings of the wrist in a cohort of children suffering from connective tissue disease with musculoskeletal involvement. Ten patients with pediatric connective tissue disease [median age 14.7 years (IQR 12.7-16.6 years), 70% female] were identified from a large MRI database. Clinical findings during the disease course were retrospectively obtained from patient charts and findings at the time of MRI were prospectively registered in the MRI database. MRI wrist datasets were evaluated by three readers in consensus for synovitis, tenosynovitis, bone marrow changes, bone erosions and myositis. Patients suffered from connective tissue disease with clinical overlap of subtypes systemic lupus erythematosus, Sjögren syndrome and dermatomyositis. Median onset of disease was at 12.3 years (IQR 7.8-14.8 years). Clinical arthritis activity was scored low (median visual analogue scale physician 19, IQR 7-31). Notwithstanding, extensive inflammatory abnormalities such as synovitis and tenosynovitis were found in the wrist of 7/10 patients. Osteochondral involvement was detected in 3/10 patients. In a small cohort of children with connective tissue disease and musculoskeletal symptoms, severe inflammatory abnormalities of the involved wrist were present in the MRI, while clinical disease scores suggested mild disease activity. Therefore, clinicians should consider the wrist as vulnerable for joint damage and can add MRI as a helpful tool in the management of patients with pediatric connective tissue disease and musculoskeletal involvement.

Effect of the Inclusion of the Metacarpophalangeal Joints on the Wrist Magnetic Resonance Imaging Scoring System in Juvenile Idiopathic Arthritis

Objective.

To extend the magnetic resonance imaging (MRI) score for assessment of wrist synovitis in juvenile idiopathic arthritis (JIA) by inclusion of the metacarpophalangeal (MCP) joints, and to compare the metric properties of the original and the extended score.

Methods.

Wrist MRI of 70 patients with JIA were scored by 3 independent readers according to (1) the wrist component of the rheumatoid arthritis MRI synovitis score (comprising distal radioulnar, radiocarpal, and combined midcarpal and carpometacarpal joints); and (2) an extended score including the MCP joints. Thirty-eight patients had a 1-year MRI followup. The concordance between the readers [intraclass correlation coefficient (ICC), 95% limits of agreement (LOA), and weighted Cohen’s κ], correlations with clinical variables (Spearman’s ϱ), and the sensitivity to change [standardized response mean (SRM)] were calculated for both scores.

Results.

The interreader agreement was moderate for the original score (ICC 0.77; 95% CI 0.68–0.84) and good for the extended score (ICC 0.86; 95% CI 0.80–0.91). Using 95% LOA, the aggregate score variability was less favorable with relatively wide LOA. Weighted Cohen’s κ of the individual joints indicated good agreement for the original score and good to excellent agreement for the extended score. Correlations with clinical variables reflecting disease activity improved for the extended score and its SRM was higher compared to that of the original score.

Conclusion.

The extended score showed better reliability, construct validity, and sensitivity to change than the original. Inclusion of the MCP joints should be considered for a more accurate assessment of disease activity and treatment efficacy in JIA.

Juvenile idiopathic arthritis - the role of imaging from a rheumatologist's perspective

Alongside recent advances in treatment strategies for juvenile idiopathic arthritis (JIA), paediatric rheumatologists have taken increasing interest in the use of imaging. Magnetic resonance imaging (MRI) and musculoskeletal ultrasound, by providing more detailed information on disease activity than clinical examination and conventional radiography (CR), have become helpful diagnostic and managerial tools. The growing skeleton, however, with changing appearances over time, is still challenging in the establishment of valid scoring systems for pathological changes. Defining child- and age-specific reference standards is therefore a highly prioritized issue. The aim of this article is to raise awareness among radiologists of the substantial role that imaging can play to optimize the management of JIA patients and to describe the state-of-the-art validation process of imaging as an outcome measure. A closer collaboration between radiologists and pediatric rheumatologists is crucial to define a scheduled workflow for imaging in JIA.

Current status of wrist imaging in juvenile idiopathic arthritis

Wrist involvement occurs in about one-quarter of patients diagnosed with juvenile idiopathic arthritis (JIA), increasing to 40% 5 years after diagnosis. The imaging appearances, both for active inflammation and permanent change, differ from those seen in adult rheumatoid arthritis; therefore, a child-specific approach is crucial for correct assessment. In this review article, we provide an update on the current status for imaging wrist JIA, with a focus on evidence-based practice.

Imaging in juvenile idiopathic arthritis - international initiatives and ongoing work

Imaging is increasingly being integrated into clinical practice to improve diagnosis, disease control and outcome in children with juvenile idiopathic arthritis. Over the last decades several international groups have been launched to standardize and validate different imaging techniques. To enhance transparency and facilitate collaboration, we present an overview of ongoing initiatives.

Magnetic Resonance Imaging (MRI) of the Knee as an Outcome Measure in Juvenile Idiopathic Arthritis: An OMERACT Reliability Study on MRI Scales

OBJECTIVE

There is increasing evidence that early therapeutic intervention improves longterm joint outcome in juvenile idiopathic arthritis (JIA). Given the existence of highly effective treatments, there is an urgent need for reliable and accurate measures of disease activity and joint damage in JIA. Our objective was to assess the reliability of 2 magnetic resonance imaging (MRI) scoring methods: the Juvenile Arthritis MRI Scoring (JAMRIS) system and the International Prophylaxis Study Group (IPSG) consensus score, for evaluating disease status of the knee in patients with JIA.

METHODS

Four international readers independently scored an MRI dataset of 25 JIA patients with clinical knee involvement. Synovial thickening, joint effusion, bone marrow changes, cartilage lesions, bone erosions, and subchondral cysts were scored using the JAMRIS and IPSG systems. Further, synovial enhancement, infrapatellar fat pad heterogeneity, tendinopathy, and enthesopathy were scored. Interreader reliability was analyzed by using the generalized κ, ICC, and the smallest detectable difference (SDD).

RESULTS

ICC regarding interreader reliability ranged from 0.33 (95% CI 0.12-0.52, SDD = 0.29) for enthesopathy up to 0.95 (95% CI 0.92-0.97, SDD = 3.19) for synovial thickening. Good interreader reliability was found concerning joint effusion (ICC 0.93, 95% CI 0.89-0.95, SDD = 0.51), synovial enhancement (ICC 0.90, 95% CI 0.85-0.94, SDD = 9.85), and bone marrow changes (ICC 0.87, 95% CI 0.80-0.92, SDD = 10.94). Moderate to substantial reliability was found concerning cartilage lesions and bone erosions (ICC 0.55-0.72, SDD 1.41-13.65).

CONCLUSION

The preliminary results are promising for most of the scored JAMRIS and IPSG items. However, further refinement of the scoring system is warranted for unsatisfactorily reliable items such as bone erosions, cartilage lesions, and enthesopathy.

The many shades of enhancement: timing of post-gadolinium images strongly influences the scoring of juvenile idiopathic arthritis wrist involvement on MRI

BACKGROUND

Potential long-term side effects of treatment for juvenile idiopathic arthritis are concerning. This has necessitated accurate tools, such as MRI, to monitor treatment response and allow for personalized therapy.

OBJECTIVE

To examine the extent to which timing of post-contrast MR images influences the scoring of inflammatory change in the wrist in children with juvenile idiopathic arthritis.

MATERIALS AND METHODS

We studied two sets of post-contrast 3-D gradient echo MRI series of the wrist in 34 children with juvenile idiopathic arthritis. These images were obtained immediately after administration of intravenous contrast material and again after approximately 10 min. The dataset was drawn from a prospective multicenter project conducted 2006-2010. We assessed five wrist locations for synovial enhancement, effusion and overall inflammation. Examinations were scored by one radiologist in two sessions - the first was based on the early post-contrast images, and the later session, for which the previous findings were masked, was based on the later post-contrast images.

RESULTS

Fifty-two of the 170 locations (30.6%) received a higher synovial enhancement score based on the late post-contrast images as compared to the early images. Sixty of the 170 (35%) locations received a higher total inflammation score. The mean scores of synovial enhancement and total inflammation were significantly higher when based on the late post-contrast images as compared to the early post-contrast images.

CONCLUSION

An MRI-based scoring system for the presence and degree of synovitis should be based on a standardized MR-protocol with a fixed interval between intravenous contrast injection and post-contrast images.

Carpal erosions in children with juvenile idiopathic arthritis: repeatability of a newly devised MR-scoring system

BACKGROUND

Juvenile idiopathic arthritis (JIA) is characterized by synovial inflammation, with potential risk of developing progressive joint destruction. Personalized state-of-the-art treatment depends on valid markers for disease activity to monitor response; however, no such markers exist.

OBJECTIVE

To evaluate the reliability of scoring of carpal bone erosions on MR in children with JIA using two semi-quantitative scoring systems.

MATERIALS AND METHODS

A total of 1,236 carpal bones (91 MR wrist examinations) were scored twice by two independent pediatric musculoskeletal radiologists. Bony erosions were scored according to estimated bone volume loss using a 0-4 scale and a 0-10 scale. An aggregate erosion score comprising the sum total carpal bone volume loss was calculated for each examination.

RESULTS

The 0-4 scoring system resulted in good intra-reader agreement and moderate to good inter-observer agreement in the assessment of individual bones. Fair and moderate agreement were achieved for inter-reader and intra-reader agreement, respectively, using the 0-10 scale. Intra- and particularly inter-reader aggregate score variability were much less favorable, with wide limits of agreement.

CONCLUSION

Further analysis of erosive disease patterns compared with normal subjects is required, and to facilitate the development of an alternative means of quantifying disease.

Contrast-enhanced MRI of the knee in children unaffected by clinical arthritis compared to clinically active juvenile idiopathic arthritis patients

OBJECTIVES

To evaluate enhancing synovial thickness upon contrast-enhanced magnetic resonance imaging (MRI) of the knee in children unaffected by clinical arthritis compared with clinically active juvenile idiopathic arthritis (JIA) patients. A secondary objective was optimization of the scoring method based on maximizing differences on MRI between these groups.

METHODS

Twenty-five children without history of joint complaints nor any clinical signs of joint inflammation were age/sex-matched with 25 clinically active JIA patients with arthritis of at least one knee. Two trained radiologists, blinded for clinical status, independently evaluated location and extent of enhancing synovial thickness with the validated Juvenile Arthritis MRI Scoring system (JAMRIS) on contrast-enhanced axial fat-saturated T1-weighted MRI of the knee.

RESULTS

Enhancing synovium (≥2 mm) was present in 13 (52 %) unaffected children. Using the total JAMRIS score for synovial thickening, no significant difference was found between unaffected children and active JIA patients (p = 0.091). Additional weighting of synovial thickening at the JIA-specific locations enabled more sensitive discrimination (p = 0.011).

CONCLUSIONS

Mild synovial thickening is commonly present in the knee of children unaffected by clinical arthritis. The infrapatellar and cruciate ligament synovial involvement were specific for JIA, which-in a revised JAMRIS-increases the ability to discriminate between JIA and unaffected children.

KEY POINTS

• Synovial inflammation is the primary disease feature in juvenile idiopathic arthritis (JIA). • Appearance of the synovium on contrast-enhanced MRI in unaffected children is unknown. • Validation of existing scoring methods requires comparison between JIA and unaffected children. • Mild enhancing synovial thickening was detected in half of the unaffected children. • Location-weighting for JIA-specific locations increased discriminative value of the scoring methods (p = 0.011).

Current Status of Efforts on Standardizing Magnetic Resonance Imaging of Juvenile Idiopathic Arthritis: Report from the OMERACT MRI in JIA Working Group and Health-e-Child

OBJECTIVE

To report on the progress of an ongoing research collaboration on magnetic resonance imaging (MRI) in juvenile idiopathic arthritis (JIA) and describe the proceedings of a meeting, held prior to Outcome Measures in Rheumatology (OMERACT) 12, bringing together the OMERACT MRI in JIA working group and the Health-e-Child radiology group. The goal of the meeting was to establish agreement on scoring definitions, locations, and scales for the assessment of MRI of patients with JIA for both large and small joints.

METHODS

The collaborative work process included premeeting surveys, presentations, group discussions, consensus on scoring methods, pilot scoring, conjoint review, and discussion of a future research agenda.

RESULTS

The meeting resulted in preliminary statements on the MR imaging protocol of the JIA knee and wrist and determination of the starting point for development of MRI scoring systems based on previous studies. It was also considered important to be descriptive rather than explanatory in the assessment of MRI in JIA (e.g., "thickening" instead of "hypertrophy"). Further, the group agreed that well-designed calibration sessions were warranted before any future scoring exercises were conducted.

CONCLUSION

The combined efforts of the OMERACT MRI in JIA working group and Health-e-Child included the assessment of currently available material in the literature and determination of the basis from which to start the development of MRI scoring systems for both the knee and wrist. The future research agenda for the knee and wrist will include establishment of MRI scoring systems, an atlas of MR imaging in healthy children, and MRI protocol requisites.

The joints in juvenile idiopathic arthritis

Abstract

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.

Key Points

• 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.