Towards a role of ultrasound in children with juvenile idiopathic arthritis

Structural ultrasound of joints and tendons in healthy children: development of normative data

BACKGROUND

Musculoskeletal ultrasound is a well accessible technique to assess disease activity in children with juvenile idiopathic arthritis. Knowledge of reference values of joint structures is indispensable to differentiate between physiological and pathological finding. The aim of this study was to assess the structural sonographic features of joints and tendons in healthy children from several age groups (0.2-18 year), and develop a set of normative data.

METHODS

Greyscale ultrasound was performed in 500 healthy children (age 0.2-18 years) according to a predefined scanning protocol (Additional file 1) including the shoulder, elbow, wrist, second metacarpophalangeal joint, hip, knee, ankle, and first metatarsophalangeal joint). Demographic data and values of cartilage thickness, tendon diameters, and the degree of capsular distention measured by bone-capsular distance (BCD) were collected. Differences according to the sex were assessed by unpaired t-test. Single and multiple regression analyses were performed between the ultrasound outcomes and covariates such as age, height, weight and body mass index. Growth charts and tables were developed with respect to age. Nonparametric quantile regression was applied using the R-packages quantreg and quantregGrowth.

RESULTS

A total of 195 male and 305 female volunteers were included between the age of 0 and 18 years (mean age 8.9; range: 0.2-17.9 years). Cartilage diminished markedly as children aged, and cartilage of the boys was significantly thicker compared to the girls in all joints (p < 0.001). In addition, cartilage became thinner as children's height and weight increased (beta regression coefficients between - 0.27 and - 0.01, p < 0.0001). Capsular distention (i.e., BCD > 0 mm) was uncommon in the ankle, wrist and MCP2 (resp. in 3, 6, and 3% of cases). It was more common in the suprapatellar and parapatellar knee, MTP1 and posterior recess of the elbow (resp. in 34, 32, 46, and 39% of cases). In the hip, some capsular distention was always present. Age was found to be the best predictor for BCD (beta regression coefficients between 0.05 and 0.13, p < 0.0001). Height was, in addition to age, a good predictor of tendon diameter (beta regression coefficients between 0.03 and 0.14, p < 0.0001). Growth curves and tables for each variable were developed.

CONCLUSIONS

Reference values of sonographic cartilage thickness, BCD and diameters of tendons at several joints were established from 500 healthy children, aged between 0.2 and 18 years. Growth charts and tables were developed to distinguish normal findings from pathology in children with complaints suspicious of arthritis.

Ultrasonographic Evaluation of Sub-Clinical Synovitis in Juvenile Idiopathic Arthritis: The Disease Classification and Management

Background: Ultrasonography (USG) is a perfect device for analyzing more than one joint in rather brief intervals of time and is well accepted by children with no harmful ionizing radiation, usually does not require sedation, and can be carried out without difficulty in an outpatient setting. Purpose: To demonstrate the ability of ultrasonography (USG) in detecting clinical and subclinical synovitis in children with juvenile idiopathic arthritis (JIA) and compare the USG findings with clinical findings. Methods: 20 patients with JIA diagnosed according to the ILAR criteria were include. A total of 208 joints were examined both clinically and ultrasonographically for detection of synovitis. The presence of subclinical synovitis detected by USG was sought and its effect on the classification of JIA was assessed. USG assessment was done using the High-Resolution Linear probe including both grey scale and Power Doppler assessment. Results: The mean age of patients was 10.2 years with average disease duration of 5.9 months. A total of 49 joints (23.5%) had clinical synovitis and 59 joints (28.4%) had USG synovitis out of a total of 208 joints. A total of 14 joints had subclinical synovitis (8.8% out of the 159 clinically normal joints) upon USG. USG additionally brought about classifying three patients as having poly articular disorder who had been considered as oligo articular upon clinical examination. Conclusion: USG assessment of subclinical synovitis in JIA patients is an essential component of classifying the disease and detects more joints with synovitis than clinical examination; however, both are complimentary and should be used in combination in all patients with JIA.

Procedures for the content, conduct and format of EULAR/PReS paediatric musculoskeletal ultrasound courses

Background

Despite the worldwide increasing request of education on paediatric musculoskeletal ultrasound (PedMSUS), content, conduct and format of PedMSUS courses have never been internationally agreed.

Objectives

To produce educational procedures for the conduct, content and format of EULAR/PReS PedMSUS courses.

Methods

After a systemic literature review and expert opinion collection, a panel of items for the development of procedures on PedMSUS courses was identified. Agreement on the items was assessed through Delphi surveys among a taskforce of 24 members, which included 18 experts in PedMSUS (8 rheumatologists, 1 radiologist, 9 paediatric rheumatologists), 1 methodologist and rheumatologist expert in MSUS, 2 patient research partners, 1 health professional in rheumatology and 2 EMEUNET/EMERGE members, from 8 different European countries. Each item was assessed through a 5-point Likert scale (0, full disagreement; 5, full agreement); agreement was reached for >75% of answers rating 4–5. All items with agreement were included in the preliminary core set of educational procedures, which underwent external assessment by a broader Consensus group (Faculty and Tutors of previous EULAR PedMSUS courses and PReS Imaging Working Party members), through Delphi survey.

Results

Two Delphi surveys produced the preliminary core set of procedures for basic, intermediate, advanced and teach-the-teachers (TTT) PedMSUS courses. A Delphi survey within the Consensus group produced agreement on the proposed procedures.

Conclusions

Shared EULAR/PReS procedures for the conduct, content and format of basic, intermediate, advanced and TTT PedMSUS courses were identified on international basis.

Doppler and Spectral Ultrasound of Sacroiliac Joints in Pediatric Patients with Suspected Juvenile Spondyloarthritis

Background: Power Doppler ultrasound (PDUS) with spectral wave analysis (SWA) has been compared with magnetic resonance imaging (MRI) in documenting active sacroiliitis in early spondyloarthritis (SpA) but, to date, PDUS/SWA has not been yet applied to the study of sacroiliac joints (SIJs) in children. Methods: A group of 20 children (13 F/7 M, mean age 14.2 y) with suspected juvenile SpA (jSpA) underwent PDUS/SWA and, subsequently, MRI of the SIJs. SIJs PDUS scoring and resistance index (RI) of the SIJs flows were recorded. The accuracy of PDUS/SWA for the diagnosis of active sacroiliitis was evaluated, with MRI as the gold standard. Results: PDUS signals were detected in 19 patients and 30 SIJs. Bone marrow edema (BME) lesions on MRI were detected in 12 patients (diagnosed as jSpA) and 22 SIJs. PDUS scoring on SIJs were higher in patients with a final diagnosis of jSpA (p = 0.003). On SWA, the mean RIs in patients with or without final diagnosis of active sacroiliitis were, respectively, 0.604 and 0.767 (p = 0.005) at joint level. A RI < 0.55 and PDUS > 1 showed the higher specificity for sacroiliitis (AUROC curve 0.854 for PDUS and 0.920 for RI). SIJs PDUS/SWA showed an overall concordance of 82.35%, with substantial agreement (k = 0.627) with MRI on the diagnosis of sacroiliitis. Conclusions: In children with sacroiliitis, PDUS demonstrates a rich vascularization into SIJs and low RIs (<0.55) have high specificity for this condition. SIJs PDUS/SWA could be useful as a screening method in children with suspected jSpA.

Development and reliability of a novel ultrasonographic joint-specific scoring system for synovitis with reference atlas for patients with juvenile idiopathic arthritis

Objective

To develop an ultrasonographic image acquisition protocol and a joint-specific scoring system for synovitis with reference atlas in patients with juvenile idiopathic arthritis (JIA) and to assess the reliability of the system.

Methods

Seven rheumatologists with extensive ultrasound experience developed a scanning protocol and a semiquantitative joint-specific scoring system for B-mode (BM) synovitis for the elbow, wrist, metacarpophalangeal 2–3, proximal interphalangeal 2–3, hip, knee, ankle and metatarsophalangeal 2–3 joints. An ultrasonographic reference atlas for BM synovitis, divided in four age groups (2–4, 5–8, 9–12, 13–18 years), and power Doppler (PD) activity was then developed. Reliability was assessed for all joints on still images and in a live exercise including 10 patients with JIA, calculated by intraclass correlation coefficient (ICC) and weighted kappa.

Results

A scanning protocol and scoring system for multiple joints with reference atlas composed of images with four different score levels for BM and PD were developed. Still image scoring for BM synovitis on joint level showed good to excellent intra-reader reliability (ICC/kappa ranges: 0.75–0.95/0.63–0.91) and moderate to excellent inter-reader reliability (ICC/kappa ranges: 0.89–0.99/0.50–0.91). Still image scoring for PD activity showed excellent intra-reader and inter-reader reliability (ICC/kappa: 0.96/0.91 and ICC/kappa: 0.97/0.80, respectively). In the live scoring, inter-reader reliability (ICC/kappa) was moderate to excellent for BM synovitis (0.94/0.51) and PD activity (0.91/0.60).

Conclusion

An ultrasonographic image acquisition protocol and joint-specific scoring system with reference atlas were developed and demonstrated moderate to excellent reliability for scoring of synovitis in patients with JIA. This can be a valuable tool in clinical practice and future research.

Comparison Between Clinical and Ultrasound Assessment of the Ankle Region in Children With Juvenile Idiopathic Arthritis

OBJECTIVE

To compare the frequency of joint and tendon disease on ultrasound (US) and clinical examination, and to investigate agreement between US and clinical evaluation in ankles with clinically active juvenile idiopathic arthritis (JIA).

METHODS

US and clinical evaluation were performed independently in the joint and tendon compartments of 105 ankles. Gray-scale (GS) US and power Doppler (PD) US joint abnormalities were scored on a 4-point semiquantitative scale. A joint with a GS score ≥2 and/or a PD score ≥1 was defined as active on US. Agreement was tested using kappa statistics.

RESULTS

A total of 163 joints in 89 ankles had active synovitis on US. The tibiotalar (TT) joint was the most commonly affected joint on US and on clinical evaluation. The intertarsal (IT) joint and the subtalar (ST) joint were the second in frequency on US and on clinical evaluation, respectively. Tenosynovitis was found more commonly on US than on clinical evaluation (70.5% and 32.4%, respectively), and was more frequent in the medial and lateral than in the anterior tendon compartment. Isolated tenosynovitis was detected on US in 12 of 105 ankles. Agreement between US and clinical evaluation for detection of active synovitis and tenosynovitis was less than acceptable (κ <0.4). No correlation was found between any feature of active disease recorded on clinical evaluation (joint swelling, tenderness/pain on motion, and restricted motion) and active synovitis on US in the TT joint, ST joint, and IT joint.

CONCLUSION

Coupling clinical evaluation with US aids in correctly localizing pathology. US training of practitioners is recommended to manage ankle disease in JIA.

Utilizing ultrasound findings of a single indicator joint to assess non-systemic juvenile idiopathic arthritis

BACKGROUND

Musculoskeletal ultrasound (MSUS) has been used worldwide in adult patients with rheumatoid arthritis (RA) but is beginning to play an increasing role in patients with juvenile idiopathic arthritis (JIA). The aim of this study was to investigate the application of MSUS findings of a single indicator joint in JIA to assess the disease activity and classify disease subtype.

METHODS

Thirty-five non-systemic JIA patients with a total of 62 visits were retrospectively recruited in this study. Among the involved joints, the joint with highest value of grey-scale (GS) plus power Doppler (PD) (=GSPD) was selected as the indicator joint at each visit. The correlations between each MSUS parameter (GS, PD, GSPD) of indicator joints and the Physician Global Assessment (PGA) score, the Childhood Health Assessment Questionnaire-disability index (CHAQ-DI), and laboratory data were analyzed. The ultrasound features in different subtypes of JIA were also compared.

RESULTS

PD was weakly correlated with the PGA score (rho = 0.323, p = 0.010), while both GS and GSPD were moderately correlated with the PGA score (rho = 0.405, p = 0.001; rho = 0.434, p = 0.000). On the other hand, GS, PD, and GSPD were weakly correlated with CHAQ-DI. Although erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) had a weak correlation with PGA, they were not statistically correlated with GS, PD, or GSPD. The proportions of effusion, synovial hypertrophy, and enthesopathy in three different subtypes, showed significant differences (Fisher's exact test, p = 0.037; p = 0.004; p = 0.019). Enthesopathy was only seen in joints of enthesitis-related arthritis (ERA), but not in joints of polyarthritis and oligoarthritis.

CONCLUSIONS

MSUS is an acceptable non-invasive tool for the patients with JIA, particularly for those with non-systemic JIA, that might assist disease classification, and whose parameters of the indicator joints may potentially contribute to the evaluation of disease activity.

The Role of Ultrasound in Juvenile Idiopathic Arthritis: A Narrative Review From an Imaging Perspective

Objective:

Musculoskeletal sonography (MSKS) is increasingly being used in the setting of juvenile idiopathic arthritis (JIA). The purpose of this narrative review was to describe the role of sonography in JIA and outline strategies for operators of pediatric MSKS.

Methods:

A literature review through multiple medical databases was conducted by restricting the search to medical subject headings (MeSH). Peer-reviewed English-language articles from 2007 to 2018 were included, which focused the on common sonographic findings of JIA.

Results:

Twenty-six articles were selected for inclusion in the study after a complete reading. Many studies aimed to address the validity of sonographic techniques in the assessment of JIA, but few studies discussed the specific sonographic appearances of JIA, scanning pitfalls, and appropriate imaging techniques.

Conclusion:

MSKS reveals subclinical manifestations of arthropathy, but the true value of detecting subclinical disease is not well understood. MSKS is limited in the evaluation of articular cartilage thinning and bony erosions. Responsiveness of MSKS in JIA remains to be formally assessed with higher quality studies.

Novel Ultrasound Image Acquisition Protocol and Scoring System for the Pediatric Knee

OBJECTIVE

The use of musculoskeletal ultrasound is increasing among pediatric rheumatologists. Reliable scoring systems are needed for the objective assessment of synovitis. The aims of this study were to create a standardized and reproducible image acquisition protocol for B-mode and Doppler ultrasound of the pediatric knee, and to develop a standardized scoring system and determine its reliability for pediatric knee synovitis.

METHODS

Six pediatric rheumatologists developed a set of standard views for knee assessment in children with juvenile arthritis. Subsequently, a comprehensive literature review, practical exercises, and a consensus process were performed. A scoring system for both B-mode and Doppler was then developed and assessed for reliability. Interreader reliability or agreement among a total of 16 raters was determined using 2-way single-score intraclass correlation coefficient (ICC) analysis.

RESULTS

Twenty-one views to assess knee arthritis were initially identified. Following completion of practical exercises and subsequent consensus processes, 3 views in both B-mode and Doppler were selected: suprapatellar longitudinal and medial/lateral parapatellar transverse views. Several rounds of scoring and modifications resulted in a final ICC of suprapatellar view B-mode 0.89 (95% confidence interval [95% CI] 0.86-0.92) and Doppler 0.55 (95% CI 0.41-0.69), medial parapatellar view B-mode 0.76 (95% CI 0.68-0.83) and Doppler 0.75 (95% CI 0.66-0.83), and lateral parapatellar view B-mode 0.82 (95% CI 0.75-0.88) and Doppler 0.76 (95% CI 0.66-0.84).

CONCLUSION

A novel B-mode and Doppler image acquisition and scoring system for assessing synovitis in the pediatric knee was successfully developed through practical exercises and a consensus process. Study results demonstrate overall good-to-excellent reliability.

A fresh look at angiogenesis in juvenile idiopathic arthritis

Angiogenesis is the complex process of creating new capillaries from preexisting blood vessels due to hypoxemia, injury or inflammation of the tissues. Numerous cytokines and cell mediators have been identified to induce and stimulate angiogenesis, but vascular endothelial growth factor (VEGF) is a key regulator. The role of proangiogenic factors in the pathogenesis of chronic arthritis is currently a subject of intensive investigations in adult patients with rheumatoid arthritis (RA) and, to a limited extent, in children with juvenile idiopathic arthritis (JIA). Recent studies has shown a significant correlation between proangiogenic marker concentrations and the severity of inflammation in either RA or JIA patients. The serum neovascularization markers correlate with the power Doppler ultrasound image of the inflamed joint and hypertrophic synovium, which may be connected with the disease activity.

The aim of this paper is to describe the state of the art on the important role of angiogenesis in adult and childhood rheumatoid arthritis.

Heterogeneous Knee Effusions on Point-of-Care Ultrasound in a Toddler Diagnosed With Juvenile Idiopathic Arthritis

Point-of-care musculoskeletal ultrasound can provide information about joint effusions and the quality of the effusion. This case report describes the findings of a previously healthy pediatric patient with acute onset of knee swelling and abnormal gait. After point-of-care ultrasound demonstrated bilateral knee effusions with complex, heterogeneous material, subsequent workup revealed a diagnosis of juvenile idiopathic arthritis (JIA). We review the ultrasound technique, sonographic findings, and literature regarding point-of-care ultrasound for knee effusions and JIA.

Wrist Arthroscopy in Juvenile Idiopathic Arthritis: A Review of Current Literature and Future Implications

Introduction  Juvenile Idiopathic Arthritis (JIA) is the most common rheumatological condition in children and frequently affects the wrist. The roles for wrist arthroscopy and arthroscopic synovectomy (AS) in JIA are unclear. Our aim was to find the current evidence supporting its use. Methods  Systematic literature review of relevant publications from 1990 to present in the Cochrane Library, Clinical Knowledge Summaries, DynaMed, PEMSoft, NICE Guidance, MEDLINE, EMBASE, and PubMed. Results  We found no publications detailing the use of arthroscopy or AS specifically in patients with JIA involving the wrist. There is evidence that AS reduces pain, improves function, and induces remission in patients with rheumatoid arthritis resistant to medical management. Discussion and Conclusion  Although there is paucity in evidence for the use of AS in the wrists of patients with JIA, studies suggest it to be safe and effective, and could be applied to patients with refractive JIA. It is possible that early identification of patients suffering from JIA with extensive joint destruction and little symptoms could benefit from AS, delaying joint destruction and preserving function.

US Evaluation of Juvenile Idiopathic Arthritis and Osteoarticular Infection

Juvenile idiopathic arthritis (JIA) and osteoarticular infection can cause nonspecific articular and periarticular complaints in children. Although contrast material-enhanced magnetic resonance imaging is the reference standard imaging modality, musculoskeletal ultrasonography (US) is emerging as an important adjunct imaging modality that can provide valuable information relatively quickly without use of radiation or the need for sedation. However, diagnostic accuracy requires a systemic approach, familiarity with various US techniques, and an understanding of maturation-related changes. Specifically, the use of dynamic, Doppler, and/or multifocal US assessments can help confirm sites of disease, monitor therapy response, and guide interventions. In patients with JIA, ongoing synovial inflammation can lead to articular and periarticular changes, including synovitis, tenosynovitis, cartilage damage, bone changes, and enthesopathy. Although these findings can manifest in adult patients with rheumatoid arthritis, important differences and pitfalls exist because of the unique changes associated with an immature and maturing skeleton. In patients who are clinically suspected of having osteoarticular infection, the inability of US to evaluate the bone marrow decreases its sensitivity. Therefore, the US findings should be interpreted with caution because juxtacortical inflammation is suggestive, but neither sensitive nor specific, for underlying osteomyelitis. Similarly, the absence of a joint effusion makes septic arthritis extremely unlikely but not impossible. US findings of JIA and osteoarticular infection often overlap. Although certain clinical scenarios, laboratory findings, and imaging appearances can favor one diagnosis over the other, fluid analysis may still be required for definitive diagnosis and optimal treatment. US is the preferred modality for fluid aspiration and administering intra-articular corticosteroid therapy. ^© RSNA, 2017.

Patients with juvenile idiopathic arthritis in clinical remission with positive power Doppler signal in joint ultrasonography have an increased rate of clinical flare: a prospective study

BACKGROUND

Ultrasonography (US) studies carried out on joints of juvenile idiopathic arthritis (JIA) patients in clinical remission demonstrate the presence of subclinical synovitis. The significance of subclinical synovitis and the positive power Doppler (PD) signal on US in JIA in clinical remission is not well understood. The objectives of this study were to assess whether the changes detected by US in patients with JIA in clinical remission can predict disease flare and to evaluate factors associated with flare and joint damage over 30 months of follow-up.

METHODS

A prospective study was performed with clinical and ultrasound evaluation in 34 joints of JIA patients in clinical remission. Clinical evaluation including physical exam, functional capacity and inflammatory markers was performed at baseline and every six months thereafter, for a total period of 30 months. US evaluation included presence of synovitis, PD signal and erosion at baseline and every 12 months thereafter. Subclinical synovitis was defined when there was synovitis with or without positive PD signal in US joints of patients in clinical remission. Flare was defined as any joint presenting clinical arthritis requiring therapy modification.

RESULTS

We evaluated a total of 35 patients, 28 (80%) girls, 14 (40%) persistent oligoarticular subtype, 12 (34.3%) oligoarticular extended and 9 (25.7%) polyarticular and 26 (74.3%) in remission on medication. Twenty (57.1%) patients flared. The risk of flare was five times higher in patients with positive PD signal and 14 times higher in patients in remission on medication. Regarding the assessment of joints after 6 months and 12 months of US evaluation, 70/3162 (2.2%) joints and 80/2108 (3.8%) joints flared, respectively. Joints with subclinical synovitis with positive PD signal flared more after 6 and 12 months. Twenty five of 2108 (1.2%) joints showed erosion over time. Joints with subclinical synovitis with or without positive PD signal showed more erosion.

CONCLUSIONS

Patients in remission on medication with subclinical synovitis with positive PD signal on US have a higher risk of flare, therefore they should be monitored closely during treatment. In the same way, joints with subclinical synovitis with or without positive PD signal should be monitored due to the risk of flare and joint damage.

Preliminary Definitions for the Sonographic Features of Synovitis in Children

OBJECTIVE

Musculoskeletal ultrasonography (US) has the potential to be an important tool in the assessment of disease activity in childhood arthritides. To assess pathology, clear definitions for synovitis need to be developed first. The aim of this study was to develop and validate these definitions through an international consensus process.

METHODS

The decision on which US techniques to use and the components to be included in the definitions, as well as the final wording, were developed by 31 US experts in a consensus process. A Likert scale of 1-5 (where 1 = complete disagreement and 5 = complete agreement) was used. A minimum of 80% of the experts scoring 4 or 5 was required for final approval. The definitions were then validated on 120 standardized US images of the wrist, metacarpophalangeal joints, and tibiotalar joints, displaying various degrees of synovitis at various ages.

RESULTS

B-mode and Doppler should be used for assessing synovitis in children. A US definition of the various components (i.e., synovial hypertrophy, effusion, and Doppler signal within the synovium) was developed. The definition was validated on still images with a median of 89% of participants (range 80-100) scoring it as 4 or 5 on a Likert scale.

CONCLUSION

US definitions of synovitis and its elementary components covering the entire pediatric age range were successfully developed through a Delphi process and validated in a web-based still-images exercise. These results provide the basis for the standardized US assessment of synovitis in clinical practice and research.

Juvenile idiopathic arthritis: what is the utility of ultrasound?

Juvenile idiopathic arthritis (JIA) is a heterogeneous condition and an important cause of acquired disability in children. Evidence supports early treatment to prevent future complications. This relies on prompt diagnosis, achieved by a high index of clinical suspicion and supportive evidence, including the detection of joint and or tendon inflammation. Ultrasound is a readily accessible, well-tolerated, safe and accurate modality for assessing joints and the surrounding soft tissues. It can also be used to guide therapy into those joints and tendon sheaths resistant to systemic treatments. Ultrasound imaging is highly operator dependent, and the developing skeleton poses unique challenges in interpretation with sonographic findings that can mimic pathology and vice versa. Ultrasound technology has been rapidly improving and is more accessible than ever before. In this article, we review the normal appearances, highlight potential pitfalls and present the key pathological findings commonly seen in JIA.

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.

Pediatric musculoskeletal ultrasound: age- and sex-related normal B-mode findings of the knee

Musculoskeletal ultrasound (MSUS) is an important tool for evaluating disease activity, therapeutic progress, and remission status of rheumatic diseases in children. Knowledge of age-related normal findings is essential when interpreting pathological findings such as those seen in juvenile idiopathic arthritis. To evaluate normal findings of the knee joint, we recorded age-related stages of musculoskeletal development in the knee of 435 healthy children between 1 and 18 years of age using high-resolution B-mode MSUS. We determined approximate age- and sex-related norms for the suprapatellar recess size, ossified patella size, and distal femoral intercondylar cartilage thickness. In almost all age-groups, over 64 % of children had visible fluid accumulation in the suprapatellar recess. Significant correlations were found between chronological age and the suprapatellar recess size and ossified patella length (p < 0.05). An age-dependent decrease in intercondylar cartilage thickness of the distal femoral epiphysis was found in children between 10 and 18 years of age. High-resolution B-mode MSUS is an excellent tool for assessing joint and skeletal development in children. Our reference data can be used to discriminate better between normal physiological findings and pathological abnormalities.

Toward Standardized Musculoskeletal Ultrasound in Pediatric Rheumatology: Normal Age-Related Ultrasound Findings

OBJECTIVE

The Outcome Measures in Rheumatology Ultrasound Task Force has recently started to work on the validation and standardization of musculoskeletal ultrasound (MSUS) examination in children in order to improve its applicability to joint examination.

METHODS

This was a prospective multicenter study performed by 4 experts in pediatric MSUS, who independently collected representative images using predefined scanning procedures of 4 joints (knee, ankle, wrist, and second metacarpophalangeal joint) in different predefined age groups. Researchers were allowed to use their own settings (B-mode and Doppler) in order to get the best quality image and highest sensitivity for low blood flow. Images were evaluated for quality parameters and an atlas was created with the best images. An equipment comparative study was performed by a single examiner using 2 different types of machines.

RESULTS

Sixty-four healthy children were scanned. The quality of evaluated images, obtained by predefined scanning positions, was highly comparable among the examiners. The B-mode images clearly showed age-related variations of joint findings, while Doppler images showed the presence of blood flow, particularly within the epiphyseal cartilage of the children at a younger age. There was a high to good level of consistency between images obtained from the 2 different ultrasound machines.

CONCLUSION

The study shows a systematic method for ultrasound examination of children at different age groups. Additionally, a baseline collection of images was developed, showing blood vessels in the joints examined. The present study could provide a framework for ongoing MSUS studies as well as for clinical practice in pediatric rheumatology.

Ultrasound in juvenile idiopathic arthritis

BACKGROUND

In the recent years, musculoskeletal ultrasound (MSUS) has been regarded as especially promising in the assessment of juvenile idiopathic arthritis (JIA), as a reliable method to precisely document and monitor the synovial inflammation process.

MAIN CONTENT

MSUS is particularly suited for examination of joints in children due to several advantages over other imaging modalities. Some challenges should be considered for correct interpretation of MSUS findings in children, due to the peculiar features of the growing skeleton. MSUS in JIA is considered particularly useful for its ability to detect subclinical synovitis, to improve the classification of patients in JIA subtypes, for the definition of remission, as guidance to intraarticular corticosteroid injections and for capturing early articular damage. Current evidence and applications of MSUS in JIA are documented by several authors. Recent advances and insights into further investigations on MSUS in healthy children and in JIA patients are presented and discussed in the present review.

CONCLUSIONS

MSUS shows great promise in the assessment and management of children with JIA. Nonetheless, anatomical knowledge of sonographic changes over time, underlying immunopathophysiology, standardization and validation of MSUS in healthy children and in patients with JIA are still under investigation. Further research and educational efforts are required for expanding this imaging modality to more clinicians in their daily practice.

Juvenile idiopathic arthritis and the temporomandibular joint: A comprehensive review

Juvenile idiopathic arthritis is the most common inflammatory rheumatic disease of childhood and represents a series of chronic inflammatory arthritides of unknown cause. Involvement of the temporomandibular joint has been reported in up to 87% of children with juvenile idiopathic arthritis when based on magnetic tomography imaging; it can be asymptomatic and may lead to severe long term complications. In this review a summary of the contemporary literature of imaging of the temporomandibular joint in children with juvenile idiopathic arthritis will be provided, including ultrasound which is a valuable method for guided joint injections, but does not necessarily allow detection of acute inflammation, cone beam computed tomography, which has emerged as a feasible and accurate low-dose alternative as compared to conventional computed tomography to detect destructive change, and magnetic resonance imaging which is considered the method of choice for assessing acute, inflammatory change, although the lack of normative standards remains a challenge in children.

Ultrasound-guided corticosteroid injection of the subtalar joint for treatment of juvenile idiopathic arthritis

BACKGROUND

The subtalar joint is commonly affected in children with juvenile idiopathic arthritis and is challenging to treat percutaneously.

OBJECTIVE

To describe the technique for treating the subtalar joint with US-guided corticosteroid injections in children and young adults with juvenile idiopathic arthritis and to evaluate the safety of the treatment.

MATERIALS AND METHODS

We retrospectively analyzed 122 patients (age 15 months-29 years) with juvenile idiopathic arthritis who were referred by a pediatric rheumatologist for corticosteroid injection therapy for symptoms related to the hindfoot or ankle. In these patients the diseased subtalar joint was targeted for therapy, often in conjunction with adjacent affected joints or tendon sheaths of the ankle. We used a protocol based on age, weight and joint for triamcinolone hexacetonide or triamcinolone acetonide dose prescription. We describe the technique for successful treatment of the subtalar joint.

RESULTS

A total of 241 subtalar joint corticosteroid injections were performed under US guidance, including 68 repeat injections for recurrent symptoms in 26 of the 122 children and young adults. The average time interval between repeat injections was 24.8 months (range 2.2-130.7 months, median 14.2 months). Subcutaneous tissue atrophy and skin hypopigmentation were the primary complications observed. These complications occurred in 3.9% of the injections.

CONCLUSION

With appropriate training and practice, the subtalar joint can be reliably and safely targeted with US-guided corticosteroid injection to treat symptoms related to juvenile idiopathic arthritis.

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.

Patient-reported Joint Count in Juvenile Idiopathic Arthritis: The Reliability of a Manikin Format

Objective.

To evaluate the reliability of a manikin format, patient-reported joint count in juvenile idiopathic arthritis (JIA), and to detect changes in agreement at a second visit.

Methods.

Patients with JIA aged 12–21 were asked to mark joints with active arthritis on a manikin before their regular clinic visit. The physician then performed a joint count without having seen the patient’s assessment. Agreement between scores of physician-reported and patient-reported joint counts was assessed using ICC. Kappa statistics were used to assess reliability of scoring individual joints.

Results.

The study included 75 patients with JIA. In general, patients had a low number of active joints (median 1 joint, indicated by the physician). ICC was moderate (0.61) and κ ranged from 0.3–0.7. At the second visit, κ were similar; the ICC was 0.19. When a patient scored 0 joints, the physician confirmed this 93%–100% of the time. When the patient marked ≥ 1 joints, the physician confirmed arthritis 59%–76% of the time. Sensitivity to change was moderate.

Conclusion.

Agreement between physician and patient on the number of joints with active arthritis was reasonable. Untrained patients tended to overestimate the presence of arthritis when they marked active joints on a manikin-format joint count. When the patient indicated absence of arthritis, the physician usually confirmed this. As the agreement did not improve at followup, future research should focus on the possibility of achieving this through training. For now, the patient-reported joint count cannot replace the physicians’ joint count in clinical practice; it may be used in epidemiological studies with caution.

Assessment of disease activity by patients with juvenile idiopathic arthritis and the parents compared to the assessment by pediatric rheumatologists

BACKGROUND

Self assessment of arthritis is important for recognition of disease activity and early initiation of therapy. Proper interpretation of physical symptoms is necessary for this. The purpose was to investigate the assessment by patients and parents of disease activity in juvenile idiopathic arthritis (JIA) and to compare their assessments to rheumatologists' assessments.

METHODS

Patients and parents assessed 69 joints on a paper homunculus and marked each joint with a different color according to presumed presence of disease: active disease (AD), doubt, and non-active disease (NAD). Their assessments were compared to the rheumatologists' assessments. If patients and/or parents marked an inflamed joint, it counted as AD. Pain, functional impairment, and disease duration were analyzed to differentiate more precise between true and false positive and true and false negative assessments.

RESULTS

We collected assessments of 113 patients and/or parents. AD was assessed 54 times, 33 of which were true positives. NAD was assessed 23 times, 22 of which were true negatives. Doubt was expressed 36 times, 9 of which were assessed by the rheumatologist as AD. Sensitivity and specificity of AD was 0.77 and 0.31. Pain and functional impairment scored highest in AD, intermediate in doubt, and lowest in NAD.

CONCLUSION

Patients and/or parents seldom missed arthritis but frequently overestimated disease activity. Pain, functional impairment, disease duration, gender, and age did not differentiate between true and false positives for. Patients perceived JIA as active if they experienced pain and functional impairment. To reduce overestimation of the presence of AD we need to improve their understanding of disease activity by teaching them to distinguish between primary symptoms of JIA and symptoms like pain and functional impairment.

Current state of musculoskeletal ultrasound in paediatric rheumatology: results of an international survey

OBJECTIVE

The aim of this study was to investigate the current use of musculoskeletal US (MSUS) and the most relevant areas of interest for this imaging modality in paediatric rheumatology.

METHODS

A questionnaire was developed by the paediatric subgroup of the OMERACT US task force and e-mailed to the members of the main international paediatric rheumatology networks and societies. Responses were entered in an electronic database. Results were analysed quantitatively or summarized qualitatively in the case of open questions.

RESULTS

The overall response rate was 36% (262/719). The use of MSUS varied among members of the various networks/societies. MSUS was considered of high relevance for improvement of diagnostic skills, for the guidance of joint injections and for the assessment of specific joints, namely the hip, ankle, midfoot and wrist. It was considered useful for early detection of synovitis and in determining disease activity and disease remission.

CONCLUSION

Although at present MSUS is not widely used by paediatric rheumatologists, there is considerable interest in this imaging technology among members of the international networks. The results of this survey suggest that the next objective in the research agenda should be the standardization of the assessment of joints in healthy children. This will then help differentiate pathological (i.e. synovitic) joints from normal joints. The initial target joints should be the hip, ankle, midfoot and wrist. MSUS training focused on the assessment of paediatric patients might be very important in implementing the use of this technique in clinical practice and research.