Imaging of the knee in juvenile idiopathic arthritis

Juvenile Idiopathic Arthritis and Spondylarthritis

Juvenile idiopathic arthritis (JIA) is a heterogeneous disorder affecting children < 16 years of age. The clinical heterogeneity translates to imaging, where no specific joint is affected. This article highlights a general imaging approach to JIA, using specific examples of the knee, hand, and wrist as the typical joints affected. We then focus on unique joints that are commonly affected by JIA: the temporomandibular joint, the joints of the upper cervical spine, and the sacroiliac joint. For these latter anatomical sites, regional anatomy and development, location-specific imaging considerations, and arthritis, treatment decision making, and potential differential considerations are reviewed. We highlight, where applicable, a multimodal approach to imaging using developed or developing standardized scoring systems.

Diagnostic Accuracy Study of the Pediatric-Specific Ultrasound Scoring System for the Knee Joint in Children With Juvenile Idiopathic Arthritis

OBJECTIVE

We undertook this study to validate the Pediatric Arthritis Ultrasound Scoring System for the knee joint (PAUSS-knee) in children with juvenile idiopathic arthritis (JIA).

METHODS

Children with JIA were enrolled to prospectively receive a musculoskeletal ultrasound (MSUS) examination of the knee and a physical examination to determine presence/absence of clinical arthritis. MSUS images were scored using the PAUSS-knee, a semiquantitative MSUS scoring system (0-3, normal to severe) for B-mode and power Doppler mode. In addition to MSUS, a subset of participants also received magnetic resonance imaging (MRI) of the knee, which was scored according to the combined Juvenile Arthritis MRI Scoring (JAMRIS) system. Spearman's correlations (rs ) were used to calculate associations between variables. Test characteristics of the PAUSS-knee were calculated with MRI as the reference standard. Inflammatory biomarkers were assessed in synovial fluid from involved knees.

RESULTS

Eighty children with JIA contributed 112 MSUSs and 25 MRIs of the knee. Of the knees, 41% (n = 46) had clinical evidence of arthritis. The B-mode PAUSS-knee score moderately correlated with clinically determined arthritis (rs = 0.54, P < 0.001) and strongly correlated with the JAMRIS score (rs = 0.75, P < 0.001). Compared with MRI, the area under the curve for the B-mode PAUSS-knee was 0.92. For a cutoff of >1, the B-mode PAUSS-knee had a sensitivity of 83% and specificity of 82%. Biomarker analysis indicates that interleukin-2R levels correlate with PAUSS score.

CONCLUSION

Our data indicate that the PAUSS-knee has excellent accuracy for the diagnosis of arthritis when compared with MRI. The PAUSS-knee has the potential to effectively inform JIA medical decision-making in real time.

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.

Double inversion recovery MRI versus contrast-enhanced MRI for evaluation of knee synovitis in juvenile idiopathic arthritis

BACKGROUND

Double inversion recovery (DIR) MRI has the potential to accentuate the synovium without using contrast agents, as it allows simultaneous signal suppression of fluid and fat. The purpose of this study was (1) to compare DIR MRI to conventional contrast-enhanced (CE) MRI for delineation of the synovium in the knee in children with juvenile idiopathic arthritis (JIA) and (2) to assess the agreement between DIR MRI and CE-MRI regarding maximal synovial thickness measurements.

RESULTS

In this prospective study, 26 children with JIA who consecutively underwent 3.0-T knee MRI between January 2018 and January 2021 were included (presence of knee arthritis: 13 [50%]; median age: 14 years [interquartile range [IQR]: 11-17]; 14 girls). Median confidence to depict the synovium (0-100 mm visual analogue scale; scored by 2 readers [consensus based]) was 88 (IQR: 79-97) for DIR MRI versus 100 (IQR: 100-100) for CE-MRI (p value = < .001). Maximal synovial thickness per child (millimeters; scored by 4 individual readers) on DIR MRI was greater (p value = < .001) in the children with knee arthritis (2.4 mm [IQR: 2.1-3.1]) than in those without knee arthritis (1.4 mm [IQR: 1.0-1.6]). Good inter-technique agreement for maximal synovial thickness per child was observed (r_s = 0.93 [p value = < .001]; inter-reader reliability: ICC DIR MRI = 0.87 [p value = < .001], ICC CE-MRI = 0.90 [p value = < .001]).

CONCLUSION

DIR MRI adequately delineated the synovium in the knee of children with JIA and enabled synovial thickness measurement similar to that of CE-MRI. Our results demonstrate that DIR MRI should be considered as a child-friendly alternative to CE-MRI for evaluation of synovitis in children with (suspected) JIA.

Preliminary MRI-based investigation of characteristics and prognosis of knee bone marrow edema in children with juvenile idiopathic arthritis

Introduction

Bone marrow edema (BME) is one of the main imaging characteristics of juvenile idiopathic arthritis (JIA) in children and rheumatoid arthritis (RA) in adult. Previous studies have shown that BME occurred in approximately 64% of adults with RA and was a key predictor of poor prognosis. But BME with JIA has not been of great concern. Therefore, we evaluated the prevalence, characteristics, and prognosis of knee joint BME in children with JIA.

Methods

In this retrospective study, we included children with JIA and knee joint involvement from January 2017 to December 2019. BME was evaluated according to the Juvenile Arthritis MRI Scoring system. Clinical characteristics were compared between the BME group and the non-BME group. The characteristics and prognosis of the BME were observed.

Results

A total of 128 children with 136 knee joint MRI data were identified, with 37 knee joints (27.2%) having BME. BME has positive correlation with synovial hypertrophy (Rs = 0.562, p = 0.019). There were significant differences in age (p = 0.010) and disease duration (p = 0.013) between the BME and non-BME groups. BME was found to be more common in older children and the patients with long duration of disease. Locations with BME were the lateral tibial plateau (17/37, 45.9%), the lateral weight-bearing femur (16/37, 43.2%), the medial tibial plateau and the medial femoral condyle (both with 15/37, 40.5%), and the medial weight-bearing femur (12/37, 32.4%). The lateral femoral condyle and both the lateral and medial sides of the patella were rarely involved. Of the 15 BME joints with the MRI follow-up data (interval 6.5 ± 3.0 months), the lesions disappeared or improved within 12 months after the treatments in 13 (86.7%) joints.

Conclusions

The prevalence of knee BME in JIA was 27.2%. There was positive correlation between BME and synovial hypertrophy. Older children and children with long disease duration had a higher risk for BME, which was commonly a late presentation and more likely involved the weight-bearing surfaces of the joint. The overall prognosis was satisfactory after the standard treatments.

Key Points • To the best of our knowledge, this paper is the first one to investigate the MRI manifestation in JIA focus on knee BME sign.

Application of the OMERACT synovitis ultrasound scoring system in juvenile idiopathic arthritis: a multicenter reliability exercise

OBJECTIVES

To evaluate the reliability of the OMERACT paediatric ultrasound (US) synovitis definitions and scoring system in JIA.

METHODS

Thirteen sonographers analysed 75 images for the presence/absence of elementary lesions (binary scoring) and for grading synovitis, synovial hypertrophy, effusion and Doppler signals. Static US images of the second metacarpophalangeal joint (MCP-II), wrist, elbow, knee and ankle in JIA patients at different ages and different disease stages were collected with standardized scanning by two experienced sonographers. Intra- and inter-reader reliability were analysed with kappa coefficients.

RESULTS

Intra-reader reliability was good for binary scoring (Cohen's kappa 0.62, range 0.47-0.75), synovitis and synovial hypertrophy; excellent for Doppler signals (quadratic weighted kappa 0.77, 0.66-0.86; 0.76, 0.61-0.84; and 0.87, 0.77-0.94, respectively); and moderate for effusion (0.55, 0.24-0.76). Inter-reader reliability was good for synovitis and synovial hypertrophy (Light's kappa 0.68, 95% CI: 0.61, 0.75 and 0.63, 0.54-0.71, respectively), excellent for Doppler signals (0.85, 95% CI: 0.77, 0.90), and moderate for binary scoring and effusion (0.48, 95% CI: 0.36, 0.64 and 0.49, 0.40-0.60, respectively). We obtained the best scores for the knee (0.71, 0.54-0.85) except for Doppler signals, with reliability higher for MCP-II. We found a trend toward better results in older children.

CONCLUSIONS

This is the first study establishing the reliability of the OMERACT paediatric US synovitis definitions and scoring system in the five most commonly affected joints in JIA. The reliability was good among a large group of sonographers. These results support the applicability of these definitions and scoring system in clinical practice and multicentre studies.

Left to themselves: Time to target chronic pain in childhood rare diseases

BACKGROUND

Chronic pain is prevalent among patients with rare diseases (RDs). However, little is understood about how biopsychosocial mechanisms may be integrated in the unique set of clinical features and therapeutic challenges inherent in their pain conditions.

METHODS

This review presents examples of major categories of RDs with particular pain conditions. In addition, we provide translational evidence on clinical and scientific rationale for psychosocially- and neurodevelopmentally-informed treatment of pain in RD patients.

RESULTS

Neurobiological and functional overlap between various RD syndromes and pain states suggests amalgamation and mutual modulation of the respective conditions. Emotional sequelae could be construed as an emotional homologue of physical pain mediated via overlapping brain circuitry. Given their clearly defined genetic and molecular etiologies, RDs may serve as heuristic models for unraveling pathophysiological processes inherent in chronic pain.

CONCLUSIONS

Systematic evaluation of chronic pain in patients with RD contributes to sophisticated insight into both pain and their psychosocial correlates, which could transform treatment.

MR Imaging of Rheumatic Diseases Affecting the Pediatric Population

This article reviews the application of magnetic resonance imaging (MRI) to pediatric rheumatic diseases. MRI can detect early manifestations of arthritis, evaluate the extent of disease, and monitor disease activity and response to treatment.Juvenile idiopathic arthritis (JIA) is the most common pediatric rheumatic disorder, representing a diverse group of related diseases that share a definition of joint inflammation of unknown origin with onset before 16 years of age and lasting > 6 weeks. JIA may lead to significant functional impairment and is increasingly imaged with MRI to assess for active inflammation as a target for therapy. This is particularly true for juvenile spondyloarthritis that includes multiple subgroups of JIA and primarily involves the spine and sacroiliac joints.Other less common pediatric rheumatic diseases considered here are chronic recurrent multifocal osteomyelitis and collagen vascular diseases including polymyositis, dermatomyositis, scleroderma, and juvenile systemic lupus erythematosus.

Tumours and tumour-like lesions of joints: Differential diagnoses in a paediatric population compared to adults

OBJECTIVE

To determine the differential diagnosis of intra-articular tumours and tumour-like lesions in a paediatric population compared to adults.

METHODS

Retrospective review of children up to the age of 18 years with suspected intra-articular tumours and tumour-like lesions referred to a specialist musculoskeletal oncology service from January 2019 to August 2020. Data recorded included patient age and gender, lesion location and morphology (based on the classification system of Adams et al.), and the final diagnosis made either by image-guided biopsy/resection or by clinical and imaging features. Comparison was then made with a group of adults presenting during the same period.

RESULTS

28 paediatric patients were included (12 males and 16 females with mean age 11.2 years, range 3-18 years). Joints involved were the knee (n = 22; 78.6%), ankle (n = 4; 14.3%), hip (n = 1; 3.6%) and elbow (n = 1; 3.6%). Lesion morphology was Type 1 (n = 18; 64.3%), Type 2 (n = 3; 10.7%), Type 3 (n = 1; 3.6%) and Type 4 (n = 5; 17.9%). Final diagnosis was made by image-guided biopsy/resection in 18 (64.3%) patients. The commonest neoplastic lesion was tenosynovial giant cell tumour (n = 11; 39.3%), followed by synovial haemangioma (n = 5; 17.9%). There was only a single malignant lesion, a case of synovial sarcoma. Of eight (28.6%) non-neoplastic lesions, three were diagnosed as juvenile idiopathic arthritis and three as non-specific synovitis. There was no difference compared to adults regarding gender, joint involved or lesion morphology, but there was a significant difference in final diagnoses (p < 0.001). The range of intra-articular tumours and tumour-like lesions in children differs from that in adults, although tenosynovial giant cell tumour is the commonest diagnosis in both groups and malignant lesions are rare.

ADVANCES IN KNOWLEDGEART

In our series, ~16% of tumours and tumour-like lesions of joints occur in the paediatric population. Tenosynovial giant cell tumour remains the commonest diagnosis in children as in adults. Synovial haemangioma and juvenile idiopathic arthritis were the next commonest diagnoses in children, while primary synovial chondromatosis and reactive synovitis were the next commonest diagnoses in adults. Malignant lesions are rare in both groups.

The value of MRI STIR signal intensity on return to play prognosis and reinjury risk estimation in athletes with acute hamstring injuries

OBJECTIVES

Previous studies have shown low to moderate evidence for a variety of magnetic resonance imaging (MRI) features as prognostic factors in athletes with hamstring injuries. Short-tau inversion recovery (STIR) signal intensity has not yet been investigated for assessing the prognosis of acute muscle injuries. Our aim was to explore the relationship between MRI STIR signal intensity and time to return to play (RTP) and to investigate the association between MRI STIR and reinjury risk in athletes with acute hamstring injuries.

STUDY DESIGN

Case-control study.

METHODS

We used MRI STIR to measure intramuscular signal intensity in patients with clinically diagnosed hamstring injuries at two time points: at injury and RTP. At injury, we calculated the association of MRI STIR signal intensity with the time to RTP and reinjury risk. At RTP, the association of MRI STIR signal intensity and reinjury risk and the change in MRI STIR signal intensity over time on reinjury risk was evaluated.

RESULTS

51 patients were included. We found increased MRI STIR signal intensity: (1) at time of injury not to be associated with time to RTP, (2) at time of injury to be associated with a slightly lower risk for reinjury: odds 0.986 (0.975-0.998, p=0.02) and (3) at RTP not to be associated with reinjury risk. (4) We found no association between the change in MRI STIR signal intensity over time and reinjury risk.

CONCLUSION

Increased MRI STIR signal intensity at injury has no value in time to RTP prognosis, but is associated with a reduced reinjury risk.

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.

Isolated Facet Joint Arthritis in Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is a group of childhood inflammatory arthropathies which has variable clinical presentations and can affect multiple joints including the spine. Arthritis in facet joints is rare and very unusual to be the only presentation of JIA. We report a 16-year-old female who presented with back pain and stiffness, in which CT of the lumbar spine showed evidence of facet joint erosion and pelvis MRI showed facet joint arthritis consistent with juvenile idiopathic arthritis. 

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.

Juvenile Idiopathic Arthritis: Diffusion-weighted MRI in the Assessment of Arthritis in the Knee

Background Diffusion-weighted imaging (DWI) can depict the inflamed synovial membrane in arthritis. Purpose To study the diagnostic accuracy of DWI for the detection of arthritis compared with the clinical reference standard and to compare DWI to contrast material-enhanced MRI for the detection of synovial inflammation. Materials and Methods In this institutional review board-approved prospective study, 45 participants with juvenile idiopathic arthritis (JIA) or suspected of having JIA (seven boys, 38 girls; median age, 14 years [interquartile range, 12-16 years]) were included between December 2015 and December 2018. Study participants underwent pre- and postcontrast 3.0-T MRI of the knee with an additional DWI sequence. For the clinical reference standard, a multidisciplinary team determined the presence or absence of arthritis on the basis of clinical, laboratory, and imaging findings (excluding DWI). Two data sets were scored by two radiologists blinded to all clinical data; data set 1 contained pre- and postcontrast sequences (contrast-enhanced MRI), and data set 2 contained precontrast and DWI sequences (DWI). Diagnostic accuracy was determined by comparing the scores of the DWI data set to those of the clinical reference standard. Second, DWI was compared with contrast-enhanced MRI regarding detection of synovial inflammation. Results Sensitivity for detection of arthritis for DWI was 93% (13 of the 14 participants with arthritis were correctly classified with DWI; 95% confidence interval [CI]: 64%, 100%) and specificity was 81% (25 of 31 participants without arthritis were correctly classified with DWI; 95% CI: 62%, 92%). Scores for synovial inflammation at DWI and contrast-enhanced MRI agreed in 37 of 45 participants (82%), resulting in a sensitivity of 92% (12 of 13 participants; 95% CI: 62%, 100%) and specificity of 78% (25 of 32 participants; 95% CI: 60%, 90%) with DWI when contrast-enhanced MRI was considered the reference standard. Conclusion Diffusion-weighted imaging (DWI) was accurate in detecting arthritis in pediatric participants with juvenile idiopathic arthritis (JIA) or suspected of having JIA and showed agreement with contrast-enhanced MRI. The results indicate that DWI could replace contrast-enhanced MRI for imaging of synovial inflammation in this patient group. © RSNA, 2020 Online supplemental material is available for this article.

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.