Do musculoskeletal ultrasound and magnetic resonance imaging identify synovitis and tenosynovitis at the same joints and tendons? A comparative study in early inflammatory arthritis and clinically suspect arthralgia

Multimodal PA/US imaging in Rheumatoid Arthritis: Enhanced correlation with clinical scores

Background

Accurate assessment of Rheumatoid Arthritis (RA) activity remains a challenge. Multimodal photoacoustic/ultrasound (PA/US) joint imaging emerges as a novel imaging modality capable of depicting microvascularization and oxygenation levels in inflamed joints associated with RA. However, the scarcity of large-scale studies limits the exploration of correlating joint oxygenation status with disease activity.

Objective

This study aimed to explore the correlation between multimodal PA/US imaging scores and RA disease activity, assessing its clinical applicability in managing RA.

Methods

In this study, we recruited 111 patients diagnosed with RA and conducted examinations of seven small joints on their clinically dominant side using a PA/US imaging system. The PA and power Doppler ultrasound (PDUS) signals were semi-quantitatively assessed using a 0-3 grading system. The cumulative scores for PA and PDUS across these seven joints (PA-sum and PDUS-sum) were calculated. Relative oxygen saturation (So2) values of inflamed joints on the clinically dominant side were measured, and categorized into four distinct PA+So2 patterns. The correlation between PA/US imaging scores and disease activity indices was systematically evaluated.

Results

Analysis of 777 small joints in 111 patients revealed that the PA-sum scores exhibited a strong positive correlation with standard clinical scores for RA, including DAS28 [ESR] (ρ = 0.682), DAS28 [CRP] (ρ = 0.683), CDAI (ρ = 0.738), and SDAI (ρ = 0.739), all with p < 0.001. These correlations were superior to those of the PDUS-sum scores (DAS28 [ESR] ρ = 0.559, DAS28 [CRP] ρ = 0.555, CDAI ρ = 0.575, SDAI ρ = 0.581, p < 0.001). Significantly, in patients with higher PA-sum scores, notable differences were observed in the erythrocyte sedimentation rate (ESR) (p < 0.01) and swollen joint count 28 (SJC28) (p < 0.01) between hypoxia and intermediate groups. Notably, RA patients in the hypoxia group exhibited higher clinical scores in certain clinical indices.

Conclusion

Multi-modal PA/US imaging introduces potential advancements in RA assessment, especially regarding So2 evaluations in synovial tissues and associated PA scores. However, further studies are warranted, particularly with more substantial sample sizes and in multi-center settings.

Summary

This study utilized multi-modal PA/US imaging to analyze Rheumatoid Arthritis (RA) patients' synovial tissues and affected joints. When juxtaposed with traditional PDUS imaging, the PA approach demonstrated enhanced sensitivity, especially concerning detecting small vessels in thickened synovium and inflamed tendon sheaths. Furthermore, correlations between the derived PA scores, PA+So2 patterns, and standard clinical RA scores were observed. These findings suggest that multi-modal PA/US imaging could be a valuable tool in the comprehensive assessment of RA, offering insights not only into disease activity but also into the oxygenation status of synovial tissues. However, as promising as these results are, further investigations, especially in larger and diverse patient populations, are imperative.

Key points

⸸ Multi-modal PA/US Imaging in RA: This novel technique was used to assess the So2 values in synovial tissues and determine PA scores of affected RA joints.⸸ Correlation significantly with Clinical RA Scores: Correlations significantly were noted between PA scores, PA+So2 patterns, and standard clinical RA metrics, hinting at the potential clinical applicability of the technique.

Work-related physical strain and development of joint inflammation in the trajectory of emerging inflammatory and rheumatoid arthritis: a prospective cohort study

OBJECTIVES

Rheumatoid arthritis (RA) mainly affects small joints. Despite the mechanical function of joints, the role of mechanical stress in the development of arthritis is insufficiently understood. We hypothesised that mechanical stress/physical strain is a risk factor for joint inflammation in RA. Therefore, we studied work-related physical strain in subjects with clinically suspected arthralgia (CSA) as a risk factor for the presence of imaging-detected subclinical joint inflammation and the development of clinical arthritis/RA.

METHODS

In 501 CSA patients and 155 symptom-free persons' occupation-related physical strain was quantified using the International Standard Classification of Occupations. Contrast-enhanced hand-MRIs were made and evaluated for joint inflammation (sum of synovitis/tenosynovitis/osteitis). CSA patients were followed on RA development. Age relationship was studied using an interaction term of physical strain with age.

RESULTS

The degree of physical strain in CSA is associated with the severity of joint inflammation, independent of educational-level/BMI/smoking (interaction physical strain-age p=0.007; indicating a stronger association with increasing age). Physical strain is associated with higher tenosynovitis scores, in particular. In symptom-free persons, physical strain was not associated with imaging-detected joint inflammation. Higher degrees of physical strain also associated with higher risks for RA development in an age-dependent manner (HR=1.20 (1.06-1.37)/10-year increase in age), independent of educational-level/BMI/smoking. This association was partly mediated by an effect via subclinical joint inflammation.

CONCLUSIONS

Work-related physical strain increases the risk of subclinical joint inflammation and of developing RA. The age relationship suggests an effect of long-term stress or that tenosynovium is more sensitive to stress at older age. Together, the data indicate that mechanical stress contributes to the development of arthritis in RA.

Patient-reported swelling in arthralgia patients at risk for rheumatoid arthritis: is it of value?

OBJECTIVE

Patients with Clinically Suspect Arthralgia (CSA) are at risk for developing Rheumatoid Arthritis (RA). These patients often report joint swelling while this is not objectified by physical examination. To explore the value of patient-reported swelling in CSA, we aimed to determine its association with subclinical joint-inflammation on imaging and RA-development.

METHODS

In two independent, similarly designed CSA-cohorts from the Netherlands, symptomatic patients at risk for RA were studied. At baseline, patients indicated whether they had experienced swelling in hand joints. Subclinical joint-inflammation was assessed with MRI or ultrasound (US). Patients were followed for inflammatory arthritis development.

RESULTS

In total, 534 CSA-patients from two independent cohorts were studied, patient-reported swelling was present in 57% in cohort 1, and in 43% in cohort 2. In both cohorts patient-reported swelling was associated with subclinical joint-inflammation. Using MRI, it associated specifically with tenosynovitis (OR 3.7 (95%CI 2.0-6.9)) and when using US with synovitis (OR 2.3 (95%CI 1.04-5.3)). CSA-patients with self-reported swelling at baseline developed arthritis more often, with hazard ratios of 3.7 (95%CI 2.0-6.9) and 3.4 (95%CI 1.4-8.4) in cohort 1 and 2, respectively. This was independent of clinical predictors (e.g. morning stiffness), autoantibody-positivity and US-detected subclinical joint-inflammation. However, when corrected for MRI-detected subclinical joint-inflammation, self-reported swelling was no longer an independent predictor.

CONCLUSION

Patient-reported joint swelling in CSA relates to subclinical joint-inflammation and is an independent risk factor for RA-development, but it is less predictive than the presence of MRI-detected subclinical joint-inflammation.

High-resolution ultrasound and MRI in the evaluation of the forefoot and midfoot

Radiography is the appropriate initial imaging modality to assess for midfoot and forefoot pathology before turning to advanced imaging techniques. While most lesions of the mid- and forefoot can be diagnosed clinically, the exact nature and severity of the pathology is often unclear. This review addresses the use of the ultrasound, as well as the added value of magnetic resonance imaging, in diagnosing conditions of the midfoot and forefoot. Ultrasound allows a dynamic assessment as well as enabling imaging-guided interventions for diagnostic and therapeutic purposes. Practical tips for optimal examination of this area with ultrasound and magnetic resonance imaging are provided. Metatarsal stress fracture, Chopart's injury, Lisfranc injury, as well as the 1st metatarsophalangeal joint injury and lesser metatarsophalangeal plantar plate injury are injuries unique to the mid- and forefoot. The imaging anatomy of the 1st and lesser metatarsophalangeal joints is reviewed, as such knowledge is key to correctly assessing injury of these joints. Characteristic imaging features of masses commonly encountered in the mid- and forefoot, such as ganglion cyst, Morton neuroma, gouty tophus, plantar fibroma, foreign body granuloma, and leiomyoma are reviewed. The use of ultrasound and magnetic resonance imaging in assessing degenerative and inflammatory joint disorders, and in particular rheumatoid arthritis, of the mid- and forefoot region is also reviewed. In summary, when necessary, most lesions of the mid-and forefoot can be adequately assessed with ultrasound, supplemented on occasion with radiographs, computed tomography, or magnetic resonance imaging.

Added value of high-resolution ultrasound and MRI in the evaluation of rheumatologic diseases

Rheumatologic diseases are a widespread group of disorders affecting the joints, bones, and connective tissue, and leading to significant disability. Imaging is an indispensable component in diagnosing, assessing, monitoring, and managing these disorders, providing information about the structural and functional alterations occurring within the affected joints and tissues. This review article aims to compare the utility, specific clinical applications, advantages, and limitations of high-resolution ultrasound and magnetic resonance imaging in the context of rheumatologic diseases. It also provides insights into the imaging features of various types of inflammatory arthritis with clinical relevance and a focus on high-resolution ultrasound and magnetic resonance imaging. By understanding the comparative aspects of high-resolution ultrasound and magnetic resonance imaging, it is easier for the treating physicians to make informed decisions when selecting the optimal imaging modality for specific diagnostic purposes, effective treatment planning, and improve patient outcomes. The patterns of soft tissue and joint involvement; bony erosion and synovitis help in differentiating between various type of arthritis. Involvement of various small joints of the hands also gives an insight into the type of arthritis. We also briefly discuss the potential applications of emerging techniques, such as ultrasound elastography, contrast-enhanced ultrasound, and dual-energy CT, in the field of rheumatology.

Predictive Value of Magnetic Resonance Imaging-detected Tenosynovitis of the Metacarpophalangeal and Wrist Joints for the Development of Rheumatoid Arthritis among Patients with Undifferentiated Arthritis

Objective The early diagnosis of rheumatoid arthritis (RA) improves disease outcomes. Using bilateral magnetic resonance imaging (MRI), we investigated whether or not tenosynovitis at the level of the metacarpophalangeal (MCP) and wrist joints, as well as non-symmetrical versus symmetrical involvement, predicts RA development in undifferentiated arthritis (UA) patients. Methods We collected the clinical and serological findings as well as bilateral gadolinium-enhanced 1.5-T MRI data of UA patients after 1 year. A multivariate logistic regression analysis was used to determine the association of tenosynovitis in UA with RA development. Ninety-one UA patients from the Nagasaki Early Arthritis Clinic who did not meet the 2010 European League Against Rheumatism/American College of Rheumatology classification criteria for RA were selected. Tenosynovitis at the MCP and wrist joints was scored according to the RA MRI scoring system. Results Of these 91 UA patients, 29 (31.9%) progressed to RA, with a median disease duration of 3 months, despite only 10.9% being positive for anti-cyclic citrullinated peptide antibody (ACPA). A univariate analysis showed higher MCP tenosynovitis scores, MCP flexor tenosynovitis, and symmetrical MCP tenosynovitis in the RA development group than in the non-development group (p<0.05). A multivariate analysis showed that symmetrical MCP tenosynovitis was independently associated with RA development after adjusting for age, gender, swollen joint count, C-reactive protein level, and ACPA positivity (odds ratio: 4.96). The presence of symmetrical MCP tenosynovitis had low sensitivity (35%) but high specificity (87%) for RA development. Conclusion MRI-detected tenosynovitis, especially symmetrical findings at the MCP joint, is predictive of RA development in a UA population with low ACPA positivity.

Towards a simplified fluid-sensitive MRI protocol in small joints of the hand in early arthritis patients: reliability between modified Dixon and regular Gadolinium enhanced TSE fat saturated MRI-sequences

OBJECTIVE

MRI of small joints plays an important role in the early detection and early treatment of rheumatoid arthritis. Despite its sensitivity to demonstrate inflammation, clinical use is hampered by accessibility, long scan time, intravenous contrast, and consequent high costs. To improve the feasibility of MRI implementation in clinical practice, we introduce a modified Dixon sequence, which does not require contrast and reduces total acquisition time to 6 min. Because the reliability in relation to conventional MRI sequences is unknown, we determined this.

METHODS

In 29 consecutive early arthritis patients, coronal and axial T2-weighted modified Dixon acquisitions on 3.0 T MRI scanner were acquired from metacarpophalangeal 2-5 to the wrist, followed by the standard contrast-enhanced protocol on 1.5 T extremity MRI. Two readers scored osteitis, synovitis and tenosynovitis (summed as total MRI-inflammation), and erosions (all summed as total Rheumatoid Arthritis MRI Score (RAMRIS)). Intraclass correlation coefficients (ICCs) between readers, and comparing the two sequences, were studied. Spearman correlations were determined.

RESULTS

Performance between readers was good/excellent. Comparing modified Dixon and conventional sequences revealed good/excellent reliability: ICC for total MRI-inflammation score was 0.84 (95% CI:0.70-0.92), for erosions 0.90 (95% CI:0.79-0.96), and for the total RAMRIS score 0.88 (95% CI:0.77-0.94). The scores of total MRI-inflammation, total erosions, and total RAMRIS were highly correlated (ρ = 0.80, ρ = 0.81, ρ = 0.82, respectively).

CONCLUSION

The modified Dixon protocol is reliable compared to the conventional MRI protocol, suggesting it is accurate to detect MRI inflammation. The good correlation may be the first step towards a patient-friendly, short and affordable MRI protocol, which can facilitate the implementation of MRI for early detection of inflammation in rheumatology practice.

Ultrasound and magnetic resonance imaging of hands in systemic sclerosis: A cross-sectional analytical study of prevalence of inflammatory changes in patients with subclinical arthropathy

Objectives

Prevalence of synovitis, tenosynovitis, erosions, acro-osteolysis and bone marrow edema in systemic sclerosis is not extensively reported. We aimed to estimate the prevalence of changes in individual joints of hands in systemic sclerosis patients.

Method

A cross-sectional analytical study consisting of 34 adults (females, n = 32) with systemic sclerosis. Patients with clinical synovitis were excluded. All patients underwent ultrasound (US) and magnetic resonance imaging of bilateral hands.

Results

On US, synovitis, tenosynovitis, erosions, and acro-osteolysis were detected in 97%, 94%, 97%, and 29% patients. Grade I synovitis observed in 67% joints-first carpometacarpal joint (55%), first metacarpophalangeal joint (54%), distal radioulnar joint (50%), and intercarpal joints (47%) were commonly affected. Erosions were common in distal phalanges (first DP72% to fifth DP39%). On magnetic resonance imaging, synovitis, tenosynovitis, erosions, and bone edema were observed in 91%, 85%, 97%, and 85% patients. Grade I synovitis was seen in 70% joints, affecting intercarpal joint (70.6%) and third metacarpophalangeal joint (52.9%) commonly. Grade I erosions were seen in 61%, affecting distal phalanges (55.8%), capitate (60.3%), and lunate (55.8%). Grade I edema was commonly affecting lunate (39%) and capitate (26%). On magnetic resonance imaging, acro-osteolysis was present in 28% (97/340) distal phalanges. Fair agreement (0.21-0.40) was noted between US and magnetic resonance imaging for synovitis and erosions.

Conclusion

High prevalence of low-grade inflammation is found in systemic sclerosis patients on US and magnetic resonance imaging. Distal joint assessment in addition to proximal joints improves accurate estimation of prevalence of early arthropathy.

Synovial Oxygenation at Photoacoustic Imaging to Assess Rheumatoid Arthritis Disease Activity

Background Synovial hypoxia is a hallmark of rheumatoid arthritis (RA). Photoacoustic (PA) imaging, based on the use of laser-generated US, can detect the oxygenation status of tissue in individuals with RA. However, large studies are lacking, with few investigating the correlation between oxygenation status and disease activity. Purpose To measure synovial oxygenation status in participants with RA by using a multimodal PA US imaging system and to determine the correlation between PA imaging-measured oxygen saturation (SO₂) and disease activity. Materials and Methods In this prospective observational cohort study, multimodal PA US imaging examinations were performed on small joints of consecutive participants with RA, who were treated at two outpatient rheumatology clinics from 2019 to 2021, and healthy controls. The SO₂ values of the synovium were measured with dual-wavelength PA imaging and classified into three categories-hyperoxia, intermediate oxygenation status, or hypoxia-based on the signal coloration and clustering analysis of the SO₂ values. The correlations of oxygenation status with power Doppler US (PDUS) scoring and clinical disease activity index were evaluated with one-way analysis of variance and the Kruskal-Wallis test with Bonferroni correction. Results A total of 118 participants with RA (median age, 55 years [IQR, 41-62 years]; 92 women) and 15 healthy control participants (median age, 37 years [IQR, 33-41 years]; 11 women) were included. The wrist synovium was categorized as hyperoxic in 36 participants with RA, of intermediate oxygenation status in 48 participants, and hypoxic in 34 participants. All control participants had hyperoxic synovial tissues. For participants with RA, hyperoxic synovium had more affluent Doppler US-depicted vasculature than those with hypoxia and intermediate oxygenation status (mean PDUS grade: hyperoxia, 2.7 ± 0.6 [SD]; intermediate, 1.3 ± 0.7; hypoxia, 1.1 ± 0.8; P < .001). Participants with intermediate status synovium had a lower clinical disease activity index than those with hypoxia (intermediate, 11.0 [IQR, 5.0-21.5] vs hypoxia, 26.0 [IQR, 18.0-39.0]; P = .001). Conclusion Photoacoustic imaging-detected hypoxia in thickened synovium correlated with less vascularization and higher disease activity in participants with rheumatoid arthritis. Clinical trial registration no. NCT04297475 © RSNA, 2022 Online supplemental material is available for this article.

ACPA-negative and ACPA-positive RA patients achieving disease resolution demonstrate distinct patterns of MRI-detected joint-inflammation

OBJECTIVES

Although sustained DMARD-free remission (SDFR; sustained absence of clinical-synovitis after DMARD-discontinuation) is increasingly achievable in RA, prevalence differs between ACPA-negative (40%) and ACPA-positive RA (5-10%). Additionally, early DAS remission (DAS4months<1.6) is associated with achieving SDFR in ACPA-negative, but not in ACPA-positive RA. Based on these differences, we hypothesized that longitudinal patterns of local tissue inflammation (synovitis/tenosynovitis/osteitis) also differ between ACPA-negative and ACPA-positive RA patients achieving SDFR. With the ultimate aim being to increase understanding of disease resolution in RA, we studied MRI-detected joint inflammation over time in relation to SDFR development in ACPA-positive RA and ACPA-negative RA.

METHODS

A total of 198 RA patients (94 ACPA-negative, 104 ACPA-positive) underwent repeated MRIs (0/4/12/24 months) and were followed on SDFR development. The course of MRI-detected total inflammation, and synovitis/tenosynovitis/osteitis individually were compared between RA patients who did and did not achieve SDFR, using Poisson mixed models. In total, 174 ACPA-positive RA patients from the AVERT-1 were studied as ACPA-positive validation population.

RESULTS

In ACPA-negative RA, baseline MRI-detected inflammation levels of patients achieving SDFR were similar to patients without SDFR but declined 2.0 times stronger in the first year of DMARD treatment [IRR 0.50 (95% CI; 0.32, 0.77); P < 0.01]. This stronger decline was seen in tenosynovitis/synovitis/osteitis. In contrast, ACPA-positive RA-patients achieving SDFR, had already lower inflammation levels (especially synovitis/osteitis) at disease presentation [IRR 0.45 (95% CI; 0.24, 0.86); P = 0.02] compared with patients without SDFR, and remained lower during subsequent follow-up (P = 0.02). Similar results were found in the ACPA-positive validation population.

CONCLUSION

Compared with RA patients without disease resolution, ACPA-positive RA patients achieving SDFR have less severe joint inflammation from diagnosis onwards, while ACPA-negative RA patients present with similar inflammation levels but demonstrate a stronger decline in the first year of DMARD therapy. These different trajectories suggest different mechanisms underlying resolution of RA chronicity in both RA subsets.

An ultrasound negative for subclinical synovitis in arthralgia patients: is it helpful in identifying those not developing arthritis?

OBJECTIVE

To investigate the negative predictive value (NPV) of musculoskeletal US (MSUS) in arthralgia patients at risk for developing inflammatory arthritis.

METHODS

An MSUS examination of hands and feet was performed in arthralgia patients at risk for inflammatory arthritis in four independent cohorts. Patients were followed for one-year on the development of inflammatory arthritis. Subclinical synovitis was defined as greyscale ≥2 and/or power Doppler ≥1. NPVs were determined and compared with the prior risks of not developing inflammatory arthritis. Outcomes were pooled using meta-analyses and meta-regression analyses. In sensitivity analyses, MSUS imaging of tender joints only (rather than the full US protocol) was analysed and ACPA stratification applied.

RESULTS

After 1 year 78, 82, 77 and 72% of patients in the four cohorts did not develop inflammatory arthritis. The NPV of a negative US was 86, 85, 82 and 90%, respectively. The meta-analysis showed a pooled non-inflammatory arthritis prevalence of 79% (95% CI 75%, 83%) and a pooled NPV of 86% (95% CI 81, 89%). Imaging tender joints only (as generally done in clinical practice) and ACPA stratification showed similar results.

CONCLUSION

A negative US result in arthralgia has a high NPV for not developing inflammatory arthritis, which is mainly due to the high a priori risk of not developing inflammatory arthritis. The added value of a negative US (<10% increase) was limited.

When and how should we use imaging in individuals at risk of rheumatoid arthritis?

In recent years rheumatologists have begun to shift focus from early rheumatoid arthritis (RA) to studying individuals at risk of developing the disease. It is now possible to use blood, clinical and imaging biomarkers to identify those at risk of progression before the onset of clinical synovitis. The use of imaging, in particular ultrasound (US) and magnetic resonance imaging (MRI), has become much more widespread in individuals at-risk of RA. Numerous studies have demonstrated that imaging can help us understand RA pathogenesis as well as identifying individuals at high risk of progression. In addition, imaging techniques are becoming more sophisticated with newer imaging modalities such as high-resolution peripheral quantitative computed tomography (HR-pQRCT), nuclear imaging and whole body-MRI (WB-MRI) starting to emerge. Imaging studies in at risk individuals are heterogeneous in nature due to the different at-risk populations, imaging modalities and protocols used. This review will explore the available imaging modalities and the rationale for their use in the main populations at risk of RA.

Hand and foot MRI in contemporary undifferentiated arthritis: in which patients is MRI valuable to detect rheumatoid arthritis early? A large prospective study

OBJECTIVES

Identifying patients that will develop RA among those presenting with undifferentiated arthritis (UA) remains a clinical dilemma. Although MRI is helpful according to EULAR recommendations, this has only been determined in UA patients not fulfilling 1987 RA criteria, while some of these patients are currently considered as RA because they fulfil the 2010 criteria. Therefore, we studied the predictive value of MRI for progression to RA in the current UA population, i.e. not fulfilling RA classification criteria (either 1987 or 2010 criteria) and not having an alternate diagnosis. Additionally, the value of MRI was studied in patients with a clinical diagnosis of UA, regardless of the classification criteria.

METHODS

Two UA populations were studied: criteria-based UA as described above (n = 405) and expert-opinion-based UA (n = 564), i.e. UA indicated by treating rheumatologists. These patients were retrieved from a large cohort of consecutively included early arthritis patients that underwent contrast-enhanced MRI scans of hand and foot at baseline. MRIs were scored for osteitis, synovitis and tenosynovitis. Patients were followed for RA development during the course of 1 year. Test characteristics of MRI were determined separately for subgroups based on joint involvement and autoantibody status.

RESULTS

Among criteria-based UA patients (n = 405), 21% developed RA. MRI-detected synovitis and MRI-detected tenosynovitis were predictive for progression to RA. MRI-detected tenosynovitis was independently associated with RA progression (odds ratio (OR) 2.79; 95% CI 1.40, 5.58), especially within ACPA-negative UA patients (OR 2.91; 95% CI 1.42, 5.96). Prior risks of RA development for UA patients with mono-, oligo- and polyarthritis were 3%, 19% and 46%, respectively. MRI results changed this risk most within the oligoarthritis subgroup: positive predictive value was 27% and negative predictive value 93%. Similar results were found in expert-opinion-based UA (n = 564).

CONCLUSION

This large cohort study showed that MRI is most valuable in ACPA-negative UA patients with oligoarthritis; a negative MRI could aid in preventing overtreatment.

The value of MRI for detecting subclinical joint inflammation in clinically suspect arthralgia

In the last decade, much research has focused on the development of rheumatoid arthritis (RA) and the symptomatic phase preceding the onset of clinical arthritis. Observational studies on imaging have revealed that subclinical joint inflammation in patients with arthralgia at risk for RA precedes and predicts the onset of clinically apparent arthritis. Moreover, the results of two placebo-controlled randomised proof-of-concept trials in patients with arthralgia and MRI-detected subclinical inflammation studies will soon be available. The initial results are encouraging and suggest a beneficial effect of DMARD treatment on subclinical inflammation. Since this may increase the necessity to detect subclinical joint inflammation in persons with arthralgia that are at risk for RA, we will here review what has been learnt about subclinical inflammation in at-risk individuals by means of imaging. We will focus on MRI as this method has the best sensitivity and reproducibility. We evaluate the prognostic value of MRI-detected subclinical inflammation and assess the lessons learnt from MRIs about the tissues that are inflamed early on and are associated with the clinical phenotype in arthralgia at risk for RA, for example, subclinical tenosynovitis underlying pain and impaired hand function. Finally, because long scan times and the need for intravenous-contrast agent contribute to high costs and limited feasibility of current MRI protocols, we discuss progress that is being made in the field of MRI and that can result in a future-proof way of imaging that is useful for assessment of joint inflammation on a large scale, also in a society with social distancing due to COVID-19 restrictions.

Pre-RA: Can early diagnosis lead to prevention?

Rheumatoid arthritis (RA) is currently diagnosed and treated once an individual displays the clinical findings of inflammatory arthritis (IA). However, growing evidence supports that there is a 'pre-RA' stage that can be identified through factors such as autoantibodies in absence of clinically apparent IA. In particular, biomarkers, including antibodies to citrullinated protein antigens (ACPA), demonstrate a high risk for future IA/RA, and multiple clinical trials have been developed to intervene in individuals in pre-RA to prevent or delay clinically apparent disease. Herein, we will discuss in more depth what is currently known about the natural history of RA, and the emerging possibility that early 'diagnosis' of RA-related autoimmunity followed by an intervention can lead to the delay or prevention of the first onset of clinically apparent RA.

Subclinical synovitis in arthralgia: how often does it result in clinical arthritis? Reflecting on starting points for disease-modifying anti-rheumatic drug treatment

Objectives

According to guidelines, clinical arthritis is mandatory for diagnosing RA. However, in the absence of clinical synovitis, imaging-detected subclinical synovitis is increasingly used instead and is considered as a starting point for DMARD therapy. To search for evidence we studied the natural course of arthralgia patients with subclinical synovitis from three longitudinal cohorts and determined the frequencies of non-progression to clinically apparent inflammatory arthritis (IA) (i.e. ‘false positives’).

Methods

Subclinical synovitis in the hands or feet of arthralgia patients was visualized with US (two cohorts; definition: greyscale ≥2 and/or power Doppler ≥1) or MRI (one cohort; definition: synovitis score ≥1 by two readers). Patients were followed for 1  year on for IA development; two cohorts also had 3  year data. Analyses were stratified for ACPA.

Results

Subclinical synovitis at presentation was present in 36%, 41% and 31% in the three cohorts. Of the ACPA-positive arthralgia patients with subclinical synovitis, 54%, 44% and 68%, respectively, did not develop IA. These percentages were even higher in the ACPA-negative arthralgia patients: 66%, 85% and 89%, respectively. Similar results were seen after 3 years of follow-up.

Conclusion

Replacing clinical arthritis with subclinical synovitis to identify RA introduces a high false-positive rate (44–89%). These data suggest an overestimation regarding the value of ACPA positivity in combination with the presence of subclinical synovitis in patients with arthralgia, which harbours the risk of overtreatment if DMARDs are initiated in the absence of clinical arthritis.

Measuring Inflammatory Foot Disease in Rheumatoid Arthritis: Development and Validation of the Rheumatoid Arthritis Foot Disease Activity Index-5

OBJECTIVE

Omission of foot joints from composite global disease activity indices may lead to underestimation of foot and overall disease in rheumatoid arthritis (RA) and under-treatment. The aim of this study was to evaluate the measurement properties of the Rheumatoid Arthritis Foot Disease Activity Index-5 (RADAI-F5), a newly developed patient-reported outcome measure for capturing foot disease activity in people with RA.

METHODS

Participants with RA self-completed the RADAI-F5, modified Rheumatoid Arthritis Disease Activity Index (mRADAI-5), Foot Function Index (FFI), and Foot Impact Scale (FIS) impairment/footwear and activity/participation subscales. The 28-joint Disease Activity Score using the erythrocyte sedimentation rate (DAS28-ESR) was also recorded. Subgroups completed the RADAI-F5 at 1 week and 6 months. Psychometric properties, including construct, content and longitudinal validity, internal consistency, 1-week reproducibility, and responsiveness over 6 months were evaluated.

RESULTS

Of 142 respondents, 103 were female, with a mean ± SD age of 55 ± 12.5 years and median RA disease duration of 10 (interquartile range 3.6-20.8) months. Theoretically consistent associations confirming construct validity were observed with mRADAI-5 (0.789 [95% confidence interval (95% CI) 0.73, 0.85]), FFI (0.713 [95% CI 0.62, 0.79]), FIS impairment/footwear (0.695 [95% CI 0.66, 0.82], P < 0.001), FIS activity/participation (0.478 [95% CI 0.37, 0.63], P < 0.001), and the DAS28-ESR (0.379 [95% CI 0.26, 0.57], P < 0.001). The RADAI-F5 demonstrated high internal consistency (Cronbach's α = 0.90) and good reproducibility (intraclass correlation coefficient = 0.868 [95% CI 0.80, 0.91], P < 0.001, smallest detectable change = 2.69). Content validity was confirmed, with 82% rating the instrument relevant and easy to understand.

CONCLUSION

The RADAI-F5 is a valid, reliable, responsive, clinically feasible patient-reported outcome measure for measuring foot disease activity in RA.

MRI detected synovitis of the small joints predicts rheumatoid arthritis development in large joint undifferentiated inflammatory arthritis

Objectives

New onset undifferentiated large joint inflammatory arthritis can be diagnostically challenging. It is unknown how often these patients progress to RA, and how they can be identified at first presentation. We assessed clinical and serological features associated with RA development in patients with an undifferentiated mono- or oligo-articular large joint arthritis, and with keen interest in whether an MRI of the small joints of the hand and foot would aid diagnosis.

Methods

Leiden Early Arthritis Clinic includes 4018 patients; this prospective study follows 221 consecutively included patients with new onset undifferentiated large joint arthritis. Baseline clinical data and serology were obtained. Forty-five patients had MRIs (hand and foot). MRIs were scored according to the OMERACT RAMRIS. Univariable and multivariable logistic regression were assessed. Test characteristics, predictive values and net reclassification index (NRI) for RA were determined.

Results

Patients mostly presented with knee or ankle mono-arthritis. During the 12 months’ follow-up 17% developed RA. Autoantibody positivity (ACPA and/or RF) and MRI-detected synovitis in hands and feet were independently associated with RA development in multivariable analyses [odds ratio 10.29 (P = 0.014) and 7.88 (P = 0.017), respectively]. Positive predictive value of autoantibodies, MRI-detected synovitis and combination of both features was 63%, 55% and 100%, respectively. The addition of MRI-detected synovitis to autoantibody status improved diagnostic accuracy (NRI 18.1%).

Conclusion

In patients presenting with undifferentiated large joint arthritis, 17% will develop RA. Autoantibody positivity and subclinical synovitis are independent predictors. The data suggest MRI of small joints is beneficial for early identification of RA in large joint arthritis.

SWE and SMI ultrasound techniques for monitoring needling treatment of ankylosing spondylitis: study protocol for a single-blinded randomized controlled trial

Background

Ankylosing spondylitis (AS) is a high-incidence disease in young men that interferes with patients’ physical and mental wellbeing and overall quality of life (QoL). It is often accompanied by arthralgia, stiffness, and limited lumbar flexibility. Acupuncture is safe and effective for reducing the symptoms of AS, but the underlying mechanisms by which it does so are not fully understood. Therefore, to objectively assess acupuncture efficacy, which is critical for patients making informed decisions about appropriate treatments, we will use shear-wave elastography (SWE) and superb microvascular imaging (SMI) ultrasound techniques to evaluate elasticity of lumbar paraspinal muscles and blood flow to the sacroiliac joint (SIJ) in AS.

Methods

We will recruit a total of 60 participants diagnosed with AS and 30 healthy subjects. Participants will be randomly allocated 1:1 to either an acupuncture group or a sham control acupuncture group. Primary-outcome measures will be musculoskeletal ultrasound, Ankylosing Spondylitis Quality of Life Scale (ASQoL), Bath Ankylosing Spondylitis Metrology Index (BASMI), and the Visual Analogue Scale (VAS) for pain. Secondary outcome measures will be the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Function Index (BASFI), and Fatigue Scale-14 (FS-14). We will monitor the effect of acupuncture or sham acupuncture on blood flow and SIJ inflammation using SMI, lumbar-muscle stiffness using SWE and the lumbar paraspinal-muscle cross-sectional area (CSA) using a two-dimensional (2D) grayscale imaging. QoL, physical function, and fatigue will be assessed using an evaluation scale or questionnaire developed for this study, with outcomes measured by the ASQoL, BASMI, BASDAI, BASFI, and FS-14. Healthy subjects will not receive acupuncture but undergo only musculoskeletal ultrasound at baseline. Acupuncture and sham control acupuncture interventions will be conducted for 30 min, 2–3 times/week for 12 weeks. Musculoskeletal ultrasound will be conducted at baseline and post-intervention, while other outcomes will be measured at baseline, 6 weeks, and post-intervention. The statistician, outcome assessor, and participants will be blinded to treatment allocation.

Discussion

The results of this single-blinded, randomized trial with sham controls could help demonstrate the efficacy of acupuncture and clarify whether musculoskeletal ultrasound could be used to evaluate AS.

Trial registration

ClinicalTrials.gov ChiCTR2000031476. Registered 3 April 2020.

The pre-clinical phase of rheumatoid arthritis: From risk factors to prevention of arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease considered as a multistep process spanning from the interaction of genetic (e.g., shared epitope or non-HLA loci), environmental and behavioral risk factors (e.g., smoking) leading to breaking immune tolerance and autoimmune processes such as the production of autoantibodies (e.g., antibodies against citrullinated proteins ACPA or rheumatoid factors, RF), development of the first symptoms without clinical arthritis, and, finally, the manifestation of arthritis. Despite the typical joint involvement in established RA, the pathogenesis of the disease likely begins far from joint structures: in the lungs or periodontium in association with citrullination, intestinal microbiome, or adipose tissue, which supports normal findings in synovial tissue in ACPA+ patients with arthralgia. The presence of ACPA is detectable even years before the first manifestation of RA. The pre-clinical phase of RA is the period preceding clinically apparent RA with ACPA contributing to the symptoms without subclinical inflammation. While the combination of ACPA and RF increases the risk of progression to RA by up to 10 times, increasing numbers of novel autoantibodies are to be investigated to contribute to the increased risk and pathogenesis of RA. With growing knowledge about the course of RA, new aspiration emerges to cure and even prevent RA, shifting the "window of opportunity" to the pre-clinical phases of RA. The clinical definition of individuals at risk of developing RA (clinically suspect arthralgia, CSA) makes it possible to unify these at-risk individuals' clinical characteristics for "preventive" treatment in ongoing clinical trials using mostly biological or conventional synthetic disease-modifying drugs. However, the combination of symptoms, laboratory, and imaging biomarkers may be the best approach to select the correct target at-risk population. The current review aims to explore different phases of RA and discuss the potential of (non)pharmacological intervention aiming to prevent RA.

Tenosynovitis has a high sensitivity for early ACPA-positive and ACPA-negative RA: a large cross-sectional MRI study

OBJECTIVES

Clinically evident tenosynovitis can be seen in established rheumatoid arthritis (RA). Imaging research has recently shown that tenosynovitis at small joints occurs in early RA, contributes to typical RA symptoms (including joint swelling) and is infrequent in healthy controls. Imaging-detectable tenosynovitis is often not recognisable at joint examination, hence its prevalence can therefore be underestimated. We hypothesised that if MRI-detectable tenosynovitis is a true RA feature, the sensitivity for RA is high, in both anti-citrullinated protein antibodies (ACPA)-positive and ACPA-negative RA, and lower in other diseases that are associated with enthesitis (such as spondyloarthritis (SpA) and psoriatic arthritis (PsA)). So far, no large MRI study addressed these questions.

METHODS

Consecutive patients with early arthritis (n=1211) from one healthcare region underwent contrast-enhanced 1.5T MRI of hand and foot at diagnosis. MRIs were scored for synovitis and tenosynovitis by two readers blinded for clinical data. All included patients with ACPA-positive RA (n=250), ACPA-negative RA (n=282), PsA (n=88), peripheral SpA (n=24), reactive arthritis (n=30) and self-limiting undifferentiated arthritis (UA; n=76) were studied. Sensitivity was calculated.

RESULTS

The sensitivity of tenosynovitis in RA was 85%; 88% for ACPA-positive RA and 82% for and ACPA-negative RA (p=0.19). The sensitivity for RA was significantly higher than for PsA (65%; p=0.001), SpA (53%; p<0.001), reactive arthritis (36%; p<0.001) and self-limiting UA (42%; p<0.001). The observed sensitivity of MRI synovitis was 91% in RA and ranged from 83% to 54% in other groups.

CONCLUSIONS

MRI-detected tenosynovitis has a high sensitivity for early ACPA-positive and ACPA-negative RA. This supports that both juxta-articular (tenosynovitis) and intra-articular synovial involvement is characteristic of RA.

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.

Major reduction of ultrasound-detected synovitis during subcutaneous tocilizumab treatment: results from a multicentre 24 week study of patients with rheumatoid arthritis

Objective: Few studies have investigated the efficacy of subcutaneous tocilizumab (TCZ-SC) on ultrasound-detected inflammation. This study aimed to explore the clinical efficacy of TCZ-SC treatment in rheumatoid arthritis (RA) patients and to evaluate the response by ultrasound compared to Composite Disease Activity Scores (CDAS).Method: This open-label, single-arm study enrolled RA patients with inadequate response to conventional synthetic disease-modifying anti-rheumatic drugs initiating TCZ-SC 162 mg once weekly for 24 weeks, with clinical assessments at baseline, 2, 4, 8, 12, 16, 20, and 24 weeks. Ultrasound examinations [semi-quantitative score (0-3) of 36 joints and four tendons] were performed at baseline, 4, 12, and 24 weeks. CDAS and American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) response, and sum scores of ultrasound grey scale/Doppler were calculated. Changes during follow-up were explored by the Mann-Whitney test and correlations by Spearman's rho.Results: In total, 133 patients (mean ± sd age 55.9 ± 12.0 years) were assessed clinically and 110 patients were also examined with ultrasound. All clinical and ultrasound scores decreased significantly after 4 weeks (p < 0.001). At 24 weeks there was EULAR good response in 87.7% and ACR 70% response in 47.4%. Ultrasound scores had no or low correlations with patient-reported outcomes. At 24 weeks, CDAS remission was achieved in 27.4-83.5% and a sum score Doppler of 0 was found in 53.3%.Conclusions: Clinical and ultrasound scores decreased rapidly. Ultrasound scores were not associated with patient-reported variables. Half of the patients reached ultrasound remission, while there were large discrepancies in the percentage of patients reaching remission based on different CDAS.Trial registration: Study ML28691, registered 28 January 2014, ClinicalTrials.gov identifier: NCT02046616.

Value of musculoskeletal ultrasound in assessment of rheumatoid hand function

Background

Musculoskeletal ultrasound can be now considered a complement to physical examination in rheumatoid arthritis. This study evaluates the role of musculoskeletal ultrasound in assessment of rheumatoid hand function and underlying functional defects and disabilities in order to find out a possibly better tool for assessment.

Results

Hand grip weakness was significantly associated with metacarpophalangeal joints synovitis of ulnar 4 fingers (p = 0.045), wrist joint synovitis (p = 0.009), flexor tendons tenosynovitis of the ulnar 4 fingers (p = 0.001), flexor pollicis longus tendon tenosynovitis (p = 0.013).

Hand function impairment by grip ability test was significantly associated with metacarpophalangeal joints synovitis of ulnar 4 fingers (p = 0.009), wrist joint synovitis (p = 0.004), and flexor tendons tenosynovitis of the ulnar 4 fingers (p = 0.042). Multiple linear regression analysis showed that the most influencing factor affecting grip ability test and hand grip strength was ulnar 4 Flexor tendons tenosynovitis (P = 0.023, P = 0.037) respectively.

Conclusions

Joint synovitis and tenosynovitis that are detected by musculoskeletal ultrasound can be used as an assessment tool for hand function in rheumatoid arthritis, since they are associated with reduced hand grip strength and impaired hand ability.

The Role of Ultrasound Across the Inflammatory Arthritis Continuum: Focus on "At-Risk" Individuals

In individuals at-risk of developing inflammatory arthritis, the value of an ultrasound (US) scan assessment to predict progression has been demonstrated repeatedly. However, depending on recruitment criteria, these individuals may be at different stages in the arthritis development continuum, therefore representing a heterogeneous population. As a consequence, the predictive value of ultrasound results may differ between cohorts. As other reviews have focused on the challenges in population recruitment or have combined biomarkers predicting value according to one recruitment pathway, we wanted to focus on the sole use of ultrasound assessment and its variation according to population recruitment criteria. In this review, we discuss the use of ultrasound in the different at-risk populations across the inflammatory arthritis disease continuum. This review demonstrates that although some sub-population data is scarce, ultrasound is best predictive in three at-risk populations: those with a positive ACPA test in the context of non-specific MSK symptoms, those with clinically suspect arthralgia and those with palindromic rheumatism. We consider that ultrasound assessment will be a cornerstone in prediction risk modeling and prevention studies of the preclinical phases of IA in the future.

Contemporary imaging of rheumatoid arthritis: Clinical role of ultrasound and MRI

Magnetic resonance imaging (MRI) and musculoskeletal ultrasound (MSUS) are sensitive imaging modalities used by clinicians to assist in decision-making in the management of rheumatoid arthritis (RA). This review will examine the utility of MRI and MSUS in diagnosing RA, predicting RA flares, tapering therapy, assessing remission, and examining difficult periarticular features. We will also outline the strengths and weaknesses of utilizing MRI and MSUS as outcome measures in the management of RA.

The changing role of ultrasonography examination in patients with rheumatoid arthritis in light of recent studies

For many years, ultrasonography (US) has been a widely accepted modality used for joint assessment in patients with rheumatoid arthritis (RA). Given the efficacy of present day therapies, there is scepticism whether it is required in the first place. The most recent clinical Targeting synovitis in Early Rheumatoid Arthritis (TaSER) and Clinical Tight Control Therapy (ARCTIC) trials’ results appear to contradict it, yet this does not necessarily mean ultrasound has no place in modern rheumatology. The possibility of detecting inflammation at a subclinical level carries a tremendous predictive value, enabling identification of patients likely to experience an exacerbation in the coming months. Therefore, US should be a part of the decision-making process regarding treatment modification or introduction of any additional interventions, such as glucocorticosteroid injections.

The results of the most recent clinical trials do not negate the usefulness of US, but merely suggest that it ought to be used in moderation.

Rheumatoid Arthritis and Tenosynovitis at the Metatarsophalangeal Joints: An Anatomic and MRI Study of the Forefoot Tendon Sheaths

Background Although tenosynovitis in the hands is associated with rheumatoid arthritis (RA), it is unknown whether tenosynovitis of the forefoot is associated with RA. Purpose To determine the anatomy of tendon sheaths of the forefoot and the relationship between MRI-detected tenosynovitis at metatarsophalangeal (MTP) joints and RA. Materials and Methods Fourteen forefeet of donated bodies were examined at flexor tendons and extensor tendons for the presence and course of tendon sheaths. In the prospective study between June 2013 and March 2016, newly presenting patients with RA, patients with other early arthritides, and healthy control participants all underwent MRI of unilateral MTP joints 1-5. MRI studies were scored by two independent readers for tenosynovitis, synovitis, and bone marrow edema. The association between the presence of these features and RA was examined by using logistic regression. Results Macroscopically, all extensor and flexor tendons crossing MTP joints demonstrated sheaths surrounding tendons. Microscopically, a synovial sheath was present. MRI evaluation was performed in 634 participants: 157 newly presenting patients with RA (109 women; mean age, 59 years ± 11 [standard deviation]), 284 patients with other early arthritides (158 women; mean age, 56 years ± 17), and 193 healthy control participants (136 women; mean age, 50 years ± 16). MRI-detected tenosynovitis was associated with RA, both when compared with patients with other arthritides (odds ratio [OR], 2.5; 95% confidence interval [CI]: 1.7, 3.9; P < .001) and healthy control participants (OR, 46; 95% CI: 14, 151; P < .001). The association was OR of 2.4 (95% CI: 1.5, 3.8; P < .001) for flexor tendons and OR of 3.1 (95% CI: 1.9, 5.2; P < .001) for extensor tendons. The sensitivity of tenosynovitis in RA was 65 of 157 (41%; 95% CI: 35%, 50%). The specificity for RA was 63 of 284 (78%; 95% CI: 72%, 82%) compared with other arthritides, and three of 193 (98%; 95% CI: 96%, 99%) compared with healthy control participants. Conclusion Tendons at metatarsophalangeal joints are surrounded by tenosynovium. MRI-detected tenosynovitis at metatarsophalangeal joints was specific for rheumatoid arthritis when compared with findings in patients with other arthritides and findings in healthy control participants. © RSNA, 2020 Online supplemental material is available for this article.

Color fraction as a useful method of imaging synovium vascularization in patients with high activity of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease with joint inflammation and destruction as the main features that appears with prevalence of 1 to 2% of the general population. Women are three times more likely to suffer from RA than men. Rheumatoid arthritis occurs at any age but commonly over 40-50 years old. In the course of RA each joint may be involved but most frequently the proximal interphalangeal and metacarpophalangeal joints of the hands, wrists, and also small joints of the feet are affected. Symmetrical joint swelling with overgrowth of synovium and hypervascularization confirmed in power Doppler ultrasound imaging are very characteristic for RA. Quantification of vascularization with the color fraction index may be a useful tool to monitor disease activity and in evaluation of inflammation in scientific research. This article aims to present this imaging diagnostic method based on the literature.

A search to the target tissue in which RA-specific inflammation starts: a detailed MRI study to improve identification of RA-specific features in the phase of clinically suspect arthralgia

OBJECTIVE

Based on a unique cohort of clinically suspect arthralgia (CSA) patients, we analysed which combinations of MRI features at onset were predictive for rheumatoid arthritis (RA) development. This was done to increase our comprehension of locations of RA onset and improve the predictive accuracy of MRI in CSA.

METHODS

In the discovery cohort, 225 CSA patients were followed on clinical arthritis development. Contrast-enhanced 1.5 T MRIs were made of unilateral metacarpophalangeal (MCP) (2-5), wrist, and metatarsophalangeal (1-5) joints at baseline and scored for synovitis, tenosynovitis, and bone marrow edema. Severity, number, and combinations of locations (joint/tendon/bone) with subclinical inflammation were determined, with symptom-free controls of similar age category as reference. Cox regression was used for predictor selection. Predictive values were determined at 1 year follow-up. Results were validated in 209 CSA patients.

RESULTS

In both cohorts, 15% developed arthritis < 1 year. The multivariable Cox model selected presence of MCP-extensor peritendinitis (HR 4.38 (2.07-9.25)) and the number of locations with subclinical inflammation (1-2 locations HR 2.54 (1.11-5.82); ≥ 3 locations HR 3.75 (1.49-9.48)) as predictors. Severity and combinations of inflammatory lesions were not selected. Based on these variables, five risk categories were defined: no subclinical inflammation, 1-2 locations, or ≥ 3 locations, with or without MCP-extensor peritendinitis. Positive predictive values (PPVs) ranged 5% (lowest category; NPV 95%) to 67% (highest category). Similar findings were obtained in the validation cohort; PPVs ranged 4% (lowest category; NPV 96%) to 63% (highest category).

CONCLUSION

Tenosynovitis, particularly MCP-extensor peritendinitis, is among the first tissues affected by RA. Incorporating this feature and number of locations with subclinical inflammation improved prediction making with PPVs up to 63-67%.

The agreement between ultrasound-determined joint inflammation and clinical signs in patients with rheumatoid arthritis

Background

Ultrasound (US) is sensitive for detecting joint and tendon inflammation in patients with rheumatoid arthritis (RA). So far, which grade of abnormalities on US corresponds to clinical manifestations is unclear. This study aimed to investigate the agreement between US-detected joint inflammation and clinical signs (joint swelling and tenderness).

Methods

In this cross-sectional study, 22 joints of the wrists and hands were, respectively, evaluated by physical examination (PE) and ultrasound in RA patients. Gray scale (GS) and power Doppler (PD) of synovitis, detected by ultrasound, were graded by semi-quantitative scoring systems (0–3). Tenosynovitis and peritendinitis were assessed qualitatively (0/1).

Results

A total of 258 consecutive RA patients were included, with median disease duration of 57 months and mean Disease Activity Score based on 28 joints (DAS28)-ESR/DAS28-CRP of 4.47/3.99. In a total of 5676 joints assessed, the overall concordance rate between positive clinical signs and ultrasound-determined joint inflammation was fair (κ = 0.365, p < 0.01). In wrists, joint tenderness showed higher κ coefficient (κ = 0.329, p < 0.01) with ultrasound-determined joint inflammation than swelling (κ = 0.263, p < 0.01); however, swelling showed higher κ coefficient (κ = 0.156–0.536, p < 0.01) with ultrasound-determined joint inflammation than tenderness (κ = 0.061–0.355, p < 0.01) in metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. Synovitis had consistently higher agreement with tenderness and swelling than tenosynovitis/peritendinitis. Tenderness and swelling had the highest κ coefficient with GS ≥ 1 synovial hyperplasia in most MCP and PIP joints, while with GS ≥ 2 synovial hyperplasia in wrists. For all 22 joints, PD ≥ 1 synovitis had the highest κ coefficient with clinical tenderness and swelling.

Conclusions

Synovitis had better agreement with clinical signs than tenosynovitis/peritendinitis. Joint swelling showed better agreement with US-determined inflammation than tenderness for MCP and PIP joints, while the opposite for wrists. Both tenderness and swelling are more likely to correspond to GS ≥ 2 for wrists, GS ≥ 1 for MCP and PIP joints, and PD ≥ 1 for any joint.