Development of a Preliminary Ultrasonographic Enthesitis Score in Psoriatic Arthritis - GRAPPA Ultrasound Working Group

Using Ultrasound to Improve Diagnostic Confidence and Management of Psoriatic Disease: Highlights From the GRAPPA 2023 Ultrasound Workshop

The sensitivity of ultrasound (US) to detect, characterize, and monitor the relevant pathologies of psoriatic arthritis (PsA), including synovitis, enthesitis, tenosynovitis, and dactylitis, has made it an attractive tool for informing clinical decisions. The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) US working group ran 2 sessions during the annual GRAPPA meeting held in July 2023 in Dublin, Ireland. During the first workshop, the group presented 2 topics, followed by a live demonstration and a group discussion. The 2 topics were (1) an overview of the Diagnostic Ultrasound Enthesitis Tool (DUET) enthesitis scoring methodology, and (2) small hand-held probes-will the promise deliver? The live demonstration that followed compared the performance of 2 hand-held US (HHUS) devices vs a console US machine in patients with PsA, and the interactive group discussion considered gaps in the literature and future research suggestions relating to HHUS and its application in psoriatic disease. During the second session, the US working group provided further updates regarding the GRAPPA US studies currently underway or recently completed.

Ultrasound assessment of Achilles enthesitis: a dedicated training program

OBJECTIVE

To describe an intensive and multimodal ultrasound (US) training program focused on Achilles enthesitis and to illustrate the learning curve of trainees without experience.

METHODS

Three medical students (trainees) and two rheumatologists experienced in musculoskeletal US (trainers) were involved in the training program, which encompassed one preliminary theoretical-practical meeting and five scanning sessions (two patients per session). The students and one expert performed the US examination of the Achilles enthesis bilaterally. The trainees acquired representative images and assessed the presence of Outcome Measures in Rheumatology (OMERACT) US abnormalities of enthesitis. The experts provided feedback addressing trainees' misinterpretations, and the quality of the acquired images was evaluated. A dedicated questionnaire was used to evaluate the students' confidence. After each session, five sets of static images (total=100 images of most commonly scanned entheses) were provided and scored by the students according to OMERACT US definitions. Total agreement and prevalence and bias adjusted kappa (PABAK) were used to evaluate the concordance between the trainees and the expert sonographer.

RESULTS

The total agreement and PABAK significantly improved between the first and fifth scanning sessions (76.2% versus 92.9%, p<0.01, and 0.5 versus 0.79, p<0.01) and between the first and fifth static image sets (64.5% versus 81.9%, p<0.01, and 0.29 versus 0.74, p<0.01). Image quality did not significantly improve (p=0.34). A significant increase in trainees' confidence was registered (p<0.01).

CONCLUSIONS

The described training program rapidly improved the students' performance in the US assessment of Achilles enthesitis, appearing to be an effective starting model for the future development of pathology-oriented teaching programs for the US in rheumatology.

Updates in Ultrasound in Rheumatology

BACKGROUND

The purpose of the authors' narrative review was to outline the current literature regarding the use of ultrasound in main rheumatic disorders and summarize the updates, specifically about rheumatoid arthritis, psoriatic arthritis, and crystal-induced arthropathies.

METHODS

The authors searched on PubMed for articles discussing the major updates regarding the role of ultrasound in the previously mentioned rheumatic conditions.

RESULTS

The authors have provided the updated definitions, new criteria, and diagnostic scores.

CONCLUSIONS

In rheumatology's dynamic landscape, this review provides valuable insights for researchers and clinicians on ultrasound's role in improving patient care and outcomes in rheumatic diseases.

From Psoriasis to Psoriatic Arthritis: Ultrasound Insights Connecting Psoriasis with Subclinical Musculoskeletal Inflammation and the Path to Psoriatic Arthritis

PURPOSE OF REVIEW

This review summarizes the literature about the transition from psoriasis to psoriatic arthritis (PsA), focusing on musculoskeletal ultrasound (MSUS) for detecting subclinical inflammation and its role in diagnosis and triage of high-risk patients.

RECENT FINDINGS

MSUS effectively detects subclinical musculoskeletal inflammation in patients with psoriasis; however, some of these lesions are non-specific and can be found in healthy individuals. Preliminary evidence suggest that subclinical sonographic findings may predict progression to PsA in psoriasis patients. MSUS can also improve referrals' accuracy and its integration in the PsA classification criteria may improve early PsA detection. MSUS is a valuable tool for detecting subclinical abnormalities in psoriasis patients, which indicate an increased likelihood of progressing to PsA. Its integration into referral protocols and clinical use could improve PsA diagnosis. We propose an MSUS-inclusive algorithm for PsA referrals and triage, which requires validation. The potential of early intervention in reducing PsA progression in psoriasis patients with subclinical inflammation remains to be established.

Clinical course of psoriatic arthritis treated with biologics delineated with ultrasonography

Psoriatic arthritis (PsA) is a chronic, inflammatory articular disease regarded as a specific subtype of psoriasis. Long-term assessment for PsA using ultrasonography has not yet been investigated. The present study was conducted to delineate the changes in articular lesions after the initiation of biologics using ultrasonography, and to provide the evidence of the utility of ultrasonography in long-term follow-up of PsA patients. We retrospectively recruited 17 Japanese PsA patients treated with biologics who met the classification criteria for psoriatic arthritis. Ultrasonographic images were recorded using a high-frequency linear 18 MHz probe through Doppler- and B-modes. Before the treatment with biologics, all examined patients (100%) had enthesitis and extensor tendinitis, while only six patients (35.3%) had loss of the fibrillar pattern of the tendon (LFP). There were significant changes over time in the numerical rating scale score for pain, and in the degree of ultrasonographic findings, including enthesitis, extensor tendinitis, and LFP. Also, there were significant changes over time between these ultrasonographic findings. The study identified the improvement course for a specific PsA lesion after the initiation of biologics. The improvement courses in enthesitis, extensor tendinitis, and LFP were found to differ from each other. These results may contribute to deeper understanding of the pathogenesis of PsA.

Power Doppler signal at the enthesis and bone erosions are the most discriminative OMERACT ultrasound lesions for SpA: results from the DEUS (Defining Enthesitis on Ultrasound in Spondyloarthritis) multicentre study

OBJECTIVES

To assess, in spondyloarthritis (SpA), the discriminative value of the Outcome Measures in Rheumatology (OMERACT) ultrasound lesions of enthesitis and their associations with clinical features in this population.

METHODS

In this multicentre study involving 20 rheumatology centres, clinical and ultrasound examinations of the lower limb large entheses were performed in 413 patients with SpA (axial SpA and psoriatic arthritis) and 282 disease controls (osteoarthritis and fibromyalgia). 'Active enthesitis' was defined as (1) power Doppler (PD) at the enthesis grade ≥1 plus entheseal thickening and/or hypoechoic areas, or (2) PD grade >1 (independent of the presence of entheseal thickening and/or hypoechoic areas).

RESULTS

In the univariate analysis, all OMERACT lesions except enthesophytes/calcifications showed a significant association with SpA. PD (OR=8.77, 95% CI 4.40 to 19.20, p<0.001) and bone erosions (OR=4.75, 95% CI 2.43 to 10.10, p<0.001) retained this association in the multivariate analysis. Among the lower limb entheses, only the Achilles tendon was significantly associated with SpA (OR=1.93, 95% CI 1.30 to 2.88, p<0.001) in the multivariate analyses. Active enthesitis showed a significant association with SpA (OR=9.20, 95% CI 4.21 to 23.20, p<0.001), and unlike the individual OMERACT ultrasound lesions it was consistently associated with most clinical measures of SpA disease activity and severity in the regression analyses.

CONCLUSIONS

This large multicentre study assessed the value of different ultrasound findings of enthesitis in SpA, identifying the most discriminative ultrasound lesions and entheseal sites for SpA. Ultrasound could differentiate between SpA-related enthesitis and other forms of entheseal pathology (ie, mechanical enthesitis), thus improving the assessment of entheseal involvement in SpA.

Advanced Imaging of Gout and Other Inflammatory Diseases Around the Knee

The knee is one of the most commonly affected joints in the course of inflammatory arthropathies, such as crystal-induced and autoimmune inflammatory arthritis. The latter group includes systemic connective tissue diseases and spondyloarthropathies. The different pathogenesis of these entities results in their varied radiologic images. Some lead quickly to joint destruction, others only after many years, and in the remaining, destruction will not be a distinguishing radiologic feature.Radiography, ultrasonography, and magnetic resonance imaging have traditionally been the primary modalities in the diagnosis of noninflammatory and inflammatory arthropathies. In the case of crystallopathies, dual-energy computed tomography has been introduced. Hybrid techniques also offer new diagnostic opportunities. In this article, we discuss the pathologic findings and imaging correlations for crystallopathies and inflammatory diseases of the knee, with an emphasis on recent advances in their imaging diagnosis.

A clinical review of structural damage in psoriatic arthritis for dermatologists: From pathogenesis to ongoing controversies

Psoriatic arthritis (PsA) is a chronic inflammatory disease that often goes unrecognized in patients with psoriasis. As a result, patients may develop significant structural damage before diagnosis and initiation of adequate treatment. Dermatologists are in an unique position to identify early signs and symptoms of PsA. Here, we briefly review the pathogenesis of PsA, differences in PsA presentation within real-world dermatology practice versus rheumatology clinical trials, and imaging modalities that can be used to assess structural damage. We then discuss several ongoing controversies related to prediction, assessment, and treatment of PsA-related structural damage. Debated questions include the following: (1) Does subclinical enthesitis predict progression from psoriasis to PsA?, (2) Does methotrexate inhibit progression of structural damage?, (3) Does structural damage correlate with clinical disease activity?, and (4) Can progression from psoriasis to PsA be prevented? Evidence presented herein suggests that dermatologists, together with rheumatologists, can play important roles in the early diagnosis and treatment of PsA, thereby potentially preventing irreversible structural damage.

Evaluation of Standard and Proposed Reference Values for Entheseal Thickening by Using Musculoskeletal Ultrasound

OBJECTIVE

Ultrasound (US) is increasingly used to evaluate enthesitis. One of the US features of enthesitis is thickening. However, there is no consensus on how the entheseal thickening needs to be defined, and existing cut-off levels have been criticized for being frequently positive in healthy controls (HCs). Our objective was to determine the frequency of thickening of entheses on US using the existing cut-off values in HCs and in patients with axial spondyloarthritis (axSpA) and propose new values to improve discriminative value.

METHODS

Eighty HCs and 100 patients with axSpA had US scans of 2160 entheses. Sensitivity, specificity, odds ratio (OR), and accuracy were calculated according to accepted cut-off levels from the literature and proposed cut-offs were calculated as the mean ± 2 SD.

RESULTS

Thickening according to current cut-off levels was found in 20.4% (196/960) of healthy participants' entheses and 33% (396/1200) of entheses of patients with axSpA. Thickening according to proposed cut-off levels decreased frequency of thickening in both groups, and therefore increased specificity at the cost of decreasing sensitivity. The only anatomical site where the thickness had a value to discriminate disease from health was seen at the triceps tendon enthesis with an OR of 13.4 (95% CI 4.0-44.8) according to the current cut-offs compared to 10.3 (95% CI 4.0-26.6) with the proposed cut-off levels.

CONCLUSION

Although using cut-offs appears to be an appealing method to evaluate entheseal thickness, the measurements may be affected by several confounding factors, leading to a low discriminative value, except for at the triceps tendon enthesis.

Reliability assessment of the definition of ultrasound enthesitis in SpA: results of a large, multicentre, international, web-based study

OBJECTIVES

To investigate the reliability of the OMERACT US Task Force definition of US enthesitis in SpA.

METHODS

In this web exercise, based on the evaluation of 101 images and 39 clips of the main entheses of the lower limbs, the elementary components included in the OMERACT definition of US enthesitis in SpA (hypoechoic areas, entheseal thickening, power Doppler signal at the enthesis, enthesophytes/calcifications, bone erosions) were assessed by 47 rheumatologists from 37 rheumatology centres in 15 countries. Inter- and intra-observer reliability of the US components of enthesitis was calculated using Light's kappa, Cohen's kappa, Prevalence And Bias Adjusted Kappa (PABAK) and their 95% CIs.

RESULTS

Bone erosions and power Doppler signal at the enthesis showed the highest overall inter-reliability [Light's kappa: 0.77 (0.76-0.78), 0.72 (0.71-0.73), respectively; PABAK: 0.86 (0.86-0.87), 0.73 (0.73-0.74), respectively], followed by enthesophytes/calcifications [Light's kappa: 0.65 (0.64-0.65), PABAK: 0.67 (0.67-0.68)]. This was moderate for entheseal thickening [Light's kappa: 0.41 (0.41-0.42), PABAK: 0.41 (0.40-0.42)], and fair for hypoechoic areas [Light's kappa: 0.37 (0.36-0.38); PABAK: 0.37 (0.37-0.38)]. A similar trend was observed in the intra-reliability exercise, although this was characterized by an overall higher degree of reliability for all US elementary components compared with the inter-observer evaluation.

CONCLUSIONS

The results of this multicentre, international, web-based study show a good reliability of the OMERACT US definition of bone erosions, power Doppler signal at the enthesis and enthesophytes/calcifications. The low reliability of entheseal thickening and hypoechoic areas raises questions about the opportunity to revise the definition of these two major components for the US diagnosis of enthesitis.

Ultrasound Enthesitis in Psoriasis Patients with or without Psoriatic Arthritis, a Cross-Sectional Analysis

Background and objectives: The main objective of the current study was to describe the prevalence of enthesitis at different sites in a group of patients with psoriasis with or without psoriatic arthritis (PsA). Materials and Methods: The study included adult patients with psoriasis who underwent clinical examination, laboratory tests and ultrasound examination of the entheses. The enthesitis ultrasound scores (BUSES, MASEI, GUESS) were evaluated; the presence of OMERACT-defined enthesitis was also recorded for each scan site. Results: The study included 16 (57.1%) patients with PsA and 12 (42.9%) patients with psoriasis, with an increased average body mass index (29.3 kg/m2). Compared to psoriasis patients, PsA patients had a higher prevalence of nail psoriasis (68.8% compared to 33.3%; p = 0.063). There were no significant differences regarding the clinical examination of entheses between patients with psoriasis and patients with PsA (p = 0.459). Ultrasound scores, BUSES, GUESS and MASEI proved to have statistically significant higher median values in PsA patients compared to psoriasis patients. Compared to psoriasis patients, PsA patients had a significantly higher prevalence of OMERACT-defined enthesitis of the quadriceps tendon and inferior patellar ligament (both 81.3% compared to 25.0%, p = 0.003). Clinical examination of the lateral epicondyle and of the superior patellar ligament was consistent with their ultrasound examination (κ = 0.357, p = 0.043, respectively, κ = 0.404, p = 0.008). Conclusions: Clinical enthesitis scores do not differ between psoriasis and PsA patients. All analyzed ultrasound scores are significantly higher in patients with PsA. OMERACT-defined enthesitis has the ability to discriminate sonographic enthesitis between the two subgroups for bilateral quadriceps and inferior patellar tendon enthesitis. Bilateral ultrasound damage of entheses can suggest a PsA diagnosis.

Role of Shear-Wave Elastography in Achilles Tendon in Psoriatic Arthritis and Its Correlation with Disease Severity Score, Psoriasis Area and Severity Index

Purpose  The aim of this study was to compare accuracy of shear-wave elastography (SWE) with gray scale (GS) ultrasound and power Doppler (pD) for diagnosing Achilles tendinopathy in psoriatic patients with and without arthritis and correlation with achillodynia and disease severity score, psoriasis area and severity index (PASI).

Methods  A total of 100 Achilles tendons were evaluated where 56% were cases of psoriatic arthritis with achillodynia; 44% were controls of psoriasis without arthritis in this prospective study. Evaluation was done with GS, pD, SWE at proximal, mid, and distal third of the tendon. Qualitative (color maps) and quantitative data, elastic modulus, kilopascal (kPa), were generated. Pearson's correlation was done to see association between kPa, PASI and clinical symptoms, achillodynia, scored using visual analog scale (VAS).

Results  Significant negative correlation was seen between duration of arthritis, VAS and PASI with SWE values with r  = −0.34, −0.47, and −0.41, respectively. SWE could identify abnormal tendons in 71/100 (71%) in the overall study, 53/56 (94.6%) in cases, and 18/44 (40.9%) in control. The statistical significance was set at p  ≤ 0.05. In comparison, conventional ultrasound, GS, and pD together could identify 13/56 (23.21%) in cases and no abnormal tendon was identified in the control group.

Conclusion  SWE is a reliable, noninvasive, and valuable tool to detect early tendinopathy and monitor progression of disease.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice.

A Narrative Review of the Design of Ultrasound Indices for Detecting Enthesitis

With the increased utilization of musculoskeletal ultrasound in clinical practice, there has been rapid proliferation of publications on sonographic evaluation of enthesitis. This has led to the development of multiple new approaches to scoring sonographic findings in the detection of enthesitis, with variations including entheseal sites and sonographic features that limit cross-study comparisons. Furthermore, despite efforts to standardize the definition of enthesitis, there is still heterogeneity in the sonographic features included in existing ultrasound scores, and additional adjustments are required to distinguish active inflammatory changes from non-inflammatory conditions and to adjust for demographic features associated with increased prevalence of abnormal sonographic findings. This review provides an update on the current landscape of ultrasound scoring systems for enthesitis and emphasizes the importance of future data-based ultrasound scoring systems to improve the distinction between inflammatory and non-inflammatory or degenerative changes of the enthesis.

Improving Imaging Modalities in Early Psoriatic Arthritis: The Role of Ultrasound in Early Diagnosis of Psoriatic Arthritis

Objective: Despite recent advances, early diagnosis of psoriatic arthritis (PsA) remains a challenge in clinical practice. Ultrasound (US) could be a useful tool for the diagnosis and management of PsA. The objective of this review was to determine the role of US in early diagnosis of PsA.

Methods: We have performed a literature review aiming to evaluate studies on US findings in psoriasis and their predictive value of progression to PsA, as well as studies on US features specific for PsA in comparison with other conditions.

Results: A total of 40 studies were included. Sixteen studies assessed US findings in psoriasis, of which only 3 prospectively evaluated the role of US in predicting progression to PsA. Patients with PsA had a greater frequency of US abnormalities, in particular enthesitis and Power Doppler(PD) signal compared to patients with psoriasis only. In the longitudinal studies, psoriatic patients with higher enthesopathy scores at baseline were more likely to progress to PsA. Twenty-four studies evaluated US abnormalities in PsA and compared them to other conditions. Most specific US features that distinguish PsA from psoriasis were PD signal and erosions in joints and entheses. Extra-synovial changes, including peri-tendinous dermal soft tissue oedema with associated PD signal and flexor tendon enthesopathy, as well as thickening of the pulleys in the flexor tendons were highly characteristic for PsA, as they were frequently found in PsA patients, but in none of the RA patients. US-detected entheseal abnormalities in particular erosions and PD signal were more frequent in patients with PsA compared to fibromyalgia.

Conclusion: Despite the wide use of US in PsA, more research is needed to identify predictive factors of progression to PsA in patients with psoriasis, as well as to determine most specific US features that differentiate PsA from other conditions.

Use of Ultrasonography to Discriminate Psoriatic Arthritis from Fibromyalgia: A Post-Hoc Analysis of the ULISSE Study

In psoriatic arthritis (PsA) patients with concomitant chronic widespread pain, the differential diagnosis with fibromyalgia syndrome (FMS) can be challenging. We evaluated whether ultrasound (US) examination of entheseal sites can distinguish pain from (PsA) enthesitis versus FMS. PsA and FMS patients underwent clinical evaluation and gray-scale (GS; B-mode) and power Doppler (PD) US examination of the entheses. At least one enthesis with GS- and PD-mode changes was found in 90% and 59.3% of PsA patients (n = 140) and 62.7% and 35.3% of FMS patients (n = 51), respectively. GS and PD identified changes in 49.5% and 19.2% of the 840 PsA entheses and 22.5% and 7.9% of the 306 FMS entheses, respectively. Receiver operating characteristic curve analysis showed an area under the curve of 0.77 and 0.66 for B- and PD-mode, respectively, 3.5 being the best cut-off GS-score to discriminate the two conditions. Multivariate regression showed that Achilles and proximal patellar tendon enthesitis (B-mode) were strongly associated with PsA (odds ratio, ~2). Principal component analysis (B-mode) confirmed that PsA patients have a higher number of involved entheses and patterns of entheseal involvement than FMS patients. US evaluation of the entheses may help differentiate chronic widespread pain from PsA versus FMS.

Integrating imaging and biomarker assessment to better define psoriatic arthritis and predict response to biologic therapy

The treatment options for PsA have substantially expanded over the last decade. Approximately 40% of patients will not respond to first-line anti-TNF-α therapies. There is limited data to help clinicians select the most appropriate biologic therapy for PsA patients, including guidance for decisions on biologic therapy switching. In this review we will examine the current understanding of predictors of response to treatment. Imaging technology has evolved to allow us to better study psoriatic disease and define disease activity, including synovitis and enthesitis. Enthesitis is implicated in the pathogenesis, diagnosis and prognosis of PsA. It appears to be a common thread among all of the various PsA clinical presentations. Enthesitis mainly manifests as tenderness, which is difficult to distinguish from FM, chronic pain and mechanically associated enthesopathy, and it might be relevant for understanding the apparent 40% failure of existing therapy. Excess adipose tissue makes if more difficult to detect joint swelling clinically, as many PsA patients have very high BMIs. Integrating imaging and clinical assessment with biomarker analysis could help to deliver stratified medicine in PsA and allow better treatment decision making. This could include which patients require ongoing biologic therapy, which class of biologic therapy that should be, and who alternatively requires management of non-inflammatory disease.

Differentiating Psoriatic Arthritis from Osteoarthritis and Rheumatoid Arthritis: A Narrative Review and Guide for Advanced Practice Providers

Psoriatic arthritis (PsA) is a chronic inflammatory disease that affects multiple organ systems and is characterized by skin and joint manifestations. PsA is frequently undiagnosed and/or misdiagnosed, especially because of the similarities in clinical presentation shared with other arthritic diseases, including rheumatoid arthritis (RA) and osteoarthritis (OA). An accurate and timely diagnosis of PsA is crucial to prevent delays in optimal treatment, which can lead to irreversible joint damage and increased functional disability. Patients are usually seen by a number of different healthcare providers on their path to a diagnosis of PsA, including advanced practice providers (APPs). This review provides a comprehensive overview of the characteristic features that can be used to facilitate the differentiation of PsA from RA and OA. Detailed information on clinical manifestations, biomarkers, radiologic features, and therapeutic recommendations for PsA included here can be applied in routine clinical settings to provide APPs with the confidence and knowledge to recognize and refer patients more accurately to rheumatologists for management of patients with PsA.

Imaging update in inflammatory arthritis

Ultrasonography and magnetic resonance imaging have become important imaging modalities in rheumatological disorders next to standard radiography. Due to their ability to assess both morphological and functional changes they play a significant role in early diagnosis and treatment monitoring. This review presents the latest advancements in imaging of inflammatory arthritis with a focus on two main groups of rheumatic diseases: connective tissue diseases and spondyloarthritis. New developments related to peripheral and sacroiliac joints imaging are discussed, including Superb Micro Flow Imaging and Shear Wave Elastography in ultrasonography, as well as Whole Body MRI, quantitative MRI, and the recent advances in cartilage imaging in MRI, including T2-and T1p-mapping, and dGEMRIC. The role of emerging imaging techniques in the early diagnosis of inflammatory arthritis is discussed, including DECT, VIBE, BoneMRI, and pQCT.

Enthesitis in Psoriatic Arthritis, the Sonographic Perspective

Purpose of Review

To provide an overview of the ultrasound (US) studies focusing on enthesitis in psoriatic arthritis (PsA).

Recent Findings

Last-generation US equipment has demonstrated the ability to detect subtle morphostructural and vascular abnormalities at entheseal level. US is able to identify pathologic changes in both “classical” (i.e., the site of attachment of tendons, ligaments, and joint capsules into the bone) and “functional” entheses (i.e., anatomical regions where tendons or ligaments wrap around bony pulleys).

Summary

US has the potential to be the first-line method in the assessment of enthesitis. In the present review we critically discussed the current definitions of US enthesitis, the scoring systems, and the main fields of application (i.e., the detection of enthesitis in PsA and psoriasis, the identification of different disease subsets, and the assessment of response to treatment).

Ultrasound Doppler enthesitis shows sensitivity to change after biological therapy in spondyloarthritis and psoriatic arthritis patients

Objective: To explore the sensitivity to change in power Doppler (PD) enthesitis in active spondyloarthritis (SpA) and psoriatic arthritis (PsA) patients.Method: This was a longitudinal study in patients with SpA and PsA with active disease [patients starting or switching to biological disease-modifying anti-rheumatic drugs (bDMARDs)]. The MAdrid Sonographic Enthesitis Index (MASEI) was performed at baseline and at 3 and 6 month visits. The MASEI and Outcome Measures in Rheumatology (OMERACT) PD enthesitis definitions were checked. Reliability analysis among three readers was performed with ultrasound (US)-recorded videos.Results: US examinations of 25 patients were included; 16 (64%) had SpA and nine (36%) PsA. The median (interquartile range, IQR) age was 49 (41-61) years, and 13 patients (52%) were female. The median (IQR) 28-joint Disease Activity Score of 3.6 (2.3-4.2), Bath Ankylosing Spondylitis Disease Activity Index of 6.7 (6.1-7.4), and C-reactive protein value of 8.2 (1.6-20) reflected moderate to high disease activity at baseline. Both MASEI and OMERACT PD enthesitis improved significantly at 3 and 6 month follow-up (p < 0.05) and showed sensitivity to change (standard error of measurement = 0.47 and 0.61, respectively). Improvement in clinical activity outcomes was significantly associated with decreases in MASEI and OMERACT PD enthesitis counts (p < 0.05). The MASEI and OMERACT PD definitions had excellent reliability (kappa = 0.918 and 0.865, respectively).Conclusion: PD enthesitis significantly improved at 3 and 6 month follow-up in patients undergoing bDMARD therapy. Both MASEI and OMERACT PD US enthesitis reflect response to treatment.

Musculoskeletal Imaging for Dermatologists: Techniques in the Diagnosis and Management of Psoriatic Arthritis

Psoriatic arthritis is an inflammatory condition affecting up to 30% of patients with psoriasis. Patients may experience irreversible joint damage if not treated early, and diagnostic delays of even 6 months are associated with radiographic progression and impaired function. Therefore, early detection and intervention are of critical importance in patients with psoriatic arthritis. Given that psoriasis often precedes symptoms of psoriatic arthritis, dermatologists are uniquely positioned to identify patients with psoriatic arthritis early in their disease course, before permanent damage has occurred. Several screening tools have been developed to help dermatologists identify patients who may have psoriatic arthritis, but these tools may not capture patients with subclinical disease or quantify the type and severity of the underlying tissue insult, which is often the presenting sign of psoriatic arthritis. In these cases, a combination of clinical assessment and musculoskeletal imaging (e.g., ultrasound) is required. This review summarizes three common musculoskeletal imaging techniques used in the diagnosis and management of patients with psoriatic arthritis: conventional radiography, ultrasound, and magnetic resonance imaging. Further understanding of musculoskeletal imaging will assist dermatologists in making treatment decisions and allow them to have a more active role in the detection of psoriatic arthritis.

A Systematic Review of the Inclusion of Non-Inflammatory Ultrasonographic Enthesopathy Findings in Enthesitis Scoring Indices

Ultrasound has advanced the diagnosis and management of patients with inflammatory rheumatic conditions. It can be used to identify and monitor enthesitis, a cardinal feature of spondyloarthropthies. Several enthesitis scoring systems utilizing ultrasound to determine entheseal involvement have been developed. These scoring systems generally rely on determining the presence or absence of erosions, tendon enlargement, power Doppler signal, or enthesophytes. This systematic review identified ultrasound scoring systems that have been utilized for evaluating enthesitis and what key components derive the score. Review of these scoring systems, however, demonstrated confounding as some of the score components including enthesophytes may be seen in non-inflammatory conditions and some components including erosions can be seen from chronic damage, but not necessarily indicate active inflammatory disease. What is furthermore limiting is that currently there is not an agreed upon term to describe non-inflammatory enthesopathies, further complicating these scoring systems. This review highlights the need for a more comprehensive ultrasound enthesopathy scoring index.

High Prevalence of Ultrasound Verified Enthesitis in Patients With Inflammatory Bowel Disease With or Without Spondylarthritis

Background: Inflammatory bowel disease (IBD) is closely associated with spondylarthritis (SpA) and enthesitis, as an important feature of SpA, is a common extraintestinal manifestation of IBD. Enthesitis may be clinically silent in a high proportion of patients with IBD without clinical signs or a diagnosis of SpA.

Objectives: The aim of this study was to compare the prevalence of ultrasound (US) verified enthesitis in IBD patients with and without SpA, with patients with irritable bowel syndrome (IBS) and healthy subjects (HC) serving as controls.

Methods: IBD patients with or without SpA, patients with IBS and HC were prospectively recruited and clinically assessed. Ultrasound examination was performed at 14 entheses. The ultrasound abnormalities were scored according to the Madrid Ankylosing Spondylitis Enthesitis Index (MASEI).

Results: We included 33 IBD patients without SpA, 14 IBD patients with SpA, 26 IBS patients and 18 HC. Higher MASEI scores were found in patients with IBD without SpA [median 21.0 range (8.0–53.0)] and IBD associated SpA [33.0 (8–50)] than in IBS patients [10.5 (0–42.0)-p < 0.001 for both comparison] and HC [12.0 (2.0–38.0)-p < 0.01]. PD, enthesophytes and erosions were more common in patients with IBD with or without SpA as compared to IBS patients and HC. IBD patients with SpA compared to IBD without SpA demonstrated significant higher prevalence of erosion and structural irregularity and consequently significant higher MASEI (p < 0.05 for all comparison).

Conclusions: Ultrasound verified enthesitis is more common in patients with IBD with or without SpA as compared to patients with IBS or HC.

Enthesitis in psoriatic arthritis (Part 2): imaging

Enthesitis is a hallmark finding in PsA and may predate the onset of synovitis. Clinical examination of enthesitis provides no structural information, relies on eliciting tenderness at entheseal sites and may not be sensitive or specific. Soft tissue imaging techniques such as musculoskeletal ultrasound and MRI can depict ultrastructural and inflammatory changes. Although these imaging techniques are complimentary, ultrasound can image superficial entheses with high fidelity and examine vascularity with the use of Doppler but cannot image subchondral bone. MRI depicts bone and can visualize bone marrow edema as well as soft tissue edema. However, due to short relaxation times, entheseal structures are not easily differentiated. There has been increasing recognition of biomechanical confounding, especially since the majority of the entheses examined are in the lower extremity. Imaging entheseal indices are being developed to minimize the effect of body weight and activity. In the following article, contemporary concepts of entheses in relation to imaging will be reviewed as well as important confounders in assessing entheseal alterations. The role and limitations of imaging techniques will be discussed.

Doppler enthesitis: a potential useful outcome in the assessment of axial spondyloarthritis and psoriatic arthritis

OBJECTIVE

To analyse the frequency of power Doppler (PD) enthesitis in active axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) patients and its potential usefulness in clinical practice.

METHODS

A prospective multicentre cross-sectional study in patients with axSpA and PsA with active disease was undertaken. Patients underwent bilateral ultrasound (US) examination of the peripheral entheses according to the Madrid Sonographic Enthesis Index (MASEI). The MASEI and Outcome Measures in Rheumatology (OMERACT) PD enthesitis definitions were checked. An inter-reader analysis of recorded videos was performed to determine reliability.

RESULTS

Sixty-four consecutive patients were included. The mean DAS28 (3.9 ± 1.3) for peripheral involvement, mean BASDAI (5.6 ± 2.2) for axial involvement, and CRP values (10 ± 10.9) reflected moderate-high disease activity at baseline. The mean global MASEI score was 29.4 (± 11.4), and 55 patients (86%) scored ≥ 18 (proposed cut-off point to diagnose SpA). At the patient level, abnormal US findings consistent with at least one enthesis showing a PD signal were observed in 52 (81.3%) patients using the MASEI PD definition and 48 (75%) using the OMERACT PD definition, without significant variation between axSpA and PsA. The inter-reader reliability was excellent (kappa = 0.92 for MASEI PD and 0.86 for OMERACT PD).

CONCLUSIONS

PD enthesitis was found in the majority of patients with active axSpA and PsA, independent of axial or peripheral affectation. Both MASEI and OMERACT PD definitions were useful in detecting active enthesitis. These findings support the usefulness of a PD US evaluation of entheses in the assessment of axSpA and PsA. Key Points • PD enthesitis is a very common finding in patients with active axSpA and PsA • Both MASEI and OMERACT PD definitions are useful to detect active enthesitis • US enthesitis may reveal information in axSpA and PsA.

Imaging in the diagnosis and management of peripheral psoriatic arthritis

Psoriatic arthritis is a heterogenous disease affecting peripheral and axial joints, tendons, ligaments, and their insertions, in addition to the skin and the nails. The complexity of the involved structures has puzzled clinicians trying to understand the underlying pathology that leads to symptoms in order to choose the appropriate medications with different modes of actions. Imaging, mainly ultrasound and magnetic resonance imaging, allows of accurate detection of inflammatory changes in the musculoskeletal structures, which helps to avoid false positive and negative assessments. The linking of different anatomical structures' involvement using imaging also provides insights into the pathogenesis of psoriatic arthritis. In this review, ultrasound and magnetic resonance imaging will be discussed in depth with regard to their use in the field of peripheral psoriatic arthritis, with a focus on the literature from the last 4 years and recent advances.

Updating the use of the Madrid Sonographic Enthesis Index (MASEI): a systematic review of the literature

OBJECTIVE

To perform a systematic review of the literature to evaluate the use of the enthesis ultrasound Madrid Sonographic Entesis Index (MASEI) from its publication.

METHODS

A systematic search of MEDLINE, EMBASE, and Cochrane Central Register databases was performed. The search strategy was constructed to identify publications containing terms related to enthesis and ultrasound. The only applied filter was studies conducted in humans. One reviewer systematically screened the search. A second reviewer verified the selection. The data extraction was focused on study characteristics, including population and components of the OMERACT filter.

RESULTS

Sixty-eight of the 1581 identified studies had used MASEI, including 41 (60%) abstracts and 27 (40%) articles. Of the 27 articles, MASEI was mainly used for spondyloarthritis and related diseases in 12 (44%) articles, followed by both psoriatic arthritis and rheumatoid arthritis in five (19%) articles; however, it was also used in diseases such as Behçet disease, FM, familiar Mediterranean fever, SS, crystal arthropathies and systemic sclerosis. The feasibility of MASEI was reported in three (11%) articles, and the reliability in 12 (44%) with good to excellent values. No article evaluated the responsiveness to treatment. The construct validity of MASEI was assessed using biomarkers in seven (26%) articles, clinical examination in 13 (48%) and imaging procedures (only X-rays) in two (7%). The discriminative validity was assessed in 16 (59%) articles, not only in SpAs.

CONCLUSION

MASEI is a feasible, reliable and valid ultrasound score for the study of enthesis in spondyloarthritis, psoriatic arthritis and other diseases.

Ultrasound Imaging in Psoriatic Arthritis: What Have We Learnt in the Last Five Years?

Psoriatic arthritis (PsA) is a complex heterogeneous disease with multiple inter-related pathologies such as synovitis, enthesitis, tendinopathy, and dactylitis. Clinical assessment is limited in its detail to assess pathology, thus in recent years, ultrasound (US) has become more popular, given its high sensitivity to detect inflammatory arthritis and ability to inform clinical decisions. Although a qualitative technique, US findings can be graded semi-quantitatively for grayscale (GS) and power Doppler (PD). Synovitis is frequently present in inflammatory arthritis pathologies, and in PsA, recent evidence shows a propensity for tendon and entheseal lesions. The presence of flexor tenosynovitis and flexor tendon insertional enthesopathy at accessory pulleys is supportive of the “Deep Koebner” concept. Peri-tendinous inflammation—mutual to PsA or rheumatoid arthritis (RA), is associated with soft tissue oedema with PD signal frequently at the flexor tendon compartments in PsA. Research on enthesitis in PsA/PsO has improved understanding in subclinical and clinical PsA, explored associations with progression to PsA, and investigated links to prognosis assessment. Dactylitis is a pathognomonic PsA lesion where US has enhanced knowledge of the disease course and pathology of lesions such as: flexor tenosynovitis; synovitis; and soft tissue oedema. Increased US sensitivity has also brought innovation including promising automated ultrasound scanning techniques. So, what have we learnt in recent years and what are the unmet needs to focus future research initiatives in this disabling disease? This narrative review article assesses the neoteric evidence, bringing into context the knowledge gained and highlighting potential areas of research.

Visualization of Enthesitis by Ultrasound: a Key Diagnostic Tool in Spondyloarthropathy Diagnosis and Management

PURPOSE OF REVIEW

The purpose of this review is to report on the current status of evaluation of enthesitis with sonography. Sonography can visualize peripheral entheses in great detail since most of them are superficial. Visualization of entheses has provided insights into the pathophysiology of enthesitis and highlighted the interconnectivity of stress dissipation mechanisms about the enthesis. The primary use of entheseal sonography presently revolves around diagnostic use.

RECENT FINDINGS

There is increasing awareness of biomechanical confounders that lead to entheseal changes, which are more prevalent in males, patients with higher body mass index, and those who are more active-though there are several approaches to mitigate biomechanical confounders in sonographic evaluation. Entheseal sonography may also provide prognostic information in predicting the severity of axial syndesmophyte formation. Although entheseal outcome scoring systems are available, there is sparse data on its use as an outcome tool, and hence, this is a fertile area for future research.

The management of enthesitis in clinical practice

PURPOSE OF REVIEW

Enthesitis is a hallmark feature of the spondyloarthropathies (SpA). This review provides an overview of recent insights on diagnosis and management of enthesitis.

RECENT FINDINGS

Recent studies support the use of imaging for diagnosis because of its higher sensitivity and specificity compared with clinical examination. Several new MRI and ultrasound scoring systems have been developed for enthesitis, which may facilitate the use of imaging in research. Enthesitis has been evaluated as a primary study outcome mainly in psoriatic arthritis (PsA); however, the use of different indices and definitions of improvement limits comparison across studies. There is very limited information about the efficacy of synthetic disease modifying antirheumatic drugs (DMARDs) for the treatment of enthesitis. In contrast, targeted and biologic DMARDs have all shown efficacy in treating enthesitis compared with placebo. There have been only a few head-to-head trials that compared two different cytokine inhibitors for the treatment of enthesitis. Preliminary data suggest that targeting IL-17 or IL12/23 may be more efficacious for controlling enthesitis than TNF inhibition.

SUMMARY

Emerging data suggest interleukin-17 and 12/23 inhibitors may be the first choice in PsA patients with enthesitis. Further head-to-head studies are needed before making definitive recommendations.

Juvenile-Versus Adult-Onset Spondyloarthritis: Similar, but Different

This article provides an overview of juvenile spondyloarthritis and important differences in the classification criteria, clinical presentation, outcomes, and pathology in juvenile versus adult-onset disease. Key differences in classification criteria between children and adults with spondyloarthritis are important to understand, as they can make transition from pediatric to adult care challenging. MRI and ultrasonography are increasingly relied on for the assessment of adult-onset disease activity and change over time in the pediatric population. The unique features of the maturing axial and peripheral skeleton are described for each modality, as they are key to understand for accurate interpretation of pathology in the pediatric population.

Challenges in the clinical diagnosis of psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic heterogeneous inflammatory musculoskeletal disease. The non-specific and often subtle manifestations make early diagnosis and subsequent treatment challenging. In the absence of diagnostic criteria and biomarkers, the diagnosis is often delayed leading to poor long-term outcomes. In addition, the differential diagnosis of a patient presenting with arthritis in the setting of skin psoriasis is wide due to symptom overlap with many other diseases. Peripheral arthritis, dactylitis, enthesitis and axial arthritis are the 4 domains of musculoskeletal involvement in PsA and careful examination of each domain by a rheumatologist is the first step for a correct diagnosis. Other extra-musculoskeletal features such as the presence of uveitis, inflammatory bowel disease, nail psoriasis and elevated acute phase reactants aid in the diagnosis of PsA. Screening patients with skin psoriasis using validated questionnaires might help in early diagnosis especially when coupled with imaging.

Role of the IL-23 pathway in the pathogenesis and treatment of enthesitis in psoriatic arthritis

INTRODUCTION

Enthesitis is a key feature of spondyloarthritis (SpA). Several studies have underlined the role of interleukin (IL)-23 in SpA development as a crucial cytokine in the pathogenesis of enthesitis.

AREA COVERED

This review summarizes recent evidence of the role of IL-23 in the pathogenesis of and as a target of the treatment of enthesitis. We review the definition, diagnosis and clinical impact of enthesitis and its connection with microbial infections, gut dysbiosis, and mechanical stress. We also review clinical trials and real-life studies of drugs targeting the p19 or p40 subunits of IL-23.

EXPERT OPINION

Novel therapies targeting the p19 or p40 subunit of IL-23 appear to be promising treatment options for patients with enthesitis. Although we are currently unable to identify the best therapeutic window to target IL-23 in SpA disease evolution, the promising ability of this therapy to control the gut-entheseal axis is increasing our knowledge of SpA pathogenesis.

Entheseal Changes in Response to Age, Body Mass Index, and Physical Activity: An Ultrasound Study in Healthy People

OBJECTIVE

We aimed to investigate the prevalence of ultrasonographic (US) lesions in healthy entheses and contributing factors.

METHODS

US scans were performed on 960 entheses of 80 healthy subjects. Factors contributing to entheseal changes were investigated with regression analysis.

RESULTS

Thickening (20.4% of the entheses) and enthesophytes (23.1%) were the most common inflammatory and structural damage lesions, respectively. Age (p < 0.001), male sex (p = 0.003), body mass index (BMI; p = 0.001), and high physical activity (p = 0.007) were independent predictors of enthesitis scores on US.

CONCLUSION

The effects of age, sex, BMI, and physical activity on the entheses need to be considered when differentiating disease from health.

The importance of ultrasound in identifying and differentiating patients with early inflammatory arthritis: a narrative review

Early differentiation between different types of inflammatory arthritis and subsequent initiation of modern treatments can improve patient outcomes by reducing disease activity and preventing joint damage. Routine clinical evaluation, laboratory testing, and radiographs are typically sufficient for differentiating between inflammatory and predominantly degenerative arthritis (e.g., osteoarthritis). However, in some patients with inflammatory arthritis, these techniques fail to accurately identify the type of early-stage disease. Further evaluation by ultrasound imaging can delineate the inflammatory arthritis phenotype present. Ultrasound is a noninvasive, cost-effective method that enables the evaluation of several joints at the same time, including functional assessments. Further, ultrasound can visualize pathophysiological changes such as synovitis, tenosynovitis, enthesitis, bone erosions, and crystal deposits at a subclinical level, which makes it an effective technique to identify and differentiate most common types of inflammatory arthritis. Limitations associated with ultrasound imaging should be considered for its use in the differentiation and diagnosis of inflammatory arthritides.

Imaging Techniques: Options for the Diagnosis and Monitoring of Treatment of Enthesitis in Psoriatic Arthritis

Psoriatic arthritis (PsA) affects up to 30% of patients with psoriasis and may include musculoskeletal manifestations such as enthesitis. Enthesitis is associated with joint damage, and early detection and treatment are essential to management of the disease. Traditionally assessed by clinical examination and conventional radiography, entheseal inflammation can now be more accurately assessed earlier in the disease using techniques such as ultrasound, magnetic resonance imaging, computed tomography, and molecular imaging. However, there is little consensus on the optimum definition for diagnosing enthesitis in PsA or on the ideal scoring system for measuring response to treatment. This review aims to summarize the benefits and limitations of different imaging modalities in the assessment of enthesitis. It also proposes that adoption of standardized definitions and validation of scoring systems and imaging techniques in clinical trials will allow the efficacy of new treatment options to be assessed more accurately.

Psoriatic arthritis

Psoriasis is a multisystemic, inflammatory skin condition that can affect many areas of the body, but most commonly the extensor surfaces of the elbows and knees, and sometimes the intergluteal and umbilical area. It has a prevalence of 2–4% in western adults, and 20­–30% of psoriasis patients will develop psoriatic arthritis (PsA). PsA is an inflammatory musculoskeletal disease associated with cutaneous psoriasis. It affects men and women almost equally with a peak age at onset of 40 and 50 years. It is a diverse disease that affects multiple organ systems includes peripheral and axial joints, entheses, skin, and nails. PsA is associated with comorbidities such as osteoporosis, uveitis, subclinical bowel inflammation, and cardiovascular disease. Given this heterogeneity, its diagnosis has been difficult. Here we present an updated review of its classification criteria CASPAR (classification criteria for PsA), use of screening tools to aid in early diagnosis, recent findings on pathogenesis, and new therapeutic approaches including new biologic medications.

Ixekizumab and complete resolution of enthesitis and dactylitis: integrated analysis of two phase 3 randomized trials in psoriatic arthritis

BACKGROUND

Ixekizumab improves signs/symptoms of psoriatic arthritis (PsA). We present an integrated analysis of baseline disease burden and post-baseline outcomes in ixekizumab-treated patients with enthesitis or dactylitis.

METHODS

Data from SPIRIT-P1 and SPIRIT-P2 were integrated. Patients with PsA were randomized to 80-mg ixekizumab every 4 weeks (IXEQ4W) or 2 weeks (IXEQ2W), after a 160-mg starting dose, or to placebo. Inadequate responders at week 16 received rescue therapy. Among patients with baseline enthesitis (Leeds Enthesitis Index [LEI] > 0) or dactylitis (Leeds Dactylitis Index-Basic [LDI-B] > 0), baseline characteristics and disease burden were reported. At week 24, LEI and LDI-B (percentage of patients with resolution [LEI = 0, LDI-B = 0]) were assessed. In pooled treatment groups, the impact of enthesitis or dactylitis resolution on health-related quality of life (HRQoL) (EuroQol-5 Dimensions Visual Analogue Scale [EQ-5D VAS]), physical function (Health Assessment Questionnaire-Disability Index [HAQ-DI]), and pain was assessed.

RESULTS

The integrated analysis set comprised 679 patients; of these, 60% (n = 403 of 675) had baseline enthesitis (LEI > 0) and 23% (n = 155 of 676) had baseline dactylitis (LDI > 0). At week 24, ixekizumab-treated patients experienced significantly more resolution than placebo of enthesitis (39% IXEQ4W, 35% IXEQ2W, 21% placebo) and dactylitis (78% IXEQ4W, 65% IXEQ2W, 24% placebo). Furthermore, at entheseal points measured by the LEI, ixekizumab-treated patients had significantly higher resolution of enthesitis compared to placebo. At week 24, among all placebo- and ixekizumab-treated patients, resolution of enthesitis was associated with improvements in function and HRQoL whereas dactylitis resolution was associated with more limited improvements. The least squares mean HAQ-DI improvements from baseline were - 0.44 and - 0.25 for patients who did/did not resolve enthesitis, and - 0.41 and - 0.31 for patients who did/did not resolve dactylitis. EQ-5D VAS improvements were 12.3 and 5.8 for patients who did/did not resolve enthesitis, and 10.8 and 9.8 for patients who did/did not resolve dactylitis.

CONCLUSIONS

Among patients with pre-existing enthesitis or dactylitis, IXEQ2W- and IXEQ4W-treatment resulted in significant improvements in enthesitis and dactylitis. Enthesitis resolution was associated with improvements in patients' function, pain, and HRQoL.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01695239 , registered on September 25, 2012, and NCT02349295 , registered on October 10, 2014.