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

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.

Sonographic assessment of Achilles tendon in patients with cutaneous psoriasis

Background

Psoriasis is a common, chronic, immune-‌‌‌‌‌‌mediated inflammatory disease with a variety of skin manifestations. The aim of this study was to determine the prevalence of subclinical Achilles tendon disorder in cutaneous psoriasis patients and compare it with healthy controls.

Methods

This was a cross-sectional case-control study conducted on psoriasis patients that were referred to dermatology clinic. Thirty patients in the case group and 30 healthy controls were included in the study. Thickness of Achilles tendon enthesis was scanned by an expert rheumatologist using ultrasound equipped with a 5-14 MHz linear prob bilaterally.

Results

The mean age of the patient and control groups was 43.97±16.82 years and 38.87±12.71 years, respectively (P=0.190). The mean thickness of the Achilles tendon enthesis in the dominant limb was 4.31±0.86 mm in the patient group and 4.10±0.54 mm in the control group. There was no significant difference between the two groups in terms of thickness of the Achilles tendon enthesis in the dominant limb (P=0.276). The mean thickness of the Achilles tendon enthesis in the non-dominant limb was 4.44±0.91 mm in the patient group and 4.14±0.59 mm in the control group. There was no significant difference between the two groups in terms of thickness of Achilles tendon enthesis in the non-dominant limb (P = 0.134).

Conclusion

Although ultrasonography may be utilized for assessment of both structural and inflammatory changes, we revealed no difference in the mean thickness of Achilles tendon enthesis in patients with cutaneous psoriasis. Contradiction between clinical and ultrasonography features required further research.

The role of ultrasound in screening subclinical psoriatic arthritis in patients with moderate to severe psoriasis

OBJECTIVE

To identify patients in the subclinical psoriatic arthritis (Sub-PsA) phase by ultrasound (US) and provide a solution to screen them.

METHODS

A total of 490 participants with moderate-to-severe psoriasis were evaluated. Among them, 384 participants without arthritis symptoms were enrolled into the silent psoriasis group and 106 participants with arthritis symptoms, called prodromal/active PsA phase, were enrolled into the clinical PsA group. Another 80 non-psoriasis participants were enrolled into the control group. Each participant received clinical assessments and US examinations of 60 joints, 38 tendons, and 40 entheses. We compared the incidences of synovio-enthesitis, synovitis, tenosynovitis, erosion, and dactylitis detected on US among the three groups. Subsequently, on the basis of significant US findings, we distinguished Sub-PsA from psoriasis alone (PsO) in the silent psoriasis group and analyzed the clinical characteristics, mainly including basic clinical characteristics, body surface area (BSA), and Psoriasis Area and Severity Index (PASI) score.

RESULTS

Only synovio-enthesitis significantly differed between the control group and the silent psoriasis group (1.3% vs. 16.1%, p < 0.001). The knee was the most commonly involved site of synovio-enthesitis (79.0%). Taking synovio-enthesitis as the standard, 16.1% of silent psoriasis participants and 12.7% of all psoriasis participants were in the Sub-PsA phase. Furthermore, there were no differences in BSA and PASI among the three phases of PsO, Sub-PsA, and prodromal/active PsA.

CONCLUSIONS

Since the psoriasis patients in Sub-PsA phase was as high as 12.7% in all patients with moderate-to-severe psoriasis, US-detected synovio-enthesitis was recommended routinely for screening them regardless of arthritis symptoms, especially in the lower limbs.

KEY POINTS

• Synovio-enthesitis on ultrasound was significantly associated with subclinical psoriatic arthritis, especially in the lower limbs. • Routine ultrasound evaluation could help screen psoriasis patients in the subclinical psoriatic arthritis phase, which was as high as 12.7% in all psoriasis patients.

An overview of psoriatic arthritis including clinical manifestations, assessment, diagnostic criteria, investigations, drug management and GRAPPA guidelines

Psoriatic arthritis (PsA) is a chronic and often progressive inflammatory disease, occurring in up to 30% of patients with psoriasis. Assessment of patients with PsA requires consideration of all disease domains, including peripheral arthritis, axial disease, enthesitis, dactylitis, skin psoriasis, psoriatic nail disease, uveitis and inflammatory bowel disease. Co-morbidities and related conditions should all be considered including: obesity, metabolic syndrome, cardiovascular disease, anxiety/depression, liver disease, chronic infections, malignancy, osteoporosis, fibromyalgia and reproductive health.

The role of trauma and isomorphic reaction in the pathogenesis of psoriatic arthritis

The role of biomechanical stress and trauma in the initiation of inflammation of the joints and periarticular structures in psoriatic arthritis (PA) is currently not fully understood. Soft tissues and joints are the target for constant biomechanical stress and microtrauma, leading to inflammation. There is an opinion that this inflammation in PA is due to an analogue of the skin isomorphic reaction that develops in the skin of psoriatic patients in response to trauma. Some authors have called this reaction the deep Koebner phenomenon. It is assumed that the early, preclinical phase of psoriatic arthritis may be based on inflammation of the enthesis as a response to microtrauma, and explained by the proximity of the entheses and the articular membranes. Detection of early changes in entheses in psoriatic patients, including those who do not have complaints from the musculoskeletal system, is of great importance for the early diagnosis of psoriatic arthritis. In the literature review, the sources for the period 20102021 were studied, devoted to the role of the isomorphic reaction and microtraumatization in the pathogenesis of PA, as well as the role of various imaging methods for the early diagnosis of enthesitis in psoriatic patients.

Psoriatic arthritis: Ultrasound peculiarities with particular emphasis on enthesitis

The prevalence of psoriatic arthritis among patients with psoriasis has a marked variability with ethnic and geographic variations. Inflammatory changes associated with psoriatic arthritis include bone erosion, tenosynovitis, and synovial hypertrophy, but enthesitis is considered the hallmark. Both X-ray and magnetic resonance imaging (MRI) are usefull in the diagnosis of psoriatic arthritis, but ultrasonography is the best imaging modality to assess entheses. Ultrasound findings of enthesitis include a loss of the regular fibrillar architecture, hypoechoic thickening, hypervascularization of tendons, ligaments, and joint capsules at their bony attachment, bony changes (including irregularities and erosions). Ultrasound has also proved the ability to detect inflammatory subclinical findings and to be useful in the follow-up of therapies.

Pachydermodactyly: the role of ultrasonography, superb microvascular imaging, and elastography in diagnosis

Pachydermodactyly is a rare and benign superficial fibromatosis characterized by painless and progressive swelling of periarticular soft tissues of the proximal interphalangeal (PIP) joints, most commonly of both hands. There is no tenderness, warmth, morning stiffness, or reduced range of motion associated. Our purpose is to highlight the diagnostic utility of ultrasonography, superb microvascular imaging (SMI), and elastography in pachydermodactyly. We report the case of a 15-year-old adolescent white boy, with a 6-month history of insidious and progressive, asymptomatic swelling of the lateral and dorsal regions of the metacarpophalangeal (MCP), and PIP joints of both hands. Articular ultrasonography showed thickening of the skin around the lateral regions of the PIP and MCP joints, with no synovitis, hydrarthrosis, or muscle, tendon, or bone changes. Strain elastography revealed lower elasticity in the aforementioned skin regions, corresponding to increased tissue hardness due to hyperkeratosis. No SMI or Doppler signals were detected in epidermal or dermal tissues, as well as in tendons, joints, and bone. This case report shows that ultrasonography, SMI, and elastography may play a significant role in the accurate diagnosis of pachydermodactyly and exclusion of alternative conditions. These imaging modalities have no ionizing radiation; they are fast, inexpensive, and performed on site. They do not require usage of contrast agents and thus can eliminate the need of invasive procedures such as skin biopsy. They also contribute to reduce health care costs with unnecessary complementary tests and inappropriate treatment.

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.

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.

Development of a Predictive Model for Screening Patients with Psoriasis at Increased Risk of Psoriatic Arthritis

Introduction

This study aimed to develop a predictive model based on ultrasound variables which can be used to screen patients with psoriasis who are prone to progress to psoriatic arthritis (PsA) in clinical practice.

Methods

This is a cross-sectional study conducted in a single center from October 2018 to November 2020. All subjects (non-PsA group, PsA group, and control group) underwent an ultrasound examination and their ultrasound abnormalities were recorded. On the basis of statistical analysis and clinical experts’ advice, several variables were selected for modelling. We used logistic regression to establish the prediction model. To assess the discrimination and accuracy of this model, internal validation and external validation were performed.

Results

A total of 852 patients with psoriasis but without PsA, 261 patients with PsA, and 86 healthy volunteers were included. Ultimately, the predictive model consisted of six variables, namely hand joint power Doppler (PD) signals (grade 0: OR 2.94, 95% CI 1.94–4.47; grade ≥ 1: OR 109.30, 95% CI 14.35–832.27; P < 0.001), wrist joint synovial thickening (grade 1: OR 1.29, 95% CI 0.69–2.43; grade 2: OR 4.30, 95% CI 1.92–9.65; grade 3: OR 11.05, 95% CI 1.01–120.64; P = 0.001), knee joint PD signals (grade 0: OR 1.01, 95% CI 0.56–1.80; grade ≥ 1: OR 14.77, 95% CI 3.99–54.69; P < 0.001), toe joint PD signals (grade 0: OR 1.18, 95% CI 0.78–1.79; grade ≥ 1: OR 5.74, 95% CI 2.84–11.63; P < 0.001), quadriceps tendon and patellar tendon enthesitis (OR 1.95, 95% CI 1.36–2.78, P < 0.001), Achilles tendon and plantar aponeurosis enthesitis (OR 1.63, 95% CI 1.14–2.32, P = 0.007). C-index for the predictive model was 0.80 (95% CI 0.76–0.83). After bootstrapping validation (1000 times), it was confirmed to be 0.79. The external validation showed the accuracy of the predictive model is 0.87 (95% CI 0.69–0.95).

Conclusion

This study succeeded in developing a predictive model with a high degree of accuracy to predict the risk of PsA in patients with psoriasis.

Psoriatic arthritis often occurs in the population of patients with psoriasis. It brings a huge burden and pain to patients. At present, the diagnosis for psoriatic arthritis is very challenging. Numerous research studies have begun to focus on identifying patients with psoriasis at increased risk of psoriatic arthritis. Among a lot of modalities, ultrasound has been considered as a sensitive and convenient tool for screening early psoriatic arthritis. Our study successfully established a predictive model based on ultrasound variables to screen patients with psoriasis at high risk of transiting to psoriatic arthritis. After internal and external validation, it showed great accuracy and generalizability. We recommend that clinicians perform ultrasound screening of patients with psoriasis in clinical routine and get their risk value of transiting to psoriatic arthritis by using this model. For those patients with a high risk of progression to psoriatic arthritis, clinicians should refer them to a rheumatology department as soon as possible so that they could have access to early and effective management which might bring them good clinical and imaging outcomes.

Ultrasound features of Achilles enthesitis in psoriatic arthritis: a systematic review

Objectives

The objectives were to evaluate the methodological and reporting quality of ultrasound (US) studies of Achilles enthesitis in people with psoriatic arthritis (PsA), to identify the definitions and scoring systems adopted and to estimate the prevalence of ultrasound features of Achilles enthesitis in this population.

Methods

A systematic literature review was conducted using the AMED, CINAHL, MEDLINE, ProQuest and Web of Science databases. Eligible studies had to measure US features of Achilles enthesitis in people with PsA. Methodological quality was assessed using a modified Downs and Black Quality Index tool. US protocol reporting was assessed using a checklist informed by the European League Against Rheumatism (EULAR) recommendations for the reporting of US studies in rheumatic and musculoskeletal diseases.

Results

Fifteen studies were included. One study was scored as high methodological quality, 9 as moderate and 5 as low. Significant heterogeneity was observed in the prevalence, descriptions, scoring of features and quality of US protocol reporting. Prevalence estimates (% of entheses) reported included hypoechogenicity [mean 5.9% (s.d. 0.9)], increased thickness [mean 22.1% (s.d. 12.2)], erosions [mean 3.3% (s.d. 2.5)], calcifications [mean 42.6% (s.d. 15.6)], enthesophytes [mean 41.3% (s.d. 15.6)] and Doppler signal [mean 11.8% (s.d. 10.1)].

Conclusions

The review highlighted significant variations in prevalence figures that could potentially be explained by the range of definitions and scoring criteria available, but also due to the inconsistent reporting of US protocols. Uptake of the EULAR recommendations and using the latest definitions and validated scoring criteria would allow for a better understanding of the frequency and severity of individual features of pathology.

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.

Hand Erosive Osteoarthritis and Distal Interphalangeal Involvement in Psoriatic Arthritis: The Place of Conservative Therapy

Hand erosive osteoarthritis (HEOA) and Psoriatic Arthritis (PsA) with DIP involvement are common diseases affecting the hand. Both of them evolve with a progressive limitation in grip due to limited range of motion of the affected joints and stenosing tenosynovitis. Pharmacological options currently available (corticosteroids and clodronate or Idrossicloroquine) for the treatment of EHOA are mostly symptomatic and currently there are no effective drugs able to modify the course of the disease. In addition, data on drug effectiveness of PsA with DIP involvement are lacking. Conservative therapy should be considered in order to reduce pain and improve hand functionality. There are many studies debating a wide range of non-pharmacological intervention in the management of HEOA: joint protection program, range of motion and strengthening exercise, hand exercise with electromagnetic therapy, application of heat with paraffin wax or balneotherapy, occupational therapy and education. Concerning conservative treatment strategies to treat PsA, on the contrary, current evidence is still weak. Further research is needed to find the correct place of physical therapy to prevent stiffness and ankylosis due to the vicious circle of inflammation-pain-immobility-rigidity.

Ultrasound-Verified Peripheral Arthritis in Patients with HLA-B*35 Positive Spondyloarthritis

Background: We aimed to investigate possible association between the HLA-B*35 allele and peripheral arthritis, tenosynovitis and enthesitis. Methods: Ultrasound of peripheral joints and tendons was performed in 72 HLA-B*35 positive patients with preliminary diagnosis of undifferentiated axial form of spondyloarthitis and joint and tendon pain. Patients with other known types of axial and peripheral spondyloarthritis were excluded as well as patients with other known types of arthritis. Results: Pathological changes were found in the joints of 33 (46%) patients and on the tendons in 13 (18%) patients. The most common ultrasound findings were joint effusion and synovial proliferation with positive power Doppler signal grade 1. The most common ultrasound finding in patients with painful tendons was tenosynovitis. A higher disease activity and an increased incidence of elevated CRP (≥5 mg/L) were more often observed in the group with positive ultrasound findings. Conclusion: In this study, we showed that the HLA-B*35 allele could be a potential risk factor for developing peripheral arthritis, but not for tenosynovits and enthesitis in patients with the undifferentiated axial form of spondyloarthritis. This result may influence the follow up of these patients, especially since it gives us an opportunity to consider the use of different types of DMARDs in the treatment of these patients.

Effects of TNF-α inhibition on pre-clinical enthesitis: observational study on 49 psoriatic patients

BACKGROUND

Enthesitis is a hallmark of psoriatic arthritis (PsA) and echographic ultrasounds (US) represent a support for diagnosis of pre-clinical signs of enthesitis in asymptomatic patients at high risk for advanced forms. Early treatment with anti-TNFα could prevent permanent damage contrasting the degenerative course of the disease.

OBJECTIVES

To evaluate the effects of adalimumab on echographic and preclinical enthesitis signs in patients affected by plaque psoriasis.

METHODS

49 psoriatic patients undergoing adalimumab treatment for plaque-type psoriasis were subjected to echographic screening for identifying pre-clinical signs of enthesitis. Patients underwent clinical and ultrasonographic examination of hands, elbows and knees before starting adalimumab and after 24 and 48 weeks of treatment.

RESULTS

We observed a reduction of the total number of echographic abnormalities and a significant decrease of the thickness of quadriceps tendons at week 24 and week 48. Furthermore, there was no evidence of significant articular damage progression during the entire study duration.

CONCLUSIONS

Entheseal ultrasonography may be used for preclinical diagnosis of PsA.Our study demonstrates that early detection and management with adalimumab leads to a block of articular damage progression. On quadriceps tendon, adalimumab has shown to be effective with a significant thickening reduction at week 24 and 48.