The emerging role of ultrasound in detecting interstitial lung disease in patients with rheumatoid arthritis

A Feasible Simplified Pulmonary Ultrasound Scoring System for Evaluating Interstitial Lung Disease

ABSTRACT

Transthoracic lung ultrasound is becoming increasingly important in the diagnosis and treatment of interstitial lung disease. However, no standard examination has been developed for pulmonary ultrasound scanning. The purpose of this study was to evaluate the clinical value of simplified transthoracic pulmonary ultrasound scoring through 6 intercostal spaces for the assessment of interstitial lung disease severity. Two hundred nineteen patients who underwent pulmonary ultrasound at our institution were included. Patients were divided into a non-interstitial lung disease group (57 participants) and an interstitial lung disease group (162 participants). The 6-intercostal space method was used for pulmonary ultrasound examination and scoring. The Warrick score of high-resolution computed tomography and lung function indicators were used as the gold standards to evaluate the consistency of the 3 methods in grading interstitial lung disease severity. When lung function indicators were used as the gold standard, a strong consistency was observed between the 6-rib interstitial lung ultrasound scores and the lung function indicators (κ value = 0.841, 95% CI = 0.740-0.941); a strong consistency was also observed between the high-resolution computed tomography scores and the lung function indicators (κ value = 0.664, 95% CI = 0.525-0.803). When the high-resolution computed tomography score was used as the gold standard, a strong consistency was observed between the 6-rib interstitial lung ultrasound score and the high-resolution computed tomography score (κ value of 0.718 (95% CI = 0.618-0.818). A simplified 6-intercostal space pulmonary ultrasound score can be used to evaluate interstitial lung disease severity and better facilitate clinical treatment.

A Proposal for a New Lung Ultrasound Score in Rheumatoid Arthritis: The Reliability of Lung Ultrasound for Rheumatoid Arthritis-Associated Interstitial Lung Disease Diagnosis

Background/Objectives: The objective of this study is to investigate the intra- and inter-explorer reliability of different lung ultrasound (LUS) scores in patients with suspected rheumatoid arthritis with associated interstitial lung disease (RA-ILD). Methods: Fourteen consecutive patients with suspected RA-ILD based on the presence of respiratory symptoms, lung function tests (LFTs) or imaging alterations were recruited. The screening protocol consisted of an LFT, a chest X-ray, and HRCT. LUS examinations of different B-line and pleural line scores including 14 intercostal spaces were performed by three experienced sonographers, guaranteeing blinding. Intra- and inter-explorer reliability were calculated for all LUS scores and at the intercostal space level by weighted Cohen's kappa and Fleiss' kappa, respectively, relying on absolute differences using Stata/IC 14.2 software® (StataCorp, College Station, TX, USA). Results: Both global (ĸ = 0.73-0.82) and binary (ĸ = 0.80-0.90) scores of B lines showed substantial to excellent intra-explorer reliability, with slightly better results for the binary score. The inter-explorer reliability was equally excellent for the global score (ĸ = 0.93) and the binary score (ĸ = 0.90) of B lines. The intra-explorer reliability of the semiquantitative pleural score was excellent for all the sonographers (ĸ = 0.88-0.91), and the binary pleural score had slightly lower intra-explorer reliability (ĸ = 0.77-0.84). Regarding inter-explorer reliability, both semiquantitative and binary pleural scores were equally excellent (ĸ = 0.84). Good to excellent inter-explorer reliability was found in all the scanned areas. Conclusions: Substantial to excellent intra- and inter-explorer reliability of different feasible B-line and pleural LUS scores were found, adding evidence in favor of the potential implementation of LUS for RA-ILD diagnosis in clinical practice.

Ultrasound Beyond Joints: A Review of Extra-Articular Applications in Rheumatology

PURPOSE OF REVIEW

This review highlights key ultrasound applications for evaluating extra-articular involvement in rheumatic diseases, including the lungs, vessels, salivary glands, muscles, nerves, skin, and nails. It explores recent advances, emerging areas of assessment, and future research directions. Additionally, the review examines current limitations in the routine use of ultrasound for these purposes and considers the potential of new technologies, such as shear-wave elastography, contrast-enhanced ultrasound, and artificial intelligence, to enhance the early detection and monitoring of extra-articular manifestations in rheumatic diseases.

RECENT FINDINGS

Extra-articular manifestations in patients with rheumatic diseases are crucial for diagnosis, management (including treatment strategies), and prognosis, making accurate assessment essential. Growing evidence supports the role of ultrasound in assessing these manifestations for diagnosis, monitoring, and gaining insights into disease pathogenesis. Recent studies emphasize the significant utility of ultrasound in evaluating extra-articular involvement across various organ systems, including the lungs, vessels, salivary glands, muscles, nerves, skin, and nails. Technological advances, such as shear-wave elastography, contrast-enhanced ultrasound, and artificial intelligence, are expanding the scope and precision of ultrasound applications. Despite its potential, challenges such as operator dependency, lack of standardized protocols, and the need for specialized training hinder its widespread adoption. Ultrasound is a non-invasive, cost-effective, and radiation-free imaging modality with high diagnostic accuracy, making it a valuable tool for assessing extra-articular manifestations in rheumatic diseases. Emerging technologies may further enhance its clinical utility. However, efforts to standardize techniques and improve accessibility are necessary to optimize its integration into routine practice.

The global prevalence of interstitial lung disease in patients with rheumatoid arthritis: a systematic review and meta-analysis

This study aims to review the literature and estimate the global pooled prevalence of interstitial lung disease among patients with rheumatoid arthritis (RA-ILD). The influence of risk factors like geography, socioeconomic status, smoking and DMARD use will be explored. A systematic review was performed according to the PRISMA and JBI guidelines. Studies published between January 1980 and February 2024 were sourced from 7 electronic databases and screened for eligibility. A random-effects meta-analysis model was used to produce pooled prevalences and the potential between-study heterogeneity was identified using sensitivity, subgroup, meta-regression and correlation analyses. 33 studies were included in this meta-analysis containing 14,281 RA patients. The global pooled prevalence of RA-ILD was 21.38% (CI: 0.1542-0.2886), with a high heterogeneity (I2) of 98%. The prevalence of usual interstitial pneumonia and non-specific interstitial pneumonia among RA patients were 11.01% and 6.86% respectively. Africa had the highest RA-ILD prevalence with an imprecise estimate of 38.15% (95% Confidence Interval [CI]: 2.29-94.2) and Europe had the lowest prevalence of 10.15% (CI: 2.86-30.23). Other risk factors associated with a higher prevalence of RA-ILD included living in low-income countries, smoking and DMARD use. The biggest limitation of this study is the high heterogeneity of results and underrepresentation of Oceania and low-income countries. This study has clarified the global prevalence of RA-ILD. The risk factors identified in this study can aid clinicians in identifying high-risk populations and highlight the need for screening these populations. Smoking cessation should also be encouraged.

Rheumatoid Arthritis-Associated Interstitial Lung Disease (RA-ILD): Update on Prevalence, Risk Factors, Pathogenesis, and Therapy

PURPOSE OF REVIEW

Rheumatoid arthritis is frequently complicated by interstitial lung disease (RA-ILD), an underappreciated contributor to excess morbidity and mortality. The true prevalence of RA-ILD is difficult to define given the variability in diagnostic criteria used. The lack of standardized screening methods, an incomplete understanding of disease pathogenesis, and dearth of validated biomarkers have limited the development of controlled clinical trials for this disease.

RECENT FINDINGS

Numerous studies have focused on clinical, radiographic, genetic, molecular, and/or serologic markers of disease severity as well as risk of disease progression. In addition to defining valuable clinical biomarkers, these studies have provided insights regarding the pathogenesis of RA-ILD and potential therapeutic targets. Additional studies involving immunomodulatory and/or anti-fibrotic agents have assessed new therapeutic options for different stages of RA-ILD. RA-ILD continues to be a major contributor to the increased morbidity and mortality associated with RA. Advancements in our understanding of disease pathogenesis at a molecular level are necessary to drive the development of more targeted therapy.

Clinical utility of lung ultrasound for the detection of interstitial lung disease in patients with rheumatoid arthritis

OBJECTIVE

To establish the diagnostic value of lung ultrasound (LUS) in patients with rheumatoid arthritis (RA) for the detection of interstitial lung disease (ILD).

METHODS

A cross-sectional study was performed. Consecutive patients with RA (American College of Rheumatology/European League Against Rheumatism 2010 criteria) who had a chest high-resolution computed tomography (HRCT) performed within 12 months before inclusion, regardless of symptomatology, were included. Demographic, clinical, laboratory, and pharmacological data were recorded. Each patient underwent a LUS with assessment of B-lines (BL) and pleural irregularities (PI). HRCT was considered the gold standard for the confirmatory diagnosis of ILD. Receiver operating characteristic (ROC) curves were calculated to test the ability of LUS findings (BL and PI) in discriminating patients with ILD.

RESULTS

A total of 104 RA patients were included, of which 21.8% had ILD. Patients with ILD had more BL (median 26 versus 1, p<0.001) and PI (median 16 versus 5, p<0.001) than patients without ILD. The diagnostic accuracy in ROC curves was as follows: area under the curve (AUC) 0.88 and 95% confidence interval (CI) 0.78-0.93 for BL and AUC 0.82 and 95% CI 0.74-0.89 for PI. The best cut-off points for (ILD detection) discriminating the presence of significant interstitial lung abnormalities were 8 BL and 7 PI.

CONCLUSIONS

The presence of 8 BL and/or 7 PI in the LUS showed an adequate cut-off value for discriminating the presence of significant interstitial lung abnormalities, evocative of ILD.

Detection of Interstitial Lung Disease in Rheumatoid Arthritis by Thoracic Ultrasound: A Diagnostic Test Accuracy Study

OBJECTIVE

To determine the diagnostic accuracy of thoracic ultrasound (TUS) for detecting interstitial lung disease (ILD) in rheumatoid arthritis (RA) with respiratory symptoms.

METHODS

Individuals with RA visiting rheumatologic outpatient clinics in the Region of Southern Denmark were systematically screened for dyspnea, cough, recurrent pneumonia, prior severe pneumonia, or a chest x-ray indicating interstitial abnormalities. Eighty participants with a positive screening were consecutively included. Individuals were not eligible if they had a chest high-resolution computed tomography (HRCT) less than 12 months ago or were already diagnosed with ILD. A blinded TUS expert evaluated TUS, and TUS was registered as positive for ILD if at least 10 B-lines or bilateral thickened and fragmented pleura were present. The primary outcomes were TUS's sensitivity, specificity, and positive predictive value and negative predictive value. An ILD-specialized thoracic radiologist assessed HRCT, followed by a multidisciplinary team discussion, which was the reference standard. The accepted window of HRCT was less than 30 days after TUS was performed.

RESULTS

A total of 77 participants received HRCT less than 30 days after TUS, and 23 (30%) were diagnosed with ILD. TUS had a sensitivity of 82.6% (95% confidence interval [CI] 61.2%-95.0%) and a specificity of 51.9% (95% CI 37.8%-65.7%), corresponding to a positive predictive value of 42.2% (95% CI 27.7%-57.8%) and a negative predictive value of 87.5% (95% CI 71.0%-96.5%).

CONCLUSION

To our knowledge, this prospective study is the first to use respiratory symptoms in RA as inclusion criteria. Systematic screening for respiratory symptoms combined with TUS can reduce the diagnostic delay of ILD in RA.

The Burden of Interstitial Lung Involvement in Rheumatoid Arthritis: Could Lung Ultrasound Have a Role in Its Detection? A Literature Review

Lung involvement represents a fearful complication in rheumatoid arthritis (RA), potentially involving all compartments of the pulmonary system. Regarding interstitial lung disease (ILD), the HRCT represents the gold standard technique for its diagnosis; however, the examination is burdened by radiation exposure and high costs. In addition, although some risk factors for ILD are known, no algorithms exist to know which patients to submit to HRCT and when. In this context, lung ultrasound (LUS) showed promising results for at least 10 years, demonstrating correlation with high resolution computed tomography (HRCT) findings in other rheumatic diseases. Here, LUS may represent a screening test providing additional information to clinical examination and pulmonary function tests. The data deriving from LUS experience in other rheumatic diseases could steer the future towards the use of this technique also in RA patients, and in this review, we report the most relevant literature regarding LUS in RA-ILD.

Lung Ultrasonography in the Evaluation of Late Sequelae of COVID-19 Pneumonia-A Comparison with Chest Computed Tomography: A Prospective Study

The onset of the COVID-19 pandemic allowed physicians to gain experience in lung ultrasound (LUS) during the acute phase of the disease. However, limited data are available on LUS findings during the recovery phase. The aim of this study was to evaluate the utility of LUS to assess lung involvement in patients with post-COVID-19 syndrome. This study prospectively enrolled 72 patients who underwent paired LUS and chest CT scans (112 pairs including follow-up). The most frequent CT findings were ground glass opacities (83.3%), subpleural lines (72.2%), traction bronchiectasis (37.5%), and consolidations (31.9%). LUS revealed irregular pleural lines as a common abnormality initially (56.9%), along with subpleural consolidation >2.5 mm ≤10 mm (26.5%) and B-lines (26.5%). A strong correlation was found between LUS score, calculated by artificial intelligence percentage involvement in ground glass opacities described in CT (r = 0.702, p < 0.05). LUS score was significantly higher in the group with fibrotic changes compared to the non-fibrotic group with a mean value of 19.4 ± 5.7 to 11 ± 6.6, respectively (p < 0.0001). LUS might be considered valuable for examining patients with persistent symptoms after recovering from COVID-19 pneumonia. Abnormalities identified through LUS align with CT scan findings; thus, LUS might potentially reduce the need for frequent chest CT examinations.

Practical guidance for the early recognition and follow-up of patients with connective tissue disease-related interstitial lung disease

BACKGROUND

The early detection and management of (progressive) interstitial lung disease in patients with connective tissue diseases requires the attention and skills of a multidisciplinary team. However, there are currently no well-established standards to guide the daily practice of physicians treating this heterogenous group of diseases.

RESEARCH QUESTION

This paper aimed to identify gaps in scientific knowledge along the journey of patients with connective tissue disease-related interstitial lung disease and to provide tools for earlier identification of interstitial lung disease and progressive disease.

STUDY DESIGN AND METHODS

The opinions of an international expert panel, which consisted of pulmonologists and rheumatologists were collected and interpreted in the light of peer-reviewed data.

RESULTS

Interstitial lung disease is a common complication of connective tissue diseases, but prevalence estimates vary by subtype. Screening and monitoring by means of clinical examination, chest radiography, pulmonary function testing, and disease-specific biomarkers provide insight into the disease activity of patients presenting with connective tissue diseases in a routine setting. Multiple phenotypic and genotypic characteristics have been identified as predictors of the development and progression of interstitial lung disease. However, these risk factors differ between subtypes. To ensure earlier diagnosis of rapidly progressive phenotypes, a risk-based method is necessary for determining the need for HRCT and additional testing.

INTERPRETATION

To reduce the underdiagnosis of CTD-ILDs in clinical practice, a standardized and systematic multidisciplinary risk-based approach is suggested. Collaboration across disciplines is essential for the management of CTD-ILD.

Design of ANCHOR-RA: a multi-national cross-sectional study on screening for interstitial lung disease in patients with rheumatoid arthritis

BACKGROUND

Patients with rheumatoid arthritis (RA) are at risk of developing interstitial lung disease (ILD), which is associated with high mortality. Screening tools based on risk factors are needed to decide which patients with RA should be screened for ILD using high-resolution computed tomography (HRCT). The ANCHOR-RA study is a multi-national cross-sectional study that will develop a multivariable model for prediction of RA-ILD, which can be used to inform screening for RA-ILD in clinical practice.

METHODS

Investigators will enrol consecutive patients with RA who have ≥ 2 of the following risk factors for RA-ILD: male; current or previous smoker; age ≥ 60 years at RA diagnosis; high-positive rheumatoid factor and/or anti-cyclic citrullinated peptide (titre > 3 x upper limit of normal); presence or history of certain extra-articular manifestations of RA (vasculitis, Felty's syndrome, secondary Sjögren's syndrome, cutaneous rheumatoid nodules, serositis, and/or scleritis/uveitis); high RA disease activity in the prior 12 months. Patients previously identified as having ILD, or who have had a CT scan in the prior 2 years, will not be eligible. Participants will undergo an HRCT scan at their local site, which will be assessed centrally by two expert radiologists. Data will be collected prospectively on demographic and RA-related characteristics, patient-reported outcomes, comorbidities and pulmonary function. The primary outcomes will be the development of a probability score for RA-ILD, based on a multivariable model incorporating potential risk factors commonly assessed in clinical practice, and an estimate of the prevalence of RA-ILD in the study population. It is planned that 1200 participants will be enrolled at approximately 30 sites in the USA, UK, Germany, France, Italy, Spain.

DISCUSSION

Data from the ANCHOR-RA study will add to the body of evidence to support recommendations for screening for RA-ILD to improve detection of this important complication of RA and enable early intervention.

TRIAL REGISTRATION

clinicaltrials.gov NCT05855109 (submission date: 3 May 2023).

Standardization of interstitial lung disease assessment by ultrasound: results from a Delphi process and web-reliability exercise by the OMERACT ultrasound working group

OBJECTIVES

Over the last years ultrasound has shown to be an important tool for evaluating lung involvement, including interstitial lung disease (ILD) a potentially severe systemic involvement in many rheumatic and musculoskeletal diseases (RMD). Despite the potential sensitivity of the technique the actual use is hampered by the lack of consensual definitions of elementary lesions to be assessed and of the scanning protocol to apply. Within the Outcome Measures in Rheumatology (OMERACT) Ultrasound Working Group we aimed at developing consensus-based definitions for ultrasound detected ILD findings in RMDs and assessing their reliability in dynamic images.

METHODS

Based on the results from a systematic literature review, several findings were identified for defining the presence of ILD by ultrasound (i.e., Am-lines, B-lines, pleural cysts and pleural line irregularity). Therefore, a Delphi survey was conducted among 23 experts in sonography to agree on which findings should be included and on their definitions. Subsequently, a web-reliability exercise was performed to test the reliability of the agreed definitions on video-clips, by using kappa statistics.

RESULTS

After three rounds of Delphi an agreement >75 % was obtained to include and define B-lines and pleural line irregularity as elementary lesions to assess. The reliability in the web-based exercise, consisting of 80 video-clips (30 for pleural line irregularity, 50 for B-lines), showed moderate inter-reader reliability for both B-lines (kappa = 0.51) and pleural line irregularity (kappa = 0.58), while intra-reader reliability was good for both B-lines (kappa = 0.72) and pleural line irregularity (kappa = 0.75).

CONCLUSION

Consensus-based ultrasound definitions for B-lines and pleural line irregularity were obtained, with moderate to good reliability to detect these lesions using video-clips. The next step will be testing the reliability in patients with ILD linked to RMDs and to propose a consensual and standardized protocol to scan such patients.

Identification, Monitoring, and Management of Rheumatoid Arthritis-Associated Interstitial Lung Disease

Interstitial lung disease (ILD) is a frequent complication of rheumatoid arthritis (RA) that is associated with a significant increase in mortality. Several risk factors for the development of ILD in patients with RA have been identified, but ILD can still develop in the absence of these risk factors. Screening tools for RA-ILD are required to facilitate early detection of RA-ILD. Close monitoring of patients with RA-ILD for progression is crucial to enable timely implementation of treatment strategies to improve outcomes. Patients with RA are commonly treated with immunomodulatory therapies, although their efficacy in slowing the progression of RA-ILD remains the subject of debate. Clinical trials have shown that antifibrotic therapies slow decline in lung function in patients with progressive fibrosing ILDs, including patients with RA-ILD. The management of patients with RA-ILD should be based on multidisciplinary evaluation of the severity and progression of their ILD and the activity of their articular disease. Close collaboration between rheumatologists and pulmonologists is essential to optimize patient care.

Unmet needs and perspectives in rheumatoid arthritis-associated interstitial lung disease: A critical review

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovitis as the most common clinical manifestation, and interstitial lung disease (RA-ILD) represents one of the most common and potentially severe extra-articular features. Our current understanding of the mechanisms and predictors of RA-ILD is limited despite the demonstration that an early identification of progressive fibrosing forms is crucial to provide timely treatment with antifibrotic therapies. While high resolution computed tomography is the gold standard technique for the diagnosis and follow-up of RA-ILD, it has been hypothesized that serum biomarkers (including novel and rare autoantibodies), new imaging techniques such as ultrasound of the lung, or the application of innovative radiologic algorithms may help towards predicting and detecting early forms of diseases. Further, while new treatments are becoming available for idiopathic and connective tissue disease-associated forms of lung fibrosis, the treatment of RA-ILD remains anecdotal and largely unexplored. We are convinced that a better understanding of the mechanisms connecting RA with ILD in a subgroup of patients as well as the creation of adequate diagnostic pathways will be mandatory steps for a more effective management of this clinically challenging entity.