Ultrasound as a potential tool for the assessment of interstitial lung disease in rheumatic patients. Where are we now?

Establishment of seven lung ultrasound phenotypes: a retrospective observational study of an LUS registry

BACKGROUND

Lung phenotypes have been extensively utilized to assess lung injury and guide precise treatment. However, current phenotypic evaluation methods rely on CT scans and other techniques. Although lung ultrasound (LUS) is widely employed in critically ill patients, there is a lack of comprehensive and systematic identification of LUS phenotypes based on clinical data and assessment of their clinical value.

METHODS

Our study was based on a retrospective database. A total of 821 patients were included from September 2019 to October 2020. 1902 LUS examinations were performed in this period. Using a dataset of 55 LUS examinations focused on lung injuries, a group of experts developed an algorithm for classifying LUS phenotypes based on clinical practice, expert experience, and lecture review. This algorithm underwent validation and refinement with an additional 140 LUS images, leading to five iterative revisions and the generation of 1902 distinct LUS phenotypes. Subsequently, a validated machine learning algorithm was applied to these phenotypes. To assess the algorithm's effectiveness, experts manually verified 30% of the phenotypes, confirming its efficacy. Using K-means cluster analysis and expert image selection from the 1902 LUS examinations, we established seven distinct LUS phenotypes. To further explore the diagnostic value of these phenotypes for clinical diagnosis, we investigated their auxiliary diagnostic capabilities.

RESULTS

A total of 1902 LUS phenotypes were tested by randomly selecting 30% to verify the phenotypic accuracy. With the 1902 LUS phenotypes, seven lung ultrasound phenotypes were established through statistical K-means cluster analysis and expert screening. The acute respiratory distress syndrome (ARDS) exhibited gravity-dependent phenotypes, while the cardiogenic pulmonary edema exhibited nongravity phenotypes. The baseline characteristics of the 821 patients included age (66.14 ± 11.76), sex (560/321), heart rate (96.99 ± 23.75), mean arterial pressure (86.5 ± 13.57), Acute Physiology and Chronic Health Evaluation II (APACHE II)score (20.49 ± 8.60), and duration of ICU stay (24.50 ± 26.22); among the 821 patients, 78.8% were cured. In severe pneumonia patients, the gravity-dependent phenotype accounted for 42% of the cases, whereas the nongravity-dependent phenotype constituted 58%. These findings highlight the value of applying different LUS phenotypes in various diagnoses.

CONCLUSIONS

Seven sets of LUS phenotypes were established through machine learning analysis of retrospective data; these phenotypes could represent the typical characteristics of patients with different types of critical illness.

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: 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.

Breast ultrasound: An opportunity to detect unsuspected pleural and pulmonary abnormalities

PURPOSE

While scanning women for breast US, is possible to observe changes in the appearance of the pleural line or in the most superficial portion of the lung. The objective of this single-center, prospective study was to determine the prevalence of a variety of pleural and pulmonary US findings during routine breast US.

METHODS

In this study, there were 200 women undergoing standard breast US examination. The presence of pleural and pulmonary abnormalities in these cases was recorded. Two off-site reviewers confirmed the presence of pleura and lung changes.

RESULTS

There was no abnormal finding in 168 out of 200 cases (84%) while there were one or more abnormal findings in 32 cases (16%). Pleural effusion was observed in 0.5% of cases, thickening of the pleural line 5% of cases, irregularity of the pleural line in 6% of cases, increased number of vertical artifacts in 9% of cases, subpleural nodulations in 2% of cases, and lung consolidation in 0.5%.

CONCLUSION

Pleural and lung changes are not uncommon during breast US. Operators performing breast US examinations should be aware of the possibility to identify unsuspected pleuro-pulmonary abnormalities.

Primary-Sjögren's-Syndrome-Related Interstitial Lung Disease: A Clinical Review Discussing Current Controversies

Lung involvement, especially interstitial lung disease, is a potentially severe extra-glandular manifestation of Primary Sjogren's Syndrome (pSS-ILD). ILD can manifest either as a late complication of pSS or anticipate sicca symptoms, likely reflecting two different patho-physiological entities. Presence of lung involvement in pSS subjects can remain subclinical for a long time; therefore, patients should be actively screened, and lung ultrasound is currently being investigated as a potential low cost, radiation-free, easily repeatable screening tool for detection of ILD. In contrast, rheumatologic evaluation, serology testing, and minor salivary gland biopsy are crucial for the recognition of pSS in apparently idiopathic ILD patients. Whether the HRCT pattern influences prognosis and treatment response in pSS-ILD is not clear; a UIP pattern associated with a worse prognosis in some studies, but not in others. Many aspects of pSS-ILD, including its actual prevalence, association with specific clinical-serological characteristics, and prognosis, are still debated by the current literature, likely due to poor phenotypic stratification of patients in clinical studies. In the present review, we critically discuss these and other clinically relevant "hot topics" in pSS-ILD. More specifically, after a focused discussion, we compiled a list of questions regarding pSS-ILD that, in our opinion, are not easily answered by the available literature. We subsequently tried to formulate adequate answers on the basis of an extensive literature search and our clinical experience. At the same, we highlighted different issues that require further investigation.

Novel diagnostic techniques in interstitial lung disease

Research into novel diagnostic techniques and targeted therapeutics in interstitial lung disease (ILD) is moving the field toward increased precision and improved patient outcomes. An array of molecular techniques, machine learning approaches and other innovative methods including electronic nose technology and endobronchial optical coherence tomography are promising tools with potential to increase diagnostic accuracy. This review provides a comprehensive overview of the current evidence regarding evolving diagnostic methods in ILD and to consider their future role in routine clinical care.

ThOracic Ultrasound in Idiopathic Pulmonary Fibrosis Evolution (TOUPIE): research protocol of a multicentric prospective study

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is the most common and severe interstitial lung disease (ILD). It is a progressive disease that requires a regular follow-up: clinical examination, pulmonary function testing (PFT) and CT scan, which is performed yearly in France. These exams have two major disadvantages: patients with severe dyspnoea have difficulties to perform PFT and repeated CT scans expose to high dose of radiations. Considering these limits, it would be relevant to develop new tools to monitor the progression of IPF lesions. Three main signs have been described in ILD with lung ultrasound (LUS): the number of B lines, the irregularity and the thickening of the pleural line. Cross-sectional studies already correlated the intensity of these signs with the severity of fibrosis lesions on CT scan in patients with IPF, but no prospective study described the evolution of the three main LUS signs, nor the correlation between clinical evaluation, PFT and CT scan. Our hypothesis is that LUS is a relevant tool to highlight the evolution of pulmonary lesions in IPF. The main objective of our study is to show an increase in one or more of the three main LUS signs (total number of B lines, pleural line irregularity score and pleural line thickness) during the follow-up.

METHODS

ThOracic Ultrasound in Idiopathic Pulmonary Fibrosis Evolution is a French prospective, multicentric and non-interventional study. Every 3 months, patients with IPF will have a clinical examination, PFT and LUS. CT data will be collected if the CT scan is performed within 3 months before the inclusion; the second CT scan will be performed from 9 to 12 months after the inclusion. The presence, location and severity of LUS signs will be recorded for each patient, and their correlation with clinical, functional and CT scan evolution will be evaluated. 30 patients will be enrolled.

ETHICS AND DISSEMINATION

The protocol was approved by the French Research Ethics Committee (Comité de Protection des Personnes SUD OUEST ET OUTRE MER II, reference RIPH3-RNI19-TOUPIE) on 11 April 2019. Results will be disseminated via peer-reviewed publication and presentation at international conferences.

TRIAL REGISTRATION NUMBER

NCT03944928;Pre-results.

Comparison of admission chest computed tomography and lung ultrasound performance for diagnosis of COVID-19 pneumonia in populations with different disease prevalence

PURPOSE

Chest computed tomography (CT) is considered a reliable imaging tool for COVID-19 pneumonia diagnosis, while lung ultrasound (LUS) has emerged as a potential alternative to characterize lung involvement. The aim of the study was to compare diagnostic performance of admission chest CT and LUS for the diagnosis of COVID-19.

METHODS

We included patients admitted to emergency department between February 21-March 6, 2020 (high prevalence group, HP) and between March 30-April 13, 2020 (moderate prevalence group, MP) undergoing LUS and chest CT within 12 h. Chest CT was considered positive in case of "indeterminate"/"typical" pattern for COVID-19 by RSNA classification system. At LUS, thickened pleural line with ≥ three B-lines at least in one zone of the 12 explored was considered positive. Sensitivity, specificity, PPV, NPV, and AUC were calculated for CT and LUS against real-time reverse transcriptase polymerase chain reaction (RT-PCR) and serology as reference standard.

RESULTS

The study included 486 patients (males 61 %; median age, 70 years): 247 patients in HP (COVID-19 prevalence 94 %) and 239 patients in MP (COVID-19 prevalence 45 %). In HP and MP respectively, sensitivity, specificity, PPV, and NPV were 90-95 %, 43-69 %, 96-72 %, 20-95 % for CT and 94-93 %, 7-31 %, 94-52 %, 7-83 % for LUS. CT demonstrated better performance than LUS in diagnosis of COVID-19, both in HP (AUC 0.75 vs 0.51; P < 0.001) and MP (AUC 0.85 vs 0.62; P < 0.001).

CONCLUSIONS

Admission chest CT shows better performance than LUS for COVID-19 diagnosis, at varying disease prevalence. LUS is highly sensitive, but not specific for COVID-19.

Multimodality imaging in connective tissue disease-related interstitial lung disease

Interstitial lung disease is a well-recognised manifestation and a major cause of morbidity and mortality in patients with connective tissue diseases. Interstitial lung disease may arise in the context of an established connective tissue disease or be the initial manifestation of an otherwise occult autoimmune disorder. Early detection and characterisation are paramount for adequate patient management and require a multidisciplinary approach, in which imaging plays a vital role. Computed tomography is currently the imaging method of choice; however, other imaging techniques have recently been investigated, namely ultrasound, magnetic resonance imaging, and positron-emission tomography, with promising results. The aim of this review is to describe the imaging findings of connective tissue disease-related interstitial lung disease and explain the role of each imaging technique in diagnosis and disease characterisation.

The lung ultrasound: facts or artifacts? In the era of COVID-19 outbreak

Ultrasound is the most disruptive innovation in intensive care life, above all in this time, with a high diagnostic value when applied appropriately. In recent years, point-of-care lung ultrasound has gained significant popularity as a diagnostic tool in the acutely dyspnoeic patients. In the era of Sars-CoV-2 outbreak, lung ultrasound seems to be strongly adapting to the follow-up for lung involvement of patients with ascertaining infections, till to be used, in our opinion emblematically, as a screening test in suspected patients at the emergency triage or at home medical visit. In this brief review, we discuss the lung ultrasound dichotomy, certainties and uncertainties, describing its potential role in validated clinical contexts, as a clinical-dependent exam, its limits and pitfalls in a generic and off-label clinical context, as a virtual anatomical-dependent exam, and its effects on the clinical management of patients with COVID-19.

The emerging role of lung ultrasound in COVID-19 pneumonia

In the last decades lung ultrasound (LUS) has become of crucial importance in the evaluation and monitoring of a widely range of pulmonary diseases. One of the major benefits which favours this examination, is that this is a non-invasive, low-cost and radiation-free imaging modality which allows repeated imaging. LUS plays an important role in a wide range of pathologies, including cardiogenic oedema, acute respiratory distress syndrome and fibrosis. Specific LUS findings have proved useful and predictive of acute respiratory distress syndrome which is of particular relevance in the suspicion and monitoring of patients with lung disease. Furthermore, several studies have confirmed the role of LUS in the screening of interstitial lung diseases in connective tissue diseases. Given these data, LUS will likely play an important role in the management of COVID-19 patients from identification of specific abnormalities corresponding to definite pneumonia phases and CT scans findings. In addition, LUS could allow reduction in the exposure of health-care workers to potential infection. Herein, we provide a summary on emerging role of lung ultrasound in COVID-19 pneumonia.

PD-L1-targeted microbubbles loaded with docetaxel produce a synergistic effect for the treatment of lung cancer under ultrasound irradiation

Immunotherapy is gradually becoming as important as traditional therapy in the treatment of cancer, but adverse drug reactions limit patient benefits from PD1/PD-L1 checkpoint inhibitor drugs in the treatment of non-small cell lung cancer (NSCLC). As a chemotherapeutic drug for NSCLC, docetaxel (DTX) can synergize with PD1/PD-L1 checkpoint inhibitors but increase haematoxicity and neurotoxicity. Herein, anti-PD-L1 monoclonal antibody (mAb)-conjugated and docetaxel-loaded multifunctional lipid-shelled microbubbles (PDMs), which were designed with biologically safe phospholipids to produce synergistic antitumour effects, reduced the incidence of side effects and promoted therapeutic effects under ultrasound (US) irradiation. The PDMs were prepared by the acoustic-vibration method and then conjugated with an anti-PD-L1 mAb. The material features of the microbubbles and their cytotoxic effects, cellular apoptosis and cell cycle inhibition were studied. A subcutaneous tumour model was established to test the drug concentration-dependent and antitumour effects of the PDMs combined with US irradiation, and an orthotopic lung tumour model simultaneously confirmed the antitumour effect of this synergistic treatment. The PDMs achieved higher cellular uptake than free DTX, especially when combined with US irradiation. The PDMs combined with US irradiation also induced an increased rate of cellular apoptosis and an elevated G2-M arrest rate in cancer cells, which was positively correlated with PD-L1 expression. An in vivo study showed that synergistic treatment had relatively strong effects on tumour growth inhibition, increased survival time and decreased adverse effect rates. Our study possibly provides a well-controlled design for immunotherapy and chemotherapy and has promising potential for clinical application in NSCLC treatment.

Ultrasound and interstitial lung disease: use and limitations

The Connective Tissue Diseases (CTDs)-related Interstitial Lung Disease (ILD) early diagnosis by Transthoracic Ultrasound (TUS) still arises several issues. Gutierrez et al. clearly underlined the current role of ultrasound artifacts for ILD definition according to some Authors. In this Letter to the Editor, we would like to highlight the proper role of TUS and its pitfalls.

Correlation between Transthoracic Lung Ultrasound Score and HRCT Features in Patients with Interstitial Lung Diseases

Chest high-resolution computed tomography (HRCT) is considered the “gold” standard radiological method in interstitial lung disease (ILD) patients. The objectives of our study were to evaluate the correlation between two transthoracic lung ultrasound (LUS) scores (total number of B-lines score = the total sum of B-lines in 10 predefined scanning sites and total number of positive chest areas score = intercostal spaces with ≥3 B-lines) and the features in HRCT simplified scores, in different interstitial disorders, between LUS scores and symptoms, as well as between LUS scores and pulmonary function impairment. We have evaluated 58 consecutive patients diagnosed with ILD. We demonstrated that there was a good correlation between the total number of B-lines score and the HRCT simplified score (r = 0.784, p < 0.001), and also a good correlation between the total number of positive chest areas score and the HRCT score (r = 0.805, p < 0.005). The results confirmed the value of using LUS as a diagnostic tool for the assessment of ILD compared to HRCT. The use of LUS in ILD patients can be a useful, cheap, accessible and radiation-free investigation and can play a complementary role in the diagnosis and monitoring of these patients.