Usefulness of lung ultrasound B-lines in connective tissue disease-associated interstitial lung disease: a literature review

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.

Do Ultrasound Lung Abnormalities Correlate to Biomarkers and Male Gender in Rheumatoid Arthritis Patients? A Monocentric Cross-Sectional Study

Background: Lung ultrasound (LUS) is a tool of growing interest in Rheumatoid Arthritis (RA) oligo- symptomatic ILD to avoid. Objective: We aimed to evaluate (i) the prevalence of pleural (PLUS) and parenchymal (PAUS) abnormalities in LUS in the RA population and their possible correlation to biomarkers; (ii) the predictivity of gender, smoking habits, previous infections (past COVID-19 tuberculosis), and treatments; (iii) the differences in LUS between sexes. Methods: We collected the data of 155 (15 early and 140 late) RA patients with mild respiratory symptoms, evaluating PLUS and PAUS, in fourteen lung areas and also summing the scores (LUS-T). Results: Only 13/155 (8.4%) were completely negative; LUS correlated to age (all parameters p 0.0001), rheumatoid factor IgM (PLUS p 0.0006, PAUS p 0.02, LUS-T p 0.001) and ACPA (p 0.001, 0.006, 0.001, respectively), and PLUS also correlated to IL6 (p 0.02). The male gender was predictive of all LUS evaluations (p 0.001, 0.05, 0.001, respectively), which were higher than in women (p 0.001, 0.01, 0.001, respectively). Other potential risk factors were independent, except biological treatments, which showed a low predictivity to PLUS (p < 0.05). Conclusions: We can conclude that LUS is a useful technique in RA low respiratory symptoms and correlates with age, the most important RA biomarkers, and male sex.

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.

Screening value of lung ultrasound and pleural shear wave elastography in connective tissue disease-related interstitial lung disease: a preliminary study

OBJECTIVE

To explore the diagnostic value of lung ultrasound (LUS) and pleural shear wave elastography (SWE) for connective tissue disease-interstitial lung disease (CTD-ILD).

METHODS

We selected 104 patients diagnosed with connective tissue disease (CTD) at our hospital. All patients underwent LUS, SWE, and high-resolution computed tomography (HRCT). With HRCT as the imaging gold standard for diagnosis, patients were categorized into CTD-ILD and CTD-non-ILD groups. We employed paired chi-square tests to compare the diagnostic differences between HRCT and LUS for ILD. Receiver operating characteristic (ROC) curves were used to assess the diagnostic value of pleural SWE for ILD. Correlation analysis was performed between pleural elasticity values and lung ultrasound scores.

RESULTS

The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of LUS for diagnosing CTD-ILD were 93.3%, 86.2%, 6.761, and 0.078, respectively. There was no statistically significant difference in the results between HRCT and LUS (P = 1.000), with a kappa value of 0.720 (P < 0.001). There was a statistically significant difference in the pleural elasticity in the bilateral lower back region between the case and control groups (P < 0.001). The area under the receiver operating characteristic (ROC) curve (AUC) for pleural SWE in diagnosing CTD-ILD was 0.685. In CTD-ILD patients, there was no significant correlation between pleural elasticity values and LUS scores (P > 0.05).

CONCLUSION

The LUS can serve as an important imaging method for screening for CTD-ILD and assessing the severity of the disease. However, pleural SWE has been shown to demonstrate lower diagnostic efficacy for CTD-ILD, and its ability to assess disease severity is limited.

Ultrasonic surface acoustic wave elastography: A review of basic theories, technical developments, and medical applications

Physiological and pathological changes in tissues often cause changes in tissue mechanical properties, making tissue elastography an effective modality in medical imaging. Among the existing elastography methods, ultrasound elastography is of great interest due to the inherent advantages of ultrasound imaging technology, such as low cost, portability, safety, and wide availability. However, most current ultrasound elastography methods are based on the bulk shear wave; they can image deep tissues but cannot image superficial tissues. To address this challenge, ultrasonic elastography methods based on surface acoustic waves have been proposed. In this paper, we present a comprehensive review of ultrasound-based surface acoustic wave elastography techniques, including their theoretical foundations, technical implementations, and existing medical applications. The goal is to provide a concise summary of the state-of-the-art of this field, hoping to offer a reliable reference for the further development of these techniques and foster the expansion of their medical applications.

Thoracic ultrasound use in hospitalized and ambulatory adult patients: a quantitative picture

INTRODUCTION AND OBJECTIVES

Thoracic ultrasound (TUS) has been established as a powerful diagnostic and monitoring tool in the Intensive Care Unit (ICU). However, studies outside the critical care setting are scarce. The aim of this study was to investigate the value of TUS for hospitalized or ambulatory community patients.

MATERIALS AND METHODS

This was a retrospective study conducted from 2016 to 2020 in the TUS clinic at Heraklion University Hospital. TUS examination was performed using a standard ultrasound machine (EUB HITACHI 8500), and a high-frequency microconvex probe (5-8 MHz). Patients had been referred by their primary physician to address a range of different questions. The various respiratory system entities were characterised according to internationally established criteria.

RESULTS

762 TUS studies were performed on 526 patients due to underlying malignancy (n = 376), unexplained symptoms/signs (n = 53), pregnancy related issues (n = 42), evaluation of abnormal findings in X-ray (n = 165), recent surgery/trauma (n = 23), recent onset respiratory failure (n = 12), acute respiratory infection (n = 66) and underlying non-malignant disease (n = 25). Pleural effusion was the commonest pathologic entity (n = 610), followed by consolidation (n = 269), diaphragmatic dysfunction/paradox (n = 174) and interstitial syndrome (n = 53). Discrepancies between chest X-ray and ultrasonographic findings were demonstrated in 96 cases. The TUS findings guided invasive therapeutic management in 448 cases and non-invasive management in 43 cases, while follow-up monitoring was decided in 271 cases.

CONCLUSIONS

This study showed that TUS can identify the most common respiratory pathologic entities encountered in hospitalized and community ambulatory patients, and is especially useful in guiding the decision making process in a diverse group of patients.

Usefulness of Lung Ultrasound as a Method for Early Diagnosis of Interstitial Lung Disease in Patients with Rheumatoid Arthritis

Purpose

To determine the value of lung ultrasound (LUS) compared to high-resolution computed tomography (HRCT) in the early diagnosis of interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA).

Patients and Methods

An observational prospective study was performed. Were included patients with respiratory symptoms or/and, patients with crackles in auscultation during medical consultation. All patients underwent to chest X-rays, LUS, HRCT,and respiratory function tests.

Results

A total of 192 patients with RA were included. Mean disease duration was 16.8 ± 11.1 years. 72% were positive for rheumatoid factor or anti-citrullinated antibodies. Of the total number of subjects, 54.7% had respiratory symptoms. The other patients did not have respiratory symptoms, but they did have had crackles on pulmonary auscultation. B lines > 11.5 on the ROC curve predicted ILD (AUC 0.63; CI 95%: 0.55-0.71; p < 0.003). A DLCO value of <7.13 significantly predicted the presence of ILD (AUC 0.61; 95% CI: 0.52-0.70; p < 0.028).

Conclusion

The findings of this study suggest that LUS is a valuable tool for the early diagnosis of ILD in patients with RA, and together with DLCO, can adequately predict the presence of ILD in this population. LUS also helps to determine which patients with respiratory symptoms and signs suggestive for ILD are undergo to HRCT.

A Novel Automatic Algorithm to Support Lung Ultrasound Non-Expert Physicians in Interstitial Pneumonia Evaluation: A Single-Center Study

INTRODUCTION

Lung ultrasound (LUS) is widely used in clinical practice for identifying interstitial lung diseases (ILDs) and assessing their progression. Although high-resolution computed tomography (HRCT) remains the gold standard for evaluating the severity of ILDs, LUS can be performed as a screening method or as a follow-up tool post-HRCT. Minimum training is needed to better identify typical lesions, and the integration of innovative artificial intelligence (AI) automatic algorithms may enhance diagnostic efficiency.

AIM

This study aims to assess the effectiveness of a novel AI algorithm in automatic ILD recognition and scoring in comparison to an expert LUS sonographer. The "SensUS Lung" device, equipped with an automatic algorithm, was employed for the automatic recognition of the typical ILD patterns and to calculate an index grading of the interstitial involvement.

METHODS

We selected 33 Caucasian patients in follow-up for ILDs exhibiting typical HRCT patterns (honeycombing, ground glass, fibrosis). An expert physician evaluated all patients with LUS on twelve segments (six per side). Next, blinded to the previous evaluation, an untrained operator, a non-expert in LUS, performed the exam with the SensUS device equipped with the automatic algorithm ("SensUS Lung") using the same protocol. Pulmonary functional tests (PFT) and DLCO were conducted for all patients, categorizing them as having reduced or preserved DLCO. The SensUS device indicated different grades of interstitial involvement named Lung Staging that were scored from 0 (absent) to 4 (peak), which was compared to the Lung Ultrasound Score (LUS score) by dividing it by the number of segments evaluated. Statistical analyses were done with Wilcoxon tests for paired values or Mann-Whitney for unpaired samples, and correlations were performed using Spearman analysis; p < 0.05 was considered significant.

RESULTS

Lung Staging was non-inferior to LUS score in identifying the risk of ILDs (median SensUS 1 [0-2] vs. LUS 0.67 [0.25-1.54]; p = 0.84). Furthermore, the grade of interstitial pulmonary involvement detected with the SensUS device is directly related to the LUS score (r = 0.607, p = 0.002). Lung Staging values were inversely correlated with forced expiratory volume at first second (FEV1%, r = -0.40, p = 0.027), forced vital capacity (FVC%, r = -0.39, p = 0.03) and forced expiratory flow (FEF) at 25th percentile (FEF25%, r = -0.39, p = 0.02) while results directly correlated with FEF25-75% (r = 0.45, p = 0.04) and FEF75% (r = 0.43, p = 0.01). Finally, in patients with reduced DLCO, the Lung Staging was significantly higher, overlapping the LUS (reduced median 1 [1-2] vs. preserved 0 [0-1], p = 0.001), and overlapping the LUS (reduced median 18 [4-20] vs. preserved 5.5 [2-9], p = 0.035).

CONCLUSIONS

Our data suggest that the considered AI automatic algorithm may assist non-expert physicians in LUS, resulting in non-inferior-to-expert LUS despite a tendency to overestimate ILD lesions. Therefore, the AI algorithm has the potential to support physicians, particularly non-expert LUS sonographers, in daily clinical practice to monitor patients with ILDs. The adopted device is user-friendly, offering a fully automatic real-time analysis. However, it needs proper training in basic skills.

Advancing healthcare through thoracic ultrasound research in older patients

This paper reports the proceedings of a meeting convened by the Research Group on Thoracic Ultrasound in Older People of the Italian Society of Gerontology and Geriatrics, to discuss the current state-of-the-art of clinical research in the field of geriatric thoracic ultrasound and identify unmet research needs and potential areas of development. In the last decade, point-of-care thoracic ultrasound has entered clinical practice for diagnosis and management of several respiratory illnesses, such as bacterial and viral pneumonia, pleural effusion, acute heart failure, and pneumothorax, especially in the emergency-urgency setting. Very few studies, however, have been specifically focused on older patients with frailty and multi-morbidity, who frequently exhibit complex clinical pictures needing multidimensional evaluation. At the present state of knowledge, there is still uncertainty on the best requirements of ultrasound equipment, methodology of examination, and reporting needed to optimize the advantages of thoracic ultrasound implementation in the care of geriatric patients. Other issues regard differential diagnosis between bacterial and aspiration pneumonia, objective grading of interstitial syndrome severity, quantification and monitoring of pleural effusions and solid pleural lesions, significance of ultrasonographic assessment of post-COVID-19 sequelae, and prognostic value of assessment of diaphragmatic thickness and motility. Finally, application of remote ultrasound diagnostics in the community and nursing home setting is still poorly investigated by the current literature. Overall, the presence of several open questions on geriatric applications of thoracic ultrasound represents a strong call to implement clinical research in this field.

Predicting In-Hospital Acute Heart Failure Worsening in the Oldest Old: Insights from Point-of-Care Ultrasound

The decompensation trajectory check is a basic step to assess the clinical course and to plan future therapy in hospitalized patients with acute decompensated heart failure (ADHF). Due to the atypical presentation and clinical complexity, trajectory checks can be challenging in older patients with acute HF. Point-of-care ultrasound (POCUS) has proved to be helpful in the clinical decision-making of patients with dyspnea; however, to date, no study has attempted to verify its role in predicting determinants of ADHF in-hospital worsening. In this single-center, cross-sectional study, we consecutively enrolled patients aged 75 or older hospitalized with ADHF in a tertiary care hospital. All of the patients underwent a complete clinical examination, blood tests, and POCUS, including Lung Ultrasound and Focused Cardiac Ultrasound. Out of 184 patients hospitalized with ADHF, 60 experienced ADHF in-hospital worsening. By multivariable logistic analysis, total Pleural Effusion Score (PEFs) [aO.R.: 1.15 (CI95% 1.02-1.33), p = 0.043] and IVC collapsibility [aO.R.: 0.90 (CI95% 0.83-0.95), p = 0.039] emerged as independent predictors of acute HF worsening after extensive adjustment for potential confounders. In conclusion, POCUS holds promise for enhancing risk assessment, tailoring diuretic treatment, and optimizing discharge timing for older patients with ADHF.

Diagnostic and Prognostic Value of Clinical Scoring and Lung Ultrasonography to Assess Pulmonary Lesions in Veal Calves

This study on veal calf respiratory disease assessed the association between an on-farm clinical scoring system and lung ultrasonography with the postmortem inspection of the lungs. The comparisons allowed the calculation of predictive values of the diagnostic methods. In total, 600 calves on an Austrian veal calf farm were examined at the beginning and the end of the fattening period. Overall, the area under the curve (AUC) for ultrasonographic scores was 0.90 (rsp = 0.78) with a sensitivity (Se) of 0.86. The specificity (Sp) was 0.78, and the positive predictive value (PPV) was 0.74. The AUC for the physical examination was 0.76 (rsp = 0.55) with a Se of 0.64, an Sp of 0.81, and a PPV of 0.69. For the combination of ultrasonography and physical examination, an AUC curve of 0.85 (rsp = 0.69) was calculated. A Se of 0.65 and a Sp of 0.88 with a PPV of 0.73 was calculated. This study concluded that both physical and ultrasonographic examination scoring are reliable examination methods for the detection of lung diseases in veal calves.

Ultrasound for diagnosis of interstitial lung disease in diffuse connective tissue diseases

Patients with diffuse connective tissue diseases frequently develop interstitial lung disease, which carries a worse prognosis and shortens survival. High-resolution computed tomography is the first-choice test, and is competitive with histopathology, however, the cost and radiation may limit its use, particularly for screening. Lung ultrasound is a rapid, accessible, reproducible, and inexpensive study that is useful for diagnosis of interstitial lung disease. Furthermore, extensive training is not required to identify the alterations associated with these lung diseases. B lines and pleural irregularities compose the ultrasonographic interstitial syndrome, although, it must be kept in mind that it is not specific, and it is necessary to rule out haemodynamic, cardiovascular, and infectious abnormalities. This review highlights the elevated prevalence of this lung condition in the main rheumatological diseases, with emphasis on the usefulness of pulmonary ultrasound.

Ultrasound imaging of lung disease and its relationship to histopathology: An experimentally validated simulation approach

Lung ultrasound (LUS) is a widely used technique in clinical lung assessment, yet the relationship between LUS images and the underlying disease remains poorly understood due in part to the complexity of the wave propagation physics in complex tissue/air structures. Establishing a clear link between visual patterns in ultrasound images and underlying lung anatomy could improve the diagnostic accuracy and clinical deployment of LUS. Reverberation that occurs at the lung interface is complex, resulting in images that require interpretation of the artifacts deep in the lungs. These images are not accurate spatial representations of the anatomy due to the almost total reflectivity and high impedance mismatch between aerated lung and chest wall. Here, we develop an approach based on the first principles of wave propagation physics in highly realistic maps of the human chest wall and lung to unveil a relationship between lung disease, tissue structure, and its resulting effects on ultrasound images. It is shown that Fullwave numerical simulations of ultrasound propagation and histology-derived acoustical maps model the multiple scattering physics at the lung interface and reproduce LUS B-mode images that are comparable to clinical images. However, unlike clinical imaging, the underlying tissue structure model is known and controllable. The amount of fluid and connective tissue components in the lung were gradually modified to model disease progression, and the resulting changes in B-mode images and non-imaging reverberation measures were analyzed to explain the relationship between pathological modifications of lung tissue and observed LUS.

Ultrasonographic Presentation and Anatomic Distribution of Lung Involvement in Patients with Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic auto-immune disease, typically affecting the joints, which can also present with lung involvement (pleuritis, interstitial lung disease, pulmonary nodules, etc.). Lung ultrasound (LUS) is an upcoming tool in the detection of these pulmonary manifestations.

METHODS

We performed a 72-window LUS in 75 patients presenting to the outpatient rheumatology clinic and describe the abnormalities (presence of B-lines (vertical comet-tail artefacts), pleural abnormalities, pleural effusions, and subpleural nodules) on lung ultrasound. We created a topological mapping of the number of B-lines per intercostal zone.

RESULTS

We observed pleural effusions, pleural abnormalities, and pleural nodules in, respectively, 1.3%, 45.3%, and 14% of patients. There were 35 (46.7%) patients who had less than 5 B-lines, 15 (20%) patients who had between 5 and 10 B-lines, 11 (14.6%) between 10 and 20, 10 (13.3%) between 20 and 50, 1 (1.3%) between 50 and 100, and 3 (4%) of patients who had more than 100 B-lines.

CONCLUSIONS

LUS in patients with RA shows an array of abnormalities ranging from interstitial syndromes to pleural abnormalities, subpleural nodules, and pleural effusions. Hotspots for the presence of B-lines are situated bilaterally in the posterior subscapular regions, as well as the anterior right mid-clavicular region.

Extracorporeal veno-venous ultrafiltration in congestive heart failure: What’s the state of the art? A mini-review

Hospitalizations for heart failure exceed 1 million per year in both the United States and Europe and more than 90% are due to symptoms and signs of fluid overload. Rates of rehospitalizations or emergency department visit at 60 days are remarkable regardless of whether loop diuretics were administered at low vs high doses or by bolus injection vs continuous infusion. Ultrafiltration (UF) has been considered a promising alternative to stepped diuretic therapy and it consists in the mechanical, adjustable removal of iso-tonic plasma water across a semipermeable membrane with the application of hydrostatic pressure gradient generated by a pump. Fluid removal with ultrafiltration presents several advantages such as elimination of higher amount of sodium with less neurohormonal activation. However, the conflicting results from UF studies highlight that patient selection and fluid removal targets are not completely understood. The best way to assess fluid status and therefore establish the fluid removal target is also still a matter of debate. Herein, we provide an up-to-date systematic review about the role of ultrafiltration among patients with fluid overload and its gaps in daily practice.

Pulmonary Ultrasonography in Systemic Sclerosis-Induced Interstitial Lung Disease-A Systematic Review and Meta-Analysis

BACKGROUND

The aim of the current systematic review was to summarize and evaluate the overall advantages of lung ultrasonography (LUS) examination using high-resolution computed tomography (HRCT) as a reference standard in assessing the presence of interstitial lung disease (ILD) in systemic sclerosis (SSc) patients.

METHODS

Databases PubMed, Scopus, and Web of Science were searched for studies evaluating LUSs in ILD assessments including SSc patients on 1 February 2023. In assessing risk of bias and applicability, the Revised Tool for the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used. A meta-analysis was performed and the mean specificity, sensitivity, and diagnostic odds ratio (DOR) with a 95% confidence interval (CI) were obtained. In addition, in a bivariate meta-analysis, the summary receiver operating characteristic (SROC) curve area was additionally calculated.

RESULTS

Nine studies with a total of 888 participants entered the meta-analysis. A meta-analysis was also performed without one study that used pleural irregularity to assess the diagnostic accuracy of LUSs using B-lines (with a total of 868 participants). Overall sensitivity and specificity did not differ significantly, with only the analysis of the B-lines having a specificity of 0.61 (95% CI 0.44-0.85) and a sensitivity of 0.93 (95% CI 0.89-0.98). The diagnostic odds ratio of univariate analysis of the eight studies using the B-lines as a criterion for ILD diagnosis was 45.32 (95% CI 17.88-114.89). The AUC value of the SROC curve was 0.912 (and 0.917 in consideration of all nine studies), which indicates high sensitivity and a low false-positive rate for the majority of the included studies.

CONCLUSIONS

LUS examination proved to be a valuable tool in discerning which SSc patients should receive additional HRCT scans to detect ILD and therefore reduces the doses of ionizing radiation exposure in SSc patients. However, further studies are needed to achieve consensus in scoring and the evaluation methodology of LUS examination.

Thoracic Ultrasound in COVID-19: Use of Lung and Diaphragm Ultrasound in Evaluating Dyspnea in Survivors of Acute Respiratory Distress Syndrome from COVID-19 Pneumonia in a Post-ICU Clinic

INTRODUCTION

Dyspnea is a common symptom in survivors of severe COVID-19 pneumonia. While frequently employed in hospital settings, the use of point-of-care ultrasound in ambulatory clinics for dyspnea evaluation has rarely been explored. We aimed to determine how lung ultrasound score (LUS) and inspiratory diaphragm excursion (DE) correlate with patient-reported dyspnea during a 6-min walk test (6MWT) in survivors of COVID-19 acute respiratory distress syndrome (ARDS). We hypothesize higher LUS and lower DE will correlate with dyspnea severity.

STUDY DESIGN AND METHODS

Single-center cross-sectional study of survivors of critically ill COVID-19 pneumonia (requiring high-flow nasal cannula, invasive, or non-invasive mechanical ventilation) seen in our Post-ICU clinic. All patients underwent standardized scanning protocols to compute LUS and DE. Pearson correlations were performed to detect an association between LUS and DE with dyspnea at rest and exertion during 6MWT.

RESULTS

We enrolled 45 patients. Average age was 61.5 years (57.7% male), with average BMI of 32.3 Higher LUS correlated significantly with dyspnea, at rest (r =  + 0.41, p =  < 0.01) and at exertion (r =  + 0.40, p =  < 0.01). Higher LUS correlated significantly with lower oxygen saturation during 6MWT (r = -0.55, p =  < 0.01) and lower 6MWT distance (r = -0.44, p =  < 0.01). DE correlated significantly with 6MWT distance but did not correlate with dyspnea at rest or exertion.

CONCLUSION

Higher LUS correlated significantly with patient-reported dyspnea at rest and exertion. Higher LUS significantly correlated with more exertional oxygen desaturation during 6MWT and lower 6MWT distance. DE did not correlate with dyspnea.

Infectious Pneumonia and Lung Ultrasound: A Review

The application of thoracic ultrasound examination has not long been developed because ultrasound's interaction with the lung does not generate an anatomical image but an artifactual one. Subsequently, the evaluation of pulmonary artifacts and their correlation to specific diseases allowed the development of ultrasound semantics. Currently, pneumonia still represents one of the main causes of hospitalization and mortality. Several studies in the literature have demonstrated the ultrasound features of pneumonia. Although ultrasound cannot be considered the diagnostic gold standard for the study of all lung diseases, it has experienced an extraordinary development and growth of interest due to the SARS-CoV-2 pandemic. This review aims to provide essential information on the application of lung ultrasound to the study of infectious pneumonia and to discuss the differential diagnosis.

A study of the diagnostic value of a modified transthoracic lung ultrasound scoring method in interstitial lung disease

Background

Interstitial lung disease (ILD) is a serious complication of connective tissue disease (CTD) with significant morbidity and mortality. Lung ultrasound (LUS) has been widely used in the diagnosis of a variety of lung diseases. However, there is no standard ultrasound scanning method or scoring method for connective tissue disease associated with interstitial lung disease (CTD-ILD); therefore, it is necessary to establish a set of standard evaluation methods.

Methods

A total of 60 consecutive patients with clinically confirmed CTD and suspected ILD were prospectively included in this study. LUS and high-resolution computed tomography (HRCT) were used to examine all patients. The time between HRCT and LUS examinations was less than 2 weeks. The ultrasonographic results were evaluated with the modified scoring method and the Buda scoring method. The imaging results were evaluated with the HRCT Warrick scoring method. The primary aim was to evaluate the diagnostic value of a modified ultrasound scoring method in CTD-ILD.

Results

The results of the Youden index for the diagnosis of CTD-ILD by the modified method, the Buda method, and the HRCT method were 0.845, 0.711, and 0.911, respectively, with areas under the receiver operating characteristic (ROC) curve (AUC) of 0.982 [95% confidence interval (CI): 0.945-1.000], 0.950 (95% CI: 0.851-0.990), and 0.985 (95% CI: 0.949-1.000), respectively. With a clinical diagnosis as the gold standard, the consistency of the modified method and the HRCT method for CTD-ILD was high (Kappa values =0.872 and 0.913, respectively). The values of the modified method and the Buda method consistently and significantly increased with the increasing severity of CTD-ILD. For the former, there were significant differences between the mild, moderate, and severe groups (P<0.05). The ROC curve used to calculate the modified ultrasound score predicted the critical values of mild and severe pulmonary fibrotic lesions at 34 points (sensitivity, 100%; specificity, 92.9%; AUC =0.933; 95% CI: 0.807-1.000) and 64.5 points (sensitivity, 92.0%; specificity, 85.3%; AUC =0.972; 95% CI: 0.929-1.000).

Conclusions

The modified ultrasound method has a higher diagnostic value than the Buda method for CTD-ILD.

Lung ultrasound in the follow-up of severe COVID-19 pneumonia: six months evaluation and comparison with CT

While lung ultrasonography (LUS) proved to be a useful diagnostic and prognostic tool in acute phase of COVID 19 pneumonia, its role in detecting long-term pulmonary sequelae has yet to be explored. In our prospective observational study we assessed the potential of LUS in detecting the presence of computed tomography (CT) fibrotic-like changes after 6 months from COVID-19 pneumonia. Patients who were discharged with a diagnosis of severe COVID-19 pneumonia were enrolled. After 6 months from hospital discharge they underwent LUS, chest CT scan and pulmonary function tests. A logistic regression analysis was performed to assess the association between presence of symptoms, LUS score and diffusing capacity for carbon monoxide (DLCO) at 6-month after hospital discharge and CT scan fibrotic-like changes. A second logistic model was performed to assess the value of some predefined baseline factors (age, sex, worst PaO2/FiO2, ventilator support, worst CRP value, worst D-dimer value and worst LUS score during hospitalization) to predict fibrotic-like changes on 6-month CT scan. Seventy-four patients were enrolled in the study. Twenty-four (32%) showed lung abnormalities suitable for fibrotic-like changes. At multivariate logistic regression analysis LUS score after 6 months from acute disease was significantly associated with fibrotic-like pattern on CT scan. The second logistic model showed that D-dimer value was the only baseline predictive variable of fibrotic-like changes at multivariate analysis. LUS performed after 6 months from severe COVID-19 pneumonia may be a promising tool for detection and follow-up of pulmonary fibrotic sequelae.

The effect of attenuation inside the acoustic traps on the configuration of vertical artifacts in lung ultrasound: an experimental study with simple models

Purpose

Using simple experimental models for lung ultrasound, we evaluated the relationship of the attenuation inside the sources of vertical artifacts to the echo intensity and attenuation of artifacts.

Methods

As sources of artifacts, we made 10 different hemispherical gel objects with two different mediums (pure agar or agar containing graphite with an attenuation coefficient of 0.5 dB/cm · MHz) and five different diameters (3.6, 5.6, 7.5, 9.5, or 11.4 mm). Ten of each hemispherical gel object were prepared for the statistical analyses. Each object was placed onto a chest wall phantom as the plane of the hemisphere was placed in an upward position. The echo intensity and attenuation of the artifact generated from each object was measured and compared.

Results

For all sizes, the intensity and attenuation of the artifacts in the objects made of agar containing graphite were significantly lower and larger, respectively, than those in the objects made of pure agar. In the objects containing graphite, the intensity decreased when the frequency was changed from 5 to 9 MHz.

Conclusion

Based on this experiment, assessing the intensity and attenuation of vertical artifacts may help estimate the physical composition of sources of vertical artifacts in lung ultrasound.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10396-022-01244-0.

Evaluation of connective tissue disease-related interstitial lung disease using ultrasound elastography: a preliminary study

BACKGROUND

Interstitial lung disease (ILD) is a common pulmonary complication of connective tissue disease (CTD), which can lead to shortened survival. This article explores the ability of shear wave elastography (SWE) to assess lung surface elastic properties and to distinguish healthy lungs from diseased lungs with connective tissue disease-related interstitial lung disease (CTD-ILD). We aimed to determine whether SWE can be used to assess the severity of CTD-ILD.

METHODS

A total of 65 CTD-ILD patients and 60 healthy volunteers were included for the case group and the control group, respectively. All participants underwent lung ultrasound (count of B-line and measurement of pleural line thickness) and SWE [measurement of Young's modulus (Emean) and shear wave velocity (SMV) (Cmean)] examinations at 50 lung sites. All participants also underwent an examination with high-resolution computed tomography (HRCT) and a pulmonary function test (PFT). For SWE assessment, the Q-box was set to its minimum size (1 mm) and manually placed on the pleural line, rather than inside the lung, to measure the stiffness of the lung surface. The intra- and inter-reliability of SWE measurements of healthy controls (HC), the receiver operating characteristic (ROC) curve for SWE for CTD-ILD, and correlations between different assessment methods were analyzed.

RESULTS

Excellent intra- and inter-reliability of SWE measurements on the mid-anterior lung site of HCs (correlation coefficient >0.97; P<0.01) were found. The results of the lung ultrasound of case group participants were significantly higher than those of HCs at each site (P<0.001). The SWE results revealed a significant increase in both Emean and Cmean in CTD-ILD patients (P<0.001) compared with HCs at certain sites (P<0.001). The areas under the curve (AUC) of Emean and Cmean for CTD-ILD were 0.646 and 0.647 (P<0.05), respectively, and the cutoff values for Emean and Cmean to distinguish CTD-ILD from healthy lungs were 15.81 kPa and 2.31 m/s, respectively. There was no significant correlation between the SWE measured values and the number of B-lines, or the HRCT and PFT results, respectively (P>0.05).

CONCLUSIONS

As a noninvasive ultrasound elastography (UE) technique, SWE may provide a novel method to differentiate CTD-ILD-affected lungs and healthy lungs. It is a reliable way to measure the stiffness of a healthy lung surface in the supine position. However, the ability of SWE to evaluate the severity of CTD-ILD may be limited.

Performance of Lung Ultrasound for Monitoring Interstitial Lung Disease

OBJECTIVES

In this study, we sought to assess the validity of lung ultrasound (LUS) during the follow-up of patients with a wide spectrum of interstitial lung diseases (ILDs).

METHODS

Twenty-four patients (13 males, 11 females; mean age ± SD, 65.4 ± 14.3 years; age range, 40-84 years) with a diagnosis of ILDs who were admitted to the Interstitial Lung Disease Unit were prospectively enrolled. Patients were examined with a 56-lung intercostal space LUS protocol in lateral decubitus position, at baseline, 6-months, and 1-year. The LUS score was defined as the sum of B-lines counted in each intercostal space. All patients underwent complete pulmonary function tests at baseline and follow-up time-points. High-resolution computed tomography (HRCT) was performed at baseline and during follow-up, according to personalized patients' needs. All HRCT studies were graded according to the Warrick scoring system (WS).

RESULTS

Pooled data analysis showed a significant correlation between WS and LUS scores (P < .001). For separate time-point analysis, a significant correlation between LUS scores and WS was found at baseline (P < .001) and 1 year (P = .005). LUS scores negatively correlated with alveolar volume (VA) (P < .046) and diffusing capacity for carbon monoxide (DLCO) (P < .001) at 6 months and with transfer coefficient of the lung for carbon monoxide (KCO) (P < .031) and DLCO (P = .002) at 12-months. A multivariate regression model showed DLCO to be an independent predictor of LUS score at 1 year (P = .026).

CONCLUSIONS

Our results highlight the validity and potential applicability of LUS for disease monitoring in a wide spectrum of ILDs.

The role of antifibrotics in the treatment of rheumatoid arthritis–associated interstitial lung disease

The major pulmonary complication of rheumatoid arthritis (RA) is interstitial lung disease (ILD), which causes significant morbidity and mortality and influences the natural course of disease. Recent advances in the management of arthritis have improved patient outcomes. However, exceptionally high medical needs still remain for effective therapies for the patients with ILD in RA. Better understanding of the shared and distinct pathophysiology of fibrotic diseases led to the development of novel antifibrotic agents such as nintedanib and pirfenidone. The further stratification analysis of the phase III INBUILD trial demonstrated beneficial effects of nintedanib in RA-ILD with a progressive phenotype by reducing the rate of decline in forced vital capacity (FVC) over 52 weeks by 60%. Pirfenidone is another antifibrotic agent currently under phase II clinical study (TRAIL1) aiming to evaluate its effects for RA-ILD. This review provides an overview of state-of-the-art pathogenesis and the current therapeutic options for RA-ILD, with a focus on antifibrotic strategies.

Education and Use of Lung Ultrasound in Rheumatology and Pneumology in Spain: A SER-SEPAR Survey

INTRODUCTION

Lung ultrasound (LUS) is a clinical and research tool with great potential in the diagnosis and monitoring of diffuse interstitial lung disease (ILD) present in systemic autoimmune diseases (SAD). Appropriate training in LUS is essential for the correct and safe use of this technique.

OBJECTIVE

To document the current state of LUS education and use among Spanish rheumatologists and pneumologists.

MATERIAL AND METHODS

A national online survey was designed for members of the Spanish Society of Rheumatology and the ILD Area of the Spanish Society of Pneumology and Thoracic Surgery. The survey consisted of 22 questions on demographics, professional activity, performance and training in LUS.

RESULTS

One hundred and thirty-five (56.72% rheumatologists, 41.79% pneumologists) responded to the survey. Of these, 56.30% were part of an ILD Unit in their centre. LUS in clinical practice was performed by 35.82% but only 14.93% performed it in ILD, mainly for diagnostic purposes. Training in LUS of responders had been diverse in format, content and sponsors. The vast majority (87.79%) considered that the optimal model of education in LUS should be standardized and structured and consist of a combination of theoretical-practical courses and the conduct of a minimum number of supervised LUS examinations, with competency assessment.

CONCLUSIONS

The current lack of formal structured education in LUS is an opportunity to develop quality educational programmes in this emerging field.

Serum B-cell activating factor and lung ultrasound B-lines in connective tissue disease related interstitial lung disease

OBJECTIVE

To investigate the role of serum B-cell activating factor (BAFF) and lung ultrasound (LUS) B-lines in connective tissue disease related interstitial lung disease (CTD-ILD), and their association with different ILD patterns on high resolution computed tomography (HRCT) of chest.

METHODS

We measured the levels of BAFF and KL-6 by ELISA in the sera of 63 CTD-ILD patients [26 with fibrotic ILD (F-ILD), 37 with non-fibrotic ILD (NF-ILD)], 30 CTD patients without ILD, and 26 healthy controls. All patients underwent chest HRCT and LUS examination.

RESULTS

Serum BAFF levels were significantly higher in CTD patients compared to healthy subjects (617.6 ± 288.1 pg/ml vs. 269.0 ± 60.4 pg/ml, p < 0.01). BAFF concentrations were significantly different between ILD group and non-ILD group (698.3 ± 627.4 pg/ml vs. 448.3 ± 188.6 pg/ml, p < 0.01). In patients with ILD, BAFF concentrations were significantly correlated with B-lines number (r = 0.37, 95% CI 0.13-0.56, p < 0.01), KL-6 level (r = 0.26, 95% CI 0.01-0.48, p < 0.05), and Warrick score (r = 0.33, 95% CI 0.09-0.53, p < 0.01), although all correlations were only low to moderate. B-lines number correlated with Warrick score (r = 0.65, 95% CI 0.48-0.78, p < 0.01), and KL-6 levels (r = 0.43, 95% CI 0.21-0.61, p < 0.01). Patients with F-ILD had higher serum BAFF concentrations (957.5 ± 811.0 pg/ml vs. 516.1 ± 357.5 pg/ml, p < 0.05), KL-6 levels (750.7 ± 759.0 U/ml vs. 432.5 ± 277.5 U/ml, p < 0.05), B-lines numbers (174.1 ± 82 vs. 52.3 ± 57.5, p < 0.01), and Warrick score (19.9 ± 4.6 vs. 13.6 ± 3.4, p < 0.01) vs. NF-ILD patients. The best cut-off values to separate F-ILD from NF-ILD using ROC curves were 408 pg/ml for BAFF (AUC = 0.73, p < 0.01), 367 U/ml for KL-6 (AUC = 0.72, p < 0.05), 122 for B-lines number (AUC = 0.89, p < 0.01), and 14 for Warrick score (AUC = 0.87, p < 0.01) respectively.

CONCLUSION

Serum BAFF levels and LUS B-lines number could be useful supportive biomarkers for detecting and evaluating the severity and/or subsets of CTD-ILD. If corroborated, combining imaging, serological, and sonographic biomarkers might be beneficial and comprehensive in management of CTD-ILD.

Diaphragm Ultrasound in the Evaluation of Diaphragmatic Dysfunction in Lung Disease

The diaphragm is the most important respiratory muscle, and its function may be limited by acute and chronic diseases. A diaphragmatic ultrasound, which quantifies dysfunction through different approaches, is useful in evaluating work of breathing and diaphragm atrophy, predicting successful weaning, and diagnosing critically ill patients. This technique has been used to determine reduced diaphragmatic function in patients with chronic obstructive pulmonary disease and interstitial diseases, while in those with COVID-19, diaphragmatic ultrasound has been used to predict weaning failure from mechanical ventilation.

High-Resolution Computed Tomography and Lung Ultrasound in Patients with Systemic Sclerosis: Which One to Choose?

Imaging plays a pivotal role in systemic sclerosis for both diagnosis management of pulmonary complications, and high-resolution computed tomography (HRCT) is the most sensitive technique for the evaluation of systemic sclerosis-associated interstitial lung disease (SSc-ILD). Indeed, several studies have demonstrated that HRCT helps radiologists and clinicians to make a correct diagnosis on the basis of recognised typical patterns for SSc-ILD. Most SSc patients affected by ILD have a non-specific interstitial pneumonia pattern (NISP) on HRCT scan, whilst a minority of cases fulfil the criteria for usual interstitial pneumonia (UIP). Moreover, several recent studies have demonstrated that lung ultrasound (LUS) is an emergent tool in SSc diagnosis and follow-up, although its role is still to be confirmed. Therefore, this article aims at evaluating the role of LUS in SSc screening, aimed at limiting the use of CT to selected cases.

Lung ultrasound B-lines in systemic sclerosis: cut-off values and methodological indications for interstitial lung disease screening

OBJECTIVES

Lung ultrasound (LUS), through assessment of B-lines and pleural line alterations, is able to evaluate interstitial lung disease (ILD), a frequent complication of systemic sclerosis (SSc). Different scanning schemes and counting methods have been proposed, but no clear cut-off values have been indicated for screening. We aimed to evaluate the accuracy of different LUS methodological approaches to detect ILD, compared with high resolution computed tomography (HRCT) as gold standard.

METHODS

Sixty-nine SSc patients underwent LUS and chest HRCT on the same day. Both exams were scored by expert readers. The accuracy of different scanning schemes and counting methods was assessed, and clinical and functional data were compared with imaging findings.

RESULTS

B-lines were more numerous in patients with the diffuse skin subset and Scl70 autoantibody positivity. The number of B-lines correlated with the Scleroderma Lung Study (SLS) I HRCT score (R = 0.754, p< 0.0001). A total number >10 B-lines on the whole chest or > 1 B-line on the postero-basal chest showed 97% sensitivity for detecting even very early ILD signs (corresponding to SLS I score =1). Sensitivity increased to 100% when pleural line alterations were included in the analysis.

CONCLUSIONS

LUS has a very high sensitivity in detecting SSc-related ILD. A cut-off value of > 10 B-lines on the whole chest or > 1 B-line on the postero-basal chest can be used for the screening of SSc-ILD. Assessing only the postero-basal chest seems mostly effective to combine high sensitivity with a less time-consuming approach.

Lung Ultrasound in the Screening of Pulmonary Interstitial Involvement Secondary to Systemic Connective Tissue Disease: A Prospective Pilot Study Involving 180 Patients

OBJECTIVES

The aim of the study was the assessment of lung ultrasound (LUS) as a screening of pulmonary interstitial involvement secondary to systemic connective tissue diseases.

METHODS

A prospective study was conducted on the study group comprising 180 patients diagnosed with different systemic connective tissue diseases. Each patient underwent lung ultrasound (LUS), high-resolution chest computed tomography (HRCT), and echocardiography (ECHO). Each imaging examination was blinded and performed by an independent operator. LUS was conducted with convex and linear transducers.

RESULTS

The sensitivity and specificity of LUS as compared to HRCT in detecting pulmonary interstitial involvement in the study group were 99.3% and 96.4%, respectively; positive predictive value (PPV) 0.7, negative predictive value (NPV) 3.6. Abnormalities indicating interstitial lung disease (ILD) with fibrosis were most frequently localized bilaterally in the lower fields of the lungs, assessed in the dorsal view.

CONCLUSIONS

LUS is an efficient imaging modality that can detect pulmonary interstitial involvement in patients with systemic connective tissue disease with a high sensitivity and specificity. Further prospective studies conducted on a larger population are deemed necessary.

Development and Assessment of Novel Lung Ultrasound Interpretation Criteria for the Detection of Interstitial Lung Disease in Systemic Sclerosis

OBJECTIVE

Interstitial lung disease (ILD) is a frequent complication of systemic sclerosis (SSc), and ILD screening, characterization, and monitoring are important for therapeutic decision-making and prognostication. Lung ultrasonography (US) is a potential alternative imaging modality for ILD detection. In this study, our objective was to develop and test a novel lung US examination technique and interpretation criteria for detecting SSc-ILD.

METHODS

Lung US acquisition was performed by collecting short US movies at 14 lung positions. Lung US interpretation criteria for SSc-ILD detection focused on visualized pleural changes. To assess the performance of our methodology for SSc-ILD detection, we prospectively enrolled SSc patients with high-resolution computed tomography (HRCT) imaging within 3 months of lung US. Lung US examinations were scored independently by 2 blinded readers (1 ultrasonographer and 1 nonultrasonographer). The sensitivity and specificity for SSc-ILD detection were assessed, and agreement was measured with Cohen's kappa statistic.

RESULTS

To test the performance of our lung US acquisition technique and interpretation criteria, 20 SSc patients were evaluated by lung US (278 lung zones) and HRCT. HRCT confirmed ILD in 9 patients (45%). Lung US was positive for SSc-ILD in 11 patients (55%) with a sensitivity of 100% and specificity of 82% versus HRCT, with perfect agreement between the 2 readers (κ = 1). Analysis by individual lung zones found excellent agreement between readers, with 93.8% concordance and κ = 0.82.

CONCLUSION

We developed a novel lung US examination technique and interpretation criteria that are highly sensitive and specific for SSc-ILD detection in an SSc cohort, affording perfect agreement between ultrasonographer and nonultrasonographer readers.

Canadian Internal Medicine Ultrasound (CIMUS) Expert Consensus Statement on the Use of Lung Ultrasound for the Assessment of Medical Inpatients With Known or Suspected Coronavirus Disease 2019

OBJECTIVES

To develop a consensus statement on the use of lung ultrasound (LUS) in the assessment of symptomatic general medical inpatients with known or suspected coronavirus disease 2019 (COVID-19).

METHODS

Our LUS expert panel consisted of 14 multidisciplinary international experts. Experts voted in 3 rounds on the strength of 26 recommendations as "strong," "weak," or "do not recommend." For recommendations that reached consensus for do not recommend, a fourth round was conducted to determine the strength of those recommendations, with 2 additional recommendations considered.

RESULTS

Of the 26 recommendations, experts reached consensus on 6 in the first round, 13 in the second, and 7 in the third. Four recommendations were removed because of redundancy. In the fourth round, experts considered 4 recommendations that reached consensus for do not recommend and 2 additional scenarios; consensus was reached for 4 of these. Our final recommendations consist of 24 consensus statements; for 2 of these, the strength of the recommendations did not reach consensus.

CONCLUSIONS

In symptomatic medical inpatients with known or suspected COVID-19, we recommend the use of LUS to: (1) support the diagnosis of pneumonitis but not diagnose COVID-19, (2) rule out concerning ultrasound features, (3) monitor patients with a change in the clinical status, and (4) avoid unnecessary additional imaging for patients whose pretest probability of an alternative or superimposed diagnosis is low. We do not recommend the use of LUS to guide admission and discharge decisions. We do not recommend routine serial LUS in patients without a change in their clinical condition.

The role of lung ultrasound B-lines and serum KL-6 in the screening and follow-up of rheumatoid arthritis patients for an identification of interstitial lung disease: review of the literature, proposal for a preliminary algorithm, and clinical application to cases

Screening and follow-up of interstitial lung disease associated with rheumatoid arthritis (RA-ILD) is a challenge in clinical practice. In fact, the majority of RA-ILD patients are asymptomatic and optimal tools for early screening and regular follow-up are lacking. Furthermore, some patients may remain oligosymptomatic despite significant radiological abnormalities. In RA-ILD, usual interstitial pneumonia (UIP) is the most frequent radiological and pathological pattern, associated with a poor prognosis and a high risk to develop acute exacerbations and infections. If RA-ILD can be identified early, there may be an opportunity for an early treatment and close follow-up that might delay ILD progression and improve the long-term outcome.In connective tissue disease-associated interstitial lung disease (CTD-ILD), lung ultrasound (LUS) with the assessment of B-lines and serum Krebs von den Lungen-6 antigen (KL-6) has been recognized as sensitive biomarkers for the early detection of ILD. B-line number and serum KL-6 level were found to correlate with high-resolution computed tomography (HRCT), pulmonary function tests (PFTs), and other clinical parameters in systemic sclerosis-associated ILD (SSc-ILD). Recently, the significant correlation between B-lines and KL-6, two non-ionizing and non-invasive biomarkers, was demonstrated. Hence, the combined use of LUS and KL-6 to screen and follow up ILD in RA patients might be useful in clinical practice in addition to existing tools. Herein, we review relevant literature to support this concept, propose a preliminary screening algorithm, and present 2 cases where the algorithm was used.

Lung Ultrasound Examination in Patients with SARS-CoV-2 Infection: Multicenter Study

BACKGROUND

The COVID-19 pandemic has, by necessity, contributed to rapid advancements in medicine. Owing to the necessity of following strict anti-epidemic sanitary measures when taking care of infected patients, the accessibility of standard diagnostic methods may be limited. Consequently, the significance and potential of bedside diagnostic modalities increase, including lung ultrasound (LUS).

METHOD

Multicenter registry study involving adult patients with confirmed COVID-19, for whom LUS was performed.

RESULTS

A total of 228 patients (61% males) qualified for the study. The average age was 60 years (±14), 40% were older than 65 years of age. In 130 from 173 hospitalized patients, HRCT (high-resolution computed tomography) was performed. In 80% of patients, LUS findings indicated interstitial pneumonia. In hospitalized patients multifocally located single B-lines, symmetrical B-lines, and areas of white lung were significantly more frequent as compared to ambulatory patients. LUS findings, both those indicating interstitial syndrome and consolidations, were positively correlated with HRCT images. As compared to HRCT, the sensitivity and specificity of LUS in detecting interstitial pneumonia were 97% and 100%, respectively.

CONCLUSIONS

As compared to HRCT, LUS is characterized by a very high sensitivity and specificity in detecting interstitial pneumonia in COVID-19 patients. Potentially, LUS can be a particularly useful diagnostic modality for COVID-19 patients pneumonia.

Quantitative Lung Ultrasound: Technical Aspects and Clinical Applications

Lung ultrasound is increasingly used in emergency departments, medical wards, and critical care units-adult, pediatric, and neonatal. In vitro and in vivo studies show that the number and type of artifacts visualized change with lung density. This has led to the idea of a quantitative lung ultrasound approach, opening up new prospects for use not only as a diagnostic but also as a monitoring tool. Consequently, the multiple scoring systems proposed in the last few years have different technical approaches and specific clinical indications, adaptable for more or less time-dependent patients. However, multiple scoring systems may generate confusion among physicians aiming at introducing lung ultrasound in their clinical practice. This review describes the various lung ultrasound scoring systems and aims to clarify their use in different settings, focusing on technical aspects, validation with reference techniques, and clinical applications.

Association between lung ultrasound B-lines and exercise-induced pulmonary hypertension in patients with connective tissue disease

BACKGROUND

Identification of elevation in pulmonary pressures during exercise may provide prognostic and therapeutic implications in patients with connective tissue disease (CTD). Interstitial lung disease (ILD) is common in CTD patients and subtle interstitial abnormalities detected by lung ultrasound could predict exercise-induced pulmonary hypertension (PH).

METHODS AND RESULTS

Echocardiography and lung ultrasound were performed at rest and bicycle exercise in CTD patients (n = 41) and control subjects without CTD (n = 24). Ultrasound B-lines were quantified by scanning four intercostal spaces in the right hemithorax. We examined the association between total B-lines at rest and the development of exercise-induced PH during ergometry exercise. Compared to controls, the number of total B-lines at rest was higher in CTD patients (0 [0, 0] vs 2 [0, 9], P < .0001) and was correlated with radiological severity of ILD assessed by computed tomography (fibrosis score, r = .70, P < .0001). Pulmonary artery systolic pressure (PASP) was increased with ergometry exercise in CTD compared to controls (48 ± 14 vs 35 ± 13 mm Hg, P = .0006). The number of total B-lines at rest was highly correlated with higher PASP (r = .52, P < .0001) and poor right ventricular pulmonary artery coupling (tricuspid annular plane systolic excursion/PASP ratio, r = -.31, P = .01) during peak exercise. The number of resting B-lines predicted the development of exercise-induced PH with an area under the curve .79 (P = .0003).

CONCLUSIONS

These data may suggest the value of a simple resting assessment of lung ultrasound as a potential tool for assessing the risk of exercise-induced PH in CTD patients.

Assessment of Volume Status and Fluid Responsiveness in Small Animals

Intravenous fluids are an essential component of shock management in human and veterinary emergency and critical care to increase cardiac output and improve tissue perfusion. Unfortunately, there are very few evidence-based guidelines to help direct fluid therapy in the clinical setting. Giving insufficient fluids and/or administering fluids too slowly to hypotensive patients with hypovolemia can contribute to continued hypoperfusion and increased morbidity and mortality. Similarly, giving excessive fluids to a volume unresponsive patient can contribute to volume overload and can equally increase morbidity and mortality. Therefore, assessing a patient's volume status and fluid responsiveness, and monitoring patient's response to fluid administration is critical in maintaining the balance between meeting a patient's fluid needs vs. contributing to complications of volume overload. This article will focus on the physiology behind fluid responsiveness and the methodologies used to estimate volume status and fluid responsiveness in the clinical setting.

B-Line Artifact as a Diagnostic Tool in Various Conditions at the Emergency Department

BACKGROUND: B-line artifacts (BLAs) play an important role in identifying lung pathology. They may indicate different diseases. However, the diagnostic study of BLA as applied to emergency patients has not been well studied. AIM: The aim of this study was to determine the diagnostic accuracy of BLA in various conditions. METHODS: This was a retrospective observational study of emergency patients who had received lung ultrasound at Srinagarind Hospital’s Emergency Department throughout January 2020–December 2020. Ultrasound artifacts were recorded. Ultrasonography findings were correlated with final diagnosis. Sensitivity and specificity were also calculated. RESULTS: A total of 105 patients were evaluated. The most prevalent condition which BLA found in this study was pulmonary edema (44.12%) with 88.24% sensitivity and 46.48% specificity. BLA also indicated pneumonia with 66.67% sensitivity and 35.71% specificity. Diffuse BLA indicated pulmonary edema with 70% sensitivity and 70.42% specificity. Focal BLA indicated pneumonia with 28.57% sensitivity and 76.19% specificity. CONCLUSIONS: The sensitivity of BLA for pulmonary edema and pneumonia diagnosis in this study was of moderate to good sensitivity, but low specificity. BLA may become crucial in the diagnosis of lung pathology in the emergency department.

Utility of lung ultrasound to identify interstitial lung disease: An observational study based on the STROBE guidelines

Lung ultrasound (LUS) has recently been used to identify interstitial lung disease (ILD). However, data on the role of LUS in the detection of ILD remain limited. The aim of this study was to investigate the diagnostic value of LUS compared with high-resolution computed tomography (HRCT) in patients with ILD.The retrospective study was carried out by reviewing the medical records of patients with respiratory signs and symptoms discharged from the respiratory ward. Only patients with suspected ILD who underwent HRCT and LUS within a week were selected. ILD was identified with a semi-quantitative score of B-lines >5 and a Warrick score >0 points. The endpoints of LUS in diagnosing ILD (i.e., sensitivity, specificity, positive likelihood ratio [PLR], negative likelihood ratio [NLR], positive predictive value [PPV], and negative predictive value [NPV], and receiver operating characteristic [ROC] curve) was compared with that of HRCT. The reference standard used for the diagnosis of ILD was based on history, clinical findings and examination, and laboratory and instrumental tests, including pulmonary function tests, lung histopathology, and HRCT (without LUS findings).The final clinical diagnosis of ILD was 55 in 66 patients with suspected ILD. HRCT was positive in 55 patients, whereas LUS detected ILD in 51 patients. Four patients with negative LUS findings were positive on HRCT. The results showed 93% sensitivity, 73% specificity, 3.40 PLR, 0.10 NLR, 94% PPV, and 67% NPV for LUS, whereas 100% sensitivity, 82% specificity, 5.49 PLR, 0.01 NLR, 97% PPV, and 100% NPV for HRCT. Comparison of the 2 ROC curves revealed significant difference in the diagnostic value of the 2 methods for the diagnosis of ILD (P = .048).Our results indicated that LUS is a useful technique to identify ILD. Considering its non-radiation, portable and non-invasive advantages, LUS should be recommended as a valuable screening tool in patients with suspected ILD.

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.

European Respiratory Society statement on thoracic ultrasound

Thoracic ultrasound is increasingly considered to be an essential tool for the pulmonologist. It is used in diverse clinical scenarios, including as an adjunct to clinical decision making for diagnosis, a real-time guide to procedures and a predictor or measurement of treatment response. The aim of this European Respiratory Society task force was to produce a statement on thoracic ultrasound for pulmonologists using thoracic ultrasound within the field of respiratory medicine. The multidisciplinary panel performed a review of the literature, addressing major areas of thoracic ultrasound practice and application. The selected major areas include equipment and technique, assessment of the chest wall, parietal pleura, pleural effusion, pneumothorax, interstitial syndrome, lung consolidation, diaphragm assessment, intervention guidance, training and the patient perspective. Despite the growing evidence supporting the use of thoracic ultrasound, the published literature still contains a paucity of data in some important fields. Key research questions for each of the major areas were identified, which serve to facilitate future multicentre collaborations and research to further consolidate an evidence-based use of thoracic ultrasound, for the benefit of the many patients being exposed to clinicians using thoracic ultrasound.

Thoracic ultrasound in viral infections

Ultrasonography has proven useful in the study of many pulmonary diseases that affect the subpleural regions. This article reviews the current evidence regarding the role of ultrasonography in the diagnosis and management of viral lung infections. It describes the examination technique and the main ultrasonographic findings for different viruses that can affect the lungs.

Utility of pulmonary ultrasound to identify interstitial lung disease in patients with rheumatoid arthritis

OBJECTIVES

To analyze the diagnostic utility of lung ultrasound (US) to detect interstitial lung disease (ILD) in rheumatoid arthritis (RA) patients comparing with high-resolution computed tomography (HRCT) PATIENTS AND METHODS: We performed a cross-sectional, observational study in patients with RA-ILD (cases) controlled with a group of RA patients without ILD (controls) paired by sex, age, and time of disease evolution. Patients were assessed using HRCT, PFT, and US. The main variables were B-line number, evaluation of the lung-US score already described, pleural irregularities, and A pattern US lost. ROC curve analysis was performed to establish the cut-off point of the US B-lines number for detecting the presence of significant RA-ILD in relation to HRCT, and logistic regression analysis was performed to identify the intercostal spaces.

RESULTS

Seventy-one patients were included, 35 (49.2%) with ILD-RA and 36 (50.8%) RA controls. Regarding US score, we found that the detection of 5.5 lines in a reduced score of 8 intercostal spaces had a sensitivity = 62.2%, specificity = 91.3%, PPV = 88.4%, and NPV = 69.5%. In multivariate analysis, the intercostal spaces which showed independent association with ILD were 3rd right anterior axillary space (OR [IC 95%] 19.0 [1.3-27.5]), 8th right posterior axillary space (OR [IC 95%] 0.04 [0.0-0.6]), 8th right subscapular space (OR [IC 95%] 16.5 [1.8-45.5]), 9th right paravertebral space (OR [IC 95%] 7.11 [1.0-37.1]), and 2nd left clavicular middle space (OR [IC 95%] 21.9 [1.26-37.8]).

CONCLUSIONS

Lung ultrasound could be a useful tool for ILD diagnosis associated with rheumatoid arthritis. A 8-space reduced score showed a similar total predictive capacity than 72-space score. Key Points • Lung ultrasound could be a useful tool for ILD diagnosis associated with rheumatoid arthritis. • The 72-space evaluation is highly sensitive, whereas a simplified score enables a more specific and faster diagnosis. • The number of B lines is correlated with DLCO, ACPA, inflammatory activity, and physical function.

Early changes in renal resistive index and mortality in diabetic and nondiabetic kidney transplant recipients: a cohort study

Background

Renal resistive index (RI) predicts mortality in renal transplant recipients (RTR). However, its predictive value may be different according to the time of measurement. We analysed RI changes between 1 month and 3 months after transplantation and its predictive value for death with a functioning graft (DWFG).

Methods

We conducted a retrospective study in 1685 RTR between 1985 and 2017. The long-term predictive value of changes in RI value from 1 month to 3 months was assessed in diabetic and non-diabetic RTR.

Results

Best survival was observed in RTR with RI < 0.70 both at 1 and 3 months, and the worst survival was found in RTR with RI ≥ 0.70 both at 1 and 3 months (HR = 3.77, [2.71–5.24], p < 0.001). The risk of DWFG was intermediate when RI was < 0.70 at 1 month and ≥ 0.70 at 3 months (HR = 2.15 [1.29–3.60], p = 0.003) and when RI was ≥0.70 at 1 month and < 0.70 at 3 months (HR = 1.90 [1.20–3.03], p = 0.006).

In diabetic RTR, RI was significantly associated with an increased risk of death only in those with RI < 0.70 at 1 month and ≥ 0.70 at 3 months (HR = 4.69 [1.07–20.52], p = 0.040). RI considered as a continuous variable at 1 and 3 months was significantly associated with the risk of DWFG in nondiabetic but not in diabetic RTR.

Conclusion

RI changes overtime and this impacts differently diabetic and nondiabetic RTR. RI short-term changes have a strong prognosis value and refines the risk of DWFG associated with RI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02263-8.

Lung Ultrasound vs. Chest X-Ray Study for the Radiographic Diagnosis of COVID-19 Pneumonia in a High-Prevalence Population

Background

The viral illness severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), more commonly known as Coronavirus 2019 (COVID-19), has become a global pandemic, infecting over 100 million individuals worldwide.

Objectives

The objective of this study was to compare the test characteristics of point-of-care lung ultrasound (LUS) with chest x-ray study (CXR) at radiographically detecting COVID-19 pneumonia.

Methods

This was a single-center, prospective, observational study at an urban university hospital with > 105,000 patient visits annually. Patients ≥ 18 years old, who presented to the Emergency Department with predefined signs and symptoms of COVID-19, were eligible for enrollment. Each patient received an LUS using a portable, handheld ultrasound followed by a single-view, portable anteroposterior CXR. Patients with an abnormal LUS or CXR underwent a non-contrast-enhanced computed tomography scan (NCCT). The primary outcome was the radiographic diagnosis of COVID-19 pneumonia on NCCT.

Results

One hundred ten patients underwent LUS, CXR, and NCCT; 99 LUS and 73 CXRs were interpreted as positive; 81 NCCTs were interpreted as positive, providing a prevalence of COVID-19 pneumonia of 75% (95% confidence interval [CI] 66–83.2) in our study population. LUS sensitivity was 97.6% (95% CI 91.6–99.7) vs. 69.9% (95% CI 58.8–79.5) for CXR. LUS specificity was 33.3% (95% CI 16.5–54) vs. 44.4% (95% CI 25.5–64.7) for CXR. LUS positive predictive value and negative predictive value were 81.8% (95% CI 72.8–88.9) and 81.8% (95% CI 48.2–97.7), respectively, vs. 79.5% (95% CI 68.4–88), and 32.4% (95% CI 18–49.8), respectively, for CXR.

Conclusion

LUS was more sensitive than CXR at radiographically identifying COVID-19 pneumonia.

The association between renal resistive index and premature mortality after kidney transplantation is modified by pre-transplant diabetes status: a cohort study

BACKGROUND

Renal resistive index (RI) predicts mortality in renal transplant recipients, but we do not know whether this is true in diabetic patients. The objective of this study was to analyse the long-term predictive value of RI for death with a functioning graft (DWFG) in renal transplant recipients with or without pre-transplant diabetes.

METHODS

We conducted a retrospective study in 1800 renal transplant recipients between 1985 and 2017 who were followed for up to 30 years (total observation period: 14 202 patient years). Donor and recipient characteristics at time of transplantation and at 3 months were reviewed. The long-term predictive value of RI for DWFG and the age-RI and arterial pressure-RI relationships were assessed.

RESULTS

A total of 284/1800 (15.7%) patients had diabetes mellitus before transplantation. RI was <0.75 in 1327/1800 patients (73.7%). High RI was associated with a higher risk of DWFG in non-diabetic patients [hazard ratio (HR) = 3.39, 95% confidence interval 2.50-4.61; P < 0.001], but not in patients with pre-transplant diabetes (HR = 1.25, 0.70-2.19; P = 0.39), even after multiple adjustments. There was no interaction between diabetes and age. In contrast, there was an interaction between RI and pulse pressure.

CONCLUSION

Our study indicates that RI is not a predictor of DWFG in diabetic renal transplant recipients, in contrast to non-diabetic recipients. These findings could be due to a different age-RI or pulse pressure-RI relationship.

Education and Use of Lung Ultrasound in Rheumatology and Pneumology in Spain: A SER-SEPAR Survey

INTRODUCTION

Lung ultrasound (LUS) is a clinical and research tool with great potential in the diagnosis and monitoring of diffuse interstitial lung disease (ILD) present in systemic autoimmune diseases (SAD). Appropriate training in LUS is essential for the correct and safe use of this technique.

OBJECTIVE

To document the current state of LUS education and use among Spanish rheumatologists and pneumologists.

MATERIAL AND METHODS

A national online survey was designed for members of the Spanish Society of Rheumatology and the ILD Area of the Spanish Society of Pneumology and Thoracic Surgery. The survey consisted of 22 questions on demographics, professional activity, performance and training in LUS.

RESULTS

One hundred and thirty-five (56.72% rheumatologists, 41.79% pneumologists) responded to the survey. Of these, 56.30% were part of an ILD Unit in their centre. LUS in clinical practice was performed by 35.82% but only 14.93% performed it in ILD, mainly for diagnostic purposes. Training in LUS of responders had been diverse in format, content and sponsors. The vast majority (87.79%) considered that the optimal model of education in LUS should be standardized and structured and consist of a combination of theoretical-practical courses and the conduct of a minimum number of supervised LUS examinations, with competency assessment.

CONCLUSIONS

The current lack of formal structured education in LUS is an opportunity to develop quality educational programmes in this emerging field.

Serum Krebs von den Lungen-6 and lung ultrasound B lines as potential diagnostic and prognostic factors for rheumatoid arthritis-associated interstitial lung disease

INTRODUCTION

Rheumatoid arthritis (RA)-associated interstitial lung disease (ILD) (RA-ILD) is a serious systemic RA manifestation with high mortality that needs proper, accurate, and sensitive assessment tools.

OBJECTIVES

Firstly, evaluate serum Krebs von den Lungen-6 (KL-6) levels and lung ultrasound B lines (LUS B lines) score in RA-ILD correlating them with the severity of ILD assessed by high-resolution computed tomography (HRCT) and pulmonary function tests (PFTs). Secondly, determine cut-off values for LUS and KL-6 in RA-ILD assessment and outcome prediction.

METHODS

A case-control study included seventy-five RA-ILD patients with an equal number of matched RA patients without ILD. Clinical assessment includes DAS-28 and PFTs, laboratory assessment of serum KL-6 by latex-enhanced immunoturbidimetric assay, and radiological evaluation of ILD using semiquantitative CT grade and LUS B lines.

RESULTS

RA-ILD patients had significantly higher serum KL6 compared to those without ILD (1025.5 ± 419.6 vs. 237.5 ± 51.9, p ≤ 0.001). Serum KL6 was positively correlated with HRCT and LUS scores (r = 0.93, r = 0.97, respectively) with negative correlation with FVC% and FEV1% (r = - 0.93, r = - 0.91, respectively). LUS was positively correlated with KL6 and HRCT (r = 0.97, r = 0.944, respectively) while, negatively correlated with PFTs. Cut-off values of KL6 and LUS were 277.5 U/ml and < 5.5, with AUC 0.878 and 1, sensitivity 86.7% and 100%, and specificity 88% and 100%, respectively.

CONCLUSIONS

The non-invasive, radiation-free LUS with a score < 5.5 combined with serum KL6 could be helpful for RA-ILD assessment correlating with HRCT and disease severity. Serum KL6 combined with LUS is important new and potential prognostic factor predicting poor outcomes in RA-ILD. Further large-scale, multi-center, and prospective studies are needed to confirm these findings.

KEY POINTS

• Combination of the non-invasive, radiation-free LUS with a score < 5.5 and serum KL6 levels of 277.5 U/ml is recommended as prognostic tools for RA-ILD. • Easily obtainable tests such as serum KL-6, inflammatory markers, and LUS are sensitive for assessing RA-ILD and the risk of poor outcomes in patients with RA-ILD. • RA-ILD patients with higher KL6 levels, higher LUS scores had a poor prognosis with short survival. • LUS B lines could be used as the first imaging tool for the evaluation of RA-ILD decreasing the risk of HRCT radiation exposure in asymptomatic or mild RA-ILD patients.