Lung B-line artefacts and their use

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

ABSTRACT

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

The Utility of Lung Ultrasound Scoring in Predicting Post-Extubation Respiratory Support After Congenital Heart Surgery

OBJECTIVES

Lung ultrasound (LU) is effective in diagnosing the accumulation of extravascular lung water and assessing real-time fluid status in infants following congenital cardiac surgery with cardiopulmonary bypass. This study evaluated whether LU can be used as a prognostic marker for changes in noninvasive respiratory support after extubation.

METHODS

Infants with congenital heart disease (CHD) <1 year of age requiring mechanical ventilation for more than 24 hours postoperatively were included. Using a linear probe, 3 scan fields from each hemithorax were assessed for B-lines and consolidations, with scores ranging from 0 to 3 assigned per area. LU scores were rated then by 4 independent operators. After extubation, patients were monitored for respiratory support modifications over the following 48 hours and were divided into 3 subgroups: steady state, escalation, and de-escalation, accordingly.

RESULTS

In this single-center observational pilot study, a total of 30 patients with a median age of 116 (interquartile range: 17-196) days were included in the prospective analysis between July 2022 and December 2023. LU scores differed significantly among groups: 3.47 ± 2.3 (steady state), 6.14 ± 2.55 (escalation), and 1.63 ± 1.41 (de-escalation), P = .002. ROC analysis identified a cut-off score of ≥5 as predictive of escalation risk with a sensitivity of 86% and specificity of 83%. A score <2 suggested potential for de-escalation within 48 hours, with a sensitivity of 75% and specificity of 73%.

CONCLUSIONS

LU scoring may be a valuable tool for optimizing ventilator weaning and post-extubation respiratory strategies in infants undergoing congenital cardiac surgery. Further studies are warranted to validate these findings.

Intraoperative Lung Ultrasound in the Detection of Pulmonary Nodules: A Valuable Tool in Thoracic Surgery

In the last two decades, there has been an increased interest in the application of lung ultrasound (LUS), especially intraoperatively, owing to its safety and simple approach to detecting and assessing pulmonary nodules. This review focuses on recent advancements in intraoperative lung ultrasound in detecting lung nodules. A systematic search was conducted using databases such as PubMed and Google Scholar. Keywords included "Lung ultrasound", "intraoperative lung ultrasound", and "video-assisted transthoracic surgery (VATS)". Articles published between 1963 and 2024 in peer-reviewed journals were included, focusing on the ones from the 2000s. Data on methodology, key findings, and research gaps were reviewed. Results indicated a significant advantage of intraoperative lung ultrasound (ILU) in the assessment of pulmonary nodules. ILU offers a noninvasive, real-time imaging modality that demonstrates up to 100% accuracy in detecting pulmonary nodules, with shorter time needed compared to other modalities, as well as less intraoperative periods and postoperative complications. However, some disadvantages were detected, such as operator dependency and a lack of specificity and knowledge of specific signs, as well as assisted localization via percutaneous puncture and its correct interpretation. The findings suggest that ILU has a promising future in pulmonary surgeries such as LUS-VATS but needs to be engaged more in clinical applications and modified with new techniques such as artificial intelligence (AI).

Emergency Ultrasound in the Context of Cardiac Arrest and Circulatory Shock: "How to Avoid Cardiac Arrest"

In the recently published 2021 European Resuscitation Council Guidelines on Adult Advanced Life Support, focused echocardiography was upgraded to a target recommendation. Several key recommendations were made, including that point-of-care ultrasound (POCUS) should only be used during CPR performed by experienced users and prolonged interruptions longer than 10 s (as accepted for pulse checking) during chest compressions should be avoided. Ultrasound does not replace clinical evaluation nor awareness of the clinical scenario. However, in addition to other assessments such as laboratory analyses, ultrasound can help to directly identify a cause for the peri-arrest state. The advantage of ultrasound is that examinations can be performed at the bedside while other tests are being carried out and repeated as frequently as required. This article focusses on how to use ultrasound during peri-arrest situations, requirements for ultrasound equipment, reversible causes of cardiac arrest, and the use of the RUSH protocol, focused echocardiography, and "deresuscitation" (post resuscitation/return of spontaneous circulation).

Lung ultrasound outperforms symptom-based screening to detect interstitial lung disease associated with rheumatoid arthritis

OBJECTIVES

Interstitial lung disease associated with rheumatoid arthritis (RA-ILD) is linked to high mortality. Currently, effective screening tools are lacking. We assessed the role of symptoms and lung ultrasound (LUS) as potential screening tools.

METHODS

116 adult patients with RA presenting to the rheumatology outpatient clinic underwent high-resolution CT (HRCT) scans, pulmonary function tests, LUS (72 zones) and completed a Visual Analogue Scale (VAS) for cough and modified Medical Research Council dyspnoea scale (mMRC). Kruskal-Wallis (KW) tests evaluated the correlation between clinical-radiological HRCT score (no ILD, non-specific abnormalities, subclinical ILD or ILD) and the B-lines on LUS, diffusion capacity (DLCO%pred), forced vital capacity (FVC%pred), VAS Cough and mMRC. Sensitivity and specificity analyses were performed to assess symptom-based questionnaires and the number of B-lines to detect RA-ILD. Area under the receiver operating characteristics (AUROC) for detecting clinical ILD and subclinical ILD were calculated.

RESULTS

In 11.8% of patients, an ILD was detected on HRCT. Additionally, in 5%, a diagnosis of subclinical interstitial lung changes was made. The number of B-lines was most strongly associated with the clinical-radiological score (KW χ²=41.2, p=<0.001). DLCO%pred was also significantly correlated with the clinical-radiological score (KW χ²=27.4, p=<0.001), but FVC%pred, mMRC and VAS cough were not. Cough and dyspnoea only weakly predicted the ILD score in the sensitivity-specificity analyses, while B-lines showed AUROCs>0.9 for predicting subclinical and clinical ILD.

CONCLUSION

LUS is a promising tool for early detection of RA-ILD, outperforming symptom-based questionnaires or the presence of dyspnoea or cough.

Inter-rater agreement and characterization of pleural line and subpleural fields in canine lung ultrasound: a comparative pilot study between high-frequency linear and curvilinear transducers using B- and M-mode ultrasonographic profiles

BACKGROUND

Lung ultrasound (LUS) is increasingly utilized in veterinary medicine to assess pulmonary conditions. However, the characterization of pleural line and subpleural fields using different ultrasound transducers, specifically high-frequency linear ultrasound transducers (HFLUT) and curvilinear transducers (CUT), remains underexplored in canine patients. This study aimed to evaluate inter-rater agreement in the characterization of pleural line and subpleural fields using B- and M-mode ultrasonography in dogs with and without respiratory distress.

RESULTS

Eighty-eight ultrasound clips from nine dogs were analyzed. HFLUT demonstrated strong inter-rater agreement in B-mode (κ = 0.89) and near-perfect agreement in M-mode (κ = 1.00) for pleural line homogeneity. In contrast, CUT showed minimal agreement in both B-mode (κ = 0.34) and M-mode (κ = 0.37). Homogeneous pleural lines were predominantly observed in control dogs or those with cardiogenic pulmonary edema (CPE), while non-homogeneous pleural lines were more common in dogs with non-cardiogenic alveolar-interstitial syndrome (NCAIS). Vertical subpleural fields identified in M-mode were associated with both CPE and NCAIS, whereas horizontal fields were more often observed in control dogs.

CONCLUSIONS

HFLUT offers superior inter-rater reliability for characterizing pleural and subpleural features in canine LUS compared to CUT, particularly in M-mode. These findings suggest HFLUT may enhance diagnostic accuracy for pulmonary conditions in dogs. Further studies are needed to explore the diagnostic potential of LUS in differentiating vertical artifact (e.g., B-lines) etiologies in veterinary patients.

Ultrasound Lung Aeration Map via Physics-Aware Neural Operators

Lung ultrasound is a growing modality in clinics for diagnosing and monitoring acute and chronic lung diseases due to its low cost and accessibility. Lung ultrasound works by emitting diagnostic pulses, receiving pressure waves and converting them into radio frequency (RF) data, which are then processed into B-mode images with beamformers for radiologists to interpret. However, unlike conventional ultrasound for soft tissue anatomical imaging, lung ultrasound interpretation is complicated by complex reverberations from the pleural interface caused by the inability of ultrasound to penetrate air. The indirect B-mode images make interpretation highly dependent on reader expertise, requiring years of training, which limits its widespread use despite its potential for high accuracy in skilled hands. To address these challenges and democratize ultrasound lung imaging as a reliable diagnostic tool, we propose Luna (the Lung Ultrasound Neural operator for Aeration), an AI model that directly reconstructs lung aeration maps from RF data, bypassing the need for traditional beamformers and indirect interpretation of B-mode images. Luna uses a Fourier neural operator, which processes RF data efficiently in Fourier space, enabling accurate reconstruction of lung aeration maps. From reconstructed aeration maps, we calculate lung percent aeration, a key clinical metric, offering a quantitative, reader-independent alternative to traditional semi-quantitative lung ultrasound scoring methods. The development of Luna involves synthetic and real data: We simulate synthetic data with an experimentally validated approach and scan ex vivo swine lungs as real data. Trained on abundant simulated data and fine-tuned with a small amount of real-world data, Luna achieves robust performance, demonstrated by an aeration estimation error of 9% in ex-vivo swine lung scans. We demonstrate the potential of directly reconstructing lung aeration maps from RF data, providing a foundation for improving lung ultrasound interpretability, reproducibility and diagnostic utility.

Can the lung ultrasound score predict pulmonary complications after non-thoracic surgery in patients with blunt thoracic trauma: A single-center observational study

STUDY OBJECTIVE

Patients with blunt thoracic trauma have a high risk of developing postoperative pulmonary complications (PPCs). In this study, we aimed to identify the risk factors for PPCs after non-thoracic surgery in patients with blunt thoracic trauma and investigate the efficacy of perioperative lung ultrasound scores in predicting PPC occurrence.

DESIGN

Prospective observational study.

SETTING

A Chinese tertiary orthopedic hospital.

PARTICIPANTS

This observational study included 369 patients with blunt thoracic trauma who underwent surgery for pelvic and upper or lower extremity fractures.

INTERVENTIONS

Lung ultrasonography was performed pre- and postoperatively.

MEASUREMENTS

Patients were followed up for 1 week to assess PPCs and assigned to the PPC or non-PPC groups. We identified risk factors for PPCs using univariate and multivariate logistic regression analyses. The predictive value of these risk factors was evaluated using receiver operating characteristic (ROC) curves.

MAIN RESULTS

PPCs incidence was 36.58 %. The two groups differed significantly in Injury Severity Scores, American Society of Anesthesiologists (ASA) classification, chronic obstructive pulmonary disease, hydrothorax, preoperative hypoxemia, lung ultrasound score, preoperative hemoglobin level, intraoperative infusion volume, and Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) scores (P < 0.05). Independent risk factors for PPCs included ASA classification III, higher postoperative lung ultrasound scores, preoperative anemia, higher intraoperative infusion volume, and higher ARISCAT scores. ROC curve analysis revealed that postoperative lung ultrasound score (area under the curve [AUC]: 0.810, cutoff: 10), preoperative hemoglobin level (AUC: 0.627, cutoff: 97), intraoperative infusion volume (AUC: 0.701, cutoff: 886.51 mL/h) and ARISCAT score (AUC: 0.718, cutoff: 33) predicted postoperative outcomes effectively.

CONCLUSIONS

Postoperative lung ultrasound scores reliably predicted pulmonary complications after non-thoracic surgery in patients with blunt thoracic trauma. ASA classification III, preoperative anemia, excessive intraoperative fluid infusion, higher ARISCAT, and postoperative lung ultrasound scores were significant risk factors associated with PPCs.

TRIAL REGISTRATION

Clinical Trial Number: 1900023408. Registered on May 26, 2019.

Advanced emphysema leads to high false positivity rate for pneumothorax in point of care ultrasound

PURPOSE

Point of Care Ultrasound (POCUS) is widely used to evaluate pleural apposition in acute disease; however, the prevalence of abnormal findings among emphysematous patients is unknown. The aim of the study was to characterize POCUS findings in advanced emphysema and correlate parenchymal and spirometric changes with abnormal POCUS results.

MATERIALS AND METHODS

We retrospectively evaluated POCUS images obtained in hyperinflated COPD patients. Images were obtained in the 2nd intercostal space (upper lobes) and above diaphragm insertion (lower lobes). Pleural sliding was graded as "present" or "absent," and M-mode images graded as "seashore," "barcode," or "hybrid" patterns; patients were then assigned to four groups based on the combination of findings. Differences between pulmonary function testing and high-resolution CT were made by Chi Square or ANOVA testing, and association by Spearman's correlation. Agreement among three scorers (two pulmonologists and one radiologist) was assessed using Kappa statistics.

RESULTS

Our study included 48 patients with 159 lobes imaged. We found a substantial percentage of lobes had either barcode M-mode appearance (13.8 %) or indeterminate/absent lung sliding (20.3 %). We identified 87 lobes (54.7 %) that did not fit any typical definition for M-mode ultrasound findings. There was no strong association of abnormal ultrasound patterns with airflow obstruction or emphysema percentage. There was wide interrater variability among B-mode (0.20-0.611) and M-mode (0.24-0.049) among the three graders.

CONCLUSIONS

Hyperinflated patients often show abnormal pleural sliding appearance on POCUS, with a high false positive rate of barcode pattern. This should be considered when interpretation of POCUS drives therapeutic decisions.

Resuscitative Ultrasound and Protocols

The management of patients in shock or arrest is a critical aspect of emergency medicine and critical care. Rapid and accurate assessment is paramount in determining the underlying causes and initiating timely interventions. This article provides a summary of essential ultrasound protocols for the critically ill patient including the extended focused assessment with sonography for trauma (EFAST), rapid ultrasound for shock and hypotension (RUSH), and sonography in hypotension and cardiac arrest in the emergency department (SHoC-ED).

Deep-learning model accurately classifies multi-label lung ultrasound findings, enhancing diagnostic accuracy and inter-reader agreement

Despite the increasing use of lung ultrasound (LUS) in the evaluation of respiratory disease, operators' competence constrains its effectiveness. We developed a deep-learning (DL) model for multi-label classification using LUS and validated its performance and efficacy on inter-reader variability. We retrospectively collected LUS and labeled as normal, B-line, consolidation, and effusion from patients undergoing thoracentesis at a tertiary institution between January 2018 and January 2022. The development and internal testing involved 7580 images from January 2018 and December 2020, and the model's performance was validated on a temporally separated test set (n = 985 images collected after January 2021) and two external test sets (n = 319 and 54 images). Two radiologists interpreted LUS with and without DL assistance and compared diagnostic performance and agreement. The model demonstrated robust performance with AUCs: 0.93 (95% CI 0.92-0.94) for normal, 0.87 (95% CI 0.84-0.89) for B-line, 0.82 (95% CI 0.78-0.86) for consolidation, and 0.94 (95% CI 0.93-0.95) for effusion. The model improved reader accuracy for binary discrimination (normal vs. abnormal; reader 1: 87.5-95.6%, p = 0.004; reader 2: 95.0-97.5%, p = 0.19), and agreement (k = 0.73-0.83, p = 0.01). In conclusion, the DL-based model may assist interpretation, improving accuracy and overcoming operator competence limitations in LUS.

Innovative integration of lung ultrasound and wearable monitoring for predicting pulmonary complications in colorectal surgery: A prospective study

BACKGROUND

Postoperative pulmonary complications (PPCs) are common in patients who undergo colorectal surgery. Studies have focused on how to accurately diagnose and reduce the incidence of PPCs. Lung ultrasound has been proven to be useful in preoperative monitoring and postoperative care after cardiopulmonary surgery. However, lung ultrasound has not been studied in abdominal surgeries and has not been used with wearable devices to evaluate the influence of postoperative ambulation on the incidence of PPCs.

AIM

To investigate the relationship between lung ultrasound scores, PPCs, and postoperative physical activity levels in patients who underwent colorectal surgery.

METHODS

In this prospective observational study conducted from November 1, 2019 to August 1, 2020, patients who underwent colorectal surgery underwent daily bedside ultrasonography from the day before surgery to postoperative day (POD) 5. Lung ultrasound scores and PPCs were recorded and analyzed to investigate their relationship. Pedometer bracelets measured the daily movement distance for 5 days post-surgery, and the correlation between postoperative activity levels and lung ultrasound scores was examined.

RESULTS

Thirteen cases of PPCs was observed in the cohort of 101 patients. The mean (standard deviation) peak lung ultrasound score was 5.32 (2.52). Patients with a lung ultrasound score of ≥ 6 constituted the high-risk group. High-risk lung ultrasound scores were associated with an increased incidence of PPCs after colorectal surgery (logistic regression coefficient, 1.715; odds ratio, 5.556). Postoperative movement distance was negatively associated with the lung ultrasound scores [Spearman's rank correlation coefficient (r), -0.356, P < 0.05].

CONCLUSION

Lung ultrasound effectively evaluates pulmonary condition post-colorectal surgery. Early ambulation and respiratory exercises in the initial two PODs will reduce PPCs and optimize postoperative care in patients undergoing colorectal surgery.

Conventional and Contrast-enhanced US of the Lung: From Performance to Diagnosis

In recent years, lung US has evolved from a marginal tool to an integral component of diagnostic chest imaging. Contrast-enhanced US (CEUS) can improve routine gray-scale imaging of the lung and chest, particularly in diagnosis of peripheral lung diseases (PLDs). Although an underused tool in many centers, and despite inherent limitations in evaluation of central lung disease caused by high acoustic impedance between air and soft tissues, lung CEUS has emerged as a valuable tool in diagnosis of PLDs. Owing to the dual arterial supply to the lungs via pulmonary and bronchial (systemic) arteries, different enhancement patterns can be observed at lung CEUS, thereby enabling accurate differential diagnoses in various PLDs. Lung CEUS also assists in identifying patients who may benefit from complementary diagnostic tests, including image-guided percutaneous biopsy. Moreover, lung CEUS-guided percutaneous biopsy has shown feasibility in accessible subpleural lesions, enabling higher histopathologic performance without significantly increasing either imaging time or expenses compared with conventional US. The authors discuss the technique of and basic normal and pathologic findings at conventional lung US, followed by a more detailed discussion of lung CEUS applications, emphasizing specific aspects of pulmonary physiology, basic concepts in lung US enhancement, and the most commonly encountered enhancement patterns of different PLDs. Finally, they discuss the benefits of lung CEUS in planning and guidance of US-guided lung biopsy. ©RSNA, 2024 Supplemental material is available for this article.

Transfer Learning-Based B-Line Assessment of Lung Ultrasound for Acute Heart Failure

OBJECTIVE

B-lines assessed by lung ultrasound (LUS) outperform physical exam, chest radiograph, and biomarkers for the associated diagnosis of acute heart failure (AHF) in the emergent setting. The use of LUS is however limited to trained professionals and suffers from interpretation variability. The objective was to utilize transfer learning to create an AI-enabled software that can aid novice users to automate LUS B-line interpretation.

METHODS

Data from an observational AHF LUS study provided standardized cine clips for AI model development and evaluation. A total of 49,952 LUS frames from 30 patients were hand scored and trained on a convolutional neural network (CNN) to interpret B-lines at the frame level. A random independent evaluation set of 476 LUS clips from 60 unique patients assessed model performance. The AI models scored the clips on both a binary and ordinal 0-4 multiclass assessment.

RESULTS

A multiclassification AI algorithm had the best performance at the binary level when applied to the independent evaluation set, AUC of 0.967 (95% CI 0.965-0.970) for detecting pathologic conditions. When compared to expert blinded reviewer, the 0-4 multiclassification AI algorithm scale had a reported linear weighted kappa of 0.839 (95% CI 0.804-0.871).

CONCLUSIONS

The multiclassification AI algorithm is a robust and well performing model at both binary and ordinal multiclass B-line evaluation. This algorithm has the potential to be integrated into clinical workflows to assist users with quantitative and objective B-line assessment for evaluation of AHF.

The application value of lung ultrasound scoring in assessing disease severity: Evaluation of small-scale outbreaks of COVID-19

PURPOSE

This study explored the use of transthoracic lung ultrasound for evaluating COVID-19 patients, compared it with computed tomography (CT), and examined its effectiveness using 8 and 12 lung regions.

METHODS

A total of 100 patients with COVID-19 and 40 healthy volunteers were assessed using 12 regions (bilateral upper/lower regions of the anterior/lateral/posterior chest) and simplified 8 zones (bilateral upper/lower regions of the anterior/lateral chest) transthoracic lung ultrasound. The relationships between ultrasound, CT, and clinical indicators were analyzed to evaluate the diagnostic value of ultrasound scores in COVID-19.

RESULTS

Increased disease severity correlated with increased 8- and 12-zone ultrasound and CT scores (all p < 0.05). The modified 8-zone method strongly correlated with the 12-zone method (Pearson's r = 0.908, p < 0.05). The 8- and 12-zone methods correlated with CT scoring (correlation = 0.568 and 0.635, respectively; p < 0.05). The intragroup correlation coefficients of the 8-zone, 12-zone, and CT scoring methods were highly consistent (intragroup correlation coefficient = 0.718, p < 0.01). The 8-zone ultrasound score correlated negatively with oxygen saturation (rs  = 0.306, p < 0.05) and Ca (rs  = 0.224, p < 0.05) and positively with IL-6 (rs  = 0.0.335, p < 0.05), erythrocyte sedimentation rate (rs  = 0.327, p < 0.05), alanine aminotransferase (rs  = 0.230, p < 0.05), and aspartate aminotransferase (rs  = 0.251, p < 0.05). The 12-zone scoring method correlated negatively with oxygen saturation (rs  = 0.338, p < 0.05) and Ca (rs  = 0.245, p < 0.05) and positively with IL-6 (rs  = 0.354, p < 0.05) and erythrocyte sedimentation rate (rs  = 0.495, p < 0.05).

CONCLUSION

Lung ultrasound scores represent the clinical severity and have high clinical value for diagnosing COVID-19 pneumonia. The 8-zone scoring method can improve examination efficiency and reduce secondary injuries caused by patient movement.

Lung Ultrasonography Does Not Distinguish between Interstitial and Alveolar Pulmonary Edema

For a long time, lung diseases have been considered the "forbidden zone" for ultrasound diagnosis because the lung is filled with gas, and the ultrasound waves are totally reflected when they encounter gas [...].

Lung Ultrasound and Pleural Artifacts: A Pictorial Review

Lung ultrasound is a well-established diagnostic approach used in detecting pathological changes near the pleura of the lung. At the acoustic boundary of the lung surface, it is necessary to differentiate between the primary visualization of pleural parenchymal pathologies and the appearance of secondary artifacts when sound waves enter the lung or are reflected at the visceral pleura. The aims of this pictorial essay are to demonstrate the sonographic patterns of various pleural interface artifacts and to illustrate the limitations and pitfalls of the use of ultrasound findings in diagnosing any underlying pathology.

Inter-System Variability of Eight Different Handheld Ultrasound (HHUS) Devices-A Prospective Comparison of B-Scan Quality and Clinical Significance in Intensive Care

BACKGROUND

the use of handheld ultrasonography (HHUS) devices is well established in prehospital emergency diagnostics, as well as in intensive care settings. This is based on several studies in which HHUS devices were compared to conventional high-end ultrasonography (HEUS) devices. Nonetheless, there is limited evidence regarding potential variations in B-scan quality among HHUS devices from various manufacturers, and regarding whether any such differences hold clinical significance in intensive care medicine settings.

METHODS

this study included the evaluation of eight HHUS devices sourced from diverse manufacturers. Ultrasound videos of five previously defined sonographic questions (volume status/inferior vena cava, pleural effusion, pulmonary B-lines, gallbladder, and needle tracking in situ) were recorded with all devices. The analogue recording of the same pathologies with a HEUS device served as gold standard. The corresponding findings (HHUS and HEUS) were then played side by side and evaluated by sixteen intensive care physicians experienced in sonography. The B-scan quality and the clinical significance of the HHUS were assessed using a five-point Likert scale (5 points = very good; 1 point = insufficient).

RESULTS

both in assessing the quality of B-scans and in their ability to answer clinical questions, the HHUS achieved convincing results-regardless of the manufacturer. For example, only 8.6% (B-scan quality) and 9.8% (clinical question) of all submitted assessments received an "insufficient" rating. One HHUS device showed a significantly higher (p < 0.01) average points score in the assessment of B-scan quality (3.9 ± 0.65 points) and in the evaluation of clinical significance (4.03 ± 0.73 points), compared to the other devices.

CONCLUSIONS

HHUS systems are able to reliably answer various clinical intensive care questions and are-while bearing their limitations in mind-an acceptable alternative to conventional HEUS devices. Irrespective of this, the present study was able to demonstrate relevant differences in the B-scan quality of HHUS devices from different manufacturers.

Ultrasound of the lung

The CME review is intended to explain and discuss the clinical value of lung ultrasound but also to enable a pragmatically oriented approach by analyzing the clinical aspect. This includes knowledge of the pre-test probability, the acuteness of the disease, the current clinical situation, detection and/or characterization, initial diagnosis or follow up assessment and the peculiarities of exclusion diagnosis. Diseases of the pleura and lungs are described using these criteria with their direct and indirect sonographic signs and the specific clinical significance of ultrasound findings. The importance and criteria of conventional B-mode, color Doppler ultrasound with or without spectral analysis of the Doppler signal and contrast-enhanced ultrasound are discussed as well.

[Geriatric ultrasound : Prospective evaluation of ultrasound as extended screening in acute geriatric patients]

BACKGROUND

The aim of this study was to evaluate ultrasound as a routinely used procedure and extended physical examination in geriatric patients in acute care.

METHODS

Prospective study of 86 patients using ultrasound as a screening examination (abdomen, basal sections of the thorax, thyroid glands) under comparative use of a hand-held ultrasound device (HHUSD) and a high-end ultrasound (HEUS = gold standard).

RESULTS

In 20/86 (23.2%) clinically relevant findings with therapeutic consequences were found (pleural effusion, urinary retention, choledocholithiasis metatases, colon tumor). In 22/86 (25.6%) patients, additional questions existed besides the screening indication: tumor search (9.3%), anemia (5.8%), liver value elevation (5.8%), dyspnea (5.8%), splenic pathologies (2.3%), weight loss (1.2%), infectious focus (1.2%), diarrhea (1.2%), intra-abdominal hematoma (1.1%), abdominal aortic aneurysm (1.2%). The most common sonographic findings included: cholecystolithiasis (32.6%); right pleural effusion (31.4%), thyroid nodules (30.2%), renal cysts (27.9%), and fatty liver (26.7%). There were significant differences in sizing between HHUSD and HEUS (kidneys, pancreatic corpus and pancreatic caudal diameters, portal vein, left hepatic vein) without diagnostic relevance.

CONCLUSION

The extended screening by ultrasound provided important answers to classical questions in geriatrics (e.g. urinary retention, volume deficiency/pleural effusion) in many cases. The new findings had therapeutic consequences in one fifth of the patients. The HHUSD can be used in screening.

Two- Versus 8-Zone Lung Ultrasound in Heart Failure: Analysis of a Large Data Set Using a Deep Learning Algorithm

OBJECTIVE

Scanning protocols for lung ultrasound often include 8 or more lung zones, which may limit real-world clinical use. We sought to compare a 2-zone, anterior-superior thoracic ultrasound protocol for B-line artifact detection with an 8-zone approach in patients with known or suspected heart failure using a deep learning (DL) algorithm.

METHODS

Adult patients with suspected heart failure and B-lines on initial lung ultrasound were enrolled in a prospective observational study. Subjects received daily ultrasounds with a hand-held ultrasound system using an 8-zone protocol (right and left anterior/lateral and superior/inferior). A previously published deep learning algorithm that rates severity of B-lines on a 0-4 scale was adapted for use on hand-held ultrasound full video loops. Average severities for 8 and 2 zones were calculated utilizing DL ratings. Bland-Altman plot analyses were used to assess agreement and identify bias between 2- and 8-zone scores for both primary (all patients, 5728 videos, 205 subjects) and subgroup (confirmed diagnosis of heart failure or pulmonary edema, 4464 videos, 147 subjects) analyses.

RESULTS

Bland-Altman plot analyses revealed excellent agreement for both primary and subgroup analyses. The absolute difference on the 4-point scale between 8- and 2-zone average scores was not significant for the primary dataset (0.03; 95% CI -0.01 to 0.07) or the subgroup (0.01; 95% CI -0.04 to 0.06).

CONCLUSION

Utilization of a 2-zone, anterior-superior thoracic ultrasound protocol provided similar severity information to an 8-zone approach for a dataset of subjects with known or suspected heart failure.

Impact of serial cardiopulmonary point-of-care ultrasound exams in patients with acute dyspnoea: a randomised, controlled trial

BACKGROUND

Serial point-of-care ultrasound (PoCUS) can potentially improve acute patient care through treatment adjusted to the dynamic ultrasound findings. The objective was to investigate if treatment guided by monitoring patients with acute dyspnoea with serial cardiopulmonary PoCUS and usual care could reduce the severity of dyspnoea compared with usual care alone.

METHODS

This was a randomised, controlled, blinded-outcome trial conducted in three EDs in Denmark between 9 October 2019 and 26 May 2021. Patients aged ≥18 years admitted with a primary complaint of dyspnoea were allocated 1:1 with block randomisation to usual care, which included a single cardiopulmonary PoCUS within 1 hour of arrival (control group) or usual care (including a PoCUS within 1 hour of arrival) plus two additional PoCUS performed at 2 hours interval from the initial PoCUS (serial ultrasound group). The primary outcome was a reduction of dyspnoea measured on a verbal dyspnoea scale (VDS) from 0 to 10 recorded at inclusion and after 2, 4 and 5 hours.

RESULTS

There were 206 patients recruited, 102 in the serial ultrasound group and 104 in the control group, all of whom had complete follow-up. The mean difference in VDS between patients in the serial ultrasound and the control group was -1.09 (95% CI -1.51 to -0.66) and -1.66 (95% CI -2.09 to -1.23) after 4 and 5 hours, respectively. The effect was more pronounced in patients with a presumptive diagnosis of acute heart failure (AHF). A larger proportion of patients received diuretics in the serial ultrasound group.

CONCLUSION

Therapy guided by serial cardiopulmonary PoCUS may, together with usual care, facilitate greater improvement in the severity of dyspnoea, especially in patients with AHF compared with usual care with a single PoCUS in the ED. Serial PoCUS should therefore be considered for routine use to aid the physician in stabilising the patient faster.

TRIAL REGISTRATION NUMBER

NCT04091334.

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.

Lung Ultrasound in Predicting Outcomes in Patients with COVID-19 Treated with Extracorporeal Membrane Oxygenation

Pulmonary involvement due to SARS-CoV-2 infection can lead to acute respiratory distress syndrome in patients with COVID-19. Consequently, pulmonary imaging is crucial for management of COVID-19. This study aimed to evaluate the prognostic value of lung ultrasound (LUS) with a handheld ultrasound device (HHUD) in patients with COVID-19 treated with extracorporeal membrane oxygenation (ECMO). Therefore, patients underwent LUS with a HHUD every two days until they were either discharged from the intensive care unit or died. The study was conducted at the University Hospital of Bonn's anesthesiological intensive care ward from December 2020 to August 2021. A total of 33 patients (median [IQR]: 56.0 [53-60.5] years) were included. A high LUS score was associated with a decreased P/F ratio (repeated measures correlation [rmcorr]: -0.26; 95% CI: -0.34, -0.15; p < 0.001), increased extravascular lung water, defined as fluid accumulation in the pulmonary interstitium and alveoli (rmcorr: 0.11; 95% CI: 0.01, 0.20; p = 0.030), deteriorated electrolyte status (base excess: rmcorr: 0.14; 95% CI: 0.05, 0.24; p = 0.004; pH: rmcorr: 0.12; 95% CI: 0.03, 0.21; p = 0.001), and decreased pulmonary compliance (rmcorr: -0.10; 95% CI: -0.20, -0.01; p = 0.034). The maximum LUS score was lower in survivors (median difference [md]: -0.35; 95% CI: -0.55, -0.06; p = 0.006). A cutoff value for non-survival was calculated at a LUS score of 2.63. At the time of maximum LUS score, P/F ratio (md: 1.97; 95% CI: 1.12, 2.76; p < 0.001) and pulmonary compliance (md: 18.67; 95% CI: 3.33, 37.15; p = 0.018) were higher in surviving patients. In conclusion, LUS with a HHUD enables continuous evaluation of cardiopulmonary function in COVID-19 patients receiving ECMO support therapy and provides prognostic value in determining the patients' likelihood of survival.

Influence of Ultrasound Settings on Laboratory Vertical Artifacts

OBJECTIVE

The aim of the work described here was to analyze the relationship between the change in ultrasound (US) settings and the vertical artifacts' number, visual rating and signal intensity METHODS: An in vitro phantom consisting of a damp sponge and gelatin mix was created to simulate vertical artifacts. Furthermore, several US parameters were changed sequentially (i.e., frequency, dynamic range, line density, gain, power and image enhancement) and after image acquisition. Five US experts rated the artifacts for number and quality. In addition, a vertical artifact visual score was created to determine the higher artifact rating ("optimal") and the lower artifact rating ("suboptimal"). Comparisons were made between the tested US parameters and baseline recordings.

RESULTS

The expert intraclass correlation coefficient for the number of vertical artifacts was 0.694. The parameters had little effect on the "optimal" vertical artifacts but changed their number. Dynamic range increased the number of discernible vertical artifacts to 3 from 36 to 102 dB.

CONCLUSION

The intensity did not correlate with the visual rating score. Most of the available US parameters did not influence vertical artifacts.

Point-of-Care Ultrasonography in Internal Medicine: Limitations and Pitfalls for Novice Users

Point-of-care ultrasound (POCUS) is increasingly being adopted in the field of internal medicine, leading to the development of POCUS curricula in undergraduate and postgraduate medical education programs. Prominent internal medicine societies and organizations worldwide recognize the expanding utilization of POCUS by internal medicine physicians, emphasizing the need for practitioners to be aware of both its benefits and limitations. Despite the growing enthusiasm for POCUS, clinicians, particularly those with limited clinical experience, must be cautious regarding its inherent limitations and the potential impact on their clinical practice. This review aims to outline the limitations and potential drawbacks of POCUS for medical students, residents, and internists who wish to stay abreast of the escalating use of POCUS in internal medicine and have a desire, or have already commenced, to incorporate POCUS into their practice. Additionally, it provides recommendations for enhancing POCUS proficiency to mitigate these limitations.

Effect of driving pressure on early postoperative lung gas distribution in supratentorial craniotomy: a randomized controlled trial

BACKGROUND

Neurosurgical patients represent a high-risk population for postoperative pulmonary complications (PPCs). A lower intraoperative driving pressure (DP) is related to a reduction in postoperative pulmonary complications. We hypothesized that driving pressure-guided ventilation during supratentorial craniotomy might lead to a more homogeneous gas distribution in the lung postoperatively.

METHODS

This was a randomized trial conducted between June 2020 and July 2021 at Beijing Tiantan Hospital. Fifty-three patients undergoing supratentorial craniotomy were randomly divided into the titration group or control group at a ratio of 1 to 1. The control group received 5 cmH₂O PEEP, and the titration group received individualized PEEP targeting the lowest DP. The primary outcome was the global inhomogeneity index (GI) immediately after extubation obtained by electrical impedance tomography (EIT). The secondary outcomes were lung ultrasonography scores (LUSs), respiratory system compliance, the ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO₂/FiO₂) and PPCs within 3 days postoperatively.

RESULTS

Fifty-one patients were included in the analysis. The median (IQR [range]) DP in the titration group versus the control group was 10 (9-12 [7-13]) cmH₂O vs. 11 (10-12 [7-13]) cmH₂O, respectively (P = 0.040). The GI tract did not differ between groups immediately after extubation (P = 0.080). The LUS_S was significantly lower in the titration group than in the control group immediately after tracheal extubation (1 [0-3] vs. 3 [1-6], P = 0.045). The compliance in the titration group was higher than that in the control group at 1 h after intubation (48 [42-54] vs. 41 [37-46] ml·cmH₂O^-1, P = 0.011) and at the end of surgery (46 [42-51] vs. 41 [37-44] ml·cmH₂O^-1, P = 0.029). The PaO₂/FiO₂ ratio was not significantly different between groups in terms of the ventilation protocol (P = 0.117). At the 3-day follow-up, no postoperative pulmonary complications occurred in either group.

CONCLUSIONS

Driving pressure-guided ventilation during supratentorial craniotomy did not contribute to postoperative homogeneous aeration, but it may lead to improved respiratory compliance and lower lung ultrasonography scores.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT04421976.

Prognostic value of the early lung ultrasound B-line score for postoperative pulmonary insufficiency in patients undergoing thoracic surgery: an observational study

BACKGROUND

Postoperative pulmonary insufficiency (PPI) is an important contributor to morbidity and mortality after thoracic surgery. Lung ultrasound is a reliable tool for assessing respiratory function. We sought to determine the clinical value of the early lung ultrasound B-line score for predicting changes in pulmonary function after thoracic surgery.

METHODS

Eighty-nine patients undergoing elective lung surgery were included in this study. The B-line score was determined 30 min after removal of the endotracheal tube, and the PaO2/FiO2 ratio was recorded 30 min after extubation and on the third postoperative day. Patients were divided into normal (PaO2/FiO2 ≥ 300) and PPI (PaO2/FiO2 < 300) groups according to their PaO2/FiO2 ratios. A multivariate logistic regression model was used to identify independent predictors of postoperative pulmonary insufficiency. Receiver operating characteristic (ROC) analysis was performed for significantly correlated variables.

RESULTS

Eighty-nine patients undergoing elective lung surgery were included in this study. We evaluated 69 patients in the normal group and 20 in the PPI group. Patients conforming to NYHA class 3 at administration were significantly more represented in the PPI group (5.8 and 55%; p < 0.001). B-line scores were significantly higher in the PPI group than in the normal group (16; IQR 13-21 vs. 7; IQR 5-10; p < 0.001). The B-line score was an independent risk factor (OR = 1.349 95% CI 1.154-1.578; p < 0.001), and its best cutoff value for predicting PPI was 12 (sensitivity: 77.5%; specificity: 66.7%).

CONCLUSIONS

Lung ultrasound B-line scores 30 min after extubation are effective in predicting early PPI in patients undergoing thoracic surgery. Trial registration This study was registered with the Chinese Clinical Trials Registry (ChiCTR2000040374).

Diagnosing Lung Abnormalities Related to Heart Failure in Chest Radiogram, Lung Ultrasound and Thoracic Computed Tomography

Heart failure (HF) is a multidisciplinary disease affecting almost 1-2% of the adult population worldwide. Symptoms most frequently reported by patients suffering from HF include dyspnoea, cough or exercise intolerance, which is equally often observed in many pulmonary diseases. The spectrum of lung changes related to HF is wide. The knowledge of different types of these abnormalities is essential to distinguish patients with HF from patients with lung diseases or both disorders and thus avoid unnecessary diagnostics or therapies. In this review, we aimed to summarise recent research concerning the spectrum of lung abnormalities related to HF in three frequently used lung imaging techniques: chest X-ray (CXR), lung ultrasound (LUS) and chest computed tomography (CT). We discussed the most prevalent abnormalities in the above-mentioned investigations in the context of consecutive pathophysiological stages identified in HF: (i) redistribution, (ii) interstitial oedema, and (iii) alveolar oedema. Finally, we compared the utility of these imaging tools in the clinical setting. In conclusion, we consider LUS the most useful and promising imaging technique due to its high sensitivity, repeatability and accessibility. However, the value of CXR and chest CT is their potential for establishing a differential diagnosis.

Pulmonary Sonography - Neonatal Diagnosis Part 1

Diseases of the respiratory system are among the main problems of premature patients in the neonatal intensive care unit. Radiography of the thorax is the gold standard of imaging. This results in high cumulative radiation exposure with potential negative long-term consequences. Ultrasound examination of thoracic structures represents a promising radiation-free and ubiquitously available alternative.A healthy, ventilated lung can only be imaged via artifacts, since total reflection of the sound waves occurs due to the high impedance difference between tissue and air-filled lung. Pathologies of pleura and subpleural lung tissue lead to changes in the acoustic properties of the tissue and thus to variations in the artifacts that can be imaged. The main sonographic characteristics of pulmonary pathology are: pleural line abnormalities, increased B-lines and comet-tail artifacts, lung consolidations, a visible pulmonary pulse, pleural sliding abnormalities, and visualization of effusions. Deviations from normal sonographic findings can be assigned to specific underlying pathophysiologies, so that conclusions about the disease can be drawn in conjunction with the clinical symptoms.

Lung Ultrasonographic Signs in Pulmonary Disease - A Video Review

Lung ultrasound (US) is a well-established imaging tool in the inpatient and critical care setting. It has proven its worth in the rapid bedside diagnosis of a variety of conditions pertaining to the lungs and the thorax. Lung US was initially introduced as a bedside imaging tool to evaluate the size and characteristics of pleural effusion. Over the years, the field of lung ultrasonography has rapidly expanded introducing nuances in image interpretation. Numerous primary and secondary signs have been described in the literature to identify both normal and abnormal findings. The primary signs can help narrow the list of differential diagnoses, whereas the addition of secondary signs help create an imaging pattern facilitating the confirmation of diagnosis or recognition of the underlying disease process. These wide variety of signs and patterns can present a challenge to the learning of lung ultrasonography, particularly to a novice user. We sought to compile a comprehensive list of these findings to serve as a useful resource to aid effortless adoption of lung ultrasonography in clinical practice. In this review, we narrate the evolution of lung US, describe common protocols applied in performance of the lung US, and illustrate a comprehensive list of common lung US signs and patterns along with their differential diagnosis and clinical utility.

Vertical Artifacts as Lung Ultrasound Signs: Trick or Trap? Part 2- An Accademia di Ecografia Toracica Position Paper on B-Lines and Sonographic Interstitial Syndrome

Although during the last few years the lung ultrasound (LUS) technique has progressed substantially, several artifacts, which are currently observed in clinical practice, still need a solid explanation of the physical phenomena involved in their origin. This is particularly true for vertical artifacts, conventionally known as B-lines, and for their use in clinical practice. A wider consensus and a deeper understanding of the nature of these artifactual phenomena will lead to a better classification and a shared nomenclature, and, ultimately, result in a more objective correlation between anatomo-pathological data and clinical scenarios. The objective of this review is to collect and document the different signs and artifacts described in the history of chest ultrasound, with a particular focus on vertical artifacts (B-lines) and sonographic interstitial syndrome (SIS). By reviewing the possible physical and anatomical interpretation of the signs and artifacts proposed in the literature, this work also aims to bring order to the available studies and to present the AdET (Accademia di Ecografia Toracica) viewpoint in terms of nomenclature and clinical approach to the SIS.

The use of lung ultrasound in COVID-19

This review article addresses the role of lung ultrasound in patients with coronavirus disease 2019 (COVID-19) for diagnosis and disease management. As a simple imaging procedure, lung ultrasound contributes to the early identification of patients with clinical conditions suggestive of COVID-19, supports decisions about hospital admission and informs therapeutic strategy. It can be performed in various clinical settings (primary care facilities, emergency departments, hospital wards, intensive care units), but also in outpatient settings using portable devices. The article describes typical lung ultrasound findings for COVID-19 pneumonia (interstitial pattern, pleural abnormalities and consolidations), as one component of COVID-19 diagnostic workup that otherwise includes clinical and laboratory evaluation. Advantages and limitations of lung ultrasound use in COVID-19 are described, along with equipment requirements and training needs. To infer on the use of lung ultrasound in different regions, a literature search was performed using key words "COVID-19", "lung ultrasound" and "imaging". Lung ultrasound is a noninvasive, rapid and reproducible procedure; can be performed at the point of care; requires simple sterilisation; and involves non-ionising radiation, allowing repeated exams on the same patient, with special benefit in children and pregnant women. However, physical proximity between the patient and the ultrasound operator is a limitation in the current pandemic context, emphasising the need to implement specific infection prevention and control measures. Availability of qualified staff adequately trained to perform lung ultrasound remains a major barrier to lung ultrasound utilisation. Training, advocacy and awareness rising can help build up capacities of local providers to facilitate lung ultrasound use for COVID-19 management, in particular in low- and middle-income countries.

B-line Elastography Measurement of Lung Parenchymal Elasticity

This paper proposes a method to determine the elasticity of the lung parenchyma from the B-line Doppler signal observed using continuous shear wave elastography, which uses a small vibrator placed on the tissue surface to propagate continuous shear waves with a vibration frequency of approximately 100 Hz. Since the B-line is generated by multiple reflections in fluid-storing alveoli near the lung surface, the ultrasonic multiple-reflection signal from the B-line is affected by the Doppler shift due to shear waves propagating in the lung parenchyma. When multiple B-lines are observed, the propagation velocity can be estimated by measuring the difference in propagation time between the B-lines. Therefore, continuous shear wave elastography can be used to determine the elasticity of the lung parenchyma by measuring the phase difference of shear wave between the B-lines. In this study, three elastic sponges (soft, medium, and hard) with embedded glass beads were used to simulate fluid-storing alveoli. Shear wave velocity measured using the proposed method was compared with that calculated using Young's modulus obtained from compression measurement. Using the proposed method, the measured shear wave velocities (mean ± S.D.) were 3.78 ± 0.23, 4.24 ± 0.12, and 5.06 ± 0.05 m/s for soft, medium, and hard sponges, respectively, which deviated by a maximum of 5.37% from the values calculated using the measured Young's moduli. The shear wave velocities of the sponge phantom were in a velocity range similar to the mean shear wave velocities of healthy and diseased lungs reported by magnetic resonance elastography (3.25 and 4.54 m/s, respectively). B-line elastography may enable emergency diagnoses of acute lung disease using portable ultrasonic echo devices.

To B or not to B. The rationale for quantifying B-lines in pediatric lung diseases

Lung ultrasound (LUS) is emerging as adjunct tool to be used during clinical assessment. Among the different hallmarks of LUS, B-lines are well known artifacts, which are not correlated with identifiable structures, but which can be used for pathological classification. The presence of multiple B-lines is a sonographic sign of lung interstitial syndrome. It has been demonstrated in adults that there is a direct correlation between the number of B-lines and the severity of the interstitial involvement of lung disease. Counting B-lines is an attempt to enrich the clinical assessment and clinical information, beyond obtaining a simple dichotomous answer. Semiquantitative or quantitative B-line assessment has been shown to correlate with fluid overload and demonstrated prognostic implications in specific neonatal and pediatric conditions. LUS with quantitative B-lines assessment is promising. Current evidence allows for quantification of B-lines in a limited number of neonatal and pediatric diseases.

Unsupervised landmark detection and classification of lung infection using transporter neural networks

Supervised deep learning techniques have been very popular in medical imaging for various tasks of classification, segmentation, and object detection. However, they require a large number of labelled data which is expensive and requires many hours of careful annotation by experts. In this paper, an unsupervised transporter neural network framework with an attention mechanism is proposed to automatically identify relevant landmarks with applications in lung ultrasound (LUS) imaging. The proposed framework identifies key points that provide a concise geometric representation highlighting regions with high structural variation in the LUS videos. In order for the landmarks to be clinically relevant, we have employed acoustic propagation physics driven feature maps and angle-controlled Radon Transformed frames at the input instead of directly employing the gray scale LUS frames. Once the landmarks are identified, the presence of these landmarks can be employed for classification of the given frame into various classes of severity of infection in lung. The proposed framework has been trained on 130 LUS videos and validated on 100 LUS videos acquired from multiple centres at Spain and India. Frames were independently assessed by experts to identify clinically relevant features such as A-lines, B-lines, and pleura in LUS videos. The key points detected showed high sensitivity of 99% in detecting the image landmarks identified by experts. Also, on employing for classification of the given lung image into normal and abnormal classes, the proposed approach, even with no prior training, achieved an average accuracy of 97% and an average F1-score of 95% respectively on the task of co-classification with 3-fold cross-validation.

Lung Ultrasound Induction of Pulmonary Capillary Hemorrhage in Neonatal Swine

This study investigated induction of pulmonary capillary hemorrhage (PCH) in neonatal pigs (piglets) using three different machines: a GE Venue R1 point-of-care system with C1-5 and L4-12t probes, a GE Vivid 7 Dimension with a 7L probe and a SuperSonic Imagine machine with an SL15-4 probe and shear wave elastography (SWE). Female piglets were anesthetized, and each was mounted vertically in a warm bath for scanning at two or three intercostal spaces. After aiming at an innocuous output, the power was raised for a test exposure. Hydrophone measurements were used to calculate in situ values of mechanical index (MIIS). Inflated lungs were removed and scored for PCH area. For the C1-5 probe at 50% and 100% acoustical output (AO), a PCH threshold of 0.53 MIIS was obtained by linear regression (r2 = 0.42). The L4-12t probe did not induce PCH, but the 7L probe induced zones of PCH in the scan planes. The Venue R1 automated B-line tool applied with the C1-5 probe did not detect PCH induced by the C1-5 probe as B-line counts. However, when PCH induced by C1-5 and 7L exposures were subsequently scanned with the L4-12t probe using the automated tool, B-lines were counted in association with the PCH. The SWE induced PCH at push-pulse positions for 3, 30 and 300 s of SWE with PCH accumulating at 0.33 mm2/s and an exponential rise to a maximum of 18.4 mm2 (r2 = 0.61). This study demonstrated the induction of PCH by LUS of piglets, and supports the safety recommendation for use of MIs <0.4 in neonatal LUS.

Association Between Lung Ultrasound Patterns and Pneumonia

ABSTRACT

Pneumonia is a common respiratory infection that affects the lungs. Lung ultrasound (LUS) is a portable, cost-effective imaging method, which is free of ionizing radiation and has been shown to be useful for evaluating pneumonia. The aim of this retrospective analytical study was to determine the association between lung ultrasound patterns and pneumonia. For the purpose of performing the required analysis, LUS patterns including consolidations, pleural line irregularities, A lines and B lines from 90 subjects (44 patients with confirmed pneumonia and 46 controls) were retrieved from a published open-access data set, which was reviewed and approved by medical experts. A χ 2 test was used for the comparison of categorical variables to determine the association between each LUS pattern and the presence of pneumonia. There is a significant association between LUS consolidation and the presence of pneumonia ( P < 0.0001). Lung ultrasound A lines are significantly associated with the absence of pneumonia ( P < 0.0001), whereas there are no associations between B lines or pleural line irregularities with pneumonia. Lung ultrasound consolidation is found to be associated with the presence of pneumonia. A lines are associated with healthy lungs, and there is no association of B lines and pleural irregularities with the presence of pneumonia. Further studies investigating LUS patterns with clinical information and symptoms of patients with pneumonia are required.

Role of Lung Ultrasound in the Management of Patients with Suspected SARS-CoV-2 Infection in the Emergency Department

Background: The lung ultrasound (LUS) score has been proposed as an optimal scheme for the ultrasound study of patients with suspected/confirmed COVID-19 pneumonia. The aims of our study were to evaluate the use of lung ultrasound as a diagnostic tool for diagnosing SARS-CoV-2 pneumonia, to examine the validity of the LUS score for the diagnosis of COVID-19 pneumonia, and to correlate this score with hospitalization rate and 30-day mortality. Materials and Methods: A retrospective analysis was performed on 1460 patients who were referred to the General Emergency Department of the S. Orsola-Malpighi Hospital from April 2020 to May 2020 for symptoms suspected to indicate SARS-CoV-2 infection. The ultrasound examination was based on a common execution scheme called the LUS score, as previously described. Results and Conclusions: The LUS score was found to correlate with the degree of clinical severity and respiratory failure (paO2/FiO2 ratio and the alveolar−arterial gradient increase than expected for age). It was shown that COVID-19 patients with an LUS score of >7 require the use of oxygen support, and a value of >10 is associated with an increased risk of oro-tracheal intubation. The LUS score was found to present higher values in hospitalized patients, increasing according to the degree of care intensity. Patients who died from COVID-19 were characterized by a mean LUS score of 11 at presentation to the emergency department. An LUS score of >7.5 was found to indicate a sensitivity of 83% and a specificity of 89% for 30-day mortality in COVID-19 patients. The use of LUS seems to be an optimal first level method for pneumonia detection and risk stratification in patients with suspected SARS-CoV-2 infection.

What Is COVID 19 Teaching Us about Pulmonary Ultrasound?

In lung ultrasound (LUS), the interactions between the acoustic pulse and the lung surface (including the pleura and a small subpleural layer of tissue) are crucial. Variations of the peripheral lung density and the subpleural alveolar shape and its configuration are typically connected to the presence of ultrasound artifacts and consolidations. COVID-19 pneumonia can give rise to a variety of pathological pulmonary changes ranging from mild diffuse alveolar damage (DAD) to severe acute respiratory distress syndrome (ARDS), characterized by peripheral bilateral patchy lung involvement. These findings are well described in CT imaging and in anatomopathological cases. Ultrasound artifacts and consolidations are therefore expected signs in COVID-19 pneumonia because edema, DAD, lung hemorrhage, interstitial thickening, hyaline membranes, and infiltrative lung diseases when they arise in a subpleural position, generate ultrasound findings. This review analyzes the structure of the ultrasound images in the normal and pathological lung given our current knowledge, and the role of LUS in the diagnosis and monitoring of patients with COVID-19 lung involvement.

Ten conditions where lung ultrasonography may fail: limits, pitfalls and lessons learned from a computer-aided algorithmic approach

Lung ultrasonography provides relevant information on morphological and functional changes occurring in the lungs. However, it correlates weakly with pulmonary congestion and extra vascular lung water. Moreover, there is lack of consensus on scoring systems and acquisition protocols. The automation of this technique may provide promising easy-to-use clinical tools to reduce inter- and intra-observer variability and to standardize scores, allowing faster data collection without increased costs and patients risks.

Lung Ultrasound in Children with Cystic Fibrosis in Comparison with Chest Computed Tomography: A Feasibility Study

Background: Cystic fibrosis (CF) lung disease determines the outcome of this condition. For lung evaluation processes, computed tomography (CT) is the gold standard, but also causes irradiation. Lately, lung ultrasound (LUS) has proven to be reliable for the diagnosis of consolidations, atelectasis, and/or bronchiectasis. The aim of our study was to evaluate the value of a newly conceived LUS score by comparing it to the modified Bhalla CT score. A further aim was to evaluate the correlation between the score and the lung clearance index (LCI). Methods: Patients with CF were screened by LUS, followed by a CT scan. Spearman’s test was used for correlations. Results: A total of 98 patients with CF were screened, and 57 were included in the study; their mean age was 11.8 ± 5.5 (mean ± SD) years. The mean LUS score was 5.88 ± 5.4 SD. The LUS CF score had a very strong correlation with the CT score of rs = 0.87 (p = 0.000). LUS showed a good sensibility for detecting atelectasis (Se = 83.7%) and consolidations (Se = 94.4%). A lower Se (77.7%) and Sp (9%) were found for cylindrical bronchiectasis. Conclusion: Our study shows that LUS and the lung CF score are parameters that can be used with a complementary role in the diagnosis and monitoring of CF lung disease in children.

Contrast-Enhanced Ultrasound for Evaluation of Pleural Effusion: A Pictorial Essay

B-mode ultrasound (B-US) is the standard imaging modality to evaluate pleural effusion. The value of B-US for assessing the malignancy of a pleural effusion (PE) is limited. For this purpose, computed tomography (CT) and thoracoscopy are the methods of choice to evaluate an effusion. The aim of this Pictorial Essay is to demonstrate contrast-enhanced ultrasound (CEUS) as a method in addition to B-US and CT for the evaluation of PE taking into account the clinical background. The characteristic patterns of pleural pathologies, effusion morphology, and associated lung parenchymal consolidations are presented.

Automation of Lung Ultrasound Interpretation via Deep Learning for the Classification of Normal versus Abnormal Lung Parenchyma: A Multicenter Study

Lung ultrasound (LUS) is an accurate thoracic imaging technique distinguished by its handheld size, low-cost, and lack of radiation. User dependence and poor access to training have limited the impact and dissemination of LUS outside of acute care hospital environments. Automated interpretation of LUS using deep learning can overcome these barriers by increasing accuracy while allowing point-of-care use by non-experts. In this multicenter study, we seek to automate the clinically vital distinction between A line (normal parenchyma) and B line (abnormal parenchyma) on LUS by training a customized neural network using 272,891 labelled LUS images. After external validation on 23,393 frames, pragmatic clinical application at the clip level was performed on 1162 videos. The trained classifier demonstrated an area under the receiver operating curve (AUC) of 0.96 (±0.02) through 10-fold cross-validation on local frames and an AUC of 0.93 on the external validation dataset. Clip-level inference yielded sensitivities and specificities of 90% and 92% (local) and 83% and 82% (external), respectively, for detecting the B line pattern. This study demonstrates accurate deep-learning-enabled LUS interpretation between normal and abnormal lung parenchyma on ultrasound frames while rendering diagnostically important sensitivity and specificity at the video clip level.

Diagnostic ultrasound imaging of the lung: A simulation approach based on propagation and reverberation in the human body

Although ultrasound cannot penetrate a tissue/air interface, it images the lung with high diagnostic accuracy. Lung ultrasound imaging relies on the interpretation of "artifacts," which arise from the complex reverberation physics occurring at the lung surface but appear deep inside the lung. This physics is more complex and less understood than conventional B-mode imaging in which the signal directly reflected by the target is used to generate an image. Here, to establish a more direct relationship between the underlying acoustics and lung imaging, simulations are used. The simulations model ultrasound propagation and reverberation in the human abdomen and at the tissue/air interfaces of the lung in a way that allows for direct measurements of acoustic pressure inside the human body and various anatomical structures, something that is not feasible clinically or experimentally. It is shown that the B-mode images beamformed from these acoustical simulations reproduce primary clinical features that are used in diagnostic lung imaging, i.e., A-lines and B-lines, with a clear relationship to known underlying anatomical structures. Both the oblique and parasagittal views are successfully modeled with the latter producing the characteristic "bat sign," arising from the ribs and intercostal part of the pleura. These simulations also establish a quantitative link between the percentage of fluid in exudative regions and the appearance of B-lines, suggesting that the B-mode may be used as a quantitative imaging modality.