Lung transthoracic ultrasound elastography imaging and guided biopsies of subpleural cancer: a preliminary report

Current evidence for lung ultrasound elastography in the field of pneumology: a systematic review

Background and objectives

Elastography is a technology that has strongly impacted several medical specialties; however, it is not yet applied as part of standard clinical practice in the field of pulmonology. The objective of this systematic review is to analyse the evidence available to date in relation to pleuropulmonary ultrasound elastography, focusing on the three pathologies with the most publications: subpleural consolidations, interstitial lung diseases and pleural effusion.

Methods

Original in vivo studies published up until 12 August 2023 in the Embase, MEDLINE or Web of Science databases were included. The QUADAS-2 tool was applied to analyse bias.

Results

We found 613 records in database search. After duplicates removal, we screened 246 records and finally included 18 papers. The average cohort sample size was 109 patients. The elastography modes most frequently used were strain (22.2%), transient elastography (22.2%), point shear-wave elastography (38.9%) and two-dimensional shear-wave elastography (22.2%). The possibility of a meta-analysis was ruled out because of the heterogeneity of the studies included.

Discussion

The currently available literature indicates that pleuropulmonary ultrasound elastography produces promising and consistent results, although the lack of standardisation in the use of the technique and in the elastography modes employed still impedes its use in daily clinical pneumology practice. The development of a clinical guideline establishing a common nomenclature and standardised techniques for pleuropulmonary elastography will be imperative to generate quality scientific evidence in this field.

Lung ultrasound in a nutshell. Lines, signs, some applications, and misconceptions from a radiologist's point of view. Part 2

In recent years, lung ultrasound (LUS) has developed rapidly, and it is gaining growing popularity in various scenarios. There are constant attempts to introduce it to new fields. In addition, knowledge regarding lung and LUS has been augmented by the recent COVID-19 pandemics. In the first part of this review we discuss lines, signs and pheno-mena, profiles, some applications, and misconceptions. An aim of the second part of the review is mainly to discuss some advanced applications of LUS, including lung elastography, lung spectroscopy, colour and spectral Doppler, contrast-enhanced ultrasound of lung, speckled tracking of pleura, quantification of pulmonary oedema, predicting success of talc pleurodesis, asthma exacerbations, detecting chest wall invasion by tumours, lung biopsy, estimating pleural effusion volume, and predicting mechanical ventilatory weaning outcome. For this purpose, we reviewed literature concerning LUS.

The synergized diagnostic value of VTQ with chemokine CXCL13 in lung tumors

Virtual Touch Tissue Quantification (VTQ) offers several advantages in the diagnosis of various lung diseases. Chemokine expression levels, such as CXCL13, play a vital role in the occurrence and development of tumors and aid in the diagnosis process. The purpose of this study was to evaluate the combined value of VTQ and changes in CXCL13 expression levels for the diagnosis of lung tumors. A total of 60 patients with thoracic nodules and pleural effusion were included, with 30 of them having malignant pleural effusion (based on pathology) and the remaining 30 having benign thoracic nodules and pleural effusion. The relative expression level of CXCL13 was measured in the collected pleural effusions using Enzyme-Linked Immunosorbent Assay (ELISA). The relationship between CXCL13 expression levels and various clinical features was analyzed. A Receiver Operating Characteristic (ROC) curve analysis was conducted on the VTQ results and relative expression levels of CXCL13, and the areas under the curve, critical values, sensitivity, and specificity were calculated. Multivariate analysis incorporating multiple indicators was performed to determine the accuracy of lung tumor diagnosis. The results showed that the expression levels of CXCL13 and VTQ were significantly higher in the lung cancer group compared to the control group (P < 0.05). In the Non-Small Cell Lung Cancer (NSCLC) group, CXCL13 expression levels increased with later TNM staging and poorer tumor differentiation. The expression level of CXCL13 in adenocarcinoma was higher than that in squamous cell carcinoma. The ROC curve analysis revealed that CXCL13 had an area under the curve (AUC) of 0.74 (0.61, 0.86) with an optimal cut-off value of 777.82 pg/ml for diagnosing lung tumors. The ROC curve analysis of VTQ showed an AUC of 0.67 (0.53, 0.82) with a sensitivity of 60.0% and a specificity of 83.3%, and an optimal diagnostic cut-off of 3.33 m/s. The combination of CXCL13 and VTQ for diagnosing thoracic tumors had an AUC of 0.842 (0.74, 0.94), which was significantly higher than either factor alone. The results of the study demonstrate the strong potential of combining VTQ results with chemokine CXCL13 expression levels for lung tumor diagnosis. Additionally, the findings suggest that elevated relative expression of CXCL13 in cases of malignant pleural effusion caused by non-small cell lung cancer may indicate a poor prognosis. This provides promising potential for using CXCL13 as a screening tool and prognostic indicator for patients with advanced lung cancer complicated by malignant pleural effusion.

Diagnostic Performance of Point Shear Wave Elastography Using Acoustic Radiation Force Impulse Technology in Peripheral Pulmonary Consolidations: A Feasibility Study

The aim of the study described here was to evaluate the diagnostic performance of lung ultrasound point shear wave elastography using acoustic radiation force impulse (ARFI) in peripheral pulmonary consolidations (PPCs). A total of 87 patients with PPCs diagnosed from April to December 2020 were included retrospectively in the study. The inclusion criteria were (i) a PPC >1 cm; (ii) valid ARFI measurements; and (iii) confirmation of the diagnosis of a PPC by histocytological examination and/or clinical and radiological follow-up. The presence of pleural effusions and mean ARFI velocities (MAVs) of PPCs were evaluated. To examine the MAV for potential cutoff values between benign and malignant PPCs, a receiver operating characteristic analysis was implemented. In total, 48 of 87 PPCs (55.2%) were accompanied by pleural effusions. Benign PPCs had significantly lower MAVs than malignant PPCs (1.82 ± 0.97 m/s vs. 3.05 ± 0.73 m/s, p < 0.001). Selecting 2.21 m/s as a cutoff value yielded a sensitivity and specificity of 89.7% and 75.9%, respectively, in diagnosing malignant PPCs (area under the curve = 0.852, 95% confidence interval: 0.773-0.931). In summary, ARFI elastography may be an additional non-invasive tool for differentiating benign from malignant PPCs. Furthermore, the feasibility of using ARFI elastography in PPCs associated with pleural effusions was proved. However, there is some degree of overlap between different disease entities, and diagnosis should always take into account the clinical background.

Conformity of Fine Needle Aspiration Biopsy (FNAB) and Core Needle Biopsy (CNB) in peripheral lung tumor patients: A cross-sectional study

Background

The problem of establishing lung tumor diagnostics is a challenge for clinicians, especially pulmonologists, in determining a definitive diagnosis of a lung tumor.

Objective

Analyzing the conformity of anatomical pathology results between fine-needle aspiration biopsy (FNAB) and core needle biopsy (CNB) materials in peripheral lung tumors.

Methods

A cross-sectional study was conducted from July 2019 to December 2020 with 66 participants. Participants were examined for CNB and FNAB, in which the results of these examinations were compared for conformity. Statistical analysis used the Kappa test with p < 0.05.

Result

Most participants' tumor size was >70 mm, with FNAB results showing malignant category (39.5%), non-malignant (40.0%), and undiagnosed (38.9%; p = 0.757). Meanwhile, CNB examination showed a tumor size of >70 mm that was categorized into malignant (40.4%) and non-malignant (33.3%; p = 0.510). Most tumors were located in the right superior lobe that had FNAB results in the malignant (39.5%), non-malignant (30.0%) and undiagnosed (27.8%; p = 0.306) categories. The CNB examination also showed that most tumors were located in the right superior lobe, which had resulted in the category of malignant (34.4%), non-malignant (26.7%), and undiagnosed (75.0%; p = 0.240). Conformity of anatomical pathology results from FNAB and CNB subject such as malignancy category of 35 participants (74.5%), non-malignancy of 7 participants (53.8%) and undiagnosed of 4 participants (16.7%) with an accuracy of 69.69% (Κ = 0.43; p = 0.001).

Conclusion

There is a conformity between the anatomical pathology results from FNAB and CNB materials for the diagnosis of lung tumors. CNB showed better results in the detection of anatomical malignancy and specimen adequacy.

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There is a conformity between the results of FNAB and CNB assisted by ultrasound.

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FNAB and CNB results in lung cancer are similar >70%.

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The use of FNAB followed by CNB minimizes misdiagnosis.

Real-Time Pleural Elastography: Potential Usefulness in Nonintubated Video-Assisted Thoracic Surgery

Pleural adhesions are a major challenge in standard and nonintubated video-assisted thoracic surgery. The currently available imaging techniques help to assess the presence and extent of pleural adhesions, but do not provide information on tissue deformability, which is crucial for intraoperative management. In this report, we describe the utilization of real-time elastography mapping of pleural adhesions. This technique enabled us to detect areas with softer adhesions, and helped establish the surgical plan in a difficult case of a patient scheduled for nonintubated video-assisted thoracic surgery.

Lung Ultrasound in Patients With Dyspnea From Infective Lung Disease

Infective lung disease is a spectrum of pulmonary disorders with high prevalence in clinical practice. In the last decade, many studies focused on the clinical usefulness of lung ultrasound (LUS) in the management of patients presenting with dyspnea from infective lung disease. We report data on the methodological and standardized use of bedside LUS in the differential diagnosis of patients with acute dyspnea from infective lung diseases. We performed a cross-sectional study in 439 patients (160 women and 279 men, mean age 64.2 ± 11.5 years, age range 23-91 years) with infective lung diseases. A bedside LUS with a convex probe and chest X-ray were performed in all subjects. Chest CT was performed in a subgroup of patients, as clinically needed. We observed a statistically significant difference in the percentage of pleural effusion and pulmonary consolidation assessed by LUS, compared to X-ray (52.7 vs. 20%, respectively, p < 0.05; 93.6 vs. 48.2%, p < 0.001). The majority of the consolidations detected by LUS were mixed, hypo- and hyperechoic, lesions, with air bronchogram in 40% of cases. All findings assessed by LUS were confirmed by chest CT, when performed. We describe the actual role of LUS in the assessment of patients with infective lung disease. It has higher sensitivity compared to chest X-ray in the detection of pleural effusion. Consolidations from infective lung disease have mostly mixed echogenicity by LUS.

Transthoracic Ultrasound in Infectious Organizing Pneumonia: A Useful Guide for Percutaneous Needle Biopsy

In patients presenting with classical features of CAP (i.e., new peripheral pulmonary consolidations and symptoms including fever, cough, and dyspnea), a clinical response to the appropriate therapy occurs in few days. When clinical improvement has not occurred and chest imaging findings are unchanged or worse, a more aggressive approach is needed in order to exclude other non-infective lesions (including neoplasms). International guidelines do not currently recommend the use of transthoracic ultrasound (TUS) as an alternative to chest X-ray (CXR) or chest computed tomography (CT) scan for the diagnosis of CAP. However, a fundamental role for TUS has been established as a guide for percutaneous needle biopsy (US-PNB) in pleural and subpleural lesions. In this retrospective study, we included 36 consecutive patients whose final diagnosis, made by a US-guided percutaneous needle biopsy (US-PTNB), was infectious organizing pneumonia (OP). Infective etiology was confirmed by additional information from microbiological and cultural studies or with a clinical follow-up of 6–12 months after a second-line antibiotic therapy plus corticosteroids. All patients have been subjected to a chest CT and a systematic TUS examination before biopsy. This gave us the opportunity to explore TUS performance in assessing CT findings of infective OP. TUS sensitivity and specificity in detecting air bronchogram and necrotic areas were far lower than those of CT scan. Conversely, TUS showed superiority in the detection of pleural effusion. Although ultrasound findings did not allow the characterization of chronic subpleural lesions, TUS confirmed to be a valid diagnostic aid for guiding percutaneous needle biopsy of subpleural consolidations.

Application of Transthoracic Shear Wave Elastography in Evaluating Subpleural Pulmonary Lesions

AIM

The objective of this research was to investigate the feasibility of transthoracic shear wave elastography in the differentiation of subpleural masses.

METHODS

Between December 2019 and November 2020,82 consecutive patients with radiographic evidence (including chest X ray and thoracic computed tomography CT) of single subpleural lesion enrolled in this research. The Young's modulus E (including E_mean and E_max) of each lesion was detected, and the Young's modulus E of malignant lesions were compared with those of benign ones. We made diagnoses according to the results of pathology or standard clinical course for at least 3 months. Receiver operating characteristic (ROC) analysis was plotted to determine the cut-off point by maximizing the Youden index.

RESULTS

The E_mean and E_max of the benign and malignant group was 34.68 ± 12.12 kPa vs. 53.82 ± 11.95 kPa (p < 0.001), 57.77 ± 14.45 kPa vs. 76.62 ± 17.04 kPa (p < 0.001). The ROC of E_mean showed that when the cut-off point was 43.8 kPa, the Youden index (0.53) for distinguishing benign and malignant tumors was the largest (sensitivity 80.4 %, specificity 72.2 %, AUC = 0.848, p < 0.0001). When the cut-off point recommended by E_max ROC was 73.5 kPa, the Youden index (0.44) for distinguishing benign and malignant tumors was the largest (sensitivity 76.1 %, specificity 66.7 %, AUC = 0.780, p < 0.0001).

CONCLUSIONS

This study demonstrated that we can employ transthoracic shear wave elastography as a valuable instrument in differentiating benign subpleural lesions from malign ones.

A Model for Predicting Malignant Sub-pleural Solid Masses Using Grayscale Ultrasound and Ultrasound Elastography

This article aimed to establish a prediction model of grayscale sonography and ultrasound elastography for malignant sub-pleural solid masses and evaluate its diagnostic value. The study included 153 patients, including 89 patients with malignant tumors and 64 patients with benign diseases. Statistical differences between the malignant and benign groups were found in the factors of age, air bronchogram, borderline, shape and elasticity score (p < 0.05). Age, elasticity score and borderline were effective factors for predicting malignant sub-pleural solid masses, offering an area under the receiver operating characteristic curve (AUROC) value of 0.72 (95% confidence interval [CI] 0.64-0.80), 0.73 (95% CI 0.65-0.79) and 0.70 (95% CI 0.62-0.77), respectively. The AUROC value of the prediction model for malignant sub-pleural solid masses was 0.88 (95% CI 0.81-0.92), which indicates that the prediction model was able to improve the diagnostic accuracy and that it may prove a useful auxiliary diagnostic tool for malignant sub-pleural solid masses, especially in primary health care institutions in developing countries.

Transthoracic ultrasound shear wave elastography for the study of subpleural lung lesions

PURPOSE

The aim of this study was to assess whether new-generation shear wave elastography (SWE) is suitable for the characterization of lung subpleural lesions.

METHODS

In total, 190 consecutive patients with subpleural lung lesions received ultrasonography and SWE. Patients with suspected malignancy underwent ultrasound-guided transthoracic needle biopsy. Final diagnoses were made on the basis of patients' clinical course, microbiological studies, and histological results. SWE was also performed in 25 healthy volunteers.

RESULTS

We found no statistically significant differences in stiffness between lung carcinomas, lung metastases, and pneumonia (P=0.296) or between different histological types of lung cancer (P=0.393). Necrosis was associated with reduced stiffness in pneumonia. Excluding necrotic lesions, pneumonia showed higher stiffness than lung carcinomas (2.95±0.68 m/s vs. 2.60±0.54 m/s, P=0.006). Chronic pneumonia showed increased stiffness (3.03±0.63 m/s), probably due to the presence of fibrotic tissue on histology. Pleural effusion was associated with a statistically significant reduction in stiffness, both in lung carcinomas (P=0.004) and lung metastases (P=0.002). The presence of air in healthy lung tissue may lead to incorrect speed estimates due to shear wave reflection (very high values, 14.64±2.19 m/s).

CONCLUSION

Transthoracic SWE could not distinguish lung malignancy from pneumonia, or between different histological types of lung carcinomas. In particular, SWE seems unable to resolve the clinical dilemma of chronic subpleural consolidations.

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.

Role of shear-wave and strain elastography to differentiate malignant vs benign subpleural lung lesions

Elastosonography is a non-invasive diagnostic method to evaluate tissue stiffness. The aim of our study was to demonstrate the applicability and efficacy of elastosonography to differentiate benign vs malignant subpleural lung lesions compared to clinical, radiological and histological findings.We performed both strain and shear wave velocity (SWV) elastosonography on subpleural lung lesions. Moreover, we elaborated a composite score called "elasto index".Fourteen patients, 10 males and 4 females were recruited. On strain elastography, 9 lesions showed a hard pattern (type 3), 3 lesions showed an intermediate pattern (type 2), and 2 lesions a soft pattern (type 1). All lesions showed a mean SWV value of 4.46 ± 2.37 m/second. The mean SWV for malignant lesions (n = 6) was 5.92 ± 2.8 m/second. The mean SWV for benign lesions (n = 8) was 3.36 ± 1.20 m/second. SWV shows an area under the curve (AUC) of 0.792, and the Youden index shows a value of 3.6 m/second. The ROC curve elaborated for the diagnosis of malignancy by strain elastography showed an AUC of 0.688. ROC curve for the diagnosis of malignancy by elasto index demonstrated an AUC of 0.802.SWV values obtained by ARFI elastosonographic method are higher in malignant lung lesions (mean SWV: 5.92 m/second) than in benign ones (mean SWV: 3.36); a composite score (elasto index) is characterized by better statistical significance for the differentiation of the lesions.

Diagnostic value of endobronchial ultrasound image features: A specialized review

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) technology is important in the diagnosis of intrathoracic benign and malignant lymph nodes (LNs). With the development of EBUS imaging technology, its role in noninvasive diagnosis, as a supplement to pathology diagnosis, has been given increasing attention in recent years. Many studies have explored qualitative and quantitative methods for the three EBUS modes, as well as a variety of multimodal analysis methods, to find the optimal method for the noninvasive diagnosis using EBUS for LNs. Here, we review and comment on the research methods and predictive diagnostic value, discuss the existing problems, and look ahead to the future application of EBUS imaging.

Ultrasound Elastography for Lung Disease Assessment

Ultrasound elastography (US-E) is a noninvasive, safe, cost-effective and reliable technique to assess the mechanical properties of soft tissue and provide imaging biomarkers for pathological processes. Many lung diseases such as acute respiratory distress syndrome, chronic obstructive pulmonary disease, and interstitial lung disease are associated with dramatic changes in mechanical properties of lung tissues. Nevertheless, US-E is rarely used to image the lung because it is filled with air. The large difference in acoustic impedance between air and lung tissue results in the reflection of the ultrasound wave at the lung surface and, consequently, the loss of most ultrasound energy. In recent years, there has been an increasing interest in US-E applications in evaluating lung diseases. This article provides a comprehensive review of the technological advances of US-E research on lung disease diagnosis. We introduce the basic principles and major techniques of US-E and provide information on various applications in lung disease assessment. Finally, the potential applications of US-E to the diagnosis of COVID-19 pneumonia is discussed.

Adequacy of Cytologic Samples by Ultrasound-Guided Percutaneous Transthoracic Fine-Needle Aspiration Cytology of Peripheral Pulmonary Nodules for Morphologic Diagnosis and Molecular Evaluations: Comparison With Computed Tomography–Guided Percutaneous Transthoracic Fine-Needle Aspiration Cytology

Context.—

Fine-needle aspiration cytology (FNAC) of pulmonary nodules is usually guided by computed tomography (CT), whereas ultrasonography (US) is generally considered not applicable for such purposes.

Objective.—

To evaluate the clinical applicability and diagnostic utility of US-guided transthoracic FNAC of peripheral pulmonary nodules.

Design.—

Ultrasonography-guided transthoracic FNAC was obtained from 40 selected patients with peripheral, subpleural, and paravertebral pulmonary nodules. Air-dried and Diff-Quik–stained smears were used for rapid on-site evaluation; additional smears were alcohol fixed for Papanicolaou staining. Cell blocks were set up for immunocytochemical and molecular studies; in 2 cases, a flow cytometry evaluation was also performed. The series was compared to 40 CT-guided pulmonary FNAC samples from patients with pleural, peripheral, and paravertebral pulmonary nodules, to evaluate differences in terms of diagnostic rate, time of execution, safety, and cost.

Results.—

The US-guided FNAC samples had results that were adequate and representative in 95% of cases. No significant differences were observed between the 2 groups in terms of diagnostic rate, number of passes, and cellularity of both smears and cell blocks. The mean time needed for the execution of US-guided FNAC was 13.1 minutes, whereas the mean time for CT-guided FNAC was 23.6 minutes. Thus, US-guided FNAC was significantly more rapid than CT-guided pulmonary FNAC. Because pneumothorax occurred in 1 individual who underwent US-guided FNAC and in 9 who underwent CT-guided FNAC, we might conclude that US-guided FNAC is a significantly safer procedure. Finally, comparing the costs of both procedures, US-guided FNAC is less expensive.

Conclusions.—

Our experience showed an elevated clinical applicability and diagnostic utility of US-guided transthoracic FNAC for selected pulmonary nodules.

The role of endobronchial ultrasonography elastography for predicting malignancy

Background

This study aims to investigate the role of endobronchial ultrasonography elastography in predicting malignancy.

Methods

Between January 2016 and December 2016, a total of 221 lymph nodes were biopsied using the endobronchial ultrasonography-guided transbronchial needle aspiration from 119 consecutive patients (69 males, 50 females; mean age 63.2±12.4 years; range, 16 to 86 years) were included. Lymph nodes were scored by elastography according to their colors in four categories before the procedure. The strain ratio was calculated based on the region of interest after three measurements.

Results

Of the patients, 93 were diagnosed with a malignancy through endobronchial ultrasonography-guided transbronchial needle aspiration biopsy. The mean lymph node score of benign versus malignant lesions was 2.2±1.0 and 3.2±1, respectively (p<0.001). There was a positive correlation between the lymph node scores and lymph node diameter, strain ratio, ≥3 of lymph node scoring, the sensitivity for malignancy was 79% and specificity was 60%. The mean strain ratio for malignant and benign lymph nodes was 22.2±30.1 and 5.2±1.7, respectively (p<0.001). With a cut-off value of ≥2.47 of strain ratio, the sensitivity for malignancy was 75% and specificity was 65%. The combined use of positron emission tomography and lymph node score or strain ratio yielded 80.4% and 61.2% sensitivity and 80% and 70.3% specificity for malignancy, respectively.

Conclusion

Endobronchial ultrasonography elastography is useful in predicting malignancy of the lymph nodes. When combined with positron emission tomography, specificity and positive predictive value for malignancy increase.

Pulmonary Capillary Hemorrhage Induced by Super Sonic Shear Wave Elastography in Rats

The occurrence of the pulmonary capillary hemorrhage (PCH) bioeffect of diagnostic ultrasound in rats was investigated for a SuperSonic Imagine shear wave elastography system (Aixplorer, Supersonic Imagine, Aix-en-Provence, France). The elastography imaging repeated at 1 Hz and consisted of widely spaced B-mode image pulses, supersonic push (SSP) pulses and shear wave imaging (SWI) pulses. Groups of rats anesthetized with ketamine and xylazine, or with ketamine only, were imaged on their right side in a warm water bath for one frame, 30 s and 300 s. The image focus and region of interest were adjusted to give exposure only with the background B-mode imaging, or primarily with the SSP and SWI pulses. A sham group had only low power aiming scans. The lungs were removed 5 min after exposure and evaluated for PCH area and volume. The B mode was notably ineffective and produced significant PCH only at the maximum 0 dB output. The SSP pulses together with the SWI pulses produced significant PCH for 300 s, 30 s and even single image exposures. Peak rarefactional pressure amplitude PCH thresholds for 300 s exposure were the same with or without the B-mode pulses at 1.5 MPa (in situ mechanical index, MI_IS = 0.67). A 30 s duration resulted in a slightly increased threshold of 1.7 MPa (MI_IS = 0.76). The omission of xylazine from the anesthetic, which reduces the sensitivity of rat lung to PCH occurrence, resulted in an increased threshold of 2.1 MPa (MI_IS = 0.94). The unique SSP pulses were much more effective than the B mode, but thresholds were comparable to previous results with other diagnostic ultrasound modes on other systems.

Safety maximization of percutaneous transthoracic needle biopsy with ultrasound guide in subpleural lesions in the evaluation of pulmonary consolidation

The study by Kiranantawat et al. "Clinical role, safety and diagnostic accuracy of percutaneous transthoracic needle biopsy in the evaluation of pulmonary consolidation" highlights how "pulmonary consolidation can be safely evaluated with CT-guided percutaneous needle biopsy". Even if we agree about the role of CT guidance, we would like to point out how Thoracic Ultrasound could be better than CT for biopsy of subpleural lesions that could easily be detected and reached with this "real-time" and quicker technique.

The application of conventional us and transthoracic ultrasound elastography in evaluating peripheral pulmonary lesions

The aim of the present study was to evaluate the diagnostic value of ultrasound (US) elastography in differentiating between benign and malignant peripheral lung lesions (PLLs). This retrospective study included 91 consecutive patients with 91 PLLs. Conventional US, strain elastography (SE), acoustic radiation force impulse imaging (ARFIimaging) and point share wave elastography (p-SWE) were performed. All of the pathological results were confirmed by US-guided biopsies or surgeries. There were 36 benign PLLs and 55 malignant PLLs on pathology. For conventional US, a lesion diameter ≥5 cm, irregular contour, presence of air bronchogram and non-abundant vascularity were predictive factors of malignancy (P<0.05). SE scores were observed to be invalid in differentiating between malignant and benign PLLs (P=0.542). For ARFIimaging scores, an elasticity score of 3 or greater was predictive of malignancy, with a sensitivity of 83.6% (46/55) and a specificity of 52.8% (19/36). For p-SWE, the share wave velocity of malignant PLLs was higher than benign ones (2.47±0.92 vs. 1.85±0.92 m/sec; P=0.0022). When 1.951 m/sec was selected as the cut-off value, a sensitivity of 70.9% (39/55) and a specificity of 69.4% (25/36) were obtained. Thus, US, particularly US elastography, is helpful in distinguishing malignant PLLs from benign PLLs.

Value of Endobronchial Ultrasound Elastography in Diagnosis of Central Lung Lesions

BACKGROUND Ultrasound elastography is an imaging modality used to show tissue stiffness in tumor pathophysiological processes that promote the formation of stiffer tissues. Endobronchial ultrasound (EBUS) elastography is an ultrasound elastography-based technique for measuring tissue stiffness during EBUS-guided transbronchial needle aspiration (EBUS-TBNA). The diagnostic value of EBUS elastography in central lung lesions remains largely unknown. MATERIAL AND METHODS A total of 57 patients with central lung lesions underwent ultrasonic bronchoscope examination. EBUS with standard B mode evaluation and elastography with grading score measurement were performed before EBUS-guided transbronchial needle aspiration (EBUS-TBNA). Comparison of the diagnosis accuracy in malignant lung lesions between elastography and standard EBUS was made. RESULTS Our data showed that the hypoechoic lesions, uneven echo, distinct boundary, and no air bronchogram were significant indicators of standard EBUS in diagnosis of malignant lung lesions (P<0.01). The differences in elastosonography grading scores between the benign and malignant lung lesions were statistically significance (P<0.01), and the elastography grading score was more sensitive and specific than the standard EBUS criteria in diagnosing malignant lung lesions. The area under the receiver operating characteristic curve (ROC) for the elastography grading score was 0.793. The best cut-off point of the elastography grading score for distinguishing malignant from benign lung lesions was 2.5. The elastography grading score had a sensitivity of 72.2%, specificity of 76.2%, positive predictive value of 83.4%, and negative predictive value of 61.5% for distinguishing malignant from benign lung lesions. The overall accuracy of elastography grading score was 73.7%. CONCLUSIONS BUS elastography can effectively diagnose central lung lesions. The diagnostic accuracy of elastography in malignant lung lesions is higher than that of standard EBUS criteria.

State of the art thoracic ultrasound: intervention and therapeutics

The use of thoracic ultrasound outside the radiology department and in everyday clinical practice is becoming increasingly common, having been incorporated into standards of care for many specialties. For the majority of practitioners, their experience of, and exposure to, thoracic ultrasound will be in its use as an adjunct to pleural and thoracic interventions, owing to the widely recognised benefits for patient safety and risk reduction. However, as clinicians become increasingly familiar with the capabilities of thoracic ultrasound, new directions for its use are being sought which might enhance practice and patient care. This article reviews the ways in which the advent of thoracic ultrasound is changing the approach to the investigation and treatment of respiratory disease from an interventional perspective. This will include the impact of thoracic ultrasound on areas including patient safety, diagnostic and therapeutic procedures, and outcome prediction; and will also consider potential future research and clinical directions.

Ultrasound-guided Lung Biopsy in the Hands of Respiratory Physicians: Diagnostic Yield and Complications in 215 Consecutive Patients in 3 Centers

BACKGROUND

The aim of the study was to determine the diagnostic yield and prevalence of complications of ultrasound-guided transthoracic needle aspiration biopsies (US-TTNAB) performed by respiratory physicians after implementation of the procedure in an everyday clinical setting at 3 different centers.

METHODS

Patients were included if they during the period from January 2012 to August 2014 had a registered US-TTNAB procedure code or if a US biopsy registration form had been filled out at either of the participating centers. Histology or cytology results were used as a reference test for diagnoses that could be made based on these results. Reference test for the remaining diagnoses was clinical follow-up. The diagnostic yield of US-TTNAB was defined as the proportion of patients in which the result of the US-TTNAB was consistent with the reference test.

RESULTS

A total of 215 patients in which a primary US-TTNAB had been performed were identified. The most common biopsy sites were lungs and pleurae with a total of 164 (76.3%) patients and 31 patients (14.4%), respectively. US-TTNAB diagnostic yield was 76.9% (95% CI, 70.3%-83.4%) for malignant diagnoses and 47.6% (95% CI, 31.9%-63.4%) for nonmalignant diagnoses. The most common complications of US-TTNAB were pneumothorax (2.5%; 95% CI, 0.03%-4.6%) and pain at the biopsy site (2%; 95% CI, 0.04%-3.9%). No fatalities related to US-TTNAB were observed.

CONCLUSION

US-TTNAB performed by respiratory physicians is a safe procedure with a low risk of complications and the diagnostic yield to establish a malignant diagnosis is acceptable.

Emergency thoracic ultrasound and clinical risk management

PURPOSE

Thoracic ultrasound (TUS) has been proposed as an easy-option replacement for chest X-ray (CXR) in emergency diagnosis of pneumonia, pleural effusion, and pneumothorax. We investigated CXR unforeseen diagnosis, subsequently investigated by TUS, considering its usefulness in clinical risk assessment and management and also assessing the sustainability of telementoring.

PATIENTS AND METHODS

This observational report includes a period of 6 months with proactive concurrent adjunctive TUS diagnosis telementoring, which was done using freely available smartphone applications for transfer of images and movies.

RESULTS

Three hundred and seventy emergency TUS scans (excluding trauma patients) were performed and telementored. In 310 cases, no significant chest pathology was detected either by CXR, TUS, or the subsequent work-up; in 24 patients, there was full concordance between TUS and CXR (ten isolated pleural effusion; eleven pleural effusion with lung consolidations; and three lung consolidation without pleural effusion); in ten patients with lung consolidations, abnormalities identified by CXR were not detected by TUS. In 26 patients, only TUS diagnosis criteria of disease were present: in 19 patients, CXR was not diagnostic, ie, substantially negative, but TUS detected these conditions correctly, and these were later confirmed by computed tomography (CT). In seven patients, even if chest disease was identified by CXR, such diagnoses were significantly modified by ultrasound, and CT confirmed that TUS was more appropriate. The overall respective individual performances of CXR and TUS for the diagnosis of a pleural-pulmonary disease in emergency are good, with accuracy >95%.

CONCLUSION

About 20% of pneumonia cases were detectable only by CXR and 20% only by TUS and not by CXR; ie, about 40% of patients may have been misdiagnosed if, by chance, only one of the two tools had been used. The concurrent use of TUS and CXR increases the overall sensitivity and specificity. The contribution of expert telementoring and final reappraisal is a valuable and sustainable element for emergency physicians' training and performance, contributing reasonably to mitigation of clinical risks.

Thoracic Ultrasound: What Non-radiologists Need to Know

Purpose of review

The aim of this review is to provide the theoretical and practical knowledge essential for non-radiologists to develop the skills necessary to apply thoracic ultrasound as an extension of clinical assessment and intervention.

Recent findings

Issues relating to training and competence are discussed and a library of thoracic ultrasound videos is provided to illustrate artefacts, pleural, parenchymal and pneumothorax pathology as well as important pitfalls to consider. Novel and future diagnostic applications of thoracic ultrasound in the setting of acute cardiorespiratory pathology including consolidation, acute interstitial syndromes and pulmonary embolism are explored.

Summary

Thoracic ultrasound requires an understanding of imaging artefact specific to lung and pleura and a working knowledge of machine knobology for image optimisation and interpretation. Ultrasound is a valuable tool for the practicing chest clinician providing diagnostic information for the assessment of pleural and parenchymal disease and increased safety and cost effectiveness of thoracic interventions.

Electronic supplementary material

The online version of this article (doi:10.1007/s13665-017-0164-1) contains supplementary material, which is available to authorized users.

Transthoracic Ultrasound Elastography in Pulmonary Lesions and Diseases

Ultrasound elastography has shown promising result in the diagnosis of various diseases; however, its application for pulmonary diseases has yet to be clarified. This study aimed to assess the application and feasibility of ultrasound elastography in various pulmonary lesions and diseases. We enrolled 45 patients with radiographic evidence of pneumonia, tumors or obstructive pneumonitis, and 70 ultrasonic lesions were identified (eight necrosis, 17 atelectasis, seven consolidation and 38 tumors). Ultrasound elastography was performed and the strain ratio, which is the ratio of strain of the reference tissue to an equally measuring region of interest of a lesion, was measured. The strain ratio was significantly different among lesions with different ultrasound morphologies (1.03 ± 0.71 [necrosis] vs. 2.51 ± 1.14 [atelectasis] vs. 19.98 ± 15.59 [consolidation] vs. 36.19 ± 20.18 [tumor]; p < 0.05). The strain ratio of primary lung cancer was also significantly different from pneumonia (p = 0.023) and metastatic lung cancer (p = 0.015). In conclusion, transthoracic ultrasound elastography can differentiate pulmonary lesions with different ultrasound morphologies. ClinicalTrials.gov Identifier: NCT02636985.

Thoracic ultrasound: A complementary diagnostic tool in cardiology

Clinical assessment and workup of patients referred to cardiologists may need an extension to chest disease. This requires more in-depth examination of respiratory co-morbidities due to uncertainty or severity of the clinical presentation. The filter and integration of ecg and echocardiographic information, addressing to the clues of right ventricular impairment, pulmonary embolism and pulmonary hypertension, and other less frequent conditions, such as congenital, inherited and systemic disease, usually allow more timely diagnosis and therapeutic choice. The concurrent use of thoracic ultrasound (TUS) is important, because, despite the evidence of the strict links between cardiac and respiratory medicine, heart and chest US imaging approaches are still separated. Actually, available expertise, knowledge, skills and training and equipment’s suitability are not equally fitting for heart or lung examination and not always already accessible in the same room or facility. Echocardiography is useful for study and monitoring of several respiratory conditions and even detection, so that this is nowadays an established functional complementary tool in pulmonary fibrosis and diffuse interstitial disease diagnosis and monitoring. Extending the approach of the cardiologist to lung and pleura will allow the achievement of information on pleural effusion, even minimal, lung consolidation and pneumothorax. Electrocardiography, pulse oximetry and US equipment are the friendly extension of the physical examination, if their use relies on adequate knowledge and training and on appropriate setting of efficient and working machines. Lacking these premises, overshadowing or misleading artefacts may impair the usefulness of TUS as an imaging procedure.

Thoracic ultrasound: An adjunctive and valuable imaging tool in emergency, resource-limited settings and for a sustainable monitoring of patients

Imaging workup of patients referred for elective assessment of chest disease requires an articulated approach: Imaging is asked for achieving timely diagnosis. The concurrent or subsequent use of thoracic ultrasound (TUS) with conventional (chest X-rays-) and more advanced imaging procedures (computed tomography and magnetic resonance imaging) implies advantages, limitations and actual problems. Indeed, despite TUS may provide useful imaging of pleura, lung and heart disease, emergency scenarios are currently the most warranted field of application of TUS: Pleural effusion, pneumothorax, lung consolidation. This stems from its role in limited resources subsets; actually, ultrasound is an excellent risk reducing tool, which acts by: (1) increasing diagnostic certainty; (2) shortening time to definitive therapy; and (3) decreasing problems from blind procedures that carry an inherent level of complications. In addition, paediatric and newborn disease are particularly suitable for TUS investigation, aimed at the detection of congenital or acquired chest disease avoiding, limiting or postponing radiological exposure. TUS improves the effectiveness of elective medical practice, in resource-limited settings, in small point of care facilities and particularly in poorer countries. Quality and information provided by the procedure are increased avoiding whenever possible artefacts that can prevent or mislead the achievement of the correct diagnosis. Reliable monitoring of patients is possible, taking into consideration that appropriate expertise, knowledge, skills, training, and even adequate equipment’s suitability are not always and everywhere affordable or accessible. TUS is complementary imaging procedure for the radiologist and an excellent basic diagnostic tool suitable to be shared with pneumologists, cardiologists and emergency physicians.