An update on the role of endobronchial ultrasound-guided transbronchial needle aspiration in lung cancer management

INTRODUCTION

Accurate diagnosis and staging are essential for optimizing lung cancer management. The 9th edition of the TNM classification emphasizes distinguishing between single-station and multi-station N2 disease, highlighting the necessity of comprehensive mediastinal node assessment for clinical staging. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive modality used for nodal staging and diagnosis of lung cancer, offering a diagnostic yield comparable to that of mediastinoscopy when performed by experts. Additionally, EBUS-TBNA facilitates essential ancillary testing, including next-generation sequencing (NGS)-based biomarker panels and PD-L1 immunohistochemistry, which are critical for evaluating the suitability of targeted therapies and immune checkpoint inhibitors. Notably, advancements in perioperative management, such as neoadjuvant and adjuvant therapies with immunotherapy and targeted agents, have improved the outcomes of locally advanced diseases. EBUS-TBNA helps identify patients with early-stage lung cancer who are candidates for perioperative therapy.

AREAS COVERED

This review discusses lung cancer diagnosis, nodal staging, the 9th TNM classification, biomarker testing, PD-L1 immunohistochemistry, and precision medicine.

EXPERT OPINION

Lung cancer management requires pathological diagnosis, including histological subtyping, accurate nodal staging of the hilum and mediastinum, and NGS-based biomarker and PD-L1 testing. EBUS-TBNA achieves all three in a single session, making it indispensable in modern lung cancer care.

TransEBUS: The interpretation of endobronchial ultrasound image using hybrid transformer for differentiating malignant and benign mediastinal lesions

The purpose of this study is to establish a deep learning automatic assistance diagnosis system for benign and malignant classification of mediastinal lesions in endobronchial ultrasound (EBUS) images. EBUS images are in the form of video and contain multiple imaging modes. Different imaging modes and different frames can reflect the different characteristics of lesions. Compared with previous studies, the proposed model can efficiently extract and integrate the spatiotemporal relationships between different modes and does not require manual selection of representative frames. In recent years, Vision Transformer has received much attention in the field of computer vision. Combined with convolutional neural networks, hybrid transformers can also perform well on small datasets. This study designed a novel deep learning architecture based on hybrid transformer called TransEBUS. By adding learnable parameters in the temporal dimension, TransEBUS was able to extract spatiotemporal features from insufficient data. In addition, we designed a two-stream module to integrate information from three different imaging modes of EBUS. Furthermore, we applied contrastive learning when training TransEBUS, enabling it to learn discriminative representation of benign and malignant mediastinal lesions. The results show that TransEBUS achieved a diagnostic accuracy of 82% and an area under the curve of 0.8812 in the test dataset, outperforming other methods. It also shows that several models can improve performance by incorporating two-stream module. Our proposed system has shown its potential to help physicians distinguishing benign and malignant mediastinal lesions, thereby ensuring the accuracy of EBUS examination.

Clinical utility of artificial intelligence-augmented endobronchial ultrasound elastography in lymph node staging for lung cancer

Objective

Endobronchial ultrasound elastography produces a color map of mediastinal lymph nodes, with the color blue (level 60) indicating stiffness. Our pilot study demonstrated that predominantly blue lymph nodes, with a stiffness area ratio greater than 0.496, are likely malignant. This large-scale study aims to validate this stiffness area ratio compared with pathology.

Methods

This is a single-center prospective clinical trial where B-mode ultrasound and endobronchial ultrasound elastography lymph node images were collected from patients undergoing endobronchial ultrasound transbronchial needle aspiration for suspected or diagnosed non-small cell lung cancer. Images were fed to a trained deep neural network algorithm (NeuralSeg), which segmented the lymph nodes, identified the percent of lymph node area above the color blue threshold of level 60, and assigned a malignant label to lymph nodes with a stiffness area ratio above 0.496. Diagnostic statistics and receiver operating characteristic analyses were conducted. NeuralSeg predictions were compared with pathology.

Results

B-mode ultrasound and endobronchial ultrasound elastography lymph node images (n = 210) were collected from 124 enrolled patients. Only lymph nodes with conclusive pathology results (n = 187) were analyzed. NeuralSeg was able to predict 98 of 143 true negatives and 34 of 44 true positives, resulting in an overall accuracy of 70.59% (95% CI, 63.50-77.01), sensitivity of 43.04% (95% CI, 31.94-54.67), specificity of 90.74% (95% CI, 83.63-95.47), positive predictive value of 77.27% (95% CI, 64.13-86.60), negative predictive value of 68.53% (95% CI, 64.05-72.70), and area under the curve of 0.820 (95% CI, 0.758-0.883).

Conclusions

NeuralSeg was able to predict nodal malignancy based on endobronchial ultrasound elastography lymph node images with high area under the receiver operating characteristic curve and specificity. This technology should be refined further by testing its validity and applicability through a larger dataset in a multicenter trial.

Comparison of the specimen quality of endobronchial ultrasound-guided intranodal forceps biopsy using standard-sized forceps versus mini forceps for lung cancer: A prospective study

BACKGROUND AND OBJECTIVE

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a diagnostic procedure with adequate performance; however, its ability to provide specimens of sufficient quality and quantity for treatment decision-making in advanced-stage lung cancer may be limited, primarily due to blood contamination. The use of a 0.96-mm miniforceps biopsy (MFB) permits true histological sampling, but the resulting small specimens are unsuitable for the intended applications. Therefore, we introduced a 1.9-mm standard-sized forceps biopsy (SFB) and compared its utility to that of MFB.

METHODS

We prospectively enrolled patients from three institutions who presented with hilar/mediastinal lymphadenopathy and suspected advanced-stage lung cancer, or those who were already diagnosed but required additional tissue specimens for biomarker analysis. Each patient underwent MFB followed by SFB three or four times through the tract created by TBNA using a 22-gauge needle on the same lymph node (LN). Two pathologists assessed the quality and size of each specimen using a virtual slide system, and diagnostic performance was compared between the MFB and SFB groups.

RESULTS

Among the 60 enrolled patients, 70.0% were diagnosed with adenocarcinoma. The most frequently targeted sites were the lower paratracheal LNs, followed by the interlobar LNs. The diagnostic yields of TBNA, MFB and SFB were 91.7%, 93.3% and 96.7%, respectively. The sampling rate of high-quality specimens was significantly higher in the SFB group. Moreover, the mean specimen size for SFB was three times larger than for MFB.

CONCLUSION

SFB is useful for obtaining sufficient qualitative and quantitative specimens.

Quantitative evaluation of endobronchial ultrasound elastography in the diagnosis of benign and malignant mediastinal and hilar lymph nodes

OBJECTIVE

To compare the diagnostic value of different quantitative methods of endobronchial ultrasound elastography in benign and malignant mediastinal and hilar lymph nodes.

METHODS

This retrospective study included patients who underwent endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for mediastinal and hilar lymph node enlargement in our hospital between January 2019 and August 2022. We compared different quantitative elastography parameters [red area ratio (RAR, lymph node red area/lymph node area), green area ratio (GAR, lymph node green area/lymph node area), blue area ratio (SAR, lymph node blue area/lymph node area), mixed area ratio (MAR, lymph node green area/lymph node area), blue-green lymph node area/lymph node area), strain rate ratio (SR), strain rate in the target lymph node (LPA), ratio of blue area to total lymph node area outside the center of the target lymph node (PAR), and average grey value (MGV)], in order to find the best quantitative evaluation method.

RESULTS

A total of 244 patients (346 lymph nodes) were included in this study. All quantitative elastography parameters were statistically significant for the differentiation of benign and malignant lesions except the average grey value of the target lymph nodes. The area under the receiver operating characteristic curve of SAR was 0.872 (95% confidence interval: 0.83-0.91), the cutoff value was 0.409, and the sensitivity, specificity, positive and negative predictive values were 85.4%, 78.0%, 80.4%, and 83.4%, respectively.

CONCLUSION

Compared with other types of quantitative analysis, SAR has a higher predictive significance for benign and malignant lymph nodes.

A risk-scoring model based on endobronchial ultrasound multimodal imaging for predicting metastatic lymph nodes in lung cancer patients

Background and Objectives

Endobronchial ultrasound (EBUS) imaging is a valuable tool for predicting lymph node (LN) metastasis in lung cancer patients. This study aimed to develop a risk-scoring model based on EBUS multimodal imaging (grayscale, Doppler mode, elastography) to predict LN metastasis in lung cancer patients.

Patients and Methods

This retrospective study analyzed 350 metastatic LNs in 314 patients with lung cancer and 124 reactive LNs in 96 patients with nonspecific inflammation. The sonographic findings were compared with the final pathology results and clinical follow-up. Univariate and multivariate logistic regression analyses were performed to evaluate the independent risk factors of metastatic LNs. According to the β coefficients of corresponding indicators in logistic regression analysis, a risk-scoring model was established. Receiver operating characteristic curve was applied to evaluate the predictive capability of model.

Results

Multivariate analysis showed that short axis >10 mm, distinct margin, absence of central hilar structure, presence of necrosis, nonhilar vascularity, and elastography score 4 to 5 were independent predictors of metastatic LNs. Both short axis and margin were scored 1 point, and the rest of independent predictors were scored 2 points. The combination of 3 EBUS modes had the highest area under the receiver operating characteristic and accuracy of 0.884 (95% confidence interval, 0.846-0.922) and 87.55%, respectively. The risk stratification was as follows: 0 to 2 points, malignancy rate of 11.11%, low suspicion; 3 to 10 points, malignancy rate of 86.77%, high suspicion.

Conclusions

The risk-scoring model based on EBUS multimodal imaging can effectively evaluate metastatic LNs in lung cancer patients to support clinical decision making.

Biomechanical imaging biomarker during chemoradiotherapy predicts treatment response in head and neck squamous cell carcinoma

Objective. For response-adapted adaptive radiotherapy (R-ART), promising biomarkers are needed to predict post-radiotherapy (post-RT) responses using routine clinical information obtained during RT. In this study, a patient-specific biomechanical model (BM) of the head and neck squamous cell carcinoma (HNSCC) was proposed using the pre-RT maximum standardized uptake value (SUVmax) of18F-fluorodeoxyglucose (FDG) and tumor structural changes during RT as evaluated using computed tomography (CT). In addition, we evaluated the predictive performance of BM-driven imaging biomarkers for the treatment response of patients with HNSCC who underwent concurrent chemoradiotherapy (CCRT).Approach. Patients with histologically confirmed HNSCC treated with definitive CCRT were enrolled in this study. All patients underwent CT two times as follows: before the start of RT (pre-RT) and 3 weeks after the start of RT (mid-RT). Among these patients, 67 patients who underwent positron emission tomography/CT during the pre-RT period were included in the final analysis. The locoregional control (LC), progression-free survival (PFS), and overall survival (OS) prediction performances of whole tumor stress change (TS) between pre- and mid-RT computed using BM were assessed using univariate, multivariate, and Kaplan-Meier survival curve analyses, respectively. Furthermore, performance was compared with the pre and post-RT SUVmax, tumor volume reduction rate (TVRR) during RT, and other clinical prognostic factors.Main results. For both univariate, multivariate, and survival curve analyses, the significant prognostic factors were as follows (p< 0.05): TS and TVRR for LC; TS and pre-RT FDG-SUVmaxfor PFS; and TS only for OS. In addition, for 2 year LC, PFS, and OS prediction, TS showed a comparable predictive performance to post-RT FDG-SUVmax.Significance. BM-driven TS is an effective prognostic factor for tumor treatment response after CCRT. The proposed method can be a feasible functional imaging biomarker that can be acquired during RT using only routine clinical data and may provide useful information for decision-making during R-ART.

Quantitative analysis of endobronchial elastography combined with serum tumour markers of lung cancer in the diagnosis of benign and malignant mediastinal and hilar lymph nodes

Purpose: In malignant tumours, elastography and serum tumour markers have shown high diagnostic efficacy. Therefore, we aimed to quantitatively analyse the results of endobronchial elastography combined with serum tumour markers of lung cancer to accurately distinguish benign and malignant mediastinal and hilar lymph nodes. Methods: Data of patients who underwent endobronchial ultrasound-guided transbronchial needle aspiration for mediastinal lymph node enlargement in our hospital between January 2018 and August 2022 were retrospectively collected. The characteristics of quantitative elastography and serum tumour markers were evaluated. Results: We enrolled 197 patients (273 lymph nodes). In the differential diagnosis of benign and malignant mediastinal and hilar lymph nodes, the stiffness area ratio (SAR), strain ratio (SR), and strain rate in lymph nodes were significant, among which SAR had the highest diagnostic value (cut-off value, 0.409). The combination of the four tumour markers had a high diagnostic value (AUC, 0.886). Three types of quantitative elastography indices combined with serum tumour markers for lung cancer showed a higher diagnostic value (AUC, 0.930; sensitivity, 83.5%; specificity, 89.3%; positive predictive value, 88.1%; negative predictive value, 85%) (p < 0.05). In the differential diagnosis of pathological types of lung cancer, different quantitative elastography indicators and serum tumour markers for lung cancer have different diagnostic significance for the differential diagnosis of lung cancer pathological types. Conclusion: The quantitative analysis of endobronchial ultrasound elastography combined with tumour markers can improve the diagnosis rate of benign and malignant mediastinal and hilar lymph nodes, help guide the puncture of false negative lymph nodes, and reduce the misdiagnosis rate.

Clinical Applications of Endobronchial Ultrasound (EBUS) Scope: Challenges and Opportunities

Endobronchial Ultrasound (EBUS) has been widely used to stage lung tumors and to diagnose mediastinal diseases. In the last decade, this procedure has evolved in several technical aspects, with new tools available to optimize tissue sampling and to increase its diagnostic yield, like elastography, different types of needles and, most recently, miniforceps and cryobiopsy. Accordingly, the indications for the use of the EBUS scope into the airways to perform the Endobronchial Ultrasound-TransBronchial Needle Aspiration (EBUS-TBNA) has also extended beyond the endobronchial and thoracic boundaries to sample lesions from the liver, left adrenal gland and retroperitoneal lymph nodes via the gastroesophageal tract, performing the Endoscopic UltraSound with Bronchoscope-guided Fine Needle Aspiration (EUS-B-FNA). In this review, we summarize and critically discuss the main indication for the use of the EBUS scope, even the more uncommon, to underline its utility and versatility in clinical practice.

Guidelines for endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA): Joint Indian Chest Society (ICS)/Indian Association for Bronchology (IAB) recommendations

Over the past decade, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has become an indispensable tool in the diagnostic armamentarium of the pulmonologist. As the expertise with EBUS-TBNA has evolved and several innovations have occurred, the indications for its use have expanded. However, several aspects of EBUS-TBNA are still not standardized. Hence, evidence-based guidelines are needed to optimize the diagnostic yield and safety of EBUS-TBNA. For this purpose, a working group of experts from India was constituted. A detailed and systematic search was performed to extract relevant literature pertaining to various aspects of EBUS-TBNA. The modified GRADE system was used for evaluating the level of evidence and assigning the strength of recommendations. The final recommendations were framed with the consensus of the working group after several rounds of online discussions and a two-day in-person meeting. These guidelines provide evidence-based recommendations encompassing indications of EBUS-TBNA, pre-procedure evaluation, sedation and anesthesia, technical and procedural aspects, sample processing, EBUS-TBNA in special situations, and training for EBUS-TBNA.

The role of endobronchial ultrasonography elastography in the diagnosis of hilar and mediastinal lymph nodes

BACKGROUND

Endobronchial ultrasonography (EBUS) is a minimally invasive diagnostic tool in the diagnosis of mediastinal lymph nodes (LNs) and has sonographic features. We aimed to investigate the diagnostic accuracy of EBUS elastography, which evaluates tissue compressibility integrated into EBUS, on malignant vs. benign mediastinal-hilar LNs.

METHODS

A single-center, prospective study was conducted at the University of Health Sciences Yedikule Chest Diseases and Thoracic Surgery Training and Research Hospital between 01/10/2019 and 15/11/2019. The features of 219 LNs evaluated by thoracic computed tomography (CT), positron emission tomography (PET)/CT, EBUS sonography and EBUS elastography were recorded. The LNs sampled by EBUS-guided fine needle aspiration were classified according to EBUS elastography color distribution findings as follows: type 1, predominantly nonblue (green, yellow, and red); type 2, part blue, part nonblue; type 3, predominantly blue. The strain ratio (SR) was calculated based on normal tissue with the relevant region.

RESULTS

The average age of 131 patients included in the study was 55.86 ± 13 years, 76 (58%) were male. Two hundred and nineteen lymph nodes were sampled from different stations. Pathological diagnosis of 75 (34.2%) LNs was malignant, the rest was benign. When EBUS B-mode findings and pathological results were compared, sensitivity was 65.33%, specificity 63.19%, positive predictive value (PPV) 48%, negative predictive value (NPV) 77.8%, and diagnostic yield (DY) 64%. When the pathological diagnoses and EBUS elastography findings were compared, while type 1 LNs were considered to be benign and type 3 LNs malignant, sensitivity 94.12%, specificity 86.54%, PPV 82.1%, NPV 95.7%, and DY 89.5%. SR of malignant LNs was significantly higher than benign LNs (p < 0.001). When the classification according to color scale and SR were compared, no difference was found in DY (p = 0.155).

DISCUSSION

The diagnostic accuracy of EBUS elastography is high enough to distinguish malignant LN from benign ones with the SR option. When compared with EBUS-B mode sonographic findings, it was found to have a higher diagnostic yield.

Endobronchial ultrasound-guided transbronchial needle aspiration in patients with previously treated malignancies: diagnostic performance and predictive value

BACKGROUND

Endobronchial ultrasound-guided transbronchial needle aspiration is a minimally invasive and effective sampling approach for patients with mediastinal or hilar lymphadenopathy. Increased recognition of the ultrasonographic features revealed the value of its images in predicting mediastinal lymph node malignancy. However, its diagnostic validity and the predictive value of its ultrasonographic features have not been demonstrated well in patients after systemic anti-tumor therapy. This study aimed to evaluate the efficiency of endobronchial ultrasound-guided transbronchial needle aspiration in patients with suspicious lymph nodes after anti-tumor therapy.

METHODS

We retrospectively reviewed cases of endobronchial ultrasound-guided transbronchial needle aspiration performed between January 2019 and August 2021 at a single tertiary hospital center. Patients with suspected mediastinal or hilar lymph nodes within 5 years of systemic anti-tumor therapy were enrolled. Final diagnoses were determined by pathologic diagnoses of samples from transbronchial needle aspiration, surgery, or follow-up for at least 6 months. Ultrasonographic features were analyzed to assess the predictive value of malignant lymph nodes after treatment.

RESULTS

Overall, 168 lymph nodes of 138 patients were analyzed. Among 110 (65.5%) malignant lymph nodes, 75 originated from lung cancers; the other 35 were from other malignancies. No complications related to endobronchial ultrasound-guided transbronchial needle aspiration were observed. Of 58 negative results of transbronchial needle aspiration, 51 were proven to be true negatives; 7 were false. The overall sensitivity and the negative predictive value were 94.02% and 87.93%, respectively. Univariate and multivariate analysis revealed the absence of central hilar structure and short axis > 10 mm as independent predictive factors for malignancy.

CONCLUSIONS

Endobronchial ultrasound-guided transbronchial needle aspiration performs satisfactorily in diagnosing mediastinal and hilar lymphadenopathy even after anti-tumor treatment.

The diagnostic utility of ultrasound elastography to differentiate tuberculosis and sarcoidosis during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA)

Introduction

Elastography is a non-invasive tool that may allow differentiation between benign and malignant lymph nodes during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). In tuberculosis (TB) endemic areas, clinicoradiological features of mediastinal TB and sarcoidosis often overlap, rendering an accurate diagnosis challenging. There is interest in the identification of modalities to aid in this differentiation. There are currently no published data on the utility of EBUS-elastography in differentiating between TB and sarcoidosis.

Methods

Subjects undergoing EBUS-TBNA were prospectively enrolled, and elastography features were observed. Subjects with definitive diagnosis of TB or sarcoidosis were enrolled. The elastography features recorded included the three-colour classification patterns and strain ratio.

Results

We enrolled 96 subjects with a definitive diagnosis (53 with TB and 43 with sarcoidosis). Of the 27 patients in whom the lymph nodes were classified as type 1 on endobronchial ultrasound elastography colour pattern, 17 had a diagnosis of TB (62.9%), while 10 were sarcoidosis (37%). For type 2 lymph nodes, 20/45 (44.4%) were TB and 25/45 (55.6%) were sarcoidosis. Type 3 lymph nodes were TB in 16/24 (66.7%) and sarcoidosis in 8/24 (33.3%). In classifying type 1 as 'sarcoidosis' and Type 3 as 'tubercular', the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were 48.5%, 55.6%, 66.7%, 37%, and 0.51, respectively. The strain ratio (Median [IQR]) was 1.29 (0.37-5.98) in TB and 2.10 (0.83-4.52) in sarcoidosis group (P = 0.48).

Conclusion

Ultrasound elastographic lymph node characteristics have a poor diagnostic utility to differentiate between TB and sarcoidosis during EBUS-TBNA.

Predicting Malignant Lymph Nodes Using a Novel Scoring System Based on Multi-Endobronchial Ultrasound Features

Endobronchial ultrasound (EBUS) features with B-, power/color Doppler, and elastography modes help differentiate between benign and malignant lymph nodes (MLNs) during transbronchial needle aspiration (TBNA); however, only few studies have assessed them simultaneously. We evaluated the diagnostic accuracy of each EBUS feature and aimed to establish a scoring system to predict MLNs. EBUS features of consecutive patients and final diagnosis per lymph node (LN) were examined retrospectively. In total, 594 LNs from 301 patients were analyzed. Univariable analyses revealed that EBUS features, except for round shape, could differentiate MLNs from benign LNs. Multivariable analysis revealed that short axis (>1 cm), heterogeneous echogenicity, absence of central hilar structure, presence of coagulation necrosis sign, and blue-dominant elastographic images were independent predictors of MLNs. At three or more EBUS features predicting MLNs, our scoring system had high sensitivity (77.9%) and specificity (91.8%). The area under the receiver operating curve (AUC) was 0.894 (95% confidence interval (CI): 0.868−0.920), which was higher than that of B-mode features alone (AUC: 0.840 (95% CI: 0.807−0.873)). The novel scoring system could predict MLNs more accurately than B-mode features alone. Multi-EBUS features may increase EBUS-TBNA efficiency for LN evaluation.

Diagnostic Yield and Safety of CP-EBUS-TBNA and RP-EBUS-TBLB under Moderate Sedation: A Single-Center Retrospective Audit

Convex probe endobronchial ultrasound transbronchial needle aspirations (CP-EBUS-TBNAs) and radial probe endobronchial ultrasound transbronchial lung biopsies (RP-EBUS-TBLBs) can be performed under moderate sedation or general anesthesia. Moderate sedation is more convenient, however patient discomfort may result in inadequate tissue sampling. General anesthesia ensures better patient cooperation but requires more logistics and also carries sedation risks. We aim to describe the diagnostic yield and safety of CP-EBUS-TBNAs and RP-EBUS-TBLBs when performed under moderate sedation at our center. All patients who underwent CP-EBUS-TBNA and/or RP-EBUS-TBLB under moderate sedation, between January 2015 and May 2017, were reviewed. Primary outcomes were defined in regard to the diagnostic yield and safety profile. A total of 336 CP-EBUS-TBNAs and 190 RP-EBUS-TBLBs were performed between January 2015 and May 2017. The mean sedation doses used were 50 mcg of intravenous fentanyl and 2.5 mg of intravenous midazolam. The diagnostic yield of the CP-EBUS-TBNAs and RP-EBUS-TBLBs were 62.5% and 71.6%, respectively. Complication rates were low with: transient bleeding 11.9%, transient hypoxia 0.5%, and pneumothorax 0.1%. None required escalation of care, post procedure. Performing CP-EBUS-TBNAs and RP-EBUS-TBLBs under moderate sedation is safe and provides good diagnostic yield. These procedures should, therefore, be considered as first-line sampling techniques.

Pulmonary Lesion Classification Framework Using the Weighted Ensemble Classification with Random Forest and CNN Models for EBUS Images

Lung cancer is a deadly disease with a high mortality rate. Endobronchial ultrasonography (EBUS) is one of the methods for detecting pulmonary lesions. Computer-aided diagnosis of pulmonary lesions from images can help radiologists to classify lesions; however, most of the existing methods need a large volume of data to give good results. Thus, this paper proposes a novel pulmonary lesion classification framework for EBUS images that works well with small datasets. The proposed framework integrates the statistical results from three classification models using the weighted ensemble classification. The three classification models include the radiomics feature and patient data-based model, the single-image-based model, and the multi-patch-based model. The radiomics features are combined with the patient data to be used as input data for the random forest, whereas the EBUS images are used as input data to the other two CNN models. The performance of the proposed framework was evaluated on a set of 200 EBUS images consisting of 124 malignant lesions and 76 benign lesions. The experimental results show that the accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve are 95.00%, 100%, 86.67%, 92.59%, 100%, and 93.33%, respectively. This framework can significantly improve the pulmonary lesion classification.

Clinical Validation of the Canada Lymph Node Score for Endobronchial Ultrasound

BACKGROUND

The Canada Lymph Node Score (CLNS) uses four sonographic criteria to predict the risk of malignancy in lymph nodes during endobronchial ultrasound (EBUS). CLNS may play a role in identifying targets for biopsy or re-biopsy during invasive mediastinal staging for lung cancer. However, CLNS has not yet been prospectively validated in routine clinical practice.

METHODS

CLNS scores for each lymph node biopsied during EBUS were prospectively captured for one year (2019). CLNS and the presence of malignancy in each node were compared. Univariate binary logistic regression was completed for each ultrasonographic feature, as well as a multivariate logistic regression model.

RESULTS

CLNS and diagnostic pathology results were available for 367 lymph nodes. Incidence of malignancy increased with higher scores. Scores ≥3 were significantly associated with malignancy (specificity 84.4%, positive likelihood ratio 4.0). Area under the curve was 0.76, indicating a good ability of the model to predict presence or absence of malignancy. Nodes scoring <2 and negative on CT and PET were malignant in 10.1%.

CONCLUSIONS

CLNS correlates with the presence or absence of malignancy in thoracic lymph nodes, and may serve as an adjunct to currently available methods of invasive and non-invasive mediastinal staging. CLNS may be most helpful to select which non-diagnostic nodes require re-biopsy. There is a significant risk of a false negative result even with a score of 0, and using a combination of low CLNS and negative conventional radiology to obviate the need for any initial biopsy remains to be studied in prospective trials.

Utility of Elastography for Differentiating Malignant and Benign Lymph Nodes During EBUS-TBNA: A Systematic Review and Meta-analysis

BACKGROUND

Ultrasound elastography noninvasively estimates tissue hardness. Studies have evaluated elastography for differentiating malignant from benign lymph nodes during endobronchial ultrasound-guided transbronchial needle aspiration. Several methods of performing elastography are described with variable diagnostic accuracy.

METHODS

The aim of this study was to evaluate endobronchial ultrasound-guided elastography in differentiating malignant from benign mediastinal lymphadenopathy. We performed a systematic search of the PubMed and Embase databases to extract the relevant studies. A diagnostic accuracy meta-analysis was carried out to calculate the pooled sensitivity and specificity [with 95% confidence intervals (CIs)], and positive and negative likelihood ratios of elastography.

RESULTS

After a systematic search, 20 studies (1600 patients, 2712 nodes) were selected. The pooled sensitivity and specificity of elastography were 0.90 (95% CI, 0.84-0.94) and 0.79 (95% CI, 0.73-0.84), respectively. The summary receiver operating curve demonstrated an area under the curve for elastography of 0.90 (0.88-0.93). The positive and negative likelihood ratios and the diagnostic odds ratio were 4.3 (95% CI, 3.3-5.5), 0.12 (95% CI, 0.07-0.20), and 35 (95% CI, 19-63), respectively. Of the most commonly described methods, the color classification method (type 3 malignant vs. type 1 benign) demonstrated the highest area under the curve of 0.91 (0.88-0.93). There was significant heterogeneity and publication bias. Subgroup analyses indicated no significant difference between the sensitivity and specificity of quantitative and qualitative elastography methods.

CONCLUSIONS

Ultrasound elastography is useful in differentiating malignant and benign lymph nodes during endobronchial ultrasound-guided transbronchial needle aspiration. However, elastography does not replace the requirement of lymph node aspiration.

Diagnostic value of endobronchial ultrasound elastography combined with rapid onsite cytological evaluation in endobronchial ultrasound-guided transbronchial needle aspiration

Background

Endobronchial ultrasound (EBUS) elastography has been used in EBUS-guided transbronchial needle aspiration (EBUS-TBNA) to identify malignant lymph nodes based on tissue stiffness. Rapid onsite cytological evaluation (ROSE) has been widely utilized for onsite evaluation of sample adequacy and for guiding sampling during EBUS-TBNA. The aim of this study was to investigate the diagnostic value of combined EBUS elastography and ROSE in evaluating mediastinal and hilar lymph node status.

Methods

Retrospective chart review was performed from December 2018 to September 2020. Patient demographics, EBUS elastography scores, and ROSE, pathologic, and clinical outcome data were collected. The EBUS elastography scores were classified as follows: Type 1, predominantly nonblue; Type 2, partially blue and partially nonblue; and Type 3, predominantly blue. A receiver operating characteristic curve was used to compare the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for evaluation of malignant lymph nodes among the EBUS elastography, ROSE, and EBUS combined with ROSE groups.

Results

A total of 245 patients (345 lymph nodes) were included. The sensitivity and specificity of the EBUS elastography group for the diagnosis of malignant lymph nodes were 90.51% and 57.26%, respectively. The sensitivity and specificity in the ROSE group were 96.32% and 79.05%, respectively. The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of EBUS elastography combined with ROSE were 86.61%, 92.65%, 11.78, and 0.14, respectively, and the area under the curve was 0.942.

Conclusions

Combining EBUS elastography and ROSE significantly increased the diagnostic value of EBUS-TBNA in evaluating mediastinal and hilar lymph node status compared to each method alone.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01748-4.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA): Technical Updates and Pathological Yield

Since the endobronchial ultrasound bronchoscope was introduced to clinical practice, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has become the procedure of choice to sample hilar and mediastinal adenopathy. Multiple studies have been conducted in the last two decades to look at the different technical aspects of the procedure and their effects on the final cytopathological yield. In addition, newer modes of ultrasound scanning and newer tools with the potential to optimize the selection and sampling of the target lymph node have been introduced. These have the potential to reduce the number of passes, reduce the procedure time, and increase the diagnostic yield, especially in rare tumors and benign diseases. Herein, we review the latest updates related to the technical aspects of EBUS-TBNA and their effects on the final cytopathological yield in malignant and benign diseases.

Ultrasound Elastography for the Evaluation of Lymph Nodes

The differential diagnosis of lymphadenopathy is important for predicting prognosis, staging, and monitoring the treatment, especially for cancer patients. Conventional computed tomography and magnetic resonance imaging characterize lymph node (LN) with disappointing sensitivity and specificity. Conventional ultrasound with the advantage of high resolution has been widely used for the LN evaluation. Ultrasound elastography (UE) using color map or shear wave velocity can non-invasively demonstrate the stiffness and homogeneity of both the cortex and medulla of LNs and can detect early circumscribed malignant infiltration. There is a need of a review to comprehensively discuss the current knowledge of the applications of various UE techniques in the evaluation of LNs. In this review, we discussed the principles of strain elastography and shear wave-based elastography, and their advantages and limitations in the evaluation of LNs. In addition, we comprehensively introduced the applications of various UE techniques in the differential diagnosis of reactive LNs, lymphoma, metastatic LNs, and other lymphadenopathy. Moreover, the applications of endoscopic UE and endobronchial UE are also discussed, including their use for improving the positive rate of diagnosis of fine-needle aspiration biopsy.

Mediastinal lymphadenopathy: a practical approach

Introduction: Mediastinal lymphadenopathy is secondary to various benign and malignant etiologies. There is a variation in the underlying cause in different demographic settings. The initial clue to the presence of enlarged mediastinal lymph nodes is through thoracic imaging modalities. Malignancy (Lung cancer, lymphoma, and extrathoracic cancer) and granulomatous conditions (sarcoidosis and tuberculosis) are the most common causes. For a confident diagnosis, the clinician must choose from several available options and integrate the clinical, radiological, and pathology findings. An accurate diagnosis is necessary for optimal management.Areas covered: We performed a search of the PUBMED database to identify relevant articles on the causes, imaging modalities, and interventional modalities to diagnose these conditions. We discuss a practical approach toward the evaluation of a patient with mediastinal lymphadenopathy.Expert opinion: Mediastinal lymphadenopathy is a commonly encountered clinical problem. Treating physicians need to be aware of the clinico-radiological manifestations of the common diagnostic entities. Selecting an appropriate tissue diagnosis modality is crucial, with an intent to use the least invasive technique with good diagnostic yield. Endosonographic modalities (EBUS-TBNA, EUS-FNA, and EUS-B-FNA) have emerged as the cornerstone to most patients' diagnosis. An accurate diagnosis translates into favorable treatment outcomes.

Clinical validity of 25-gauge endobronchial ultrasound-guided transbronchial needle in lymph node staging of lung cancer

Background

Endobronchial ultrasound-guided transbronchial needle aspiration is recommended for lymph node (LN) staging in lung cancer. Although 22-gauge needles are widely used, they may make some stations difficult to puncture owing to an acute angle. A thinner 25-gauge needle was introduced in Japan at the end of 2016 and offered structural advantages such as improved flexibility and penetrability. We aimed to validate the clinical utility of the 25-gauge needle in LN staging.

Methods

Patients who underwent endobronchial ultrasound-guided transbronchial needle aspiration for LN staging of lung cancer using the 25-gauge needle at our institution between November 2016 and March 2019 were included. Patient characteristics, staging procedures, pathology findings, and genetic testing success rates were assessed.

Results

Data of 130 patients were included in the analysis. The sampling rate was 87.6% (589/672 lesions). In addition to stations #4R, #7, and #11, which are generally easy to puncture, multiple stations (40.1%) were sampled. The diagnostic accuracy of combined computed tomography and fluorodeoxyglucose positron emission tomography was 82.3% and that of additional endobronchial ultrasound-guided transbronchial needle aspiration was 96.9%. The overall sensitivity, specificity, and positive and negative predictive values validated using resected specimens were 97.1% (34/35), 100% (41/41), 100% (34/34), and 97.6% (41/42), respectively. The success rate of genetic testing was 100% (34/34).

Conclusions

The new 25-gauge needle enabled us to approach a wide range of LNs with a desirable sampling rate and diagnostic accuracy in LN staging using endobronchial ultrasound-guided transbronchial needle aspiration, while providing enough tissue for genetic testing.

Application of transthoracic shear-wave ultrasound elastography in lung lesions

INTRODUCTION

Tissue stiffness information may help in the diagnosis of lung lesions. This study aimed to investigate and validate the application of transthoracic two-dimensional shear-wave ultrasound elastography in differentiating malignant from benign subpleural lung lesions.

METHODS

This study involved one retrospective observational derivation cohort from January 2016 to December 2017 and one prospective observational validation cohort from December 2017 to December 2019. The inclusion criterion was radiographic evidence of pulmonary lesions. The patients were categorised into air bronchogram and hypoechoic groups based on B-mode grayscale images. The elasticity of subpleural lung lesions with acceptable shear-wave propagation was measured. Diagnoses were made on the basis of pathology, microbiological studies or following up the clinical course for at least 6 months.

RESULTS

A total of 354 patients were included. Among the 121 patients in the derivation cohort, a receiver operating characteristic curve was constructed and the cut-off point to differentiate benign from malignant lesions was 65 kPa with a Youden index of 0.60 and an accuracy of 84.3%. Among the 233 patients in the validation cohort, the diagnostic performance was maintained, with a Youden index of 0.65 and an accuracy of 86.7%. Upon applying the cut-off point to the air bronchogram group, the Youden index was 0.70 and the accuracy was 85.0%.

CONCLUSIONS

This study validated the application of transthoracic shear-wave ultrasound elastography for assessing lung malignancy. A cut-off point of 65 kPa is suggested for predicting lung malignancy. Furthermore, for pulmonary air bronchogram lesions with high elasticity, tissue proofing should be considered because of the high possibility of malignancy.

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.

Endobronchial Ultrasound Elastography Combined With Computed Tomography in Differentiating Benign from Malignant Intrathoracic Lymph Nodes

Objective. This study was to combine endobronchial ultrasound elastography (UE) with computed tomography (CT) to identify benign and malignant thoracic lymph nodes (LNs) more objectively and accurately. Methods. A total of 42 patients with intrathoracic lymphadenopathy required for endobronchial ultrasound with real-time guided transbronchial needle aspiration (EBUS-TBNA) examination were enrolled. All patients were examined by enhanced chest CT, B-mode ultrasound, and endobronchial ultrasound (EBUS)-guided elastography before EBUS-TBNA. Each lymph node was assessed by describing the characteristics of CT image (short diameter, texture, shape, boundary, and mean CT value), B-mode ultrasound (short diameter, echo characteristic, shape, and boundary), and elastography (image type, grading score, strain rate, and blue area ratio). The pathological results were used as the gold standard. The characteristics were compared alone and in combination between benign and malignant LNs. Results. The blue area ratio of elastography combined with CT had better diagnostic value in differentiating benign and malignant LNs than elastography alone, with the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) being 92%, 96%, 80%, 94%, and 86% vs 81%, 77%, 93%, 97%, and 56%, respectively. Elastography combined with B-mode ultrasound and CT characteristics showed the highest diagnostic value. Accuracy, sensitivity, specificity, PPV, and NPV were all 100%. Conclusions. Endobronchial UE combined with CT and B-mode ultrasound imaging shows a greater diagnostic value in differentiating benign and malignant intrathoracic LNs than either imaging alone.

CT texture analysis of mediastinal lymphadenopathy: Combining with US-based elastographic parameter and discrimination between sarcoidosis and lymph node metastasis from small cell lung cancer

Objectives

To investigate the potential of computed tomography (CT)-based texture analysis and elastographic data provided by endobronchial ultrasonography (EBUS) for differentiating the mediastinal lymphadenopathy by sarcoidosis and small cell lung cancer (SCLC) metastasis.

Methods

Sixteen patients with sarcoidosis and 14 with SCLC were enrolled. On CT images showing the largest mediastinal lymph node, a fixed region of interest was drawn on the node, and texture features were automatically measured. Among the 30 patients, 19 (12 sarcoidosis and 7 SCLC) underwent endobronchial ultrasound transbronchial needle aspiration, and the fat-to-lesion strain ratio (FLR) was recorded. Texture features and FLRs were compared between the 2 patient groups. Logistic regression analysis was performed to evaluate the diagnostic accuracy of these measurements.

Results

Of the 31 texture features, the differences between 11 texture features of CT ROIs in the patients with sarcoidosis versus patients with SCLC were significant. Among them, the grey-level run length matrix with high gray-level run emphasis (GLRLM-HGRE) showed the greatest difference (P<0.01). Differences between FLRs were significant (P<0.05). Logistic regression analysis together with receiver operating characteristic curve analysis demonstrated that the FLR combined with the GLRLM-HGRE showed a high diagnostic accuracy (100% sensitivity, 92% specificity, 0.988 area under the curve) for discriminating between sarcoidosis and SCLC.

Conclusion

Texture analysis, particularly combined with the FLR, is useful for discriminating between mediastinal lymphadenopathy caused by sarcoidosis from that caused by metastasis from SCLC.

Endobronchial Ultrasound Elastography for Differentiating Benign and Malignant Lymph Nodes

BACKGROUND

Endobronchial ultrasound elastography that provides information on tissue stiffness may help distinguish malignant from benign mediastinal and hilar lymph nodes.

OBJECTIVES

In this prospective trial, we assessed the diagnostic value of elastographic images and the interobserver agreement in its evaluation.

METHOD

Elastographic images from 77 lymph nodes in 65 patients were reviewed by 3 pneumologists. The elastographic image was classified based on the predominant colour: predominantly green, intermediary, and predominantly blue. With 2 or 3 interobserver matches, the corresponding elastographic image was correlated with the pathological result obtained from endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and/or other invasive procedures.

RESULTS

All 3 reviewers had agreement in classifying elastographic images in 45% (35/77). Overall, the interobserver agreement among the 3 readers for classifying elastographic pattern was found to be moderate (Fleiss Kappa index = 0.519; 95% CI = [0.427; 0.611]). On cytological/histological evaluation, 55 lymph nodes were malignant and 22 were benign. In classifying "green" as benign and "blue" as malignant, the sensitivity and specificity were 71% (95% CI = [54%; 85%]) and 67% (95%-CI = [35%; 90%]), respectively.

CONCLUSIONS

Elastography will not replace invasive EBUS-TBNA due to a moderate interobserver agreement and insufficient sensitivity and specificity. However, elastography will, maybe, present an additional feature to identify malignant lymph nodes in the context of clinical, radiological, and cytological results.

Diagnostic utility of endobronchial ultrasound (EBUS) features in differentiating malignant and benign lymph nodes - A systematic review and meta-analysis

BACKGROUND

EBUS is being widely used today for echolocation of lymph nodes for FNAC. We present a systematic review and meta-analysis to assess the diagnostic accuracy of EBUS characteristics of lymph nodes in diagnosing malignancy.

METHODS

A systematic search of published literature was undertaken using databases like PubMed, Web of Science, Cochrane, Google Scholar and Researchgate. Those studies reporting any endobronchial ultrasonography features of malignant lymph nodes like size, margins, echogenicity, shape, central hilar structure (CHS), coagulation necrosis sign (CNS) or color power doppler index (CPDI) were included for review. Random effects model was used to calculate pooled sensitivity, specificity, positive and negative likelihood ratios (LR), and diagnostic odds ratio (DOR). The review protocol was registered with the International prospective register of systematic reviews (PROSPERO registration no. CRD42019117716).

RESULTS

992 articles were retrieved of which 542 articles were evaluated in detail and finally 29 articles met the inclusion criteria. All EBUS features except CPDI showed a statistically significant area under the SROC curve. CNS showed highest area under the SROC curve [0.81 (SE: 0.09)] with maximum pooled specificity [0.93, 95%CI: 0.92-0.94], maximum pooled LR+ [5.12, 95%CI: 2.56-10.2] and DOR [9.23, 95%CI 3.85-22.15]. Maximum sensitivity was seen for CHS 0.91 [95%CI: 0.90-0.92].

CONCLUSION

EBUS features have the potential to help in more precise location of a malignant lymph node thereby helping in increasing the diagnostic yield. However, high diagnostic accuracy of various EBUS features can currently only be said to supplement tissue diagnosis.

Quantitative analysis of endobronchial ultrasound elastography in computed tomography-negative mediastinal and hilar lymph nodes

Background

Endobronchial ultrasound (EBUS) elastography assists in the differentiation of benign and malignant lymph nodes (LNs) during transbronchial needle aspiration (TBNA). However, previous studies have not compared B‐mode sonographic images (BSIs) and EBUS elastography images (EEIs) with final pathological diagnoses in radiologically normal‐sized (computed tomography [CT]‐negative) LNs.

Methods

Consecutive patients with CT‐negative LNs, who received EBUS‐TBNA, were retrospectively reviewed. Images of BSIs and EEIs of each LN were stored and independently evaluated. EEIs were assessed by calculating the stiffness area ratio (SAR, blue/overall areas). The receiver operating characteristic curve was used to calculate the cutoff value for the SAR. Diagnostic test parameters were evaluated for each EBUS finding.

Results

A total of 132 patients (149 LNs) were enrolled, and the median SAR of malignant LNs was significantly higher than that of benign LNs (0.58 vs. 0.32, P < 0.001). At the SAR cutoff of 0.41, the sensitivity, specificity, positive predictive value, negative predictive value (NPV), and diagnostic accuracy rate (DAR) of elastography were 88.2%, 80.2%, 78.9%, 89.0%, and 83.9%, respectively. The logistic regression analysis showed that elastography was the strongest predictor of malignancy (odds ratio, 18.5; 95% confidence interval [CI]: 6.48–52.6; P < 0.001). The highest NPV (96.6%) was achieved with a combination of BSIs and EEIs.

Conclusions

EBUS elastography predicted malignant LNs with a high DAR and NPV in CT‐negative LNs. The NPV was highest when EEIs were combined with BSIs. Therefore, the combined evaluation of CT‐negative LNs using EEIs and BSIs may help bronchoscopists perform EBUS‐TBNA more efficiently.

Key points

Significant findings of the study

Endobronchial ultrasound elastography accurately predicted malignancy with a high diagnostic accuracy rate and negative predictive value in radiologically normal‐sized lymph nodes. The additional use of B‐mode sonographic features resulted in a higher negative predictive value.

What this study adds

Endobronchial ultrasound elastography can guide the accurate collection of specimens with transbronchial needle aspiration, even in radiologically normal‐sized lymph nodes. It can also readily distinguish benign and malignant lymph nodes, thus avoiding unnecessary punctures.

Lung cancer staging: State of the art in the era of ablative therapies and surgical segmentectomy

Implementation of lung cancer screening and improvements in imaging are expected to increase the proportion of lung cancer diagnosed at an early stage. The standard of care has historically been anatomic lobectomy; however, there is now an array of surgical and non-surgical approaches for management of local disease either in active use or under investigation. By their nature, these new modalities offer a theoretical trade-off of reduced morbidity in exchange for reduced efficacy in the setting of advanced disease. It is therefore critical that patients being considered for these approaches (e.g. surgical segmentectomy and SABR) be accurately staged to maximize the potential for definitive treatment. In this article, we will review current approaches to the staging of patients being considered for segmentectomy or ablation. This will serve as a foundation to highlight important questions deserving further investigation.

The utility of elastography during EBUS-TBNA in a population with a high prevalence of anthracosis

BACKGROUND

Ultrasound elastography, is a pioneer sonographic modality that is conducted during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in order to increase the accuracy of sampling location. The current study aims to evaluate the usefulness of elastography during EBUS-TBNA in a population with a high prevalence of anthracosis.

METHODS

This prospective single-blinded study was performed on 69 lymph nodes (LNs) of patients with mediastinal lymphadenopathy undergoing EBUS-TBNA and EBUS-elastography from October 2017 to July 2018. The stiffness level of the tissue was translated into a color to demonstrate the hardness of tissue. Blue and total areas of each section were measured to calculate the hardness of each LN.

RESULTS

Sixty-nine LNs were evaluated by elastography. Twenty percent of LNs were malignant. There was a statistical difference between malignant and non-malignant nodes based on color dominancy (P = 0.032). However, with the exclusion of anthracosis nodes from the analysis, the difference was more significant (P < 0.001). Moreover, when the blue dominancy was used as the predictor of malignancy or anthracosis, the results showed a significant correlation (P < 001).

CONCLUSION

The usefulness of elastography in selecting the hardest area of tissue that is appropriate for diagnosing diseases has been proven previously. Since in countries with a high prevalence of anthracosis, blue color achieved using elastography predicts either malignancy or anthracosis so, cases with blue dominancy of LNs in elastography and the white color in the EBUS-TBNA indicate anthracosis-caused calcification should be reconsidered.

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.

Diagnostic Value of Elastography and Endobronchial Ultrasound in the Study of Hilar and Mediastinal Lymph Nodes

BACKGROUND

The aim of this study was to explore elastography features and its ability to distinguish between benign and malignant lymph nodes by comparing the results with an anatomopathologic examination used as gold standard.

METHODS

Patients were randomized in 2 groups [endobronchial ultrasound (EBUS) and EBUS-elastography]. Echographic characteristics of the lymph nodes were collected in both categories. In the EBUS-elastography group, elastographic data were also determined.

RESULTS

A total of 100 lymph nodes were evaluated. Group 1 (EBUS) consisted of 57 lymph nodes. Group 2 (EBUS-elastography) included 43 lymph nodes. In group 2, lymph nodes with predominantly blue pattern were associated with a pathologic determination of malignancy, and the probability of presenting malignant infiltration with this color pattern was 86.7% (P=0.00004). Malignant lymph nodes presented less color dispersion (48.8 vs. 94.8, P=0.00013), higher ratio of blue pixels (66% vs. 32.5%, P=0.016), and higher strain ratio (7.1 vs. 2.48, P=0.005). The cut-off points to distinguish between benign and malignant lymph nodes were 4 for strain ratio, 61 for frequency histograms, and 52 for blue pixel ratio. The area under the curve of the ROC curves were 0.75, 0.83, and 0.87, respectively. Group 2 presented a lower number of nondiagnostic samples (2.3% vs. 21%, P=0.001) and a higher rate of malignant results (42% vs. 16%, P=0.005).

CONCLUSION

EBUS-elastography is feasible during EBUS and may be helpful in predicting malignant lymph node infiltration. It could improve anatomopathologic sample collection and increase diagnostic efficiency.

Evaluating the use of elastography in endobronchial ultrasound technique as a diagnostic approach for mesothorax lymphadenopathy

Introduction: Non-small cell lung cancer is still diagnosed at a late stage although we have new diagnostic equipment such the radial endobronchial ultrasound, convex probe endobronchial ultrasound, and electromagnetic navigation. The diagnostic techniques have been upgraded with rapid on-site evaluation (ROSE) and currently from 2014 real-time elastography is being evaluated as a ROSE technique.Areas covered: A thorough search was performed on PubMed and Scopus with the following key words: elastography, strain ratio, convex probe EBUS, endoscopic ultrasound (EUS), elastography. In the current mini review, we will focus on published data regarding elastography with the convex probe endobronchial ultrasound in two different systems and comment on this future ROSE technique. Elastography, strain ratio, and factors such as(I) margin (indistinct or distinct); (II) shape (oval or round); (III) short-axis size less or more than 1 cm; (IV) presence or absence of central hilar structure (CHS); (V) echogenicity (homogeneous or heterogeneous); and (VI) presence or absence of coagulation necrosis sign are presented in our review based on published literature.Expert opinion: Current data indicate that we can have up to 93% sensitivity and specificity of real-time elastography and strain ratio for the evaluation of benignancy and malignancy; however, sample biopsy is still necessary. For now, we can only reduce the number of punctures.

The combination of endobronchial elastography and sonographic findings during endobronchial ultrasound-guided transbronchial needle aspiration for predicting nodal metastasis

Background

During endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA), the sonographic findings of B‐mode imaging, as well as endobronchial elastography, can be obtained noninvasively and used for the prediction of nodal metastasis.

Methods

Patients with lung cancer or suspected lung cancer who underwent EBUS‐TBNA were recorded prospectively and reviewed retrospectively. Both the B‐mode sonographic and elastographic findings were independently evaluated for each lymph node. The sonographic features were classified according to previously published criteria. If oval shape, indistinct margins, homogenous echogenicity, and the absence of coagulation necrosis sign were all observed by B‐mode imaging, then the lymph node was judged to be benign by sonographic imaging. In addition, if the stiffer area comprised more than 31% of the entire lymph node area, then the lymph node was judged to be malignant by elastography. We compared the results of these imaging‐based predictions with the pathological diagnoses.

Results

The prevalence of nodal metastasis was 78/228 (34.2%). B‐mode sonography predicted 95.8% of benign lymph nodes, and elastography predicted 72.1% of malignant lymph nodes. By combining the two modalities, 59 of 71 (83.1%) lymph nodes judged as malignant by both analyses were pathologically proven to be malignant, and 101 of 105 (96.2%) lymph nodes judged as benign by both analyses were pathologically proven to be benign.

Conclusion

The combination of elastography and sonographic findings showed good sensitivity and a high negative predictive value, which may facilitate selecting the most suspicious lymph nodes for biopsy.

Key points

Significant findings of the study.

The combination of endobronchial elastography and sonography resulted in a higher diagnostic yield than either modality alone for predicting benign and malignant lymph nodes in patients with lung cancer.

What this study adds.

The combination of endobronchial elastography and sonography will help clinicians identify the most suspicious lymph nodes for puncturing during EBUS‐TBNA, which may improve the efficiency of EBUS‐TBNA.

Contribution of endobronchial ultrasound elastography to the characterization of mediastinal lymphadenopathy: A single-center, prospective, observational study

BACKGROUND

Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is a reliable technique providing high diagnostic yield in mediastinal lymphadenopathy. However, mediastinoscopy is sometimes necessary to eliminate false-negative results. Elastography is a recent technique that can be combined with EBUS to evaluate the elasticity and consequently the nature of a tissue. The primary objective was to evaluate the diagnostic performance of EBUS-TBNA combined with elastography for the assessment of mediastinal lymph nodes.

METHODS

Single-center, prospective study in patients with mediastinal lymphadenopathy. EBUS-TBNA combined with elastography was performed in each patient. Several elastographic parameters were studied: colorimetric score, average elasticity, elasticity ratio, percentage of hard areas. The final diagnosis was that obtained by TBNA cytology, histology of a surgical biopsy, when performed, or follow-up CT and PET-CT at 6 months.

RESULTS

Overall, 110 lymph nodes were examined in 87 patients: 44 were malignant according to TBNA. These nodes had significantly higher elasticity ratio, percentage of hard areas and colorimetric score and significantly lower average elasticity compared to benign nodes (P<0.001). With a negative predictive value of 100%, the cut-offs defined by receiver operating characteristic curves were 1.4 for elasticity ratio, 84.8 for average elasticity, 32.6 for percentage of hard areas and 3 for colorimetric score. No adverse events were observed.

CONCLUSION

Endobronchial ultrasound elastography is a non-invasive technique that can contribute to prediction of the nature of lymph nodes by distinguishing malignant from benign nodes. Although EBUS cannot replace histological examination, elastography can provide reliable complementary information when combined with EBUS.

Endobronchial ultrasound elastography for diagnosing mediastinal and hilar lymph nodes

INTRODUCTION

The main objective was to analyze the technical variability of EBUS-elastography in the differentiation of benign and malignant hilar and mediastinal lymph nodes. As a secondary objective, the results of the EBUS-elastography in said differentiation were analyzed, comparing them with the anatomopathological results.

MATERIAL AND METHODS

Prospective and analytical study of lymph nodes in which EBUS-elastography was performed. Elastographic variables and their variability were analyzed.

RESULTS

24 patients and 38 lymph nodes were evaluated. Of these, 60.5% had a history of neoplasia, 71% of them were EBUS-elastography with diagnostic intention, 53% were mediastinal staging of lung cancer. Both procedures were performed in 25% of the patients. Lymph nodes were classified into elastographic colour patterns, red being characteristic of elastic tissues and blue of rigid tissues. The lymphadenopathies with apredominantly blue pattern were associated with an anatomopathological result of malignancy (86% vs. 14%, OR 20.4 (3.1 -245.1) p-value = .00015). Malignant lymph nodes presented less colour dispersion in the frequency histograms and a higher ratio of blue pixels and higher strain ratio. These variables showed a variability of 8.7, 9.9 and 31.6% respectively in repetitions in the same adenopathy. Finally, a 66% of consistency was obtained in the event of colour pattern variability (p .0000).

CONCLUSIONS

EBUS-elastography is feasible during EBUS and may be helpful in predicting malignant lymph node infiltration. The quantitative elastographic data show low variability in repetitions in the same adenopathy. The strain ratio is the most variable elastographic parameter.

Endobronchial ultrasound elastography in mediastinal lymphadenopathy: Report of two cases and systematic review of literature

Endobronchial ultrasound elastography is new ultrasound technology that is being reported recently for the evaluation of mediastinal lymphadenopathy during endobronchial ultrasound-guided (EBUS) transbronchial needle aspiration. This modality is based on the assessment of tissue stiffness that may be useful in differentiating benign from malignant lesions. Image generation leads to colored images with different colors signifying varying degrees of stiffness. The utility of this technique has been studied to differentiate between benign and malignant lymph nodes and various methods for representation of results which include visual color estimation, quantitative color estimation, and strain ratios have been described. Herein, we report two patients with mediastinal lymphadenopathy wherein EBUS elastography was employed. We also systemically review the studies describing this technique in differentiating benign from malignant lymph nodes.

Optimal Endobronchial Ultrasound Strain Elastography Assessment Strategy: An Explorative Study

BACKGROUND

In lung cancer staging, mediastinal lymph nodes are currently aspirated using endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) based on size and FDG-PET avidity. EBUS strain elastography (SE) is a new technique that may help predict the presence of malignancy. However, a standardized assessment strategy for EBUS-SE measurement is lacking.

OBJECTIVES

The aim of this study was to determine the optimal assessment strategy for investigating the predictive value of EBUS-SE in mediastinal lymph nodes.

METHODS

Two qualitative visual analogue scale strain scores and two semiquantitative strain elastography measurements (a strain histogram and strain ratio) were acquired in 120 lymph nodes of 63 patients with (suspected) lung cancer. The dataset was randomized into an 80% training dataset to determine cut-off values. Performance was consecutively tested on the remaining 20% and the overall dataset.

RESULTS

The semiquantitative mean histogram scoring strategy with a cut-off value of 78 (range 0-255) showed the best and most reproducible performance in prediction of malignancy with 93% overall sensitivity, 75% specificity, 69% positive predictive value, 95% negative predictive value, and 82% accuracy. Combining the EBUS-SE mean histogram scoring outcome with PET-CT information increased the post-test probability of disease in relevant clinical scenarios, having a positive test likelihood ratio of 4.16 (95% CI 2.98-8.13) and a negative test likelihood ratio of 0.14 (95% CI 0.04-2.81) in suspicious lymph nodes based on FDG-PET or CT imaging.

CONCLUSIONS

EBUS-SE can potentially help predict lymph node malignancy in patients with lung cancer. The best semiquantitative assessment method is the mean strain histogram technique.

Differentiating malignant and benign lymph nodes using endobronchial ultrasound elastography

BACKGROUND/PURPOSE

Endobronchial ultrasound (EBUS) elastography is a new technique that provides information on tissue compressibility during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). The purposes of this study were to evaluate the utility of EBUS elastography in differentiating malignant and benign mediastinal lymph nodes (LNs) and to explore the factors that influence its accuracy.

METHODS

A retrospective chart review of patients who underwent EBUS-TBNA from October 2016 to July 2017 was performed. EBUS with conventional B-mode features and elastographic patterns were compared with the final pathology results or clinical follow-up. We used the following EBUS elastographic patterns for classification: type 1, predominantly non-blue (green, yellow and red); type 2, part blue, part non-blue; type 3, predominantly blue. The potential impacts of the characteristics of LNs, the underlying lung diseases and obtaining fibrotic components from EBUS-TBNA specimens were evaluated relative to the accuracy of EBUS elastography.

RESULTS

A total of 206 LNs from 94 patients were retrospectively evaluated. In classifying type 1 as 'benign' and type 3 as 'malignant,' the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy rate were 90.6, 82.6, 71.6, 94.7 and 85.2%, respectively. The EBUS elastographic patterns had higher diagnostic yields and negative predictive values than conventional B-mode features. Logistic regression analysis revealed that central necrosis was a factor that influenced the accuracy of elastography in malignant LNs. The fibrotic component within benign LNs could cause an incorrect elastographic pattern.

CONCLUSION

EBUS elastography is a valuable tool in discriminating benign and malignant mediastinal LNs.

Semi-quantitative Analysis of EBUS Elastography as a Feasible Approach in Diagnosing Mediastinal and Hilar Lymph Nodes of Lung Cancer Patients

This study aimed to semi-quantitatively evaluate the elastographic imaging color distribution of mediastinal and hilar lymph nodes (LNs), and explored its utility in helping define malignant and benign LNs for lung cancer patients. We prospectively collected patients who underwent preoperative mediastinal staging of suspected lung cancer by EBUS-TBNA. We analyzed the elastography color distribution of each LN and calculated the blue color proportion (BCP). The LN elastographic patterns were compared with the final EBUS-TBNA pathological results. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of BCP. We sampled and analyzed 79 LNs from 60 patients. The average BCP in malignant LNs was remarkably higher than that in benign LNs (57.1% versus 30.8%, P < 0.001). The area under the ROC curve (AUC) for the BCP was 0.86 (95% CI: 0.78–0.94). The best cutoff BCP for differentiating between benign and malignant LNs was determined as 36.7%. All the 16 LNs (20.3%) with a BCP lower than 27.9% were diagnosed as benign tissues. Our study suggests that elastography is a feasible technique that may safely help to predict LN metastasis during EBUS-TBNA. We found a clear BCP cutoff value to help define positive and negative LNs.