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

Abstract

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.

The Impact of Core Tissues on Successful Next-Generation Sequencing Analysis of Specimens Obtained through Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration

“…Based on a previously reported B-mode image classification [ 25 , 27 ], images were evaluated according to the following parameters: size (short axis diameter >1 cm or ≤1 cm), shape (round or oval), echogenicity (heterogeneous or homogeneous), margins (distinct or indistinct), central hilar structure (presence or absence), and coagulation necrosis sign (presence or absence). The round shape was defined as a ratio of the short to long axis diameter < 1.5.…”

“…Bronchoscopists can routinely evaluate mediastinal and hilar target lesions using B-mode sonographic findings and color/power Doppler mode ultrasound images during EBUS-TBNA. Each sonographic finding allows differentiation between benign and malignant lesions [ 25 , 26 , 27 ]. Specifically, B-mode findings allow the assessment of the echogenicity of the lesion and the presence of necrosis, while color/power Doppler mode ultrasound images facilitate the assessment of the presence of abundant blood flow in the target lesion.…”

Scoring model of convex probe endobronchial ultrasound multimodal imaging in differentiating benign and malignant lung lesions

“…However, the specificity was only 52.63% in lung lesions, indicating that benign lesions in our study were relatively stiff, while elastography could only reflect the stiffness of lung lesions rather than the benign or malignant nature of lesions. Studies found that a history of pulmonary tuberculosis and apparent inhalation exposure to mineral dust such as coal or asbestos could influence the relative stiffness of LNs (34)(35)(36). Fibrosis in sarcoidosis granulomas may lead to false positive results of elastography grading score, similar to granulomatous fibrosis in tuberculosis (28,37).…”

Influential Factors for Assessing Endobronchial Ultrasound Elastography

“…EBUS-E can capture images of distortion of lymph nodes (LNs) and evaluate their stiffness. Several studies have suggested that pneumoconiosis and tuberculosis, which often show LN hardening, give false-positive results (e.g., the EBUS-E image suggests malignancy but the final diagnosis is benign) on EBUS-E [2-4]. Imaging tests, such as FDG-PET, cannot clarify whether lymphadenopathy is due to malignancy, pneumoconiosis, or tuberculosis.…”

“…We recently conducted a retrospective study of EBUS-E for radiologically normal-sized hilar and mediastinal LNs. We used the stiffness area ratio (SAR) for the quantitative analysis of EBUS-E. Our results showed that all patients with an SAR of ≥0.6 have a history of pulmonary tuberculosis and/or apparent inhalation exposure to mineral dust such as coal or asbestos [4]. Eight of 16 (50%) patients with false-positive EBUS-E results in our study had a background that could explain LN hardening.…”