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.

Background: Ultrasonographic characteristics may help differentiate between benign and malignant lymph nodes during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). There is limited data on the utility of various ultrasonographic lymph node features to differentiate between malignant and tuberculous mediastinal lymphadenopathy.Methods: We studied the various EBUS ultrasonographic lymph node characteristics (size, shape, margins, heterogeneous echotexture, calcification, central hilar structure, lymph node conglomeration, central intranodal vessel, and coagulation necrosis sign) from our available EBUS-TBNA database.Results: We extracted 1086 subjects [547 with tuberculosis (TB) and 539 with malignant diagnosis]. Comparing the 2 groups (multivariate analysis), presence of central hilar structure (8.2% vs. 2.6%), coagulation necrosis sign (37.5% vs. 13.7%), lymph node conglomeration (30.5% vs. 7.2%), calcification (5.1% vs. 1.5%), and distinct margins (83.5% vs. 69.8%), were significantly more common in TB (P < 0.05). On the other hand, malignant lymph nodes were larger and more likely to show the presence of a central intranodal vessel (20% vs. 15.8%, P = 0.04, multivariate analysis). The absence of lymph node conglomeration had the highest overall diagnostic accuracy (0.61) for the differentiation between malignant and tuberculous lymph nodes.Conclusion: Sonographic lymph node characteristics may help differentiate malignant and tuberculous mediastinal lymphadenopathy. Contrary to previously published literature, we observed coagulation necrosis sign, heterogeneous echotexture and absent central intranodal vessel, more commonly in TB than malignant nodes. These findings from a TB endemic setting are different from other settings, where the prevalence of lung cancer is high in patients undergoing 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.