Diagnostic value of endobronchial ultrasound elastography for the differentiation of benign and malignant intrathoracic lymph nodes

Background and objective: Endobronchial ultrasound (EBUS) findings can be used for benign/malignant differentiation of lymph nodes (LNs). Recently, EBUS elastography has been introduced as a complementary modality in the evaluation of intrathoracic lymphadenopathy. We evaluated the ability of EBUS elastography to differentiate between benign and malignant LNs. Methods: A prospective study was conducted on patients sent for evaluation of intrathoracic lymphadenopathy. LNs were classified qualitatively according to elastographic colour pattern: type 1, predominantly non-blue; type 2, partly blue, partly non-blue and type 3, predominantly blue. Quantitative elastography of LNs was measured by the strain ratio (SR). Qualitative and quantitative elastographies were compared for the final diagnosis of LNs. Results: There were 120 LNs from 72 patients who underwent EBUS elastography. The final diagnosis included 96 malignant and 24 benign LNs. All of the 16 type 1 LNs proved to be benign diseases, while 95 of the 101 type 3 LNs were finally diagnosed as malignancies. Three LNs classified as type 2 proved to be two benign and one malignant. Malignant LNs presented a higher median SR than benign LNs (73.50 vs 1.29, P = 0.001). An SR of >2.5 and non-type 1 elastographic pattern achieved similar diagnostic performance in benign/malignant differentiation (sensitivity, 100% vs 100%; specificity, 70.8% vs 66.7%; positive predictive value, 93.2% vs 92.3%; negative predictive value, 100% vs 100%). Conclusion: EBUS elastography is a promising diagnostic modality for the differentiation of benign and malignant LNs during EBUS-guided transbronchial needle aspiration (TBNA). Qualitative and quantitative EBUS elastographies provide similar diagnostic performance.