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

Abstract

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. 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. 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%). 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.