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, and fluorodeoxyglucose uptake value (p<0.01). With a cut-off value of ?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.