The utility of elastography during EBUS-TBNA in a population with a high prevalence of anthracosis

Background Ultrasound elastography, is a pioneer sonographic modality that is conducted during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in order to increase the accuracy of sampling location. The current study aims to evaluate the usefulness of elastography during EBUS-TBNA in a population with a high prevalence of anthracosis. Methods This prospective single-blinded study was performed on 69 lymph nodes (LNs) of patients with mediastinal lymphadenopathy undergoing EBUS-TBNA and EBUS-elastography from October 2017 to July 2018. The stiffness level of the tissue was translated into a color to demonstrate the hardness of tissue. Blue and total areas of each section were measured to calculate the hardness of each LN. Results Sixty-nine LNs were evaluated by elastography. Twenty percent of LNs were malignant. There was a statistical difference between malignant and non-malignant nodes based on color dominancy (P = 0.032). However, with the exclusion of anthracosis nodes from the analysis, the difference was more significant (P < 0.001). Moreover, when the blue dominancy was used as the predictor of malignancy or anthracosis, the results showed a significant correlation (P < 001). Conclusion The usefulness of elastography in selecting the hardest area of tissue that is appropriate for diagnosing diseases has been proven previously. Since in countries with a high prevalence of anthracosis, blue color achieved using elastography predicts either malignancy or anthracosis so, cases with blue dominancy of LNs in elastography and the white color in the EBUS-TBNA indicate anthracosis-caused calcification should be reconsidered.