Conventional ultrasound and ultrasound elastography are respectively used to examine thoracic lesions before aspiration,then the images are saved as video clips. Features of conventional ultrasound and parameters of ultrasound elastography are analysed and recorded by skilled worker. The investigators define the pathological results of EBUS-TBNA combined with results of six months follow-up as the "Gold Standard". The receiver operator characteristic curves are drawn to obtain area under the Curve (AUC) and the best diagnostic threshold values of each parameters. According to the best cutoff values, the investigators respectively calculate the accuracy, sensitivity, specificity, odds product of each parameters, and then compare them with each other to evaluate the value of ultrasound elastography