The use of transbronchial needle aspiration (TBNA) in addition to routine bronchoscopy was reported to improve the diagnostic rate for malignancies. As target lymph nodes cannot be visualized directly with the conventional TBNA procedure, aspiration efforts are directed by knowledge of thoracic anatomy and prior CT imaging. Multiple needle passes are required for each target because there is the possibility of error in puncturing the target lesion. Therefore, the diagnostic rate of TBNA seems to be related to the lymph node size and location as well as the operator’s experience.
With the development of new technology, endobronchial ultrasonography (EBUS) is reported to be useful in detecting mediastinal and hilar lymphade-nopathy in addition to assessing the depth of tracheobronchial tumor invasion. Recently, EBUS has also been used for TBNA guidance and has improved the results of N-staging, especially in difficult lymph node levels without any clear endoscopic landmarks. However, Shannon et al reported that EBUS guidance did not offer a statistically significant advantage when compared with conventional TBNA because the sensitivities of both procedures were extremely high (82.6% vs 90.5%, respectively). However, Herth, et al reported that EBUS guidance significantly increased the yield of TBNA in the mediastinal lymph node except for subcarinal lymph node in their randomized trial (84% vs 58%). The main disadvantage of EBUS guidance using a single-channel bronchoscope is that a real-time imaging of the needle position within the target lesion cannot be confirmed because the EBUS probe must be removed during the TBNA procedure. To overcome this problem, a double-channel bronchoscope, through which both a TBNA catheter and an EBUS probe can be inserted simultaneously, was necessary. This study assessed the usefulness of EBUS-guided TBNA using a double-channel bronchoscope (EBUS-D) or EBUS-guided TBNA using a single-channel bronchoscope (EBUS-S).