Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS–TBNA) is performed to investigate mediastinal masses, predominantly in the context of staging of lung cancer. Other conditions associated with mediastinal lymphadenopathy include cancer of other organs, atypical infections and sarcoidosis. EBUS–TBNA may also be used in the investigation of hilar lymph nodes.
After imaging studies (such as computer tomography [CT] and positron emission tomography [PET] scanning), histological investigation of mediastinal masses may be required. A variety of biopsy techniques may be used such as conventional non-ultrasound-guided TBNA, transthoracic needle aspiration and endoscopic transoesophageal ultrasound-guided fine-needle aspiration (EUS–FNA). EUS–FNA involves insertion of an endoscope into the oesophagus and transoesophageal needle biopsy under ultrasound control. Occasionally mediastinoscopy or mediastinotomy may be required.
EBUS–TBNA may be performed under local anaesthesia with sedation, or under general anaesthesia. A flexible bronchoscope containing an ultrasound probe is inserted via the trachea and guided through the bronchial tree towards the appropriate area of the mediastinum. The targeted lymph nodes or masses are identified using bronchoscopic visualisation and ultrasound imaging. A needle extended from the bronchoscope through the bronchial wall is used to puncture the mass and to aspirate tissue. A mass can be punctured several times to gain an adequate sample, and several masses can be punctured during the same session.
EBUS–TBNA is usually performed under real-time ultrasound, but has also been performed under non-real-time ultrasound.