Techniques of Linear Endobronchial Ultrasound

Endobronchial ultrasound (EBUS) visualizes structures within and adjacent to the airway (1). Most operators do not follow any standard positions of imaging during EBUS and use the computed tomography scan as a roadmap for imaging of the lymph nodes. A small window angle (50 to 75 degrees) in linear EBUS as compared with linear endoscopic US (130 to 180 degrees) makes visualization of the anatomic ultrasound landmarks difficult with EBUS. For better orientation, it is useful to recognize key anatomic landmarks and their relationship to the airways, apart from observing the position of the probe while performing EBUS. In this section we describe the mediastinal and parabronchial anatomy of different parts of the respiratory tract which is practically important during EBUS.