Linear EBUS - Anatomy

Hilmi Lockman
Prince Court Medical Centre, Kuala Lumpur, Malaysia

Endobronchial ultrasound (EBUS) emerged from endoscopic ultrasound in the 1980’s to 1990’s. The linear probe EBUS was introduced in 2002 and combined with the earlier work of Ko Peng Wang of flexible transbronchial needle aspiration (TBNA), this paved way for the ability of sampling mediastinal lymph nodes and masses with direct vision. Prior to performing EBUS, radiological imaging is required: CT chest with contrast or PET-CT. 

Lymph node stations are accessed by positioning the EBUS scope along the trachea and bronchi, using ultrasound landmarks like the aorta, pulmonary artery, and azygos vein to guide needle placement.

Some of the anatomy that can be viewed while using EBUS are the tracheal wall: appears as a hyperechoic (bright) line; lymph nodes: typically, hypoechoic (dark), round or oval; vessels: confirmed using doppler mode to avoid accidental puncture; surrounding structures: esophagus, vertebrae, and heart chambers may be visible depending on scope position. There will be variations to what is being seen depending on the subjects and underlying pathology.