Understanding the paths of blood vessels around the trachea and bronchi as well as the positions of lymph nodes is necessary for detecting abnormal findings in the trachea or bronchi. Such an understanding is also important for ensuring safety during puncture techniques, such as endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and biopsies. The CT anatomy and basic knowledge necessary for bronchoscopy are described. Before conducting procedures such as a transbronchial biopsy (TBB) or transbronchial lung biopsy (TBLB) for the diagnosis of peripheral pulmonary lesions, it is important to identify the segment hosting the lesion as well as the bronchi involved. In addition, before conducting procedures such as EBUS-TBNA that involve puncturing the central airway, it is important to understand the lesion's location and size as well as its positional relationship with blood vessels. Thus, regardless of the benignity or malignancy of the disease or the type of testing procedure, at the very least, chest CT should be performed before conducting bronchoscopy to collect samples. Recently, chest CT has typically been performed via multi-slice CT, the data of which facilitates virtual bronchoscopic navigation (VBN) or 3D display and thereby allows for the clear visibility of the relationship between the blood vessels and bronchi on the central side. In this section, we described CT scan-related knowledge that should be mastered in order to perform bronchoscopy, such as ensuring a thorough understanding of the segmental anatomy of the lungs on CT images as well as the relationship between bronchi, blood vessels, and lymph nodes.
