middle third of the esophagus can be visualized from the upper and lower trachea respectively Currently, we have different sizes of needle available, including 19, 21, 22, and 25 G.
EBUS anatomical landmarks
It is important to note that all right tracheal lymph node stations are found from the left lateral border of the trachea to the right aspect of the trachea.
Figure 3.6 Endobronchial ultrasound (EBUS) images of common mediastinal stations (4L, 7 and 11L). The esophagus and vertebral bodies can be visualized posteriorly from the upper and lower trachea.
Right upper paratracheal nodes (station 2R): the upper border is the apex of the right lung, the lower border is the intersection of the innominate vein with the trachea. This station is usually found facing the scope to the right lateral wall of the trachea, at 3 o’clock, at the level of the fifth tracheal cartilage.
Left upper paratracheal nodes (station 2L): the upper border is the apex of the left lung, the lower border is the superior limit of the aortic arch. This station is usually found facing the scope to the left lateral wall of the trachea, at 9 o’clock, at the level of the fifth tracheal cartilage.
Right lower paratracheal nodes (station 4R): the upper border is the innominate vein, the lower border is the azygos vein. This station is usually found just proximal to the main carina, between 12 and 3 o’clock.
Left lower paratracheal nodes (station 4L): the upper border is the superior limit of the aortic arch, the lower border is superior limit of the left pulmonary artery. This station is usually found at the level of the main carina, left lateral wall of the trachea, at 9 o ‘clock. The view of the AP window is very similar to that seen by the EUS scope with the aortic arch on the right and pulmonary artery on the left.
Subcarinal nodes (station 7): the upper border is the main carina, the inferior border is the superior limit of the left lower lobe take‐off on the left side, and the inferior limit of the bronchus intermedius on the right side. This station is found at the medial wall of the left mainstem bronchus or the medial wall of the right mainstem bronchus and bronchus intermedius.
Right hilar nodes (station 10R): the upper boder is the azygos vein, the lower border is the interlobar region. This station is usually found just proximal to the right upper lobe take‐off, facing to the anterior and lateral airway wall.
Left hilar nodes (station 10L): the upper border is the pulmonary artery, the lower border is the interlobar region. EBUS scope should be faced just proximal to the left upper lobe, at 11 o’clock.
Right interlobar superior nodes (station 11Rs): the upper limit is the right upper lobe bronchus, the lower limit is the distal bronchus intermedius. This station should be found at the lateral wall of the airway, between 2 and 4 o’clock.
Right interlobar inferior nodes (11Ri): lymph nodes are between the right middle lobe and the right lower lobe. EBUS scope should be placed just proximal to the right lower lobe bronchus, facing laterally.
Left interlobar nodes (station 11L): the upper limit is the left upper lobe bronchus, the lower limit is the left lower lobe bronchus. Place EBUS scope at the left lower lobe take‐off, facing anterior and lateral.
Right/left lobar nodes (station 12R/L): any lymph nodes adjacent to the lobar bronchi.
Complications and safety
EUS‐FNA and EBUS‐TBNA are highly safe procedures in experienced hands, with a complication rate of 0.8%. A major safety precaution with FNA is to visualize the entire length of the needle and to use color Doppler to avoid any blood vessels in the needle path.
Conclusions
EUS‐FNA and EBUS‐TBNA are complementary procedures with a high degree of sensitivity and specificity for diagnosing and staging benign and malignant diseases of the chest. Careful attention to technique must be applied to prevent the omission of important clinical information.
Chapter video clips
Video 3.1.1 Normal mediastinal anatomy by linear EUS: vascular anatomy. Source: Hitachi.
Video 3.1.2 Normal mediastinal anatomy by linear EUS: right and left atrium and AP window. Source: Aloka.
Video 3.1.3 Normal mediastinal anatomy by linear EUS: aorta, heart and great vessels. Source: Hitachi.
Video 3.2 Normal mediastinal anatomy by radial EUS.
Video 3.3 Paratracheal and subcarinal lymph node evaluation by EBUS. Source: Hitachi.
Video 3.4 Subcarinal lymph node (station 7) as seen by EBUS with performance of FNA.
4 Stomach: Radial and Linear
Joo Ha Hwang
Stanford University, Palo Alto, CA, USA
Endoscopic ultrasound (EUS) examination of the stomach is often performed to evaluate subepithelial lesions, staging of mucosa‐associated lymphoid tumor (MALT) lymphomas, staging of gastric cancer, and evaluation of thickened gastric folds. Examination can be performed using mechanically scanning or electronic array echoendoscopes, or with ultrasound catheter probes.
The basic technique for performing EUS imaging of the gastric wall initially requires clearing the gastric lumen of any mucus or debris. The lumen should be thoroughly irrigated with water and suctioned. If there are excessive amounts of bubbles in the gastric lumen, a small amount of simethicone can be added to the irrigating water and suctioned. Once the gastric lumen has been cleared the gastric lumen should be decompressed and then filled with clean water. Ideally, degassed water should be used to fill the gastric lumen; however, this is often not available and clean water typically is sufficient. However, efforts should be made to minimize the presence of bubbles within the water as this will degrade the image quality. It is important to make sure that all air is aspirated from areas where imaging is to be performed. When filling the gastric lumen with the patient on their left side, the fundus and body will fill preferentially due to gravity. If the area of interest is in the antral wall, positioning the patient on their right side may be necessary to safely fill the gastric lumen with water for imaging. Filling of the gastric lumen with water places the patient at risk of aspiration; therefore, precautions should be taken to protect against an aspiration event.
After aspirating the air out of the lumen and distending the gastric lumen with water, the gastric wall can be surveyed with a radial scanning echoendoscope by starting the exam with the ultrasound probe in the antrum and slowly withdrawing the probe (
