EBUS – An advanced diagnostic tool for lung diseases and cancers

“Compared to general bronchoscopy, in EBUS, the bronchoscope includes an ultrasound attachment. This gives an advantage of ultrasound-visualization of the various structures, which cannot be spotted with the normal eye/camera alone. It allows a superior and excellent guidance of transbronchial needle aspiration of structures in and around the airway and other lung masses.”

EBUS or endobronchial ultrasound is an advanced diagnostic technique in the field of pulmonology. This technique uses an ultrasound coupled with bronchoscopy to view and procure biopsy samples in and around the lungs.

It is usually advised for pathologies centered around airway with involvement of lymph node/mediastinal structures/staging of lung cancer/guiding endobronchial therapy.

Disease conditions that may prompt the physician to perform EBUS include: tuberculosis, sarcoidosis, lymphomas, and various other malignancies. Staging of lung cancer can provide useful additional information during interventions, such as resection of endobronchial lesions, stricture dilatation, stenting, laser therapy, and argon plasma coagulation.

Convex probe EBUS (CP-EBUS) has a tip that is flexed up and down for ultrasound and endoscopic imaging, respectively. CP-EBUS is now routinely used in staging lung cancer when lymph nodes are involved. CP-EBUS is associated with higher sensitivity and specificity for lymph node staging when compared to CT and PET scans.

And, radial EBUS (RP-EBUS) provides a 360-degree ultrasound view of the airway and structures surrounding the lungs and is used in the case of peripheral lung lesions, which are too small and cannot be biopsied by the CT-guided method. More recently, the RP-EBUS is also being used in guiding radiation treatment of malignancy.

Advantages include:

• The conventional CT-guided biopsy involves puncturing the lungs, resulting in the development of pneumothorax where air can get accumulated outside the lungs. This can be avoided using EBUS.
• EBUS plays a crucial role in the staging of many lung cancers. It is important to know the stage of cancer to opt for the right treatment regime.
• In some conditions, when mediastinal structures can get involved, which are less accessible via CT-guided approach, EBUS can be utilized for the same.
• Additionally, the pathology of the aspirated material can be known immediately at the table, to avoid any delay in the treatment.

“As compared to a CT-guided technique, complications with EBUS are very rare (27% vs 3%). It may lead to pneumothorax and bleeding in some patients, reported in about 0.8–4.2 percent and 0–5.6 percent of total cases, respectively. Other complications may include mucosal injury and risk of infections.”

It is a safe procedure with minimal complications and can be adopted even in general anesthesia, allowing the patient to be monitored adequately.

• Cryo-biopsy is a recent advancement in EBUS. In this biopsy, a cryoprobe is used to get a piece of the tissue of interest for testing instead of only fluid as in a normal biopsy

In many diseases, the structures in and around the respiratory tube get affected and getting access to them for biopsy may pose a diagnostic challenge for the clinician. In such cases, EBUS is highly beneficial and is associated with a low risk of complications, making it a preferred tool in accurately diagnosing complicated lung conditions, thereby aiding appropriate and faster treatment.

In addition, with the recent advances, EBUS can also be used for guiding endobronchial therapy, such as resection of endobronchial lesions, stricture dilatation, stenting, laser therapy, and argon plasma coagulation.