CONVEX EBUS – ENDOBRONCHIAL ULTRASOUND
Endobronchial ultrasound (EBUS) is a state-of-the-art procedure that is used in order to obtain biopsy material from the mediastinal lymph nodes. Lymphadenopathy of the mediastinum is a condition that needs to be investigated. It could be caused by an infection or a benign disease such as sarcoidosis, or a malignancy such as lymphoma or lung cancer. It could also be caused by a metastasis from other organs such as the gastrointestinal system, the breast, the urinary bladder, as well as other organs. Upon acquisition of biopsy material from the lymph node or the lymph nodes, immunohistochemistry, as well as other laboratory methods, will give the final answer.
The primary method of acquisition of biopsy material from the lymph nodes up to now was to perform a surgical procedure, mediastinoscopy. Endobronchial ultrasound (EBUS) is also used for the staging of patients that suffer from non-small cell lung cancer and may undergo therapeutic surgery, and supplements PET-CT scan examination or, in many cases, replaces it. Now, biopsy material from the mediastinal lymph nodes is obtained within half an hour and patients can return home.
The procedure is performed under conscious sedation for the safety of patients but, also, for the examination to be better received from patients. The diagnosis of a malignancy in the mediastinum can be made in various ways, and both the choice of the right method and the processing of the material are important. It is not enough to obtain a sufficient quantity of biopsy material; it is also very important to correctly process this material in the laboratory. The molecular testing of the biopsy material is now necessary for many neoplasms in order to decide on the right treatment.
Other techniques for the diagnosis of a malignancy of the thorax is bronchoscopy and thoracoscopy. Thoracoscopy is mainly used when patients present pleural effusion. Sometimes, upon diagnostic thoracoscopy, pleurodesis is also performed on patients in order to avoid the recurrence of malignant pleural effusion. When bronchoscopy cannot provide a diagnosis for a mass in the thorax, then it is considered necessary for the doctor to present patients with another diagnostic method. When bronchoscopy cannot provide a diagnosis for a mass in the thorax, then we suggest our patients to undergo endobronchial ultrasound (EBUS) or CT-guided biopsy.
Additionally, bronchoscopy cannot provide indication for the performance of biopsy in case of a paratracheal lesion or a lesion next to large vessels, such as the pulmonary arteries; in such case only endobronchial ultrasound (EBUS) can provide indication. In any case, only interventional pulmonology specialists can guide patients as to which technique is best and inform them accordingly.
Table 1: The lymph nodes from which biopsy material can be obtained for the diagnosis and staging of pulmonary cancer are shown with colored spots.
Table 2: From upper left and clockwise: 1) a lymph node that has become a mass and is near a branch of the pulmonary artery (thorax CT scan), 2) image through the bronchial tree at the point where the lesion is supposedly situated, according to the CT scan· the image we see is through the endobronchial ultrasound camera (however, the lesion is behind the bronchial wall and can be seen with the CT scan in the next image), 3) the image of the existing lesion in the CT scan can be seen during the ultrasound of the machine (EBUS)-the vessel is also shown in blue and red coloring, enabling thus the operator to safely obtain biopsy material, 4) the endobronchial ultrasound gives us two images from two devices at the same time, a visual one (on the left) and one of the ultrasound (on the right), 5) paratracheal lesion, one of the main indications for endobronchial ultrasound.