Transbronchial needle aspiration biopsy (TBNA) is a technique to obtain cytological, histological or microbiological specimens of lesions in the mediastinum of the tracheal wall, lung parenchyma and adjacent parts of the trachea and bronchi through puncture needle aspiration or excision. TBNA is simple, relatively safe and has few complications, but conventional TBNA is “blind” and its diagnostic accuracy fluctuates greatly (20%-89%) in different studies, depending on the technical proficiency of the operator, the size and location of the lymph nodes and other factors. In recent years, the newly developed EBUS-specific bronchoscope is a miniature ultrasound probe that can perform sector scanning built into the front end of the bronchoscope, allowing for real-time surveillance of TBNA while acquiring images of surrounding lesions, and the use of this technique can greatly improve the diagnostic sensitivity and accuracy of TBNA. Figure 1 Ultrasound bronchoscope and dedicated transbronchial needle aspiration biopsy needle through the working orifice Herth et al. compared the diagnostic efficiency of EBUS-TBNA with that of conventional TBNA in a randomized clinical trial, showing that the diagnostic rate of EBUS-TBNA was 84% for accessible lymph nodes other than the infundibular lymph nodes, which was significantly higher than that of conventional TBNA (58%). Some studies have shown that the application of EBUS-TBNA by the same operator significantly increases the positive diagnostic rate. The lymph node groups available for EBUS-TBNA are 2, 3, 4, 7, 10, and 11. EBUS-TBNA can reduce the number of mediastinoscopies performed due to lymph node staging and is largely free of complications. There are ongoing studies suggesting that EBUS-TBNA shows good sensitivity (92.3%-96.4%), specificity (100%) and diagnostic accuracy (97.1%-98.9%) in determining mediastinal lymph node metastasis in malignant tumors. The sensitivity and specificity of EBUS-TBNA remained high even in patients after chemotherapy or tumor recurrence. EBUS-TBNA has become an indispensable method for clinical respiratory physicians to diagnose mediastinal diseases because of its simple and minimally invasive technique, its wide area involving mediastinal lymph nodes and its reproducibility, which is more operable compared with mediastinoscopy. The EBUS-TBNA technique has been introduced and carried out by Beijing Chaoyang Hospital-Beijing Institute of Respiratory Diseases, affiliated to Capital Medical University, for nearly one year. The patient is a 70-year-old male who was admitted to the hospital with “chest tightness and shortness of breath for 4 years, with progressive aggravation for 2 months”. In the past 4 years, the patient often felt chest tightness, shortness of breath and breath-holding, and had a slight cough and a small amount of white sputum after waking up in the morning; in the past 2 months, the chest tightness, shortness of breath and breath-holding worsened after activities, and he coughed white mucous sputum in small amount, which was not easy to cough up, and the breath-holding worsened when lying down, without fever. The proposed diagnosis in the local hospital: bronchitis, which did not improve with treatment (specific details not available). External chest CT 1 day before admission showed: mass shadow in the upper lobe of the right lung with burrs and cords, localized pulmonary alveoli, and mass shadow in the posterior basal segment of the left lung with clear borders and fused enlarged lymph nodes under the bulge. Since this onset, there was a decrease in appetite and weight loss of about 4 kg. EBUS-TBNA was performed after admission, and the pathology was reported as small cell lung cancer lymph node metastasis. CT of the chest: mass shadow in the upper lobe of the right lung, mass shadow in the left lower posterior basal segment, and fused lymph nodes under the bulge. EBUS-TBNA puncture operation Case 2 The patient was a 40-year-old female admitted to the hospital with “cough and sputum for 2 months”. The patient was admitted to the local hospital with a chest X-ray showing a slightly enlarged left hilar lung. The cough and sputum were better than before, but the irritating cough still appeared intermittently, which was obvious by inhalation of cold air. The review of chest CT showed that the bronchial wall of the right middle segment was thick, and the left lower lobe of the lung showed thin lamellar faint shadow, and multiple enlarged lymph nodes were visible. After admission, he was examined by EBUS-TBNA, and the pathological report showed nodular disease. EBUS-TBNA puncture operation