The clinical study is aimed to prospectively evaluate the diagnostic accuracy and the safety of adding transbronchial mediastinal cryobiopsy to standard sampling in mediastinal diseases.

A traditional method, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) was used to be compared. The patients involved were randomly divided into two groups. In the experimental group, EBUS-TBMCB was performed following EBUS-TBNA while in the other group, EBUS-TBNA was performed respectively. The samples obtained in the two groups were analyzed by the pathologists. Patients were followed up for confirming the diagnosis and complications. The diagnostic accuracy and prevalence of procedure-related adverse events were compared between the 2 groups.

Inclusion Criteria:

• Age >=15 years;
• More than one mediastinal lesions with diameter >= 1cm was detected by thoracic CT;
• Indication of biopsy to identify the etiology, including recently discovered mediastinal lesions or combination of clinical respiratory symptoms and complicated lung lesions implicated by thoracic image ;
• Completion of necessary preoperative laboratory examination and other examinations such as cardiac ultrasound or CTA when necessary, in order to exclude potential contradictions;
• Informed consent form achievement.

Exclusion Criteria:

• Contradictions to bronchoscopy examination such as severe cardiopulmonary diseases, coagulation disorders, intolerance to anesthesia or endoscopic operation and so on;
• Failure to detect the mediastinal lesions in ultrasonic landscape;
• Cysts or abscess;
• Requirements for additional procedures other than EBUS examination (such as endobronchial biopsy);
• Psychiatric disorders or severe neurosis.
• Participation in other clinical experiments in recent 3 months;
• Any other conditions considered to be inappropriate to be involved in this study.