The goal of this clinical trial is to verify the auxiliary role of the artificial intelligence (AI) system in mediastinal endoscopic ultrasound (EUS) scans. The main questions it aims to answer are as follows:

1. A comparison of the image recognition accuracy between the AI system and EUS endoscopists.
2. Whether the AI system can improve the quality of mediastinal scans for EUS endoscopists.

Participants will conduct mediastinal EUS with or without the assistance of the AI system.

Inclusion Criteria:

1. Age ≥18 years old, <80 years old 2.Patients who need endoscopic ultrasonography; 3. Agree to participate in this study and sign the informed consent form.

Exclusion Criteria:

Subjects who meet any of the following criteria cannot be selected for this trial:

First. The patient's physical condition does not meet the requirements of conventional endoscopic ultrasonography:

Poor physical condition, including hemoglobin ≤8.0g/dl, severe cardiopulmonary insufficiency, etc. Anesthesia assessment failed Pregnancy or breastfeeding In the acute stage of chemical and corrosive injury, it is very easy to cause perforation Recent acute coronary syndrome or clinically unstable ischemic heart attack Heart disease patients with right-to-left shunt, patients with severe pulmonary hypertension (pulmonary artery pressure> 90mmHg), patients with uncontrolled systemic hypertension and patients with adult respiratory distress syndrome.

Second. Disagree to participate in this study.

Third. There are other problems that do not meet the requirements of this research or that affect the results of the research:

1. Mediastinal lesions have previously undergone surgery or radiotherapy and chemotherapy;
2. Mental illness, drug addiction, inability to express themselves or other diseases that may affect follow-up.

Some data underlying this trial cannot be shared publicly due to protection of participant's privacy.