Ultrasound endoscopy is a medical device that integrates ultrasound and endoscopy. It places a miniature high-frequency ultrasound probe at the front end of the endoscope, and after the endoscope enters the gastric or intestinal cavity, the endoscope can both directly observe the morphology of the cavity and perform real-time ultrasound scanning to obtain ultrasound images of the histological features of the canal wall at all levels and the surrounding adjacent organs. Why add an ultrasound probe to the endoscope Trivia: Usually the GI tract can be divided into 4 layers, from the inside to the outside: mucosal layer, submucosal layer, muscular layer, and plasma layer in that order. The mucosal layer is where the epithelial cells of the GI tract adhere, and it is where most of the GI tract lesions are located or start, and can be directly observed through endoscopy; the submucosal layer is rich in blood vessels and lymphatic vessels; the muscular layer is the thickest layer of the 4-layer structure of the GI tract, and is the main structure of the GI tract; the plasma layer is the outermost layer of the envelope of the GI tract, which plays the role of restriction and lubrication. Although gastroscopy and colonoscopy can make direct judgments on most of the gastrointestinal diseases, they are visible light imaging of the naked eye and can only see the most superficial layer of the GI tract (mucosal layer), however, some lesions originate from the submucosa (including submucosal layer, muscular layer, plasma layer), whose surface is smooth, at this time, ordinary gastroscopy cannot pass through the mucosa to make judgments on submucosal lesions; some lesions are located outside the stomach cavity close to the Some lesions are located outside the gastric cavity close to the gastric wall, which is even more difficult to determine by ordinary gastroscopy. In order to solve such situations, people wisely combine the functions of endoscopy and ultrasound together, and ultrasound endoscopy emerged to better observe and judge submucosal structures or lesions. Ultrasound endoscopy combines the ultrasound probe and endoscopic technology to do both endoscopy and endoscopic ultrasonography, killing two birds with one stone. Both the mucosal surface lesions can be directly observed through endoscopy, and real-time ultrasound scanning of the examined organ can be further performed to observe the ultrasound images of the tissue structure of each layer of the digestive tube wall and its adjacent organs, further improving the diagnostic level of endoscopy and ultrasound. Ultrasound endoscopy is currently the most promising new technology for gastrointestinal endoscopy. Uses of ultrasound endoscopy Few people perform ultrasound endoscopy directly. Ultrasound endoscopy is usually done after a general gastroscopy or CT that reveals a neoplastic mass in the GI tract and requires further clarification of the location and nature of this mass. Determine the suspected lesion Determine whether the endoscopic protruding mass is an extra-tubular wall lesion, organ compression, or a lesion in the wall itself; determine the exact origin, nature, and extent of the lesion. For example, gastric mesenchymal tumors are usually undiagnosed under gastroscopy; only a bulge on the surface of the gastric mucosa can be seen, but what lies beneath the bulge is unknown, and ultrasound endoscopy is particularly well suited to diagnose this condition. Accurate staging After the diagnosis of tumor by general gastroscopy, an accurate judgment of the extent of tumor invasion of the ductal wall of the digestive tract is needed for accurate TNM staging to guide treatment. Examination of special sites Pancreas: The pancreas is next to the stomach and duodenum, and it can be examined by ultrasound endoscopy, which is more accurate than direct ultrasound examination and has a greater scope for the diagnosis of chronic pancreatitis as a better auxiliary diagnosis and differential diagnosis method, and can better reflect the past love bar of pancreatic parenchymal structures. It can identify benign and malignant pancreatic tumors, and can detect tumors of 1 cm or even below, and determine the type of tumor through ultrasound-guided puncture biopsy. Examination of the biliary tract: Diagnosis of common bile duct stones, like ERCP, is a highly sensitive and specific diagnostic method, but non-invasive. It is sensitive to the diagnosis of biliary tract tumor and can determine the tumor site and size. General examination of general gastroscopy is sufficient without direct ultrasound endoscopy. If abnormalities are found under general endoscopy, further ultrasound endoscopy will be done. Here is an additional sentence: even though the examination instruments are getting more and more advanced, it does not mean that they can replace other examination methods. Inspection does not blindly pursue high-tech, project selection should be targeted, should choose the most appropriate means of inspection.