In recent years, endoscopic ultrasonography (EUS) has developed into a preferred imaging modality for the diagnosis of biliopancreatic diseases, especially small (\< 3 cm) pancreatic tumors and small (\< 4 mm) bile duct stones. Therefore, EUS is often chosen as the main tool for screening early biliopancreatic diseases among high-risk individuals. However, a plenty of studies have shown that the detection rate of biliopancreatic diseases under EUS varies from 70% to 93% among different endoscopists due to examination quality and operators differences, which suggest that there are missed diagnosis of lesions. The missed diagnosis of pancreatic cancer makes patients lose the opportunity of radical surgery, and the five-year survival rate is reduced to 7.2%; and the missed diagnosis of choledocholithiasis causes severe acute diseases such asacute cholangitis and acute pancreatitis; it has serious consequences on the prognosis and quality of life of patients. Therefore it is important to reduce the missed diagnosis of lesions while further expanding the application of EUS.

Ensuring the examination quality is a seminal prerequisite for discovering biliopancreatic lesions in EUS. There are two main reasons affecting the quality of biliopancreatic EUS examination: First, non-standard operation by endoscopists; excellent biliopancreatic EUS examinations require the continuity and integrity of the scan. According to the experience of the Japanese Society of Gastrointestinal Endoscopy and European and American experts, multi-station approach in biliopancreatic EUS has been established as the standard scanning procedure. And these standard stations include anatomical landmarks that can be used to locate the transducer and identify areas that are not scanned. The American Society for Gastrointestinal Endoscopy (ASGE) and the American Association for Gastrointestinal Endoscopy (ACG) Endoscopic Quality Working Group have also issued quality indicators that should be completed for EUS examination. But they are often not well followed because of a lack of supervision and availability of practical tools, and there are a large number of blind areas in current daily EUS scans. Secondly, it is difficult in understanding US images with gray and white texture. Even experienced endoscopists have some challenges in identifying anatomical structures in EUS images. Therefore, it is critical to develop a practical tool that can monitor the blind area of EUS examination in real time, reduce the difficulty of ultrasonographic interpretation, and standardize the quality of EUS examination.

Deep learning has been successfully applied to many areas of medicine. In the field of endoscopic ultrasonography, most researches are dedicated to the use of computer tools to assist in the diagnosis of lesions in static images, while rare work studied the role of deep learning in monitoring the blind area of EUS examinations and exploring assistance on real-time ultrasonographic interpretation. Previously, we have successfully developed and validated an EUS navigation system that can identify the standard stations of pancreas and bile duct EUS in real time. Although encouraging preliminary results have been published regarding the use of artificial intelligence in reducing the difficulty of EUS images, this system has not been validated in a real-world clinical setting, and it is unclear whether it can be successfully applied in clinical practice and improve the quality of EUS examination.

Therefore, in this study, we updated the EUS-intelligent and real-time endoscopy analytical device (named EUS-IREAD) based on the aforementioned biliopancreatic EUS station recognition models and further trained an anatomical landmark identification function to better locate the transducer position and diagnose biliopancreatic lesions. We then conducted a single-center randomized controlled trial to assess its adjunctive performance to EUS endoscopists in a clinical setting.