Background/Aims: The accuracy of endosonographers in diagnosing gastric subepithelial lesions (SELs) using endoscopic ultrasonography (EUS) is influenced by experience and subjectivity. Artificial intelligence (AI) has achieved remarkable development in this field. This study aimed to develop an AI-based EUS diagnostic model for the diagnosis of SELs, and evaluated its efficacy with external validation. Methods:We developed the EUS-AI model with ResNeSt50 using EUS images from two hospitals to predict the histopathology of the gastric SELs originating from muscularis propria. The diagnostic performance of the model was also validated using EUS images obtained from four other hospitals.Results: A total of 2,057 images from 367 patients (375 SELs) were chosen to build the models, and 914 images from 106 patients (108 SELs) were chosen for external validation. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the model for differentiating gastrointestinal stromal tumors (GISTs) and non-GISTs in the external validation sets by images were 82.01%, 68.22%, 86.77%, 59.86%, and 78.12%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in the external validation set by tumors were 83.75%, 71.43%, 89.33%, 60.61%, and 80.56%, respectively. The EUS-AI model showed better performance (especially specificity) than some endosonographers. The model helped improve the sensitivity, specificity, and accuracy of certain endosonographers. Conclusions:We developed an EUS-AI model to classify gastric SELs originating from muscularis propria into GISTs and non-GISTs with good accuracy. The model may help improve the diagnostic performance of endosonographers. Further work is required to develop a multi-modal EUS-AI system.

Background: Previous studies have identified useful endoscopic ultrasonography (EUS) features to predict the malignant potential of gastrointestinal stromal tumors (GISTs). However, the results of the studies were not consistent. Artificial intelligence (AI) has shown promising results in medicine. Objectives: We aimed to build a risk stratification EUS-AI model to predict the malignancy potential of GISTs. Design: This was a retrospective study with external validation. Methods: We developed two models using EUS images from two hospitals to predict the GIST risk category. Model 1 was the four-category risk EUS-AI model, and Model 2 was the two-category risk EUS-AI model. The diagnostic performance of the models was validated with external cohorts. Results: A total of 1320 images (880 were very low-risk, 269 were low-risk, 68 were intermediate-risk, and 103 were high-risk) were finally chosen for building the models and test sets, and a total of 656 images (211 were very low-risk, 266 were low-risk, 88 were intermediate-risk, and 91 were high-risk) were chosen for external validation. The overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the four-category risk EUS-AI model in the external validation sets by tumor were 74.50%, 55.00%, 79.05%, 53.49%, and 81.63%, respectively. The accuracy, sensitivity, specificity, PPV, and NPV for the two-category risk EUS-AI model for the prediction of very low-risk GISTs in the external validation sets by tumor were 86.25%, 94.44%, 79.55%, 79.07%, and 94.59%, respectively. Conclusion: We developed a EUS-AI model for the risk stratification of GISTs with promising results, which may complement current clinical practice in the management of GISTs. Registration: The study has been registered in the Chinese Clinical Trial Registry (No. ChiCTR2100051191).

Background The aim of this study is to evaluate and compare the safety and efficacy of endoscopic mucosal resection with a cap (EMR-c) with those of endoscopic submucosal dissection (ESD) for rectal neuroendocrine tumors (R-NETs) ≤ 15 mm in diameter, and to analyze the risk factors of incomplete resection. Methods A total of 122 patients who underwent EMR-c or ESD for R-NETs at the Fourth Hospital of Hebei Medical University between February 2007 and December 2020 were invovled in this study. The clinical outcomes of two groups were compared and evaluated. Results A total of 122 patients with 128 R-NETs underwent endoscopic resection (EMR-c, 80; ESD, 48). In terms of duration of operation, EMR-c was significantly shorter than ESD (p < 0.001). Univariate analysis and multivariate analysis suggested that tumor diameter ≥ 8 mm was an independent risk factor for incomplete resection in patients with R-NETs in this study. Conclusions Both EMR-c and ESD were safe and effective treatments for R-NETs ≤ 15 mm in diameter. In addition, tumor diameter ≥ 8 mm was an independent risk factor for incomplete resection.