[Abstract] Objective To investigate the clinical application value of gastric window ultrasonography for benign and malignant gastric lesions. Methods The ALOAK4000 color Doppler ultrasound diagnostic instrument (probe frequency 3.5-7.0 MHz) was applied to observe the sonographic characteristics of gastric lesions after patients took instant gastrointestinal ultrasound aid. The observed parameters included lesion size, shape and location, thickness of the gastric wall at the lesion, continuity of the mucosa, layers of the gastric wall, gastric peristalsis, and the echogenic type of the lesion. Results: ①The detection rate of 74 lesions by ultrasonography in the gastric window was 98.6%, the sensitivity of gastric cancer diagnosis was 86.2%, the specificity was 91.1%, and the accuracy of gastric benign and malignant lesions diagnosis was 86.2%, using pathological results as the control. The difference in the thickness of the gastric wall between benign and malignant lesions was statistically significant (P < 0.05), while the size of benign and malignant lesions was not statistically significant (P > 0.05). Conclusion Gastric window ultrasonography can be used as a screening method for the diagnosis and screening of gastric cancer. It shows the structure of the gastric wall and its lesions, and becomes another imaging method in addition to gastroscopy for the diagnosis of gastric lesions. The purpose of this paper is to investigate the clinical application value of gastric window ultrasonography for benign and malignant gastric lesions. 1, Data and methods 1.1 Study subjects 74 patients, including 48 males and 26 females, aged 20-85 years old, average age 50 years old, who underwent gastric window ultrasonography in our ultrasound department from March 2009 to August 2009 and had gastroscopic biopsy pathology results were selected. 1.2 Apparatus and contrast agent An ALOAK4000 color Doppler ultrasound diagnostic instrument with a probe frequency of 3.5-7.0 MHz was used. fast dissolving gastrointestinal ultrasound aid (the main components were Coix seed, Chinese yam, and Chen Pi) was used. 1.3 Examination method Patients fasted with water for 8-12 h, brewed 50 g of gastrointestinal ultrasound aid to 500-600 ml with boiling water at 90℃-100℃ directly, stirred rapidly into a uniform thin paste solution, and then cooled to a suitable temperature (30℃-50℃), and the amount of contrast agent could be increased to 800-1000 ml for taller patients. After 10 min, the patient is instructed to start the examination in the supine position, right lateral position, left lateral position and seat, and observe the lower esophagus and cardia, gastric fundus, gastric body size curve, gastric angle, gastric sinus, pylorus and duodenum in turn. The standard ultrasound views commonly used to observe gastric lesions were selected: lower esophagus and cardia section, gastric fundus section, gastric body section, gastric angle transverse section, gastric sinus section, and gastric coronal oblique section to observe the five layers of the gastric wall from inside to outside: mucosal layer, mucosal muscle layer, submucosal layer, muscle layer, and plasma layer. 1.4 Observation parameters Size, shape and location of the lesion, thickness of the gastric wall at the lesion, continuity of the mucosa, whether the mucosa is depressed, hierarchical nature of the gastric wall, gastric peristalsis, type of echogenicity, notch and concave base. Gastritis: localized thickening of the mucosal layer of the gastric wall, hypoechoic, mucosal surface is not bright, rough, and presents as enhanced strong echogenic bands, clear layers of the gastric wall, peristalsis is mostly normal, lesions are found in the gastric sinus or gastric body. Gastric ulcer: lesions at the level of the gastric wall is blurred, is inhomogeneously thickened hypoechoic, the thickness is often less than 15mm, the middle depression surface has gas-like strong echogenic spots of different sizes, the surrounding gastric wall peristalsis shows normal, or weakened, stiff, the notch is more than the concave bottom, the bottom is flat, the lesion is mostly extra-luminal niche, the coronal section lesion can be circular or target ring-shaped, mostly in the gastric body small curved side or the gastric sinus. Gastric polyp: It shows a small, limited mass, thin tip, which may be round, oval, papillary or lobulated, with clear boundaries, ranging from 0.5-2 cm in diameter, with homogeneous internal echogenicity and clear and intact layers of the surrounding gastric wall, mostly solitary, mostly in the gastric sinus. Gastric cancer: ultrasound can be divided into mass type and local thickening type. Early lesions show linear strong echogenicity in the submucosa layer, and progressive lesions show disappearance of the gastric wall level and indistinguishable. Some of the lesions are “crater-like” due to roughness and unevenness of the mucosal surface or irregular depressions. The peristalsis of the gastric wall is often weakened, with local stiffness, and the concave base is larger than the notch, which is more frequent in the sinus region and the body of the stomach, especially in the lesser curvature [1-2]. 1.5 Data statistics and analysis SPSS15.0 statistical software was used to analyze the obtained data, and the lesion length and thickness were expressed as mean `x±s, and the size and thickness of benign and malignant lesions were tested by independent sample t-test (P < 0.05). 2, Results 2.1 Pathological results Among the 74 lesions in 74 patients, 29 were malignant tumors and 45 were benign lesions. Among the 29 malignant lesions, 22 were adenocarcinoma, 3 were indolent cell carcinoma, 3 were tubular adenocarcinoma, and 1 was mucinous adenocarcinoma; among the 45 benign lesions, 35 were gastritis, 7 were ulcers, and 3 were polyps. 2.2 Ultrasound results Among 29 gastric cancers, 1 was located in the lower esophagus, 3 in the cardia, 2 in the fundus, 7 in the gastric body, and 16 in the gastric sinus; among 45 benign lesions, 6 were located in the fundus, 8 in the gastric body, 25 in the gastric sinus, and 6 in the duodenum. 2.3 According to the observed parameters and the diagnostic criteria of benign and malignant lesions, the detection rate of ultrasonography for lesions was 98.6%, the sensitivity for the diagnosis of gastric cancer was 86.2%, the specificity was 91.1%, and the accuracy for the diagnosis of benign and malignant gastric lesions was 86.2%, using pathological results as a control. Ultrasound measurements of benign and malignant gastric lesion size