Upper gastrointestinal submucosal masses are common clinical masses. Endoscopic mucosal resection) was originally invented and popularized in Japan as an endoscopic procedure for the treatment of submucosal masses in the gastrointestinal tract [1-3]. Small probe endoscopic ultrasonography has the advantages of flexible and convenient operation, and can distinguish the exact location of the mass in the wall of the digestive tract [4, 5]. In China, there are few reports on the treatment of SMT in the upper gastrointestinal tract by EMR and the analysis and comparison of the ultrasonographic features of SMT confirmed by histological examination. I. Objects and Methods: Subjects: 44 patients with upper gastrointestinal submucosal masses confirmed by small probe endoscopic ultrasonography for EMR treatment and pathologically confirmed by pathologic examination between January 2001 and October 2004 in our hospital, including 24 cases of esophageal submucosal masses, 19 cases of gastric submucosal masses, and 1 case of duodenal submucosal mass. Research method: double clamp channel electronic gastroscopy was used to determine the site of SMT, one clamp channel was filled with water to make the mass immersed in water, and the other clamp channel was fed with a small ultrasound probe for mass observation. The echo grade of the mass was determined with reference to the third (hyperechoic) and fourth (hypoechoic) layers of the digestive tract, and the size and image structure of the mass, the nature of the margins, and which layer of the tube wall it originated from were recorded [4-7]. After the mass was clearly located in the deep or submucosal layer, the ultrasound probe was withdrawn and the lumen was evacuated, an electrocoagulation loop was inserted into one clamp channel to hold the SMT, and an endoscopic needle was inserted into the other clamp channel to stab the base of the SMT immediately below the loop, and the mass was separated and elevated by injecting 4-10 ml of saline with a concentration of 1/10,000 of adrenaline, and then a mixture of electric current and cutting current was used to resect the submucosal mass. Acid suppressants and mucosal protectants were routinely given postoperatively [1-4]. Sections of the mass were stained with hematoxylin-eosin for pathologic examination. Endoscopic ultrasonographic features of SMT were retrospectively analyzed according to the pathological diagnosis. Equipments: PENTEX EG-3840T double-clamp channel electronic gastroscope, PENTEX CGI-4000 electrocoagulation-water injection machine, FUJINON-SP-701 small probe ultrasound system with probe frequencies of 12MHz and 20MHz. II.RESULTS: SMT was successfully resected in 44 cases, and postoperative delayed hemorrhage occurred in 2 of the patients with a bleeding volume of less than 400 ml, and was internal medicine conservative treatment cured. There were no complications such as infection and perforation. The endoscopic ultrasonographic imaging features of SMT confirmed by pathologic examination are shown in Table: III. DISCUSSION: Endoscopic mucosal resection can be widely used for the treatment of SMT masses located in the superficial layers of the gastrointestinal wall. The key to the technical operation is firstly to use endoscopic small probe high-frequency ultrasound to clarify which layer of the digestive wall the mass is located in (resection of the intrinsic muscular layer of the mass will lead to perforation), and then through the injection of fluids (usually epinephrine with saline) to make the mass lift away from the submucosal layer or intrinsic muscular layer, which serves the function of separating the mass from the normal tissues and compressing the hemostatic effect, and then the loop device is applied to the elevated mass to tighten it. energized excision (lift-cut method) [1-7]. Due to the loose tissue between the mucosal layer and the submucosal layer, the submucosal layer and the intrinsic muscular layer are more closely connected, the injection of liquid is not easy to make the swelling and the intrinsic muscular layer satisfactorily separated, the water is more likely to penetrate between the mucosal layer and the submucosal layer, so that the swelling located in the submucosal layer is covered under the liquid, the trap is difficult to trap, the trap range is enlarged, the water in the tissue is more water, and the required power of electrocutaneous excision increases, so that the effect of excision is not good. In the treatment process, we made some methodological improvements, using double-clamp endoscopy to do EMR, for the SMT located in the submucosal layer, first use the loopers to cover the base of the mass and tighten it, and then insert an injection needle to inject epinephrine saline immediately below the loopers, which not only allows the injected liquid to accurately enter the tissue below the SMT and effectively separate the mass from the intrinsic muscle layer, but also avoids the liquid penetration between the mucous layer and submucosal layer, masking the mass, and avoiding the penetration of liquid into the mucous layer and submucous layer. The fluid penetration between the mucosal layer and the submucosal layer was avoided to mask the mass. The tissue area is not large and has little water, which does not increase the power of excision current and improves the safety coefficient of the treatment. Because of the solid texture of the SMT tissue, if the mixed current fails to dislodge the mass from the wall of the alimentary canal, switching to the cutting current can dislodge the resected mass.EMR does not usually lead to infections, and even if bacteremia occurs in a small number of patients, it is transient and antibiotics are not necessary [8]. Avoiding mechanical cutting, choosing the appropriate amount of electricity, injecting a sufficient amount of epinephrine containing 1/10,000 of epinephrine, sealing the wound with titanium clips, and routinely administering PPIs for acid suppression and mucosal protector therapy postoperatively are helpful in preventing complications such as hemorrhage and perforation [1-3]. It has been reported that changing saline to hypertonic saline or sodium hyaluronate (sodium hyaluronate), which is less susceptible to water loss, can slow down the rate of water loss from the injected submucosa [9]. Recently, EMR suction method has also been applied to the clinic, i.e., after injecting saline to elevate the swollen tissue under SMT, the elevated tissue is inhaled into a cap-like structure fixed to the tip of the endoscope like varicose vein ligation, which can be ligated or not, followed by electrocoagulation and resection (suck-cut method) [2, 9]. However, this method may be effective only for SMTs located in the muscular layer of the mucosa, but not for SMTs located in the submucosal layer. The ease of use of a small high-frequency probe, high resolution of the GI tract wall, accurate localization of SMT, and reduction of the possibility of blind excision of the mass leading to perforation of the patient’s GI tract are essential means of obtaining information on patients suffering from SMT for EMR [2, 4. 9]. Generally, SMT of the same disease tends to have the same ultrasound imaging features, and analyzing these features can make a qualitative diagnosis of endoscopic ultrasound for SMT [4, 5]. However, no imaging examination can ultimately clarify the nature of the mass, and the analysis of the endoscopic ultrasound images of the 44 cases of SMT we resected showed that the ultrasound images of mesenchymal tumors were more characteristic, with clear boundaries and located in the muscular or submucosal layer of the mucosa. Ectopic pancreas ultrasound images were variable, with clear or unclear borders, and the echoes could be high or low, homogeneous or inhomogeneous, and ectopic pancreas was more likely if tubular echoes were seen. Tubular adenoma ultrasonographic image can see the lesion spreading from the mucosal layer to the submucosal layer, with unclear boundary and uneven echogenicity. Lymphoid hyperplasia is located in the submucosal layer with unclear borders and low, uneven echogenicity. Lipomas are uniformly moderately or hyperechoic, have clear borders, and are located in the submucosal layer. Cysts are located in the submucosal layer, are nonechoic, and have clear borders (see Figures 1-3). It can be seen that some different kinds of masses can have similar ultrasound images, the same kind of lesions can also have different imaging signs, the final diagnosis is still based on pathological examination. Conclusion: Endoscopic mucosal resection is a safe and effective treatment of upper gastrointestinal submucosal masses, preoperative endoscopic ultrasonography is an important means of obtaining information about the lesion, different types of masses can have similar endoscopic ultrasonographic features, the same lesion can also have different imaging signs, and the final diagnosis is based on pathological examination.