| Endoscopic ultrasonography (EUS) was first reported in the early 1980s by Di Magno in USA who carried the experiment in animals using linear EUS. GF-UM3 produced by Olympus Company was first clinically used. Though it was initially developed to obtain a better view of pancreas which was quite difficult to explore by conventional ultrasound, the further using EUS has become apparent that it has great advantage of accurate TNM staging in gastrointestinal cancer and evaluating the characters of neoplasms originated from intestinal tract. Nowadays EUS has turned to be a very important tool in these diseases.Endoscopy is of great importance in the diagnosis of gastric cancer in the site and dimension, but of great difficulty in the invasion depth of the stomach wall, not to mention the metastasis of lymph nodes. Computered tomography(CT) has advantages in local and distant metastasis .however it cannot detect the accurate invasion depth of the tumor. EUS is of great value in the diagnosis of gastric cancer and invading depth of the stomach wall, for it can accurate invading depth local metastasis of lymph nodes , EUS could accurately determine the invading depth of tumor and the local involving lymph nodes.Between May 1992 and December 2002, EUS was performed in a total of 284 patients with gastric carcinoma, this study investigated the 217 cases of which with integrated data . We compared the preoperative EUS results and the detailed histological examination of the resected specimens in order to enhance our knowledge of EUS in defining the invasion depth of the tumor , preoperative TNM staging , resectability of the tumor.There are three parts in this study, that is : 1. EUS for determining the depth of gastric cancer invasion Objective: to evaluate the accuracy of EUS in assessing normal stomach wall and the invading depth in gastric carcinoma, EUS was performed in 15 resected specimens in vitro and 217 patients in vivo preoperatively.Material and methods: EUS was performed in 217 cases of gastric cancer between May 1992 and December 2002, of which 13 were early gastric cancer, 204 were advanced cancer confirmed by postoperatively histological results. EUS was all performed 2 weeks before the operation in 151 male ,66 female with ages ranged from 24~79 ,mean 54.4. There were 15 resected specimens, 10 were gastric cancer and 5 were normal gastric wall excised for other diseases.EUS used in this study were GF-UM3 .GF-UM 200 (Olympus, Japan) with probe frequency that could alter between 7. 5MHz and 12MHz . GF-UMP230 has only a 7. 5MHz probe. Olympus UM-2R UM-3R are the miniprobes passing through the channel of the conventional endoscopy with 12MHz and 20MHz frequency respectively .Results: 1. the normal stomach wall structure: EUS showed that the stomach wall corresponded to a five layer in vitro, correlation with the various histological layers was as follows: The first hyperechoic and the second hypoechoic structure bordering the gastric lumen correspond to the mucosa and muscularis mucosae, the third echogenic structure corresponds to the submucosa, the fourth echo-poor structure corresponds to the muscularis propia, the fifth echogenic structure corresponds to the serosa and adventitia. 2. EUS for diagnosis of early gastric cancer: Of the 13 cases with early gastric cancer confirmed by histological examination, 5 were accurately interpreted by EUS , 4 weremainly accurate, the overall accuracy rates were 69.2%; 4 were overstaged to be advanced tumors, 2 of which were malignant ulcers. 3. BUS for diagnosis of advanced gastric cancer: Among the 204 advanced gastric cancers, 18 were mp(muscularis propria) cancer, 186were s(serosa) cancer . 181 were accurately staged by BUS , mainly accurate 18 the overall accuracy rates were 97.5%, 5 histologically confirmed mp lesions were understaged to be early gastric lesions. 10 histologically mp cancers were overstaged to be s cancers; 8 histologically s cancers were understaged to be mp cancers ; the accuracy rates were highest for s lesions. 4. the effect of differ... |
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