Anatomical and pathological aspects in ultrasonic endoscopy for GI tract

In this paper we tried a fundamental study to analyse the normal structure of gastro-intestinal wall by endoscopic ultrasonography, because conventional examinations of gastrointestinal tract, radiography and endoscopy, can not demonstrate the intra-mural change beneath the mucosa. We have examined 71 cases by the 3 kinds of prototype echo-endoscope I-III manufactured by Olympus Co Ltd, Japan. Moreover, using a most newly echo-endoscope type III, twenty-four patients were examined to observe the changes of normal structure of wall by gastro-intestinal disease. In this fundamental study about the normal structure of gastro-intestinal wall by endoscopic echography, the submucosal layer is demonstrated as a most high echo level zone and the mucosal layer and serosal layer followed in echogenicity. On the other hand, the proper muscle layer had not any echogenicity because ultrasound passes through these layers. As a result we concluded that all layers of gastrointestinal tract can be demonstrated by endoscopic ultrasonography. Moreover, in diagnosis of gastro-intestinal disease, endoscopic ultrasonography is useful in disease of which the normal structure of wall changes directly, for example submucosal tumor, scirrhus type gastric cancer and massive infiltrated malignant disease.