Anatomical aspects in ultrasonic endoscopy for the stomach.

Gastric wall structure cannot be visualized neither by conventional ultrasonography nor by endoscopy alone. Using a newly developed ultrasonic endoscope (Olympus GF- UM1 / EUM1 Prototype III) twenty-two patients were examined with the stomach filled with 300-500 cc of de- aired water. Ultrasonographic appearance of the normal gastric wall consists of four layers of different echogenicity. The first inner layer, echogenic, seems to correspond to the mucosa and the submucosa, the 2nd echopoor to the muscularis propria, the 3rd echogenic to the serosa and the 4th echopoor to the subserosal-fat. For a complete exploration of the gastric cavity, starting with the scope near the pylorus and withdrawing it until the fundic region, four positions have been standardized. In the first, the antral region is explored, in the 2nd the antrum and the gastric body, in the 3rd the body and antrum and in the 4th position body and fundic region are visualized. For a satisfactory examination a good filling of the stomach must be achieved; problems in interpretation may arise when the gastric wall is not well distended or when peristaltic waves are present. Promising findings have been obtained in 3 cases of cancer involvement of the stomach. No complications were encountered during this study.