CLINICAL EVALUATION OF ENDOSCOPIC ULTRASONOGRAPHY (EUS)

Abstract

Recent progress in f iberoptic endoscopy and ultrasonographic tomography has enabled us to develop endoscopic ultrasonography (EUS) for a more precise diagnosis of pancreatobiliary tract diseases and for interpretation of G-I tract lesions. In this paper, clinical evaluation of EUS is described. From April, 1980 to December, 1983, we have used three types of ultrasonic endoscopy(Olympus and Aloka Co. Ltd.) with sector scan transducer (5.0MHz or 7.5MHz)and have examined 118 cases (32 pancreatic diseases, 23 biliary diseases, 52 G-I tract diseases). The G-I tract wall was visualized as 5 layer structure by EUS, the submucosal layer was demonstrated as a wide echogenic layer and the proper muscular layer was visualized as a hypoechoic layer. By means of those results, it was possible to determine the invasion of G-I tract cancer. Advanced cancer of the G-I tract was demonstrated as destruction ofthe layer structure with hypoechic tumor mass. Benign submucosal tumors of the G-I tract with intra-and extramural wall expantion were clearly shown by EUS with detection of the tumor origin. Laser ulcer was demonstrated as a destructed submucosal layer. In the diagnosis of the pancreato-biliary small cancer, the lesions were clearly demonstrated by EUS, compared with the other diagnostics e. g. FRCP, CT, angiography and conventional US.