Endoscopic ultrasonography.

EUS has many advantages over x-ray and other endoscopic procedures for the detection of lesions located in the wall of the GI tract. In the oesophagus, invasion of cancer and spread to lymph nodes can be visualized by EUS before surgery. In the stomach, the invasion depth of cancer and the therapeutic effect of laser irradiation to early cancer can be studied. EUS may also be useful in the evaluation of chemotherapy in malignant lymphoma. In benign diseases of the GI tract, EUS can provide important information about submucosal tumours. It can improve the differential diagnosis of malignant and benign submucosal tumours. EUS will also contribute to the elucidation of the pathogenesis of giant folds developing in the stomach. In addition, EUS is beneficial in the diagnosis of chronic pancreatitis, pancreatic cyst, pancreatic cancer, cancer of the papilla Vateri and diseases of the biliary tract. In conclusion, we feel that endoscopic ultrasonography may prove to be a useful technique in the diagnosis of intra- and extramural lesions of the GI tract, but comparisons with conventional imaging procedures should be performed.