[Endosonography of the gastrointestinal tract--an assessment of current status]

Endoscopic ultrasound (EUS) combines endoscopy and ultrasonography. A small ultrasonic transducer incorporated into the rigid tip of endoscopes is transported into certain regions of the upper and lower gastrointestinal (GI) tract under visual control. The method allows for a high-resolution imaging of the gastrointestinal wall and organs and structures in its immediate vicinity. This is especially valuable in the preoperative local staging of gastrointestinal malignancies (esophagus, stomach, pancreas, biliary tract, colon and rectum) according to the new TNM system. In patients without distant metastases EUS helps guiding treatment decisions. EUS is also used with clinical benefit in the diagnosis of submucosal tumors and in the preoperative localization of pancreatic endocrine tumors. Its role in the diagnosis and management of benign gastroenterological disorders has still to be established.