Endoscopic ultrasonography of tumours of the oesophagus and the stomach.

Endoscopic ultrasonography is one of the intracavitary ultrasound procedures, all of which have as their objectives the attainment - through the use on high frequencies - of high resolution, and the avoidance of disturbing air and bone. In the technique of endoscopic ultrasonography, a high-resolution ultrasonic transducer attached to the tip of an endoscope is introduced into the gastrointestinal tract, from where it becomes possible to represent the wall of the tract, and also its neighbouring organs. The last few years have shown that the procedure is capable, in principle, of meeting the expectations placed in it.