[Endosonography in the differential diagnosis of dysphagia]

Endosonography makes it possible to judge the normal and the pathologically altered wall of the upper digestive tract. At the tip of a duodenoscope with lateral view there is a mechanical sector scanner with a visual angle of 360 degrees. Owing to its high power of resolution five layers of different echogenicity can be differentiated. The inner echo-rich and echo-poor layer corresponds to the mucosa and the muscularis mucosae, the intermediate echo-rich layer to the submucosa. The outer echo-poor layer can be attributed to the tunica muscularis, the outer echo-rich layer represents either the border echo or adventitial tissue. Thickening of the wall, inhomogeneous structure of the echo and infiltration of the outer wall contour are considered pathological. Indications for endosonography are essentially the judgement of tumours in the framework of tumour staging and the detection of paraesophageal lymph nodes. Furthermore the detection of submucosal and extramural lesions such as lymphomata, leiomyomata and intra- and extramural varices is possible. In the diagnostics of dysphagia endosonography should be applied in all cases where other established procedures of morphological and functional diagnostics do not clarify the situation or where they result in the suspicion of small intra- or extramural lesions of the esophagus. Within the framework of tumor staging, endosonography is indispensable.