Ultrasonic endoscopy--the gastrointestinal wall.

Endoscopic ultrasonography (EUT) allows the visualization of the gastric wall structure. Four and sometimes five distinct layers have been identified. The 1st inner layer echogenic seems to correspond to the mucosa, the 2nd echopoor to the muscularis mucosae, the 3rd echogenic to the submucosa, the 4th echopoor to the muscularis propria and the 5th echogenic to the serosa. In pathological conditions this architecture changes considerably. Infiltration and extension of lesions can be precisely established. Moreover, involvement of neighbouring organs can be preoperatively detected. It is still difficult to establish, only on the EUT data, whether a lesion is benign or malignant. EUT of the stomach is a new method of investigation which can be further developed but already shows a considerable interest.