[Digestive echo-endoscopy]

Since its introduction into clinical practice in 1980, echo-endoscopy has greatly contributed to improving our capacity to image the digestive tract and now plays a major role in management of digestive tract diseases. Echo-endoscopy is a second intention technique reserved for further investigation of lesions previously identified by endoscopy or other imaging techniques. All five layers of the wall and surroundings of the accessible structures (oesophagus, stomach, duodenum, rectum and colon) can be visualized. Evaluation of locoregional extension of cancer invasion is one of the predominant indications. For example, since the prognosis of tumours of the oesophagus are directly related to parietal and lymph node extension, echo-endoscopy would be indicated to precisely determine the tumoural stage and thus help in adapting therapeutic management. Today, it is generally accepted that echo-endoscopy is superior to computed tomography for staging tumours of the oesophagus and the cardia. For gastric and duodenal adenocarcinomas, the performance of echo-endoscopy is similar and can identify more readily superficial lesions accessible for photocoagulation. For adenocarcinoma of the rectum, echo-endoscopy can be used to identify the tumoural stage and local extension and thus help in therapeutic decision making. Other classical indications include the evaluation of submucosal tumefaction and biliopancreatic disorders (biliary lithiasis, pancreatitis, tumours). Thus for certain well-defined indications, echo-endoscopy is now the highest performing imaging technique currently available for lesions of the digestive tract. Operator experience is however a limiting factor, emphasizing the need for clinical training.