Miniprobe Eus

With the advent of flexible, high-frequency catheter probes that can be introduced through the working channel of any endoscope, EUS became available as an additional and very powerful diagnostic tool during routine endoscopic procedures. Miniprobes as a supplement to echoendoscopes with radial or longitudinal scanners provide detailed images with a penetration depth of about 20mm using frequencies of around 20 MHz. Not only structures of the intestinal wall but also a considerable volume of the surrounding organs can be visualised. In the intestine sonographic coupling is best accomplished using bare miniprobes with water filling of the lumen. Out of 1007 miniprobe examinations carried out in the author's clinic, the most frequent indications involved the distal bile and pancreatic ducts (36%), carcinoma of the oesophagus or the cardia (18%), submucosal tumours and GIST (14%), and others (32%). For evaluating the distal common bile duct, extraductal EUS (EDUS) allows the visualisation of small pathological lesions, especially intraductal stones without ductal dilatation with a sensitivity of 97% and a specificity of 98%. For the staging of early cancers, miniprobe EUS has its significance mainly in showing a preserved submucosal layer, thereby excluding an endoscopically non-resectable T2 lesion, as was successfully done in all of our cases. Suspicious prominent structures were easily assigned to the correct layer of the wall or identified as external impressions.