Intraductal ultrasonography (IDUS) of the pancreato-biliary duct system. Personal experience and review of literature.

Endoscopic ultrasonography (EUS) represents a major advance in endoscopic imaging. Usefulness and effectiveness of EUS have been established during the past few years. However, endosonography using dedicated echoendoscopes (7.5/12 MHz) has some serious drawbacks: (1) combining endoscopy and ultrasonography in one instrument increases the diameter of such echoendoscopes (13 mm); (2) as a result of the large diameter insertion into the pancreato-biliary duct system is not feasible at all; (3) image quality and resolution for small lesions is not always satisfactory; and (4) conventional endosonography needs a second examination separate from the previous routine endoscopy. Recently developed ultrasonographic miniprobes (diameters about 2 mm; frequencies 12-20 MHz) can be passed through the working channel of standard endoscopes to provide high-frequency ultrasound images. These miniprobes might overcome some of the above mentioned drawbacks and contribute to patients' security and convenience. Moreover, in various diseases of the pancreato-biliary duct system diagnostic accuracy of miniprobe ultrasonography has been shown to be superior to that of EUS. In summary, miniprobe ultrasonography appears to be a promising addition to the armamentarium of gastroenterologic diagnostics.