Endoscopic ultrasonography: current clinical role.

Endoscopic ultrasonography appeared in the clinical arena almost 20 years ago and it has now become a well integrated technique in everyday hospital practice. More than 2000 scientific papers published in the literature have demonstrated its high accuracy for the diagnosis and staging of a variety of benign and malignant conditions. The instrumentation consists of a special endoscope, modified by a high-frequency ultrasound transducer placed on its tip, and an ultrasound driving unit. The main indications to endoscopic ultrasonography can be explained by its ability to visualize the gut wall as a multi-layer structure corresponding to histological layers. Other important indications derive from its capability of displaying, very closely, the structures and lesions surrounding the gut wall, such as the pancreato-biliary area, masses and lymph nodes. Fine-needle aspiration has become an indispensable adjunct to the technique since 1993, when it was shown to be feasible and safe to obtain tissue diagnosis in the majority of the lesions under the reach of endoscopic ultrasonography. In recent years, some authors have dealt with the practical clinical applications of endoscopic ultrasonography, validating its use in many diagnostic and staging algorithms and showing that it is cost-effective and significantly affects patient outcome.