Endoscopic ultrasonography of the gastrointestinal tract.

Endoscopic ultrasonography (EUS) combines the advantages of conventional endoscopy with the capabilities of ultrasonography. EUS allows clinicians to see through the wall of the gastrointestinal tract. The close proximity allows the use of relatively high frequencies with the resulting increase in tissue contrast and resolution. Despite some limitations, this new modality does open new horizons in the diagnosis and characterization of upper gastrointestinal diseases.