Endoscopic ultrasonography: imaging and beyond.

Endoscopic ultrasonography (EUS), introduced into gastroenterological diagnostics more than 20 years ago, has undergone extensive evaluation of its diagnostic capability, probably to a larger extent than most other endoscopic and other imaging techniques in gastroenterology. Almost necessarily, as to be expected with an imaging method being assessed with continuing interest for two decades, initial enthusiasm has waned and questions about its influence on management and outcome have been dealt with, yielding mixed results. Other imaging techniques are usually not burdened by such a self critical approach, mostly due to the fact that technical progress has hindered proper evaluation, and techniques are marketed with only little good evidence of their real value. Methodological questions about study quality in gastrointestinal imaging have attracted limited interest, and only rarely are factors looked into, which may be responsible for divergent study results. However, it happened a few years ago that EUS was revitalised, mainly due to the advent of EUS guided fine needle aspiration (FNA), and even more recently, several emerging techniques of EUS guided therapy. The following does not aim at giving a full overview on the ever rising body of literature on the accuracy of diagnostic EUS, including FNA. For this purpose textbooks and review articles in various journals 4 are recommended. Some current trends and possible future tendencies will be outlined.