Role of a forward-viewing echoendoscope in fine-needle aspiration

Abstract A prototype forward-viewing echoendoscope has been developed for therapeutic endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). The hard tip of the forward-viewing echoendoscope, which is shorter than that of the convex type echoendoscope, can be maneuvered flexibly. Using the forward-viewing echoendoscope, the gastrointestinal wall can be vertically punctured along the same axis as the scope, and this process is done more easily than with an oblique-viewing echoendoscope. The diagnostic accuracy of EUS-FNA with the forward-viewing echoendoscope is 97.4%, which is not significantly different to that of the oblique-viewing echoendoscope. The forward-viewing echoendoscope may be useful in situations where the location and procedure are difficult with the oblique-viewing scope, The forward-viewing echoendoscope is able to puncture the gastrointestinal wall vertically with minimal effort, therefore allowing therapeutic EUS procedures such as pseudocyst and abscess drainage, biliary drainage, and pancreatic duct drainage to be performed easily. However, a significant difference between the forward-viewing and oblique-viewing echoendoscopes in pseudocyst drainage has been reported recently. In the future, the forward-viewing and oblique-viewing echoendoscopes will probably be selectively used depending on not only lesion site but also the procedure required in individual patients, thereby facilitating various processes including puncture, tissue collection, and diagnosis, as well as therapeutic procedures.