Forward Viewing US Endoscope Versus Standard Viewing US Endoscope in the Performance of EUS-guided Fine Needle Aspiration of Solid Lesions of the Gastrointestinal Tract and of Adjacent Organs: A Prospective Randomized Controlled Study

Recently, a forward viewing linear echoendoscope (FV-EUS) has been developed with the aim of potentially expanding the therapeutic applications of EUS. This prototype is a modification of the CLA scope and it is characterized primarily by a shifting of the orientation of the endoscopic and US views from oblique to forward. The US transducer is located adjacent to the working channel, at the endoscope tip, to display a forward-viewing image along to a scanning plane that is parallel to the insertion direction with a 90° scanning range. It has a 3.7 mm working channel without elevator, which allows exit of the FNA needle or any other accessory used parallel to the longitudinal axis of the scope. Preliminary experiences with this scope have reported potential advantages over the conventional linear scope (CLA-EUS) for pseudocysts drainage and for hilar biliary strictures. Moreover, a large experience still unpublished from the Catholic University, Rome, Italy in the use of the FV-EUS for FNA of solid and cystic lesions throughout the GI tract has shown the FV-EUS to be highly effective with a performance that seems at least comparable to that of the CLA-EUS. To date, however, no data comparing the performance of both scopes for FNA of target lesions are available to better clarify the advantages and disadvantages of one scope over the other. We designed a randomized comparative trial in which patients will be randomized to undergo examination with CLA-EUS or with FV-EUS. In case of failure of: (i) visualization of the presumed lesion; (ii) failure in performing the FNA with the scope used based on randomization, a second attempt will be made using the other scope.