Forward viewing US endoscope versus standard oblique 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

Since its initial report in 1992, endoscopic ultrasound-guided fine needle
aspiration (EUS-FNA) has been incorporated in diagnostic algorithms for the
evaluation of solid and cystic lesions of the gastrointestinal (GI) tract and
of adjacent organs. The expansion of EUS-FNA has been largely stimulated by the
introduction of linear-array echoendoscopes that made possible to follow the
full course of the needle from its exit from the instrument to its entrance in
the target lesion under real-time US guidance. Until now, all the available
linear echoendoscopes utilized to perform EUS-FNA have been curved linear
scopes (CLA-EUS) which are characterized by an oblique endoscopic view, 55o
rotated respect to the scope axis and the ultrasonographic probe, and by the
exit of the FNA needle that occurs with an oblique angle from the side.
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 Moreover, a large experience still unpublished from the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.

The primary aim of the study is to compare the performance of the standard
oblique-viewing US endoscope versus a prototype forward viewing ultrasonic
endoscope for EUS-FNA of solid lesions of the GI tract and of adjacent organs.

multicenter, prospective randomized controlled trial

Each patient will undergo examination with the CLA-EUS or the FV-EUS, which
will be selected based on the randomization process. FV-EUS will be performed
using the newly available FV *EUS scope (TGF-Y0001-UC) that is compatible with
last generation Aloka alpha 10. First, search of the presumed lesion will be
performed and once visualize, its characteristics (size, echogenicity, margins,
etc) will be recorded on data collection sheet. Fine needle aspiration will be
performed under EUS guidance using a 19- ,22- or a 25-gauge fine needle or
procore needles depending on endoscopist*s preference . In case an on-site
cytophatologist will not be available, a minumum of 3 needle passes for lymph
nodes and 5 needle passes for solid lesions per patient will be performed.
Picture of the visualized lesion and of the needle inside the lesion till be
taken and stored to prove visualization and puncture of the target lesion.
In case the lesion can not be found or successfully punctured with endoscope
selected based on the randomization this scope will be withdrawn and the other
(nonrandomized endoscope) will be introduced contiguous

Because sampling of the solid lesions in the GI tract or in one of the
adjacent organs will be indicated in all patients, the extra burden will be
limited. There will be a small chance that identification and/or FNA of the
target lesion is not successful with the prototype forward viewing US
endoscope. Consequently, the procedure need to be repeated with a standard
oblique viewing endoscope, which will be done contiguous. On the other hand, it
may happen that target lesion can be visualized and/or punctured with the
forward viewing and NOT with the standard oblique viewing, and participating in
this study may appear to be beneficial.