esophagogastroduodenoscopy ( egd ) has become an important examination for screening and diagnosis of diseases of the upper gastrointestinal tract .
improved endoscopic screening was accomplished by the incorporation of a thinner caliber endoscope with the capacity to capture high definition images .
however , the ability to visualize vater s papilla with front viewing endoscopes is less than satisfactory 1 .
the duodenum has a narrow lumen ; therefore , endoscopes with a side view are preferred for visualization of vater s papilla , although current side viewing scopes are not suitable for screening in egd . in addition
, switching to a side viewing endoscope may not be a viable option when considering a patient s comfort and the availability of endoscopic equipment .
alpharetta , ga , united states ) egd is a newly developed video - endoscope that provides a 245-degree field of view with double imagers on the front and side of the endoscope tip . 
a wider view for endoscopic examinations , such as ultra - wide viewing scopes , has been reported to enhance diagnostic yield in the field of colonoscopy 2 
 3 
 4 . in the upper gastrointestine , locations with a steep curve such as the squamo - columnar junction ( scj ) and the anal side of the pyloric ring
theoretically , the incorporation of double imagers in different directions has a possibility to produce a better view in these locations . however , there are no available data to determine whether a wider endoscopic view is efficient for upper gastrointestinal screening .
the aim of this study was to evaluate the feasibility , usability , and safety of fuse - egd in human subjects .
feasibility was defined by the completion of taking images according to a standardized protocol within an acceptable time .
the study included 21 healthy individuals ( 15 males and 6 females ) with a median age of 35 years ( range , 29    55 years ) who underwent upper gastrointestinal screening using fuse - egd .
each subject received a full explanation with regard to the purpose of this open - label study and gave informed consent for participation in the study .
after fasting for more than 12  h , each subject drank 100  ml of water containing pronase , sodium bicarbonate , and simethicone .
the examination was performed under oral anesthesia with 1    5 sprays of 8  % lidocaine , with no sedation .
five endoscopists who were board certified members of the japanese gastroenterological endoscopy society performed screening of the upper gastrointestine according to a standardized protocol while capturing sequential images from the esophagus to the duodenum .
the primary end point of this pilot and feasibility study was the rate of successful visualization of vater s papilla .
additional end points included the duration of the procedure , successful visualization of the anal side of the pyloric ring and the scj , adverse events , and the endoscopists subjective evaluation of the usability of the fuse - egd procedure .
the endoscopists subjective evaluation of the usability , field of view , and maneuverability of fuse was assessed using a five - point likert scale with the following answer options : unacceptable , difficult , acceptable , good , and excellent .
in addition , the endoscopists subjective evaluation compared to the standard endoscope used in our hospital ( 9.8-mm , high definition , front viewing , video endoscope ) was also evaluated .
the fuse - egd ( fsg-2500-st ) system is a 9.6-mm , flexible endoscope for repeated clinical use ( diagnostic visualization and therapeutic intervention ) .
the endoscope is equipped with a working channel ( 2.8  mm ) , air or co2 insufflation options , suction , and forward waterjet irrigators .
a wide 245-degree field of view is achieved using two lenses and groups of light - emitting diodes positioned on the front and side of the endoscope tip . 
this retrospective study was approved by the institutional review board of our hospital ( no .  27-j69 - 27 - 1 - 3 ) .
the fuse - egd ( fsg-2500-st ) system is a 9.6-mm , flexible endoscope for repeated clinical use ( diagnostic visualization and therapeutic intervention ) .
the endoscope is equipped with a working channel ( 2.8  mm ) , air or co2 insufflation options , suction , and forward waterjet irrigators .
a wide 245-degree field of view is achieved using two lenses and groups of light - emitting diodes positioned on the front and side of the endoscope tip . 
this retrospective study was approved by the institutional review board of our hospital ( no .  27-j69 - 27 - 1 - 3 ) .
gastrointestinal screening using the fuse - egd system was successfully completed for all 21 subjects with a median procedure time (   sd ) of 6.5    1.6  min .
successful visualization of vater s papilla was obtained in 90  % ( 19/21 ) of the subjects ( fig .  1 ) .
the duodenal side of the pyloric ring ( anterior wall only ) was observed in 29  % ( 6/21 ) of the subjects .
the whole circumference of the scj was observed on the two video monitors in all cases ( fig .  2 ) .
the main finding detected among the subjects was esophageal hernia ( 100  % , 21/21 ) . 

visualization of the 2nd portion of the duodenum on two video monitors with a clear view of vater s papilla . 

visualization of the squamo - columnar junction on the two video monitors of the fuse - egd system .
subjective evaluation of the usability of fuse - egd was assessed by the five endoscopists , who reported that fuse - egd was inferior compared with the standard front viewing endoscope for all participants ( table  1 ) .
however , 80  % of the participants answered that the fuse - egd system platform was feasible as a whole .
this is the first study on humans utilizing the newly developed fuse - egd for upper gastrointestinal screening .
the main end point of this study was to evaluate the feasibility of the new fuse - egd system .
successful visualization of vater s papilla was achieved in 90  % of the study participants .
the duodenum has a narrow lumen and vater s papilla is not routinely identified during screening by egd 1 or by capsule endoscopy 5 .
a previous study reported that the detection rate of vater s papilla in whole or in part was only 57  % using a routine imaging method , but it increased to 89  % using a straightening endoscopic technique 1 .
for surveillance of patients with duodenal polyposis , the use of a side viewing endoscope 6 or side and front viewing endoscopes at the same time under general anesthesia has been reported 7 .
the fuse - egd system is equipped with a side view imager on a front viewing endoscope that enables easier detection of vater s papilla with normal manipulation of the endoscope .
the fuse - egd system allowed easier visualization of vater s papilla than the conventional endoscope .
although barrett s esophagus is rare among the japanese population , a clear view of the entire scj is greatly beneficial for the detection of early scj and barrett s adenocarcinoma .
vater s papilla is an excellent marker to assess this system ; however , the real clinical benefit could be at the scj .
the anal side of the pyloric ring was observed in 29  % of the subjects .
we expected that the side lens would visualize the anal side of the pyloric ring . in most cases ,
the mucosa contacted the side lens , and therefore it was difficult to keep a distance between the mucosa and the lens in the narrow duodenal bulb .
the ability to visualize the anal side of the pyloric ring may be beneficial for gastric antral lesions extending to the duodenal bulb ; however , these lesions are quite rare .
all of the endoscopists participating in this study reported that the usability of fuse - egd was inferior to that of the conventional endoscope .
since none of the endoscopists had previous experience using fuse - egd , it may just be a matter of getting used to the maneuverability of the scope .
the image quality and brightness of the view field are expected to be further improved in the near future .
a limitation to this study was the small sample size and limited number of participating endoscopists .
however , the results of this first pilot and feasibility human study of fuse - egd are promising . in conclusion , although its usability requires further modification , fuse - egd provided excellent results for imaging vater s papilla and the scj .
 the feasibility of full - spectrum endoscopy ( fuse ) esophagogastroduodenoscopy ( egd ) , providing a 245-degree field of view with double imagers on the front and left side of the endoscope was evaluated . 
 twenty - one healthy individuals ( 15 male , median age , 35 years ) underwent upper gastrointestinal screening using fuse - egd . 
 the primary end point was the rate of successful visualization of vater s papilla . 
 secondary end points were visualization of the squamo - columnar junction ( scj ) and the anal side of the pyloric ring , and the endoscopists subjective evaluation of usability based on maneuverability and imaging of fuse - egd . 
 the mean procedure time was 6.5  min , with a median of 91 images captured . 
 the rate of successful visualization of vater s papilla was 90  % ( 19/21 ) . 
 the whole circumference of the scj was observed with two video monitors in all cases . 
 the anterior anal side of the pyloric ring was observed in 29  % ( 6/21 ) of cases . 
 however , the general impression of the usability of fuse - egd was that it was rather inferior to that of a standard front viewing endoscope . 
 although the usability requires further modification , fuse - egd provided excellent results for imaging vater s papilla and the scj . 
Introduction
Methods and materials
Endoscopy platform
Results
Discussion