Trial Information

The Usefulness of I-scan in Screening Colonoscopy: A Randomized Controlled Trial

New technologies have been developed to enhance the visualization of colorectal mucosa to
unmask even minute mucosal lesions and identify neoplastic lesion from non-neoplastic
lesions. In particular, there appears to be strong evidence that pan-colonic chromoendoscopy
enhances the detection of colorectal neoplasm in the colon and rectum. However, this
technique is time-consuming because of both the dye spraying and suction of collected dye in
the dependent portion, and therefore it is unsuitable for routine application. To overcome
this inconvenience, optical-digital method involves conversion of the optical
characteristics of the light used for illumination or imaging with a light source differing
in optical characteristics from ordinary white light (WL), such as narrow band imaging
(NBI), Fujinon imaging color enhancement (FICE), auto-fluorescence imaging (AFI) and
infra-red imaging (IRI).

I-scan technology is the newly developed image enhanced endoscopy technology, classified as
a digital contrast method among endoscopic imaging techniques.19 I-scan has three modes of
image enhancement, i.e. surface enhancement (SE); contrast enhancement (CE); and tone
enhancement (TE). The three modes (SE, CE and TE) are arranged in series, therefore, it is
possible to apply two or more of these three modes at one time. Switching the levels or
modes of enhancements can be done on a real-time basis, without any time lag by pushing a
relevant button, thus enabling efficient endoscopic observation. Furthermore, while NBI)
images are much darker than conventional white light (WL) images, i-scan images are as
bright as conventional WL images, therefore, i-scan is able to observe much larger areas in
a distant view compared with NBI. Consequently, i-scan might be more useful for performing
screening endoscopy).

However, the actual usefulness of I-scan in enhancing the detection of colonic neoplastic
lesions is not known yet in screening colonoscopy. Therefore, we tried to evaluate the
hypothesis that, in subjects undergoing colonoscopy screening, the routine application of
i-scan during withdrawal could improve adenoma detection as compared with standard WL
examination.