Standard colonoscopy versus high-definition colonoscopy with/without I-scan functions in the detection of colorectal neoplasia: a randomized multicenter study

Adenomateous polyps are precursors for colorectal cancer. Colonoscopy is
considered to be the golden standard for the detection of colonic neoplasia.
However, there is a significant number of missed lesions, as assessed by
back-to-back colonoscopy [1-2]. This mis-rate can be attributed to lack of
technique (short withdrawal time, insufficient bowel preparation) or due to
technological causes like the quality of endoscopes to visualise small lesions
and the possibility to look behind folds. Several technological innovations in
both colonoscope design, performances and image processing are tested to
improve colon visualisation and to lower the number of missed lesions. Studies
regarding the effect on adenoma detection rate (ADR) by use of high definition
(HD) endoscopes compared to standard colonoscopes are conflicting. This might
be the result of different expertise of physicians, types of endoscopes and
software applications. The ADR is the most frequently used primary outcome
parameter with respect of screening of colorectal neoplasia and as indicator of
quality assessment.
Recently, Pentax developed a digital mucosal enhancement function, called
I-scan. This function is compatible with their HD colonoscopes. These
endoscopes have the highest resolution available in flexible endoscopy
nowadays. Several function modes are available for the enhancement of vessel
structures and pit pattern. The mode that enhances the mucosal vessel
architecture, thereby improving of detection of small mucosal lesions is called
Surface Enhancement. Digital image processing with emphasis on certain
wavelengths of white light like the Colon Mode will probably add some
additional mucosal and vascular details. The present study is designed to
assess the effect of HD colonoscopy alone or combined with different I-scan
functions compared to standard colonoscopy with respect to adenoma detection
rate.

Assessment of the adenoma detection rate at colonoscopy using :
A: Standard colonoscope
B: High Definition colonoscope
C: High Definition colonoscope with surface enhancement
D: High Definition colonoscope with surface enhancement and Colon Mode

prospective randomized multicenter study

colonoscopy

Risks are associated with colonoscopy in itself, but not with the type of
endoscope or use of different I-scan functions. Differences in risks between
study groups is unlikely. Serious risks are rare in colonoscopy and are
especially related to interventions during endoscopy (ie polypectomy). Risks of
diagnostic colonoscopy are significant bleeding in 0.005% and perforation in
0.01% of subjects. There is no increased risk for subjects participating in the
study