In our retrospective study, with the HD+ plus i-Scan imaging routinely activated during the withdrawal phase of colonoscopy, once the cecum had been reached, a significantly larger number of examinations identified some mucosal lesion and adenomas, either protruding or flat, and there were also significant improvements in the overall detection rate of lesions and the mean number of lesions selleck chemicals llc recognized for each colonoscopy, compared with standard white-light imaging. The rate was most markedly higher for lesions not bigger than 10 mm and nonprotruding ones. Although the rates of detection of lesions larger than 10 mm did not differ with the two imaging techniques, protruding and nonprotruding lesions smaller than 10 mm were recognized significantly more frequently using the HD+ plus i-Scan technology.

In particular, HD+ plus i-Scan technology identified flat polyps smaller than 10 mm three times more than the white-light technique. The cumulative mean number of lesions per colonoscopy recognized by the four colonoscopists was significantly higher with HD+ plus i-Scan than with standard white-light imaging, while the withdrawal time, when recorded, did not differ between the two techniques. Only two studies published so far have assessed the combined use of HD+ plus i-Scan for colonoscopy; they have reported similar results in favor of this technique but they were obtained in a prospective trial setting and in a smaller number of selected patients[42,44]. Identifying more polyps by colonoscopy in clinical practice, including small (< 10 mm) and flat ones, may have an important impact for colorectal cancer prevention.

The polyp miss rate is probably the main factor accounting for a persistent risk of colorectal cancer reported in 10%-24% of cases after screening colonoscopy[49]. A systematic review of six tandem colonoscopy studies using standard white-light imaging showed an overall polyp miss rate of 22%. The rate rose with smaller lesions, ranging from 2.1% for lesions bigger than 10 mm, to 13% for those between 5 and 10 mm, and up to 26% for those smaller than 5 mm[8]. A prospective multicenter study of back-to-back colonoscopies with white-light imaging reported 9% and 27% miss rates for adenomas > 5 mm and < 5 mm, respectively, and 11% for advanced adenomas[9]. This means that small and flat mucosal lesions, mostly in the right colon, are the ones that may frequently be missed during colonoscopy.

A limited number of studies have compared the efficacy of HD+ colonoscopy with standard white-light colonoscopy, and the findings are far from clear: four of the nine studies concluded that high-definition imaging gave no benefit compared to standard Drug_discovery resolution[17,18,21,24]. The addition of electronic filters, such NBI and FICE, to the high-definition imaging did improve the polyp detection rate for small/flat lesions but some results were still disappointing for this end-point[16,30].