Narrow-band versus white-light high definition television endoscopic imaging for screening colonoscopy: a prospective randomized trial. A prospective randomised study on narrow-band imaging versus conventional colonoscopy for adenoma detection: does narrow-band imaging induce a learning effect? High yields of small and flat adenomas with high-definition colonoscopes using either white light or narrow band imaging. Comparative study of conventional colonoscopy and pan-colonic narrow-band imaging system in the detection of neoplastic colonic polyps: a randomized, controlled trial. A randomised tandem colonoscopy trial of narrow band imaging versus white light examination to compare neoplasia miss rates. The impact of narrow band imaging in screening colonoscopy: a randomized controlled trial.
Narrow-band imaging (NBI) has been implemented in gastrointestinal endoscopy to improve the contrast of endoluminal pathologic structures, one of the aims being to increase colonic adenoma detection. Previous studies from referral centers have yielded variable and conflicting results with regard to improvement in adenoma detection rates by using NBI. The present large randomized trial was designed to finally settle this issue.
                In a prospective study performed exclusively in a multicenter private practice setting involving 6 examiners with substantial lifetime experience (>10,000 colonoscopies), 1256 patients (men:women, 47%:53%; mean age, 64.4 y) were randomized to HDTV screening colonoscopy with either NBI or white-light imaging on instrument withdrawal. The primary outcome measure was the adenoma detection rate (ie, number of adenomas/total number of patients).
                There was no difference between the 2 groups in terms of the general adenoma detection rate (0.32 vs 0.34), the total number of adenomas (200 vs 216), or in detection in subgroups of adenomas. This was despite a minimal, but significantly longer, withdrawal time in the NBI group (8.5 vs 7.9 min; P < .05). Only hyperplastic polyps were found more frequently in the NBI group (P = .03).
                This large randomized trial in a homogeneous private practice screening setting could not show any objective advantage of the NBI technique over white-light high definition television imaging in terms of improved adenoma detection rate. Contrast enhancement therefore likely will not contribute to a reduction in adenoma miss rates among experienced colonoscopists. Colonoscopy is an established method of colorectal cancer screening, but has an adenoma miss rate of 10-20%. Detection rates are expected to improve with optimised visualisation methods. This prospective randomised study evaluated narrow-band imaging (NBI), a new technique that may enhance image contrast in colon adenoma detection.
                Eligible patients presenting for diagnostic colonoscopy were randomly assigned to undergo wide-angle colonoscopy using either conventional high-resolution imaging or NBI during instrument withdrawal. The primary outcome parameter was the difference in the adenoma detection rate between the two techniques.
                A total of 401 patients were included (mean age 59.4 years, 52.6% men). Adenomas were detected more frequently in the NBI group (23%) than in the control group (17%) with a number of 17 colonoscopies needed to find one additional adenoma patient; however, the difference was not statistically significant (p = 0.129). When the two techniques were compared in consecutive subgroups of 100 study patients, adenoma rates in the NBI group remained fairly stable, whereas these rates steadily increased in the control group (8%, 15%, 17%, and 26.5%, respectively). Significant differences in the first 100 cases (26.5% versus 8%; p = 0.02) could not be maintained in the last 100 cases (25.5% versus 26.5%, p = 0.91).
                The increased adenoma detection rate means of NBI colonoscopy were statistically not significant. It remains speculative as to whether the increasing adenoma rate in the conventional group may have been caused by a training effect of better polyp recognition on NBI. Detection of adenomas is an important goal of colonoscopy. Narrow band imaging (NBI) might highlight adenomas and lead to higher rates of adenoma detection.
                This was a randomized controlled trial of colonoscopy withdrawal in white light versus NBI in 434 patients aged 50 years or older with intact colons. All examinations were performed by a single experienced endoscopist with a known high detection rate of adenomas using high-definition, wide-angle (170 degrees field of view) colonoscopes.
                There was no difference in the percent of patients with >or=1 adenoma for the entire cohort in white light (67%) versus NBI (65%) (P = .61) or in the subset of 257 patients with indication screening (58% vs 57%; P = .91). Both the prevalences of adenomas and the numbers of adenomas per colonoscopy are the highest ever reported in colonoscopy studies. The high prevalence rates of adenomas were accounted for by detection of large numbers of adenomas, including flat adenomas, which were <or=5 mm.
                NBI did not result in better detection of adenomas by an endoscopist with a known high detection rate using white light. This result does not exclude a possible benefit of NBI in reducing variation between endoscopists in detection of adenomas. The very high adenoma detection rate in this study suggests that high definition should be directly tested for its effect on detection of adenomas. Detection and removal of adenomas by colonoscopy is an important means for preventing cancer; however, small adenomas may be missed during colonoscopy. The narrow-band imaging (NBI) system clearly enhances the microvasculature in neoplastic lesions, making it appear as a dark complex. Therefore, the NBI system may improve the detection of colonic neoplasias. However, no randomized, controlled trials have evaluated the efficacy of a pan-colonic NBI system in adenoma detection. We conducted a randomized, controlled trial to determine the efficacy of the pancolonic NBI system in adenoma detection.
                Two hundred forty-three patients were randomized, 121 to conventional colonoscopy and 122 to pan-colonic NBI system. Demographics, indication for colonoscopy, and quality of preparation were similar between groups.
                Extubation time was not significantly different between the conventional colonoscopy and pan-colonic NBI system. The proportions of patients with at least one adenoma and those with multiple adenomas were not significantly different between groups. However, the pan-colonic NBI system significantly increased the total number of adenomas detected (P < 0.05) and the number of diminutive (<5 mm) adenomas detected (P < 0.05). The pan-colonic NBI system allowed detection of more diminutive adenomas in the distal colon than did conventional colonoscopy (P < 0.01), and more patients in the NBI group had at least one diminutive adenoma than in the control group (P < 0.05).
                The pan-colonic NBI system improves the total number of adenomas detected, including significantly more diminutive adenomas, without prolongation of extubation time. These results indicate that routine use of the NBI system for surveillance of diminutive adenomas may be recommended. Colonoscopy, the "gold standard" screening test for colorectal cancer (CRC), has known diagnostic limitations. Advances in endoscope technology have focused on improving mucosal visualisation. In addition to increased angle of view and resolution features, recent colonoscopes have non-white-light optics, such as narrow band imaging (NBI), to enhance image contrast. We aimed to study the neoplasia diagnostic characteristics of NBI, by comparing the neoplasm miss rate when the colonoscopy was performed under NBI versus white light (WL).
                Randomised controlled trial.
                US Veterans hospital.
                Elective colonoscopy adults.
                We randomly assigned patients to undergo a colonoscopic examination using NBI or WL. All patients underwent a second examination using WL, as the reference standard.
                The primary end point was the difference in the neoplasm miss rate, and secondary outcome was the neoplasm detection rate.
                In 276 tandem colonoscopy patients, there was no significant difference of miss or detection rates between NBI or WL colonoscopy techniques. Of the 135 patients in the NBI group, 17 patients (12.6%; 95% confidence interval (CI) 7.5 to 19.4%) had a missed neoplasm, as compared with 17 of the 141 patients (12.1%; 95% CI 7.2 to 18.6%) in the WL group, with a miss rate risk difference of 0.5% (95% CI -7.2 to 8.3). 130 patients (47%) had at least one neoplasm. Missed lesions with NBI showed similar characteristics to those missed with WL. All missed neoplasms were tubular adenomas, the majority (78%) was < or = 5 mm and none were larger than 1 cm (one-sided 95% CI up to 1%). Nonpolypoid lesions represented 35% (13/37) of missed neoplasms.
                NBI did not improve the colorectal neoplasm miss rate compared to WL; the miss rate for advanced adenomas was less than 1% and for all adenomas was 12%. The neoplasm detection rates were similar high using NBI or WL; almost a half the study patients had at least one adenoma. Clinicaltrials.gov identifier: NCT00628147. Narrow band imaging (NBI) is an imaging technique that allows a better definition of capillary pattern and improves the contrast between adenomas and the surrounding mucosa. Conflicting data exist on the ability of NBI to improve detection of colonic neoplasm; the impact of NBI is being tested in several screening scenarios. We evaluated whether the routine use of NBI, compared with white light (WL), during the withdrawal phase of screening colonoscopy improved adenoma detection.
                This randomized controlled study included consecutive 50- to 69-year-old patients with positive immunologic fecal occult blood tests. They were randomly assigned to groups that were examined with WL (n = 108) or NBI (n = 103) during the withdrawal phase of their colonoscopies. The primary end point was the adenoma detection rate. The prevalence of non-polypoid and the total number of adenomas were also evaluated.
                The number of total and mean per-patient adenomas were 201 (1.95 +/- 2.3) and 198 (1.83 +/- 2.1) in the NBI and WL groups, respectively (P = .69). The adenoma detection rates were 57.3% for patients examined by NBI and 58.3% for those examined by WL (P = .88). A total of 41 non-polypoid adenomas were identified (26 in the NBI and 15 in the WL groups, P = .16). The flat adenoma detection rates were 21.4% and 9.3% in the NBI and WL groups, respectively (P = .019).
                The routine use of NBI in screening colonoscopy did not increase the adenoma detection rate. NBI seems to improve the detection of flat adenomas, although additional studies are necessary.