Narrow Band Imaging Group Research Articles

Narrow-band imaging does not improve detection of colorectal polyps when compared to conventional colonoscopy: a randomized controlled trial and meta-analysis of published studies

BackgroundA colonoscopy may frequently miss polyps and cancers. A number of techniques have emerged to improve visualization and to reduce the rate of adenoma miss.MethodsWe conducted a randomized controlled trial (RCT) in two clinics of the Gastrointestinal Department of the Sanitas University Foundation in Bogota, Colombia. Eligible adult patients presenting for screening or diagnostic elective colonoscopy were randomlsy allocated to undergo conventional colonoscopy or narrow-band imaging (NBI) during instrument withdrawal by three experienced endoscopists. For the systematic review, studies were identified from the Cochrane Library, PUBMED and LILACS and assessed using the Cochrane risk of bias tool.ResultsWe enrolled a total of 482 patients (62.5% female), with a mean age of 58.33 years (SD 12.91); 241 into the intervention (NBI) colonoscopy and 241 into the conventional colonoscopy group. Most patients presented for diagnostic colonoscopy (75.3%). The overall rate of polyp detection was significantly higher in the conventional group compared to the NBI group (RR 0.75, 95%CI 0.60 to 0.96). However, no significant differences were found in the mean number of polyps (MD -0.1; 95%CI -0.25 to 0.05), and the mean number of adenomas (MD 0.04 95%CI -0.09 to 0.17). Meta-analysis of studies (regardless of indication) did not find any significant differences in the mean number of polyps (5 RCT, 2479 participants; WMD -0.07 95% CI -0.21 to 0.07; I2 68%), the mean number of adenomas (8 RCT, 3517 participants; WMD -0.08 95% CI -0.17; 0.01 to I2 62%) and the rate of patients with at least one adenoma (8 RCT, 3512 participants, RR 0.96 95% CI 0.88 to 1,04;I2 0%).ConclusionNBI does not improve detection of colorectal polyps when compared to conventional colonoscopy (Australian New Zealand Clinical Trials Registry ACTRN12610000456055).

Narrow band imaging hysteroscopy: A comparative study using randomized video images

Narrow band imaging (NBI) has been used in the gastrointestinal endoscopy field as a novel endoscopic imaging technique and has contributed to improved qualitative diagnosis and detection of lesions. However, there are only a few studies of use of NBI in the gynecology field. We applied NBI in flexible hysteroscopy at our outpatient clinic and evaluated the utility of NBI hysteroscopy for diagnosis of malignant endometrial lesions by comparison of the sensitivity and specificity between white light alone and white light+NBI using hysteroscopic video images. The subjects were 65 patients with a suspected endometrial lesion in the uterine cavity. These patients underwent flexible hysteroscopy using NBI in addition to conventional white light. Video images from 65 patients were edited into two groups, white light alone (WL group) and white light+NBI (NBI group) (130 images in total). Computerized block randomization of the order was then performed. Four raters independently diagnosed the images without use of other clinical information. Using the pathological diagnosis as the gold standard, we evaluated the sensitivity and specificity of diagnosis of atypical endometrial hyperplasia (AEH) or endometrial carcinoma compared between the WL and NBI groups. The sensitivity of diagnosis of AEH or endometrial carcinoma was numerically higher in the NBI group for all raters, and the average sensitivity was significantly higher in the NBI group compared to the WL group (78.6% vs. 63.7%, P<0.001). The specificity for each rater and the average specificity were comparable between the two groups. Compared to white light hysteroscopy, NBI hysteroscopy had a higher sensitivity for diagnosis of AEH or endometrial carcinoma without loss of specificity. This suggests that NBI hysteroscopy may be more useful than white light hysteroscopy for endoscopic diagnosis of malignant endometrial lesions.

Mo1530 A Randomised Trial of NBI for Adenoma Detection in High Risk Patients: Flat Adenomas, Bowel Preparation and Endoscopist Sub-Group Analysis

Narrow Band Imaging (NBI) has been investigated as a technique to improve adenoma detection; however most randomised studies have shown no differences from white light examination (WLE). We recently reported no significant difference in adenoma detection rate for our trial of NBI for detection in high risk patients (n=214; 73% NBI vs 66% WLE, P=0.26)©; however patients were not evenly matched by gender in NBI and WLE groups. We therefore undertook a multivariate analysis to account for this and investigate other sub-groups

A randomised trial of NBI for adenoma detection in high risk groups: flat adenomas, bowel preparation and endoscopist sub-group analysis

Introduction Narrow band imaging (NBI) has been investigated as a technique to improve adenoma detection; however most randomised studies have shown no differences from white light examination (WLE). We recently reported no significant difference in adenoma detection rate for our trial of NBI for detection in high risk patients (n=214; 73% NBI vs 66% WLE, p=0.26)1; however patients were not evenly matched by gender in NBI and WLE groups. We therefore undertook a multivariate analysis to account for this and investigate other subgroups Methods The primary outcome measure, patients with at least one adenoma detected, was reanalysed after adjustment for demographic and clinical variables including all of: age, gender, indication (3+ adenomas, cancer follow up, +ve FOBT), family history of colorectal cancer, bowel preparation (good or adequate), endoscopist (three operators), and withdrawal time, using logistic regression. Count outcomes (polyp numbers by type) were analysed by Poisson regression. An interaction was noted with both endoscopist and bowel preparation, which were analysed as subgroups Results Following multivariate analysis there was no significant difference for the primary outcome measure between WLE and NBI arms, p=0.30, OR (adjusted) 1.46 (95% CI 0.72 to 2.96). No difference was seen for total number of adenomas, total polyps, advanced adenomas or non-adenomatous polyps; however the mean (SD) number of flat adenomas was higher in NBI arm 0.4 (0.9) versus 0.2 (0.4), adjusted comparison ratio 2.58 (1.42–4.68), p=0.002. One of three endoscopists performed significantly better with NBI (table 1). In patients with good bowel prep NBI significantly outperformed WLE for numbers of adenomas detected, but there was no difference with adequate bowel prep (table 1). Conclusion Overall, after adjustment, NBI did not improve adenoma detection; however detection of flat adenomas appears improved. One of three endoscopists performed better with NBI than white light, and NBI was more effective in patients with good bowel preparation. Under optimal conditions, NBI may assist some endoscopists to optimise detection particularly of flat adenomas. Aggregated results of randomised controlled trials may obscure situations where advanced imaging techniques could provide benefit. ClinicalTrials.gov identifier NCT00279357.

Effectiveness of narrow band imaging in patients with oral squamous cell carcinoma after treatment

We evaluated the effectiveness of narrow band imaging (NBI) in patients with oral squamous cell carcinoma (OSCC) after treatment. In all, 101 consecutive OSCC patients underwent NBI examination for posttreatment follow-up. Four patients had local recurrence. Twenty-six second primary malignancies were found in 18 patients; 6 patients (33%) had more than 1 lesion. Seventeen lesions (65%) were carcinoma in situ or severe dysplasia. Most of them occurred in the oral cavity (77%). A higher incidence (18% vs 9%, p = .037) and less-advanced stage (4% vs 37%, p = .0005) of second primary malignancies were found among the NBI group compared with a previous cohort without NBI examination, and fewer patients needed postoperative adjuvant therapy (12% vs 50%, p = .0005). NBI is an effective method to identify early lesions in the head and neck area, especially the oral cavity, among patients with OSCC after treatment.

Feasibility of Transurethral Resection of Bladder Lesion Performed Entirely by Means of Narrow-Band Imaging

To assess the feasibility of transurethral resection (TUR) of bladder lesions performed entirely by means of a narrowband imaging (NBI) modality. Data from an ongoing prospective randomized trial (NCT01004211) were extracted. Quality outcomes of standard TUR and NBI TUR were compared. Complications were graded according to the Clavien-Dindo system. To date, 33 and 29 subjects were randomized to standard and NBI TUR. No significant differences regarding age, sex, American Society of Anesthesiologists score, rate of multiple lesions, or lesions larger than 3 cm in the two groups were found, whereas rate of TUR for recurrent bladder cancer was greater in the NBI group. All procedures ended with complete clearance of the suspected or overt bladder tumor in the modality assigned. No death or major surgical or medical complications were registered. Overall grade I to II complications rate in the NBI and standard groups was, respectively, 8/29 (27%) and 11/33 (33%) (P = 0.831). Median surgery time was, respectively, 20 and 30 minutes in the NBI and standard group (P = 0.381). Median time to catheter removal was, respectively, 2 and 3 days in the NBI and standard groups (P = 0.288). Median time to discharge was 2 and 3 days (P = 0.173). No patient was readmitted after discharge. Muscle tissue was absent in the specimen of one patient who underwent standard TUR. NBI TUR appears to be feasible. The results of the ongoing randomized trial will show whether NBI TUR is able to reduce significantly the 1-year recurrence rate of bladder tumors.

Narrow band imaging assisted argon plasma coagulation for Barrett's esophagus

Objective To evaluate narrow band imaging （NBI） assisted argon plasma coagulation （APC） in treatment of Barrett＇s esophagus （BE）. Methods Suspected BE lesion was observed under white light, NBI and magnification, biopsies were taken at the site with characteristic pit pattern and capillary architecture of BE. A total of 86 patients with pathologically confirmed BE were randomly divided into NBI group （n= 42） to receive APC under NBI, or control group （n= 44） to receive APC under whit light. For APC procedure, the probe was inserted through biopsy channel to reach 1 cm beyond the endoscope tip, and was located 1-2 cm from the lesion to assure safe use. All patients were followed up with endoscopy and biopsy at 3 and 6 months after APC, respectively. Results There was no significant difference between 2 groups in effective rate of BE mucosal eradication at 3 and 6 months after APC procedure （P 〉 0.05）. Conclusion NBI assisted APC is safe and effective in eradication of BE epithelium, in reducing procedure time and in relieving of functional gastrointestinal symptoms related with BE. Key words: Barrett esophagus; Endoscopy; Narrow band imaging; Argon plasma coagulation

Narrow‐band imaging endoscopy with magnification is useful for detecting metachronous superficial pharyngeal cancer in patients with esophageal squamous cell carcinoma

Head and neck cancers, especially pharyngeal cancers, as well as esophageal cancers frequently coexist either synchronously or metachronously, but most cases of pharyngeal cancer are detected at an advanced stage resulting in poor prognosis. The aim of this study is to evaluate the effectiveness of using narrow-band imaging (NBI) endoscopy with magnification for early detection of pharyngeal cancer on patients following their treatment for esophageal squamous cell carcinoma (SCC). This case series was conducted at the National Cancer Center Hospital in Tokyo between April and October 2005 and included 424 consecutive patients for surveillance endoscopy who had previously undergone chemoradiotherapy (CRT) and/or surgery for esophageal SCC. Observation of the pharyngeal region was randomly conducted on 91 patients using NBI endoscopy with magnification (NBI group) and 333 patients using conventional white light endoscopy (control group). The detection rate for pharyngeal cancer was significantly higher using NBI endoscopy with magnification (10.9%; 10/91) compared with conventional endoscopy (1.2%; 4/333) (P < 0.0001). In particular, the detection rate in CRT patients was significantly higher in the NBI group (12.9%; 7/54) than the control group (0.5%; 1/191) (P < 0.0001). In addition, diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value for the NBI group were 100% (10/10), 97.5% (79/81), 97.8% (89/91), 83.3% (10/12) and 100% (79/79), respectively. NBI endoscopy with magnification is a promising technique for detecting superficial pharyngeal cancer at an early stage in patients previously treated for esophageal SCC.

The Impact of Narrow Band Imaging in Screening Colonoscopy: A Randomized Controlled Trial

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.

Narrow-band imaging for improving colorectal adenoma detection: appropriate system function settings are required

We read with considerable interest the report by Alder et al ( Gut 2008; 57 :59–64) concerning their prospective randomised study on narrow-band imaging (NBI) versus conventional high-resolution imaging for...

Narrow-Band Versus White-Light High Definition Television Endoscopic Imaging for Screening Colonoscopy: A Prospective Randomized 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.

Comparison of white light and narrow band high definition images in predicting colon polyp histology, using standard colonoscopes without optical magnification

Narrow band imaging (NBI) with optical magnification is useful in predicting colon polyp histology. As magnifying endoscopes are not routinely available, we investigated the use of NBI and high definition white light imaging in determining polyp histology, using images obtained with colonoscopes without optical magnification. Images (white light and NBI) of colon polyps less than 10 mm in diameter were collected prospectively from patients undergoing screening colonoscopy and digitally stored. Two endoscopists later reviewed all images and predicted polyp histology as neoplastic or non-neoplastic using a modified Kudo classification. Comparison was made with histopathology. Separate white light and NBI images of 80 polyps (49 neoplastic, 31 non-neoplastic) from 63 patients were recorded. Mean polyp size was 5.1 +/- 2.1 mm (5.4 +/- 2.2 neoplastic; 4.4 +/- 1.8 non-neoplastic; P = 0.02). In a pooled analysis, NBI correctly predicted neoplastic histology in 93 of 98 images (sensitivity 95 %, positive predictive value [PPV] 94 %) whereas white light did so in 58 of 98 images (sensitivity 59 %, PPV 79 %). NBI correctly predicted non-neoplastic histology in 56 of 62 images (specificity 90 %, negative predictive value [NPV] 92 %) whereas white light did so in 47 of 62 images (specificity 76 %, NPV 54 %). NBI without optical magnification was more accurate in predicting colon polyp histology compared with white light imaging. Image quality and confidence in histology were significantly higher in the NBI group. NBI without optical magnification may be useful in predicting colon polyp histology.

The Detection of Flat and Depressed Colorectal Lesions: Which Endoscopic Imaging Approach?

The secondary prevention of colorectal cancer (CRC) assumes that early detection and resection of precursor lesions disrupts the adenoma– carcinoma sequence and halts progression to invasive neoplastic disease. The adenoma– carcinoma sequence has until now formed the rationale for endoscopic therapies directed at reducing the incidence of CRC. The fact that snare polypectomy of exophytic lesions fails to prevent progression to carcinoma in up to 24% of cases has prompted reevaluation of the prevalence and clinicopathologic significance of flat and depressed colorectal lesions in Western population cohorts. Such lesions, although well-described in the Japanese literature, have only recently been reported in Western population cohorts. Debate has continued regarding their prevalence, anatomic localization, histopathologic characteristics, and proposed imaging modality of choice. Within this perspective, we summarize the key data pertinent to recently described endoscopic diagnostic modalities and detail their clinical applicability both for the detection of flat neoplastic lesions occurring in the “sporadic” patient cohort, familial polyposis syndromes, and chronic ulcerative colitis.

A randomised tandem colonoscopy trial of narrow band imaging versus white light examination to compare neoplasia miss rates

Objective: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...

Comparative study of conventional colonoscopy and pan-colonic narrow-band imaging system in the detection of neoplastic colonic polyps: a randomized, controlled trial

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.

A prospective randomised study on narrow-band imaging versus conventional colonoscopy for adenoma detection: does narrow-band imaging induce a learning effect?

Background and aims: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...

Narrow Band Imaging (NBI) Influences the Learning Curve for Conventional Endoscopy - Final Results of a Prospective Randomized Study in the Detection of Colorectal Adenomas

Background: Results concerning staining and the use of the novel technology of narrow band imaging for the detection of colorectal adenomas are conflicting. It is well known from tandem colonoscopy studies that 15-20% of - mostly small - adenomas are missed. Staining has been proposed to increase the yield of especially flat adenomas, and intermediate results of Narrow Band Imaging (NBI), a new technique using different light filtering to increase contrast, have been encouraging with significantly more adenomas been found. Methods: Consecutive patients presenting for diagnostic colonoscopy with symptoms (pos. hemoccult, pain, diarrhea), for surveillance after polypectomy or for screening (cases with known tumors or IBD were excluded) were randomly allocated to NBI or conventional colonoscopy (Olympus Corp., Hamburg, Germany) according to availability of the instrument. The instrument was introduced as usual and on withdrawal from the cecum the control group (C) was examined conventionally with the NBI function not being activated, whereas the study group (NBI) was examined with NBI exclusively, with an option to switch back to normal imaging in case of uncertainty. These instances however were recorded and the reasons given. Polyp detection rate including polyp details as well as withdrawal time were recorded in both groups. Results: 401 patients (53% male, mean age 59 years) have been included; 5 cases with cancers were found but are excluded from this analysis. The overall rates of adenomas and hyperplastic polyps found were 19.7% and 19.9%, respectively. In the NBI group adenomas were detected in 22.7% compared to 16.7% in the control group, but this difference was statistically not significant (p = 0.129), neither in the entire group nor in any of the various subgroups (location, size, form). The number of colonoscopies to be performed to find one additional patient with adenoma would be 17 on the basis of the present adenoma difference. However, when comparing the first and the last 100 cases of the study, an initial significant different in adenoma rates ((NBI 26%, controls 8%, p = 0.015) was not sustained in the last 100 cases (27% vs. 19%, P = 0.33). Hyperplastic polyps were found more frequently in the NBI group than in controls (28.3% and 11.66%, p < 0.001). Conclusions: The new technique of NBI seems enhances the polyp detection rate in a high risk population, but this effect was present for adenomas only in the initial study period. Since the percentage of adenomas found in the control group increased with this rate being stable in the control group, a learning effect from NBI for conventional endoscopy could be postulated.

A Prospective Study Comparison of Narrow Band Imaging (NBI) Versus Chromoendoscopy with Indigo Carmine (IC) Versus White Light (WL) Colonoscopy in the Detection of Adenomatous Colonic Lesions

Background: Colonic early carcinoma and adenomatous precursor flat lesions may not be diagnosed by conventional colonoscopy in up to 24% of cases. Colonic chromoendoscopy with IC or NBI could potentially increase the detection of such lesions, particularly in the right colon. The aim of this study is to evaluate if a larger number of adenomas can be diagnosed by NBI or chromoendoscopy with IC or white light colonoscopy. Methods: An Olympus HD 180 series has been used by two experienced colonoscopists. Exclusion criteria were a history of Inflammatory Bowel Diseases or right colon resection. Each colonic segment was first examined with white light colonoscopy and then followed by chromoscopy with IC 0,4% or NBI. Study outcome was the number of lesions detected with WL compared with NBI and IC. Results: The study groups were well matched for age and sex. A total of 88 patients were enrolled in the study (43 in the NBI group and 45 in the IC group). Seventy two lesions were detected in 52 patients on white light colonoscopy being 39 adenomas, 32 hyperplastic polyps and 1 adenocarcinoma. Compared with WL, NBI detected 9 more lesions in 6 patients, being all lesions flat adenomas (low grade dysplasia) of the right colon and IC found 15 more lesions in 10 patients being 10 of them low grade dysplasia sessile adenomas and 5 hyperplastic flat polyps, all in the right colon. Mean diameter of the lesions diagnosed with NBI and IC were respectively of 3.7 and 4.2 mm. No statistical differences were seen in examination time between NBI (10.6 ± 1.38 min) and IC (11.1 ± 2.32 min). Conclusion: NBI and IC allow easier detection of small/flat colonic lesions compared to WL colonoscopy. No significant differences were found between NBI and IC in polyp detection rate.