Narrow-band imaging colonoscopy—a pilot feasibility study for the detection of polyps and correlation of surface patterns with polyp histologic diagnosis

doi:10.1016/j.gie.2007.07.036

Gastrointestinal Endoscopy

Volume 67, Issue 2, February 2008, Pages 280-286

https://doi.org/10.1016/j.gie.2007.07.036 Get rights and content

Background

Colonoscopy is the preferred screening method for colorectal cancer. However, it has a substantial miss rate for colon polyps, and several techniques have been attempted to improve this limitation. Narrow-band imaging (NBI) is a novel technology that enhances the visualization of surface mucosal and vascular patterns.

Objective

The aim of this study was to determine the detection rate of additional polyps by NBI after removal of polyps visualized by standard white light colonoscopy (WLC) and to correlate the surface mucosal and vascular patterns with polyp histologic diagnosis.

Design

This was a prospective pilot feasibility study.

Setting

Kansas City Veterans Affairs Medical Center.

Patients

Subjects referred for screening colonoscopy were prospectively enrolled.

Methods

Subjects underwent colonoscopy after enrollment. After intubation of the cecum, colonic segments were sequentially examined, initially with WLC with removal of polyps followed by re-examination of the same segment with NBI. Additional polyps seen with NBI were photographed for their surface patterns and then removed. The total number of polyps visualized by WLC and NBI was calculated and the surface patterns were then correlated with polyp histologic features.

Results

Forty patients were enrolled in the study, all men, 32 white. The mean age was 62 years. A total of 72 polyps were detected by WLC (43 tubular adenoma, 28 hyperplastic polyps), whereas NBI detected an additional 51 polyps, of which 29 were tubular adenomas and 22 were hyperplastic. Five different surface/vascular patterns were observed: fine capillary network with absent mucosal pattern, circular pattern with dots, round/oval pattern, tubular pattern, and gyrus pattern. The sensitivity, specificity, and overall accuracy of the first two patterns for hyperplastic polyps were 86%, 96%, and 92%, respectively, and of the latter three patterns for tubular adenomas were 96%, 86%, and 92%, respectively.

Conclusions

This pilot study demonstrates the feasibility of polyp detection and histologic correlation with NBI. These findings need to be confirmed in future randomized controlled trials.

Section snippets

Study population

This study was conducted at the Kansas City Veterans' Affairs Medical Center and was approved by the local Institutional Review Board. Patients referred to the GI endoscopy unit for screening colonoscopy were enrolled in the study, and informed consent was obtained from all subjects. Inclusion criteria were average-risk screening for colon cancer and ability to provide written, informed consent. The exclusion criteria were prior surgical resection of any portion of the colon, inflammatory bowel

Patients

A total of 40 patients were prospectively enrolled and all completed the study. The mean age was 62 ± 9.5 years, all men. This included 32 whites, 7 blacks, and 1 Hispanic. All patients were undergoing average-risk screening for colorectal cancer with no prior history of colon polyps or cancer. The procedures (ie, both WLC and NBI) were completed in all, and the cecum was successfully intubated in every patient. Quality of the preparation was good in all examinations, and visualization of the

Discussion

Colonoscopy is the preferred and a widely used method for the detection and removal of colon polyps. Initial studies demonstrated that colonoscopy with polypectomy could prevent 76% to 90% of incident colorectal cancers.4, 10, 11 However, recent evidence involving cohorts of patients with tubular adenomas reveals that the incidence of colon cancer after a clearing colonoscopy is in fact higher than previously reported.12, 13, 14 Several factors have been implicated in the development of colon

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Cited by (135)

Real-Time Characterization of Diminutive Colorectal Polyp Histology Using Narrow-Band Imaging: Implications for the Resect and Discard Strategy
2016, Gastroenterology
Narrow-band imaging (NBI) allows real-time histologic classification of colorectal polyps. We investigated whether endoscopists without prior training in NBI can achieve the following thresholds recommended by the American Society for Gastrointestinal Endoscopy: for diminutive colorectal polyps characterized with high confidence, a ≥90% negative predictive value for adenomas in the rectosigmoid and a ≥90% agreement in surveillance intervals.
Twenty-six endoscopists from 2 tertiary care centers underwent standardized training in NBI interpretation. Endoscopists made real-time predictions of diminutive colorectal polyp histology and surveillance interval predictions based on NBI. Their performance was evaluated by comparing predicted with actual findings from histologic analysis. Multilevel logistic regression was used to assess predictors of performance. Cumulative summation analysis was used to characterize learning curves.
The endoscopists performed 1451 colonoscopies and made 3012 diminutive polyp predictions (74.3% high confidence) using NBI. They made 898 immediate post-procedure surveillance interval predictions. An additional 505 surveillance intervals were determined with histology input. The overall negative predictive value for high-confidence characterizations in the rectosigmoid was 94.7% (95% confidence interval: 92.6%−96.8%) and the surveillance interval agreement was 91.2% (95% confidence interval: 89.7%−92.7%). Overall, 97.0% of surveillance interval predictions would have brought patients back on time or early. High-confidence characterization was the strongest predictor of accuracy (odds ratio = 3.42; 95% confidence interval: 2.72−4.29; P < .001). Performance improved over time, however, according to cumulative summation analysis, only 7 participants (26.9%) identified adenomas with sufficient sensitivity such that further auditing is not required.
With standardized training, gastroenterologists without prior expertise in NBI were able to meet the negative predictive value and surveillance interval thresholds set forth by the American Society for Gastrointestinal Endoscopy. The majority of disagreement in surveillance interval brought patients back early. Performance improves with time, but most endoscopists will require ongoing auditing of performance. ClinicalTrials.gov ID NCT02441998.
Improvement in the visibility of colorectal polyps by using blue laser imaging (with video)
2015, Gastrointestinal Endoscopy
Fujifilm developed blue laser imaging (BLI) via a laser light source with a narrow-band light observation function. It has a brighter BLI bright mode for tumor detection.
To investigate whether the BLI bright mode can improve the visibility of colorectal polyps compared with white light (WL).
We studied 100 colorectal polyps (protruding, 42; flat, 58; size, 2–20 mm) and recorded videos of the polyps by using the BLI bright mode and WL at Kyoto Prefectural University of Medicine and Fukuoka Chikushi University Hospital. The videos were evaluated by 4 expert endoscopists and 4 nonexperts. Each endoscopist evaluated the videos in a randomized order. Each polyp was assigned a visibility score from 4 (excellent visibility) to 1 (poor visibility).
Japanese academic units.
The visibility scores in each mode and their relationship to the clinical characteristics were analyzed.
The mean visibility scores of the BLI bright mode were significantly higher than those of WL for both experts and nonexperts (experts, 3.10 ± 0.95 vs 2.90 ± 1.09; P = .00013; nonexperts, 3.04 ± 0.94 vs 2.78 ± 1.03; P < .0001). For all nonexperts, the visibility scores of the BLI bright mode were significantly higher than those of WL; however, these scores were significantly higher in only 2 experts. For experts, the mean visibility scores of the BLI bright mode was significantly higher than those of WL for flat polyps, neoplastic polyps, and polyps located on the left side of the colon and the rectum.
Small sample size and review of videos.
Our study showed that polyps were more easily visible with the BLI bright mode compared with WL. (Clinical trial registration number: UMIN000013770.)
High-resolution microendoscopy in differentiating neoplastic from non-neoplastic colorectal polyps
2015, Best Practice and Research: Clinical Gastroenterology
Colorectal cancer is one of the leading causes of death worldwide. The progression from adenoma to cancer is a well known phenomenon. Current clinical practice favors colonoscopy as the preferred modality for colorectal cancer screening. Many novel endoscopic technologies are emerging for the purposes of performing “optical biopsy” to allow real-time histologic diagnosis of polyps. High resolution microendoscopy is a low-cost endoscopic technology that has demonstrated high sensitivity and specificity in differentiating neoplastic and non-neoplastic polyps. With the ability to make real-time conclusions based on the endoscopic appearance of polyps, it is becoming increasingly possible to decrease the rate of unnecessary polypectomies and utilize a “resect and discard” strategy to decrease costs of pathology evaluation. Future directions for this technology include surveillance of premalignant conditions such as inflammatory bowel disease. Moreover, the low cost and relative ease of use of this technology lends itself to widespread applicability.
Methods to become a high performer in characterization of colorectal polyp histology
2015, Best Practice and Research: Clinical Gastroenterology
The recent advent of advanced imaging technologies has brought real time characterization of polyp histology to the forefront. This concept of optical diagnosis of diminutive polyp histology can bring about a huge paradigm shift in the management of these lesions. Instead of resecting and sending all the diminutive polyps to pathology, there is the potential to practice “resect and discard” for those predicted to be adenomas and “do not resect” strategy for the recto-sigmoid polyps predicted to be hyperplastic. However, one of the major steps before the clinical implementation of real-time histology can be a reality, will be training endoscopists with varying levels of experience in novel imaging technologies. The two major methods for training include didactic teaching and the computer based method. After the initial training, it is imperative that the endoscopists practice this skill during performance of routine colonoscopy to auto validate and assess their own competency. Both practice and reinforcement can help endoscopists become high performers in the characterization of polyp histology.
Tools for polyp histology prediction
2015, Gastrointestinal Endoscopy Clinics of North America
Citation Excerpt :
Two patterns were described for hyperplastic polyps and 2 for adenomas (Fig. 3, Table 3).30,31 These results showed a sensitivity, specificity, and accuracy of 96%, 89%, and 93%, respectively, for polyp histology prediction.30 A similar classification was described by Rex32 that showed an accuracy of 89% for characterizing adenomas.
Decreased numbers of vascular networks and irregular vessels on narrow-band imaging are useful findings for distinguishing intestinal lymphoma from lymphoid hyperplasia
2014, Gastrointestinal Endoscopy
No method for sufficiently making the differential diagnosis of intestinal lymphoma resembling lymphoid hyperplasia (LH) on endoscopy has yet been established.
The aim of this study was to evaluate the usefulness of narrow-band imaging (NBI) in diagnosing intestinal lymphoma.
Prospective study.
Single-center study.
Sixty-one patients with primary or systemic lymphoma were enrolled in this study.
The terminal ileum and entire colon were observed by using conventional endoscopy. NBI was subsequently performed when small polypoid lesions were detected. A decrease in the number of vascular networks (DVNs) and the presence of irregular vessels on the surface of the epithelia were defined as characteristic findings of intestinal lymphoma. The diagnostic accuracy of these 2 findings in distinguishing intestinal lymphoma from LH was examined.
The ability to use NBI to distinguish intestinal lymphoma from LH.
Two hundred ninety-four small polypoid lesions, including 59 lymphomas and 235 LH lesions, were detected. The rates of detecting DVNs and the presence of irregular vessels were significantly higher in the lymphoma samples (81.4% and 62.7%) than in the LH samples (25.5% and 4.7%). Based on these findings, the diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values for differentiating intestinal lymphoma from LH were 88.8%, 62.7%, 95.3%, 77.1%, and 91.1%, respectively, which are significantly higher than those of conventional endoscopy.
Single-center study.
DVNs and the presence of irregular vessels on NBI are thus considered to be useful findings for differentiating intestinal lymphoma from benign LH.

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Original articleClinical endoscopyNarrow-band imaging colonoscopy—a pilot feasibility study for the detection of polyps and correlation of surface patterns with polyp histologic diagnosis

Background

Objective

Design

Setting

Patients

Methods

Results

Conclusions

Section snippets

Study population

Patients

Discussion

Gastroenterol Clin North Am

Gastroentrology

Am J Gastroenterol

Gastroenterology

Gastrointest Endosc

Clin Gastroenterol Hepatol

Gastrointest Endosc

Gastrointest Endosc

Gastrointest Endosc

Cancer statistics, 2006

CA Cancer J Clin

Molecular biology of colon polyps and colon cancer

Semin Surg Oncol

Prevention of colorectal cancer by colonoscopic polypectomy: the National Polyp Study Workgroup

N Engl J Med

Prospective study of the frequency and size distribution of polyps missed by colonoscopy

J Natl Cancer Inst

Efficacy of total colonoscopy with a transparent cap in comparison with colonoscopy without the cap

Endoscopy

Impact of proximal colon retroflexion on adenoma miss rates

Am J Gastroenterol

Original article
Clinical endoscopy
Narrow-band imaging colonoscopy—a pilot feasibility study for the detection of polyps and correlation of surface patterns with polyp histologic diagnosis