Narrow-band imaging in the diagnosis of colorectal mucosal lesions: a pilot study

[Progress in diagnostics of anorectal disorders. Part I: anatomic background and clinical and neurologic procedures]

Diagnostics and therapy of anorectal disorders are still questions of surgery. Exact knowledge of functional anatomy and precise clinical examination constitute the basis for the resulting therapeutic strategies. Three-dimensional endosonography and technical advances in flexible endoscopy using high-resolution chromoendoscopy and narrow-band imaging enable exact staging and diagnosis, even of malignancies in earliest stages. Furthermore new in-vivo staining methods combined with high-resolution imaging facilitate the discrimination of inflammatory and neoplastic lesions, which often lead to diagnostic difficulties in chronic inflammatory bowel disease. Developments in neurologic testing, including surface electromyography and sacral nerve stimulation, complement the diagnostic armamentarium.

Narrow-band imaging optical chromocolonoscopy: Advantages and limitations

Narrow-band imaging (NBI) is an innovative optical technology that modifies the center wavelength and bandwidth of an endoscope’s light into narrow-band illumination of 415 ± 30 nm. NBI markedly improves capillary pattern contrast and is an in vivo method for visualizing microvessel morphological changes in superficial neoplastic lesions. The scientific basis for NBI is that short wavelength light falls within the hemoglobin absorption band, thereby facilitating clearer visualization of vascular structures. Several studies have reported advantages and limitations of NBI colonoscopy in the colorectum. One difficulty in evaluating results, however, has been non-standardization of NBI systems (Sequential and non-sequential). Utilization of NBI technology has been increasing worldwide, but accurate pit pattern analysis and sufficient skill in magnifying colonoscopy are basic fundamentals required for proficiency in NBI diagnosis of colorectal lesions. Modern optical technology without proper image interpretation wastes resources, confuses untrained endoscopists and delays inter-institutional validation studies. Training in the principles of “optical image-enhanced endoscopy” is needed to close the gap between technological advancements and their clinical usefulness. Currently available evidence indicates that NBI constitutes an effective and reliable alternative to chromocolonoscopy for in vivo visualization of vascular structures, but further study assessing reproducibility and effectiveness in the colorectum is ongoing at various medical centers.

Flat and depressed types of early colorectal cancers: from East to West

Recent advances in colonoscopy have enabled us to diagnose early-stage colorectal tumors. Magnifying colonoscopy is useful for diagnosing histologic types by assessing the microstructure of the mucosal surface in detail, which also helps to predict the depth. This article describes clinicopathologic features and endoscopic treatment of flat and depressed types of early colorectal carcinoma.

Variable detection of nonadenomatous polyps by individual endoscopists at colonoscopy and correlation with adenoma detection

BACKGROUND

There is variation between endoscopists in their detection of colorectal adenomas. There is less understanding of variation between endoscopists in detection and management of nonadenomas.

AIM

To describe the removal rates of nonadenomas, variability between endoscopists, and the association of adenoma removal with nonadenoma removal.

METHODS

Consecutive colonoscopy reports by 9 gastroenterologists at Indiana University Hospital between January 1999 and January 2004 were obtained. Patients with inflammatory bowel disease, polyp syndromes, or who were referred for polypectomy were excluded.

RESULTS

There were 10,034 included colonoscopies. The prevalence of nonadenomatous polyps increased from 26.6% at age 30 years to 29.3% at age 70 years (P=0.02); this association was much less powerful than that of age with removal of adenomas. The range of finding > or =1 nonadenomatous polyp was 11.8% to 34.9%. The correlation between adenoma detection and nonadenoma removal by individual endoscopists for the full cohort was 0.79 and for persons age > or =50 years was 0.84.

CONCLUSIONS

Detection of nonadenomatous polyps by individual endoscopists at colonoscopy is highly variable and correlates with increased removal rates of adenomatous polyps.

Optical Microangiography: High-Definition Magnification Colonoscopy with Narrow Band Imaging (NBI) for Visualizing Mucosal Capillaries and Red Blood Cells in the Large Intestine

BACKGROUND/AIMS

Recent advances in zoom endoscopy have enabled the subepithelial capillary network (SECN) in different organs of the gastrointestinal tract to be visualized. Ex vivo studies have suggested that the SECN demonstrates a honeycomb-like structure in the large intestine, but this has not yet been visualized in vivo. The high clarity and resolution of narrow-band imaging (NBI) may allow visualization at the single red-blood-cell (RBC) level and more accurate visualization of the SECN. We investigated whether high-definition magnification colonoscopy with NBI is useful for visualizing capillaries and RBCs in the large intestine.

METHODS

Sixteen patients with bowel symptoms undergoing routine colonoscopy with normal findings in a tertiary referral academic gastroenterology and endoscopy unit were included in the study. Total colonoscopies were performed using a high-definition magnification colonoscope (CF-H260AZI, Olympus, Tokyo) and a prototype high-definition electronic endoscopy system capable of NBI. Each part of the large intestine (cecum, ascending, transverse, descending, and sigmoid colon, and rectum) was observed at the maximum magnification with white-light imaging (WLI) and NBI. The normal honeycomb-like SECN and RBC movement by high-definition magnification colonoscopy with either WLI or NBI was prospectively successfully visualized for each part of the large intestine.

RESULTS

In all subjects, high-definition magnification colonoscopy with NBI allowed the visualization of a honeycomb-like SECN together with RBC movement in each segment of the large intestine except for the rectum. In contrast, with WLI alone, neither this SECN structure nor RBC movement could be detected.

CONCLUSIONS

High-definition magnification colonoscopy with NBI could be a new optical method for facilitating noninvasive investigations of both the microvascular architecture and microcirculation without the need for contrast materials.

Single wavelength micro-endoscopy in non-surgical vascular lesion diagnosis & characterization

Malignant and dysplastic epithelial lesions have often been reported to excite vascular responses by histopathological characterization. Little is reported concerning in vivo real-time imaging of vascular patterns and flow in health or disease but the development of miniature imaging instrumentation has now allowed such developments. We describe the application of a selective wavelength (540 nm) epi-illumination Hopkins pattern endoscopic imaging system to image vascular tissues and capillary blood flow in vivo. The contrast mechanism in such imaging was characterized, haemoglobin acting as a chromatic transmission filter despite endoscopy being a non-invasive and therefore principally reflection mode imaging system. In vivo adrenergic vascular responses, capillary flow rate variations over time and variations in normal capillary architecture around the oral cavity were recorded; demonstrating that simple imaging systems can be used for non-surgical diagnosis and characterization of vascular lesions, tumours and treatment responses.

Novel approaches in colorectal endoscopy: what do we need biopsies for?

Magnification chromoendoscopy, narrow band imaging (NBI) and confocal endomicroscopy can all provide accurate assessment of small and diminutive colonic lesions for neoplastic change that approaches the accuracy of standard histopathology. It is likely that there will be a move to use these techniques in clinical practice for small and particularly diminutive, non-depressed lesions in the near future. Non-neoplastic lesions would be left in situ, and neoplastic lesions resected and disposed of without histopathological assessment. Histopathology would be reserved for larger lesions, indeterminate lesions or lesions where invasion was suspected. There are potentially significant cost savings and patient benefits, with a focussing of histopathological expertise on higher risk lesions, particularly in the era of bowel cancer screening. These techniques may also help target biopsies in colitis surveillance, removing the need for large numbers of random samples. However, in order to convince patients, histopathologists and those funding healthcare of the validity of this approach, further trial data will be needed, with an accreditation process for endoscopists wishing to take on this responsibility.

Narrow band imaging with magnifying colonoscopy as diagnostic tool for predicting histology of early colorectal neoplasia

BACKGROUND

The presence of abnormal microcapillaries detected by narrow band imaging (NBI) with magnifying colonoscopy has been reported to be a marker of colorectal neoplasia.

AIM

To investigate prospectively if NBI with magnification could help predict the histology of early colorectal neoplasia.

METHODS

A series of 104 consecutive patients with 139 colorectal lesions were studied. All lesions were detected by conventional colonoscopy and subsequently evaluated by NBI with magnification. During NBI with magnification, the microvascular architecture observed on the surface of the detected lesions, capillary patterns (CP), was divided into non-neoplastic (CP I) and neoplastic (CP II and CP III) types. Only lesions endoscopically diagnosed as CP II or CP III were included in the study. All of the lesions were resected endoscopically or surgically and examined histologically for comparison.

RESULTS

Ninety-seven per cent (n = 103) of colorectal neoplastic lesions with CP II were histologically diagnosed as low-grade dysplasia. Eighty-seven per cent (n = 31) of the colorectal neoplastic lesions with CP III were high-grade dysplasia or invasive cancer.

CONCLUSION

Capillary patterns observed by NBI with magnification could be used to assess the degree of atypia in early colorectal neoplasia.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Antiglycan antibodies as serological markers in the differential diagnosis of inflammatory bowel disease

BACKGROUND

The objective of the study was to evaluate the diagnostic accuracy of recently developed antiglycan serological tests in clinical practice for the diagnosis of Crohn's disease.

METHODS

This study was a cohort analysis of both clinical and biochemical parameters of patients with diagnosed inflammatory bowel disease compared with those in a control population. Antiglycan antibodies were determined using commercially available enzyme immunoassays. The setting was the outpatient unit of the gastroenterology department of a large, tertiary-care referral academic hospital. Participants were 214 consecutive patients, enrolled over a 5-month period, including 116 with Crohn's disease and 53 with ulcerative colitis, as well as 45 with other gastrointestinal diseases and 51 healthy controls.

RESULTS

Anti-Saccharomyces cerevisiae antibodies showed the best performance (54% sensitivity and 88%-95% specificity for Crohn's disease). Among patients with negative anti-Saccharomyces antibodies, 19 (34%) had high titers of at least another tested antiglycan antibody. Anti-Saccharomyces and anti-laminaribioside antibodies were associated with disease involving the small bowel and with penetrating or stricturing phenotype. Anti-laminaribioside was significantly higher in patients with a familial history of inflammatory bowel disease.

CONCLUSIONS

The new proposed serological markers are significantly associated with Crohn's disease, with low sensitivity but good specificity. About one third of anti-Saccharomyces-negative patients may be positive for at least 1 of those markers. Antiglycan antibodies appear to be associated with characteristic localization and phenotype of the disease.

Song LMWK, Adler DG, Conway JD, Diehl DL, Farraye FA, Kantsevoy SV, Kwon R, Mamula P, Rodriguez B, Shah RJ, Tierney WM. Narrow band imaging and multiband imaging

NBI and MBI may enhance the diagnosis and characterization of mucosal lesions in the GI tract, particularly as adjunctive techniques to magnification endoscopy. Standardization of image characterization, further image-to-pathology correlation and validation, and the impact of these technologies on patient outcomes are necessary before endorsing the use of NBI and MBI in the routine practice of GI endoscopy.

Detection of colonic dysplasia in vivo using a targeted heptapeptide and confocal microendoscopy

A combination of targeted probes and new imaging technologies provides a powerful set of tools with the potential to improve the early detection of cancer. To develop a probe for detecting colon cancer, we screened phage display peptide libraries against fresh human colonic adenomas for high-affinity ligands with preferential binding to premalignant tissue. We identified a specific heptapeptide sequence, VRPMPLQ, which we synthesized, conjugated with fluorescein and tested in patients undergoing colonoscopy. We imaged topically administered peptide using a fluorescence confocal microendoscope delivered through the instrument channel of a standard colonoscope. In vivo images were acquired at 12 frames per second with 50-microm working distance and 2.5-microm (transverse) and 20-microm (axial) resolution. The fluorescein-conjugated peptide bound more strongly to dysplastic colonocytes than to adjacent normal cells with 81% sensitivity and 82% specificity. This methodology represents a promising diagnostic imaging approach for the early detection of colorectal cancer and potentially of other epithelial malignancies.

Computed virtual chromoendoscopy for classification of small colorectal lesions: a prospective comparative study

OBJECTIVES

Standard colonoscopy offers no reliable discrimination between neoplastic and nonneoplastic colorectal lesions. Computed virtual chromoendoscopy with the Fujinon intelligent color enhancement (FICE) system is a new dyeless imaging technique that enhances mucosal and vascular patterns. This prospective trial compared the feasibility of FICE, standard colonoscopy, and conventional chromoendoscopy with indigo carmine in low- and high-magnification modes for determination of colonic lesion histology.

METHODS

Sixty-three patients with 150 flat or sessile lesions less than 20 mm in diameter were enrolled. At colonoscopy, each lesion was observed with six different endoscopic modalities: standard colonoscopy, FICE, and conventional chromoendoscopy with indigo carmine (0.2%) dye spraying in both low- and high-magnification modes. Histopathology of all lesions was confirmed by evaluation of endoscopic resection or biopsy specimens. Endoscopic images were stored electronically and randomly allocated to a blinded reader.

RESULTS

Of the 150 polyps, 89 were adenomas and 61 were hyperplastic polyps with an average size of 7 mm. For identifying adenomas, the FICE system with low and high magnifications revealed a sensitivity of 89.9% and 96.6%, specificity of 73.8% and 80.3%, and diagnostic accuracy of 83% and 90%, respectively. Compared with standard colonoscopy, the sensitivity and diagnostic accuracy achieved by FICE were significantly better under both low (P < 0.02) and high (P < 0.03) magnification and were comparable to that of conventional chromoendoscopy.

CONCLUSIONS

The FICE system identified morphological details that efficiently predict adenomatous histology. For distinguishing neoplastic from nonneoplastic lesions, FICE was superior to standard colonoscopy and equivalent to conventional chromoendoscopy.

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

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.

Correlation between narrow band imaging and nonneoplastic gastric pathology: a pilot feasibility trial

BACKGROUND

A novel narrow band imaging (NBI) system is able to visualize the mucosal and vascular network in the GI tract.

OBJECTIVE

The aim of the current study was to test the feasibility of NBI to predict gastric histologic diagnosis.

DESIGN

A pilot feasibility study.

SETTING

Veterans Affairs Medical Center.

PATIENTS

Forty-seven patients undergoing upper endoscopy for various indications were prospectively enrolled.

METHODS

The gastric body and antrum were systematically examined by NBI before targeted biopsies. Images were graded according to the mucosal (ridge/villous and circular) and vascular patterns and correlated with histologic findings in a blinded manner.

MAIN OUTCOME MEASUREMENTS

Final histologic diagnosis based on updated Sydney classification system.

RESULTS

Overall, 25 patients (53.1%) had a normal biopsy specimen, 13 (27.6%) had non-Helicobacter pylori gastritis, 4 (8.5%) had H pylori gastritis, and 5 (10.6%) had intestinal metaplasia. The sensitivity, specificity, and positive predictive value of a regular mucosal and vascular pattern for the diagnosis of normal mucosa/mild gastritis were 89%, 78%, and 94%, respectively. The sensitivity and specificity of an irregular pattern with decreased density of vessels for the diagnosis of H pylori were 75% and 88%, and that of the ridge/villous pattern for the diagnosis of intestinal metaplasia were 80% and 100%, respectively.

LIMITATION

The small number of patients with H pylori and intestinal metaplasia was the main limitation.

CONCLUSIONS

This is the first U.S. study of NBI for gastric lesions. NBI may help predict in vivo histologic diagnosis of gastric pathologic conditions with a good degree of accuracy. Future larger studies are needed.

Clinical significance of type VI pit pattern subclassification in determining the depth of invasion of colorectal neoplasms

AIM: To clarify whether subclassification of the type V_I pit pattern on the basis of magnifying colonoscopy findings is useful in determining the type and depth of invasion of colorectal neoplasms.

METHODS: We retrospectively analyzed 272 colorectal neoplasms (117 dysplasias and 155 submucosal invasive carcinomas; 228 patients) with a type V pit pattern [type V_I, n = 202; type V_N, n = 70 (Kudo and Tsuruta classification system)]. We divided lesions with a type V_I pit pattern into two subclasses, mildly irregular lesions and severely irregular lesions, according to the prominent and detailed magnifying colonoscopy findings. We examined the relation between these two subclasses and histology/invasion depth.

RESULTS: One hundred and four lesions (51.5%) were judged to be mildly irregular, and 98 lesions (48.5%) were judged to be severely irregular. Ninety-seven (93.3%) mildly irregular lesions showed dysplasias or submucosal invasion of less than 1000 &mgr;m (SM < 1000 &mgr;m). Fifty-five (56.1%) severely irregular lesions showed submucosal invasion equal to or deeper than 1000 &mgr;m (SM ≥ 1000 &mgr;m). Mild irregularity was found significantly more often in dysplasias or lesions with SM < 1000 &mgr;m than in lesions with SM ≥ 1000 &mgr;m (P < 0.01).

CONCLUSION: Subclassification of the type V_I pit pattern is useful for identifying dysplasias or lesions with SM < 1000 &mgr;m.

American Gastroenterological Association (AGA) Institute technology assessment on image-enhanced endoscopy

This document presents the official recommendations of the American Gastroenterological Association (AGA) Institute Technology Assessment on "Image-Enhanced Endoscopy." It was approved by the Clinical Practice and Economics Committee on August 3, 2007, and by the AGA Institute Governing Board September 27, 2007.

Endoscopic imaging: emerging optical techniques for the detection of colorectal neoplasia

PURPOSE OF REVIEW

Advances in bioengineering have spawned various imaging modalities which have revolutionized endoscopy. Some of these technologies provide real-time, high-resolution, subcellular imaging. This review provides an update on these technologies and their role in the evaluation of colorectal neoplasia.

RECENT FINDINGS

Narrow band imaging has been shown to visualize capillary patterns in early cancer and is complementary to magnification endoscopy. Optical coherence tomography has been used to evaluate neoplastic progression and distinguish Crohn's from ulcerative colitis. Confocal endomicroscopy has been shown to accurately predict neoplastic changes in polyps and identify areas of neoplasia in patients with colitis. Among the spectroscopic techniques, autofluorescence is best studied in the colon and has been used to identify adenomas and dysplasia in inflammatory bowel disease. Endocytoscopy is a relatively new technology but shows promise in distinguishing neoplastic lesions.

SUMMARY

Recently a number of imaging technologies have arisen that have the potential to enhance our detection of colorectal neoplasia. Several of these, such as autofluorescent imaging and narrow band imaging, are 'red flag' techniques which enhance our visualization of mucosal change(s). Complementary technologies, such as confocal endomicroscopy and endocytoscopy, provide subcellular imaging. Combined with a 'red flag' technique, these may transform our approach to colonoscopy, allowing the real-time detection and diagnosis of neoplasia.

Recent advances of endoscopy in inflammatory bowel diseases

Endoscopy plays a key role in the diagnosis and treatment in inflammatory bowel disease (IBD). The most valuable tool for distinguishing different types of IBD is a complete ileocolonoscopy with mucosal biopsy. Endoscopic localization of the disease not only aids in determining prognosis and appropriateness of medical therapies but also aids decision-making in those undergoing surgical therapy. With regard to therapeutic applications, obstructive symptoms caused by benign fibrotic strictures can be treated adequately by endoscopic balloon dilation. Epidemiological studies have demonstrated an increased risk of colorectal cancer in patients with both ulcerative colitis and colonic Crohn's disease (CD). Colonoscopy is currently considered to be the gold standard for cancer surveillance. Published guidelines recommend that two to four biopsy samples should be obtained every 10 cm in the colorectum, necessitating 20-50 samplings per examination. This may result in standard colonoscopy - which is also very time-consuming and laborious - missing significant numbers of small lesions. Various novel techniques have been applied to reduce the required number of biopsy samples and the duration of examinations, including chromoendoscopy with or without magnification, fluorescence endoscopy, narrow-band imaging, optical coherence tomography, and confocal laser endomicroscopy. Until recently the only way to evaluate the small-bowel mucosa in a patient with CD was by barium small-bowel radiographs and intubation of the distal terminal ileum. Both wireless-capsule endoscopy (WCE) and double-balloon enteroscopy (DBE) allow light to be used in the inspection of the small bowel and may replace radiological methods. WCE is more convenient than DBE for probing small-bowel mucosal changes, but only DBE allows a biopsy sample to be obtained from the deep small bowel, and these two examinations can be considered complementary. The wider application of new techniques in the near future might increase the role played by endoscopy in the management of IBD.

Review article: New developments in colonic imaging

BACKGROUND

Colonoscopic detection and removal of neoplasia from the colorectum prevent the development of colorectal cancer. Sporadic adenomas and neoplasia associated with ulcerative colitis are frequently missed during colonoscopy, as a result of which, interval cancers might develop.

AIM

To review new developments in colonoscopic imaging concerning the detection of neoplasia.

METHODS

Medical databases were searched for relevant publications, dealing with advanced endoscopic imaging techniques during colonoscopy.

RESULTS

Pancolonic chromoendoscopy has shown to increase the detection of sporadic adenomas and ulcerative colitis associated neoplasia, at the expense of longer examination times. As chromoendoscopy is labour intensive and time-consuming, its widespread use has been hampered. Narrow band imaging is a novel endoscopic imaging technique, which enhances mucosal and vascular details. Recent studies indicate that narrow band imaging has a high yield for neoplasia; however, no improvement compared to standard colonoscopy has been demonstrated. Autofluorescence imaging is another new technique for which blue endoscopic light is used to induce mucosal autofluorescence. So far, preliminary results have shown promising results of autofluorescence imaging for neoplasia detection.

CONCLUSION

Whether chromoendoscopy or novel advanced imaging techniques will change current colonoscopic practice depends on results of future studies comparing these different colonoscopic techniques.

Narrow-band imaging flexible cystoscopy in the detection of recurrent urothelial cancer of the bladder

OBJECTIVE

To investigate whether narrow-band imaging (NBI) flexible cystoscopy improves the detection rate of urothelial carcinomas (UCs) of the bladder. NBI is an optical image enhancement technology in which the narrow bandwidth of light is strongly absorbed by haemoglobin and penetrates only the surface of tissue, increasing the visibility of capillaries and other delicate tissue surface structures by enhancing contrast between the two.

PATIENTS AND METHODS

Between November 2005 and May 2007 at the Queen Elizabeth Hospital, Birmingham, NBI flexible cystoscopy was performed on 29 patients with known recurrences of UC of the bladder after initial conventional white-light imaging (WLI) flexible cystoscopy with the same instrument (Olympus Lucera sequential RGB endoscopy system).

RESULTS

Subjectively, NBI provided a much clearer view of bladder UCs and in particular their delicate capillary architecture. Objectively, NBI detected 15 additional UCs in 12 of 29 patients (41%), as compared with WLI. The mean (sd) difference was 0.52 (0.74) UCs per patient (P < 0.001, Wilcoxon signed-rank test).

CONCLUSIONS

Even in the few patients studied there is strong evidence that NBI differs from WLI in the number of UCs it detects, with a significantly increased detection rate. We feel that further evaluation of NBI flexible cystoscopy in more patients will show this technique to be highly valuable in the detection of both new and recurrent bladder UCs, and this work is continuing in our unit.

Magnifying colonoscopy with narrow band imaging system for the diagnosis of dysplasia in ulcerative colitis: a pilot study

BACKGROUND

Narrow-band imaging (NBI) is a novel illumination technology for endoscopy that enhances vasculature of the GI tract.

OBJECTIVE

The aim was to elucidate whether NBI colonoscopy can identify dysplasia in patients with ulcerative colitis (UC).

DESIGN

Cross-sectional study of eligible patients.

SETTING

Single center.

PATIENTS

46 patients with UC.

INTERVENTIONS

Apparently flat mucosa at each segment and visible protruding lesions were observed by magnifying NBI colonoscopy. The surface structure was classified into honeycomb-like, villous, or tortuous pattern. The grade of dysplasia was determined in the specimens obtained from protrusions and from flat mucosa.

MAIN OUTCOME MEASUREMENTS

The positive predictive value of conventional and NBI colonoscopy for the diagnosis of dysplasia.

RESULTS

A total of 296 sites (20 protruding lesions and 276 flat areas) were examined by NBI colonoscopy. The surface pattern was determined to be honeycomb like in 161 sites, villous in 85 sites, and tortuous in 50 sites. Five dysplastic lesions were detected in 3 patients. A patient had 3 dysplastic lesions and the other 2 had a dysplastic lesion each. The positive rate of dysplasia was higher in protrusions (2/20 sites, 10%) than in flat mucosa (3/276 sites, 1.1%, P = .038; however, correction for the multiple testing of data removes this significance). When the surface pattern was taken into account, the rate of positive dysplasia was higher in the tortuous pattern (4/50 sites, 8%) than in the honeycomb-like or villous patterns (1/246 sites, 0.4%, P = .003).

LIMITATIONS

Uncontrolled study.

CONCLUSIONS

The tortuous pattern determined by NBI colonoscopy may be a clue for the identification of dysplasia during surveillance for UC.

Evaluation of microvessels in colorectal tumors by narrow band imaging magnification

BACKGROUND

Narrow band imaging (NBI) uses optical filters for sequential green and blue illumination and narrows the bandwidth of spectral transmittance.

OBJECTIVE

We determined the clinical usefulness of NBI magnification for evaluation of microvascular architecture and qualitative diagnosis of colorectal tumors.

DESIGN

This study was a retrospective study.

SETTING

Department of Endoscopy, Hiroshima University, Hiroshima, Japan.

PATIENTS AND MAIN OUTCOME MEASUREMENTS

A total of 189 colorectal lesions were analyzed. Each lesion was observed by NBI magnifying endoscopy and classified according to microvascular features (ie, thickness and irregularity). Microvessel thickness was classified as invisible, thin, or thick, and microvessel irregularity was classified as invisible, regular, mildly irregular, or severely irregular. NBI endoscopic images were compared with histologic findings.

RESULTS

With respect to microvessel thickness, invisible microvessels were found significantly more often in hyperplasia lesions, and thick microvessels were found significantly more often in carcinoma with submucosal massive invasion (sm-m) (P < .01). With respect to microvessel irregularity, invisible microvessels were found significantly often in hyperplasia lesions, and severely irregular microvessels were found significantly often in sm-m lesions (P < .01). Accuracy of diagnosis of sm-m on the basis of thick and severely irregular lesions was 100%.

CONCLUSION

Microvascular features determined by NBI magnification are associated with histologic grade and depth of submucosal invasion. These results indicate that NBI magnification is useful for the prediction of histologic diagnosis and selection of therapeutic strategies of colorectal tumors.

Peroral cholangioscopic diagnosis of biliary-tract diseases by using narrow-band imaging (with videos)

BACKGROUND

Narrow-band imaging (NBI) makes it possible to emphasize the imaging of certain features, such as mucosal structures and mucosal microvessels in GI-tract diseases. Recently, video peroral cholangioscopy (POCS) was developed as a diagnostic modality for better visualization of bile-duct lesions; however, there is no report on POCS by using NBI.

OBJECTIVE

To evaluate the clinical usefulness of POCS by using NBI for the diagnosis of biliary-tract diseases.

DESIGN

Prospective case study.

SETTING

This procedure was performed at Tokyo Medical University Hospital.

PATIENTS

Twelve consecutive patients with biliary-tract diseases, including 7 bile-duct cancers and 5 benign biliary diseases, which revealed 6 bile-duct strictures and 6 filling defects by ERCP.

INTERVENTION

All patients underwent POCS by using NBI.

MAIN OUTCOME MEASUREMENT

Efficacy and safety of this technique.

RESULTS

Twenty-one lesions were evaluated by using POCS with conventional white light imaging and NBI. Although visualization of only 2 lesions (9.5%) was "excellent" by conventional observation, visualization of 12 lesions (57.4%) was "excellent" by NBI observation. Identification of the surface structure and vessels of the lesions by NBI observation was significantly better than with conventional observation (P < .01 and P < .05, respectively).

LIMITATIONS

Maneuverability and fragility of POCS. The current POCS is not equipped with magnification.

CONCLUSIONS

POCS by using NBI may be helpful for the observation of both fine mucosal structures and tumor vessels.

Narrow band imaging in Barrett's esophagus

Barrett's esophagus is a well-recognized premalignant condition for the development of esophageal adenocarcinoma, the most rapidly rising cancer in the USA and Western Europe. Detection of intestinal metaplasia and neoplasia arising in Barrett's esophagus patients continues to be a challenge. Limitations of conventional endoscopy with random biopsies provide the necessary impetus for the development of new approaches aimed at improving current screening and surveillance strategies. Narrow band imaging is a novel endoscopic technique that uses a higher intensity of blue light with narrow band filters, which allows a detailed inspection of mucosal and vascular surface patterns with high-level resolution and contrast. Preliminary studies have provided encouraging results for Narrow band imaging alone or in combination with other advanced endoscopic techniques in the screening and surveillance of Barrett's esophagus patients.

Initial experience of peroral pancreatoscopy combined with narrow-band imaging in the diagnosis of intraductal papillary mucinous neoplasms of the pancreas (with videos)

BACKGROUND

It is very important to determine the extent of intraductal mucinous neoplasms (IPMNs), because this can greatly affect the determination of the indications of surgery. Peroral pancreatovideoscopy (POPS) has been recognized as a new diagnostic tool for clear imaging of IPMN. Recently, narrow-band imaging (NBI) has made it possible to emphasize certain image features, such as mucosal structures and capillary vessels.

OBJECTIVE

To evaluate the clinical usefulness of POPS by using NBI for the diagnosis of IPMN.

DESIGN

Case reports.

SETTING

This procedure was performed at Tokyo Medical University Hospital.

PATIENTS

Three patients with IPMN.

INTERVENTION

All patients underwent POPS with NBI.

MAIN OUTCOME MEASUREMENT

Efficacy and safety of this technique.

RESULTS

POPS with NBI was performed in 3 patients, without procedure-related complications. Identification of the surface structure and the capillary vessels by NBI observation was better than by conventional observation. Furthermore, NBI identified skip tumor lesions in the tail of pancreas, which were not detected by conventional POPS.

LIMITATIONS

Because none of the patients in the 3 cases underwent surgical resection, a comparison to clarify total agreement between the preoperative POPS findings and the resected specimen was not possible.

CONCLUSIONS

POPS with NBI may facilitate the observation of both fine mucosal structures and capillary vessels in patients with IPMN, although further study is necessary to fully establish the clinical benefit.

Technology insight: confocal laser endoscopy for in vivo diagnosis of colorectal cancer

Recent studies on a novel technology, denoted confocal laser endomicroscopy (CLE), have altered thinking about the possibilities of endoscopy in the diagnosis and treatment of colorectal cancer. CLE is a new endoscopic tool that allows in vivo histology at subcellular resolution during ongoing endoscopy, and permits subsurface imaging of normal and neoplastic human mucosa. This new technique has unequivocal major implications for the diagnosis and clinical management of patients scheduled for screening or surveillance colonoscopy for colorectal cancer. For instance, CLE allows immediate diagnosis of colonic neoplasias, and the detection of neoplastic cells helps to target endoscopic intervention to relevant areas. Furthermore, the combination of chromoendoscopy with CLE significantly decreases the number of biopsies required for cancer surveillance in patients with ulcerative colitis, but provides a fourfold higher diagnostic yield compared with white-light endoscopy used with random biopsies. Taken together, CLE has led colorectal cancer endoscopy into a new era. CLE can no longer be regarded as just another endoscopic technique, but emerges as a crucial novel imaging technique for in vivo diagnosis of colorectal cancer.

Murine microvideo endoscopy of the colonic microcirculation

Natural orifice endoscopy in small animal models has been limited in the past by instrument size and optical performance. In this report, we investigate the feasibility of using a recently developed microvideo endoscopy system to evaluate the colon microcirculation. Using a murine model of acute colitis, microvideo endoscopy was useful in mapping the topography of inflammation as well as identifying relevant structures in the microcirculation. We conclude that natural orifice endoscopy is a useful method for the minimally invasive longitudinal assessment of the colonic mucosal microcirculation.

A feasibility trial of narrow band imaging endoscopy in patients with gastroesophageal reflux disease

BACKGROUND AND AIMS

Narrow band imaging (NBI) endoscopy system enhances visualization of microvasculature and mucosal patterns. This study assessed the utility of NBI in patients with gastroesophageal reflux disease (GERD) symptoms.

METHODS

Patients with and without GERD symptoms completed 2 validated GERD questionnaires prior to enrollment. The distal esophagus was examined by standard white light endoscopy followed by NBI. The features seen only by NBI were compared between GERD patients and controls.

RESULTS

Overall, 80 patients (50 GERD, 30 controls) were eligible for final analysis (mean age, 58.4 years; males, 93.7%; white, 82.5%). A significantly higher proportion of patients with GERD had increased number (OR, 12.6; 95% CI: 3.7-42; P < .0001), dilatation (OR, 20; 95% CI: 6.1-65.3; P < .0001), tortuosity of intrapapillary capillary loops (IPCLs) (OR, 6.9; 95% CI: 2.5-19; P < .0001), presence of microerosions (P < .0001), and increased vascularity at the squamocolumnar junction (OR, 9.3; 95% CI: 1.9-43.6; P = .001) compared with controls. On multivariate analysis, increased number (OR, 5.5; 95% CI: 1.4-21.6) and dilatation (OR, 11.3; 95% CI: 3.2-39.9) of IPCLs were the best predictors for diagnosing GERD. The maximum, minimum, and average number of IPCLs/field were significantly greater in the GERD group compared with controls (P < .0001). Although the interobserver agreement for the various NBI findings was very good, the intraobserver agreement was modest.

CONCLUSIONS

NBI endoscopy may represent a significant improvement over standard endoscopy for the diagnosis of GERD. These preliminary findings including inter- and intraobserver agreement need to be evaluated in future prospective, controlled, and blinded GERD trials.

Comparison of magnified pit pattern interpretation with narrow band imaging versus chromoendoscopy for diminutive colonic polyps: a pilot study

BACKGROUND

Chromoendoscopy can accurately differentiate neoplastic from nonneoplastic polyps in the colon. Narrow band imaging (NBI) has been described as "electronic chromoendoscopy," but it is unclear whether pit patterns seen with chromoendoscopy are identical to those with NBI.

OBJECTIVE

Pilot study to compare features of diminutive polyps assessed with magnification NBI and chromoendoscopy.

DESIGN

Prospective polyp series.

SETTING

Single tertiary referral center in the United Kingdom.

PATIENTS

Twenty patients seen for routine colonoscopy.

INTERVENTION

Digital images of each polyp recorded with NBI and chromoendoscopy were subsequently assessed as single images in a random order and as paired polyp images by experienced European- and Japanese-trained endoscopists.

MAIN OUTCOME MEASUREMENTS

Pit pattern (Kudo classification); vascular pattern intensity (weak, normal, strong); predicted histology; pit pattern and vessel network clarity (scale 1-3, 1 poor, 3 excellent).

RESULTS

A total of 33 polyps <or=6 mm were assessed. Chromoendoscopic and NBI pit patterns were different for 12 and 20 of 33 polyps (Japanese and European, respectively), combined kappa 0.23, P < .001 compared with published intraobsever variation. Sensitivity, specificity, and accuracy for neoplasia were comparable for chromoendoscopic and NBI pit patterns and vascular pattern intensity for both observers. Vessel network clarity was better with NBI, P < .001 (both), as was pit pattern clarity, P = .04 (European).

LIMITATIONS

Small sample size; pilot study.

CONCLUSIONS

Pit patterns were not always identical with NBI and chromoendoscopy. The Kudo classification may need to be modified and revalidated before it can be used with confidence with NBI. Vascular pattern intensity, a simple color change, appears as accurate as pit pattern.

Intraobserver and interobserver consistency for grading esophagitis with narrow-band imaging

BACKGROUND

Narrow-band imaging (NBI) is a novel, noninvasive optical technique that adjusts reflected light to enhance the contrast between the esophageal mucosa and the gastric mucosa. Whether the use of this optical technique may increase consistency in describing the presence and severity of mucosal breaks remains elusive.

OBJECTIVES

We compared the intra- and interobserver variations in the endoscopic scoring of esophagitis by using conventional imaging with and without NBI.

DESIGN

Cross-sectional study of consecutive patients with reflux.

SETTING

Single center in Taiwan.

PATIENTS

Endoscopic photographs of 230 patients with gastroesophageal reflux were obtained with both methods. Images were randomly displayed twice to 7 endoscopists, who independently scored each photograph by using the Los Angeles classification.

MAIN OUTCOME MEASUREMENTS

We calculated intra- and interobserver kappa statistics to measure the consistency in interpretations.

RESULTS

With the addition of NBI, intraobserver reproducibility significantly improved with 3 of the 7 endoscopists. Interobserver reproducibility was more consistent with the combined approach than with conventional imaging alone, with an improved overall kappa value of 0.62 versus 0.45 (P < .05). Discordance between these methods was substantial in the grading of class A or B esophagitis.

LIMITATIONS

A small sample of class D esophagitis might have produced insufficient statistical power in this category.

CONCLUSIONS

Intra- and interobserver reproducibilities in grading esophagitis could be improved when NBI was applied with conventional imaging. The benefit appeared to derive from better depictions of small erosive foci.

Role of chromoendoscopy in colon cancer surveillance in inflammatory bowel disease

Inflammation in the intestine is a well-known risk factor for neoplastic changes in the mucosa. In fact, it has been shown that long-standing ulcerative colitis and colonic Crohn's disease have a significantly increased risk for developing colorectal cancer, although the estimates vary widely between studies. Conventional colonoscopy is effective in detecting polypoid changes in the mucosa. However, it is now generally accepted that neoplastic changes in colitis are frequently flat and depressed, which are easily missed by use of routine colonoscopy. The introduction of chromoendoscopy, especially in combination with magnifying endoscopy, has greatly advanced our means to detect and differentiate neoplastic lesions in the colorectum. Accumulating evidence-based data indicate that implementation of chromoendoscopy into colon cancer surveillance protocols for patients with inflammatory bowel disease is effective. However, the introduction of chromoendoscopy into surveillance programs requires meticulous training and further studies to compare the value of chromoendoscopy to newer endoscopic devices and techniques, such as narrow band imaging.

High yields of small and flat adenomas with high-definition colonoscopes using either white light or narrow band imaging

BACKGROUND & AIMS

Detection of adenomas is an important goal of colonoscopy. Narrow band imaging (NBI) might highlight adenomas and lead to higher rates of adenoma detection.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Magnifying endoscopy with narrow band imaging for diagnosis of colorectal tumors

BACKGROUND

Narrow band imaging (NBI) uses optical filters for red-green-blue sequential illumination and narrows the bandwidth of spectral transmittance.

OBJECTIVE

This study aimed to clarify the clinical usefulness of NBI magnification in assessment of pit patterns for diagnosis of colorectal tumors.

DESIGN

This was a retrospective study.

SETTING

Department of Endoscopy, Hiroshima University Hospital.

PATIENTS AND MAIN OUTCOME MEASUREMENTS

A total of 148 colorectal lesions, 16 hyperplasias, 84 tubular adenomas, and 48 early carcinomas were examined and diagnosed histologically. Mean size of lesions was 15.6+/-7.28 mm. Lesions were observed first under NBI magnification without chromoendoscopy and then under standard magnification with chromoendoscopy, and pit patterns were recorded. Results of NBI magnification were compared with those of standard magnification with chromoendoscopy to assess the clinical usefulness of NBI magnification for diagnosing colorectal neoplasia.

RESULTS

Correspondence between the two diagnostic methods was 88% (14/16) for type II, 100% (2/2) for type IIIs, 98% (73/75) for type IIIl, 88% (7/8) for type IV, 78% (25/32) for type Vi, and 100% (3/3) for type Vn pit patterns. NBI depicted brownish change on the basis of surface capillaries in 6% (1/16) of hyperplasia and 99% (83/84) of tubular adenomas. This difference in color depiction was significant.

LIMITATIONS

This study was performed in single center.

CONCLUSIONS

Determination of pit patterns of colorectal neoplasias by NBI magnification was nearly the same as that by standard magnification with chromoendoscopy. Furthermore, NBI can distinguish neoplastic and nonneoplastic lesions without chromoendoscopy.

Examination of normal intestine using confocal endomicroscopy

BACKGROUND AND AIM

Endoscopy is an important clinical tool for the diagnosis and treatment of gastrointestinal disorders. However, biopsy tissue is still required in many cases to obtain a definitive histopathological diagnosis. The aim of this study was to evaluate confocal endomicroscopy (CEM) as a tool for conducting virtual biopsies of the colon by comparing CEM images with biopsy samples from normal colon.

METHODS

The study cohort comprised 45 patients who underwent investigative colonoscopy between April 2004 and January 2006, 25 of whom also had biopsy due to suspected diseases such as inflammation and neoplasm. The small and large intestine were examined with CEM using an intravenous injection of fluorescein, and CEM images were compared with conventional histopathological results from biopsied samples. In addition, the injected fluorescein was localized immunohistochemically to further analyze the CEM images taken in vivo.

RESULTS

A total of 46 biopsies were taken, of which 24 demonstrated no histopathological abnormality and were regarded as normal. All of the CEM images observed from the surface to the deeper layers were concordant histopathologically with the biopsy results. Furthermore, CEM allowed observation of physiological functions such as blood flow in the capillaries of the surrounding crypts and mucus release from crypts. The immunohistochemical localization of fluorescein was consistent with the CEM images.

CONCLUSIONS

CEM provides endoscopists with a valuable new diagnostic tool, not only for observing tissue in situ at the histopathological level, but also for the coincident evaluation of physiological function during endoscopic examination.

Novel colorectal endoscopic in vivo imaging and resection practice: a short practice guide for interventional endoscopists

Colorectal cancer remains a leading cause of cancer death in the UK. With the advent of screening programmes and developing techniques designed to treat and stage colorectal neoplasia, there is increasing pressure on the colonoscopist to keep up to date with the latest practices in this area. This review looks at the basic principles behind endoscopic mucosal resection and forward to the potential endoscopic tools, including high-magnification chromoscopic colonoscopy, high-frequency miniprobe ultrasound and confocal laser scanning endomicroscopic colonoscopy, that may soon become part of routine colorectal cancer management.

Comparative study of conventional colonoscopy, chromoendoscopy, and narrow-band imaging systems in differential diagnosis of neoplastic and nonneoplastic colonic polyps

AIM

To identify the feasibility of the narrow-band imaging (NBI) method compared with that of conventional colonoscopy and chromoendoscopy for distinguishing neoplastic and nonneoplastic colonic polyps.

METHOD

This study enrolled consecutive patients who underwent colonoscopy using a conventional colonoscope between January and February 2006 at Chang-Gung Memorial Hospital, Linkou Medical Center, Taiwan. These 78 patients had 110 colorectal polyps. During the procedure, conventional colonoscopy first detected lesions, and then the NBI system was used to examine the capillary networks. Thereafter indigo carmine (0.2%) was sprayed directly on the mucosa surface prior to evaluating the crypts using a conventional colonoscope. The pit patterns were characterized using the classification system proposed by Kudo. Finally, a polypectomy or biopsy was performed for histological diagnosis.

RESULTS

Of the 110 colorectal polyps, 65 were adenomas, 40 were hyperplastic polyps, and five were adenocarcinomas. The NBI system and pit patterns for all lesions were analyzed. For differential diagnosis of neoplastic (adenoma and adenocarcinoma) and nonneoplastic (hyperplastic) polyps, the sensitivity of the conventional colonoscope for detecting neoplastic polyps was 82.9%, specificity was 80.0% and diagnostic accuracy was 81.8%, significantly lower than those achieved with the NBI system (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%) and chromoendoscopy (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%). Therefore, no significant difference existed between the NBI system and chromoendoscopy during differential diagnosis of neoplastic and nonneoplastic polyps.

CONCLUSION

The NBI system identified morphological details that correlate well with polyp histology by chromoendoscopy.