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

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

BACKGROUND AND AIMS

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).

METHODS

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).

RESULTS

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.

CONCLUSION

NBI endoscopy with magnification is a promising technique for detecting superficial pharyngeal cancer at an early stage in patients previously treated for esophageal SCC.

Successful endoscopic submucosal dissection for mucosal cancer of the duodenum

We report a case of mucosal duodenal cancer in a 62-year-old woman, which was successfully removed en bloc by endoscopic submucosal dissection (ESD). The patient underwent an upper gastrointestinal endoscopy at our hospital, which revealed an elevated flat mucosal lesion (type IIa) measuring 10 mm in diameter in the second portion of the duodenum. Histopathological examination of a biopsy specimen revealed features suggestive of a tubulovillous adenoma with severe atypia. As the findings suggested that the lesion had an adenocarcinoma component but was confined to the mucosal layer, we decided to carry out ESD and successfully removed the tumor in one piece. The resected tumor was 20 x 15 mm in size. Histopathological examination revealed that the lesion was a well-differentiated mucosal adenocarcinoma with no lymphovascular invasion. Mucosal duodenal cancer is extremely rare, and ESD of a lesion in the duodenum requires a high level of skill. To the best of our knowledge, this case is the first report of successful ESD carried out in a case of mucosal duodenal cancer.

Hexyl aminolevulinate fluorescence cystoscopy in bladder cancer

Although bladder cancer occurs frequently, early diagnosis and complete removal of malignant lesions usually lead to good clinical outcomes. In the USA, white light cystoscopy (WLC) is commonly used for bladder cancer diagnosis and guidance of the surgical resection. However, with WLC malignant and precancerous lesions may be missed, resulting in a high rate of disease recurrence. Monitoring for and treating these recurrences carry high direct and indirect costs. Because hexyl aminolevulinate (HAL; 5-ALA-hexylester) fluorescence cystoscopy has greater sensitivity than WLC, especially for detecting early stage lesions, and its use provides more complete resection and lower disease recurrence, it has been recommended in European clinical guidelines. This article reports our own HAL experiences and first time recurrence data, describes how HAL was developed, provides key clinical trial results, and discusses how HAL, which has revolutionized fluorescence cystoscopy and bladder cancer care in Europe, may ultimately revolutionize bladder cancer care in the USA.

Narrow-band imaging provides reliable screening for esophageal malignancy in patients with head and neck cancers

OBJECTIVES

The narrow-band imaging (NBI) system is a novel technology that enhances the visualization of microvasculature and mucosal patterns. The aim of this study was to assess the reliability of the NBI system for esophageal cancer screening in patients with head and neck cancers.

METHODS

A total of 142 patients with head and neck squamous cell carcinoma (SCC) were examined by NBI endoscopy, followed by Lugol chromoendoscopy between April 2006 and June 2008 at the Okayama University Hospital, Okayama, Japan. Detection of SCC and high-grade intraepithelial neoplasia (HGIN) was conducted.

RESULTS

The median age of the patients was 64 years (range: 29-86 years), and approximately three-fourths of all the patients were male. In total, 21 superficial lesions in 16 patients were detected by NBI endoscopy. Of these, 4 lesions were diagnosed histologically as SCC and 11 lesions as HGIN. An additional 22 Lugol-voiding lesions >or=5 mm were detected in 19 patients by Lugol chromoendoscopy. Although 1 of these lesions was diagnosed as HGIN, 21 lesions were diagnosed as low-grade intraepithelial neoplasia or lesions without atypical findings. The sensitivity of NBI endoscopy for detecting esophageal SCC and HGIN was 90.9% (95% confidence interval (CI), 58.7-99.8), specificity was 95.4% (95% CI, 90.3-98.3), and accuracy was 95.1% (95% CI, 90.1-98.0).

CONCLUSIONS

NBI seems to be useful and reliable for screening for esophageal SCC in patients with head and neck cancers.

Comparative study of conventional colonoscopy, magnifying chromoendoscopy, and magnifying narrow-band imaging systems in the differential diagnosis of small colonic polyps between trainee and experienced endoscopist

BACKGROUND

Removal of colorectal neoplastic polyps can reduce the incidence of colorectal cancers. It is important to distinguish neoplastic from nonneoplastic polyps. We compared the ability of a trainee and an experienced endoscopist in distinguishing between neoplastic polyps and nonneoplastic polyps by conventional white-light, magnifying narrow-band imaging (NBI), and magnifying chromoendoscopy.

MATERIALS AND METHODS

One hundred and sixty-three small colorectal polyps from 104 patients were studied. All polyps were diagnosed by trainees and experienced endoscopists using conventional white-light, magnifying NBI, and magnifying chromoendoscopy. The kappa values of interobserver agreement between trainees and experienced endoscopists were evaluated before this study. Sensitivity, specificity, and diagnostic accuracy were assessed by reference to histopathology. The first 50 polyps were diagnosed by the trainee as the first stage and the rest 113 polyps were diagnosed as the second stage.

RESULTS

Magnifying NBI and magnifying chromoendoscopy were significant better than conventional white-light by the experienced endoscopist (diagnostic accuracy: NBI 85.3%, chromoendoscopy 87.7%, conventional view 74.8%). No significant differences were found for the trainee. The kappa values (0.77 approximately 0.85) were good for each endoscopic modality for the experienced endoscopist. However, only NBI and chromoendoscopy had acceptable kappa values (0.40 approximately 0.48) for the trainee. The trainee improved diagnostic accuracy in the second stage, but not yielded the level of the experienced endoscopist.

CONCLUSION

Magnifying NBI and magnifying chromoendoscopy had a better interobserver agreement than conventional white-light among trainees and experienced endoscopists. The trainee needs learning time to improve diagnostic ability, even using a new modality such as magnifying NBI.

Validation of Fujinon intelligent chromoendoscopy with high definition endoscopes in colonoscopy

AIM

To validate high definition endoscopes with Fujinon intelligent chromoendoscopy (FICE) in colonoscopy.

METHODS

The image quality of normal white light endoscopy (WLE), that of the 10 available FICE filters and that of a gold standard (0.2% indigo carmine dye) were compared.

RESULTS

FICE-filter 4 [red, green, and blue (RGB) wavelengths of 520, 500, and 405 nm, respectively] provided the best images for evaluating the vascular pattern compared to white light. The mucosal surface was best assessed using filter 4. However, the views obtained were not rated significantly better than those observed with white light. The "gold standard", indigo carmine (IC) dye, was found to be superior to both white light and filter 4. Filter 6 (RGB wavelengths of 580, 520, and 460 nm, respectively) allowed for exploration of the IC-stained mucosa. When assessing mucosal polyps, both FICE with magnification, and magnification following dye spraying were superior to the same techniques without magnification and to white light imaging. In the presence of suboptimal bowel preparation, observation with the FICE mode was possible, and endoscopists considered it to be superior to observation with white light.

CONCLUSION

FICE-filter 4 with magnification improves the image quality of the colonic vascular patterns obtained with WLE.

Optical diagnosis of small colorectal polyps at routine colonoscopy (Detect InSpect ChAracterise Resect and Discard; DISCARD trial): a prospective cohort study

BACKGROUND

Accurate optical diagnosis of small (<10 mm) colorectal polyps in vivo, without formal histopathology, could make colonoscopy more efficient and cost effective. The aim of this study was to assess whether optical diagnosis of small polyps is feasible and safe in routine clinical practice.

METHODS

Consecutive patients with a positive faecal occult blood test or previous adenomas undergoing surveillance at St Mark's Hospital (London, UK), from June 19, 2008, to June 16, 2009, were included in this prospective study. Four colonoscopists with different levels of experience predicted polyp histology using optical diagnosis with high-definition white light, followed by narrow-band imaging without magnification and chromoendoscopy, as required. The primary outcome was accuracy of polyp characterisation using optical diagnosis compared with histopathology, the current gold standard. Accuracy of optical diagnosis to predict the next surveillance interval was also assessed and compared with surveillance intervals predicted by current guidelines using histopathology. This study is registered with ClinicalTrials.gov, NCT00888771.

FINDINGS

363 polyps smaller than 10 mm were detected in 130 patients, of which 278 polyps had both optical and histopathological diagnosis. By histology, 198 of these polyps were adenomas and 80 were non-neoplastic lesions (of which 62 were hyperplastic). Optical diagnosis accurately diagnosed 186 of 198 adenomas (sensitivity 0.94; 95% CI 0.90-0.97) and 55 of 62 hyperplastic polyps (specificity 0.89; 0.78-0.95), with an overall accuracy of 241 of 260 (0.93, 0.89-0.96) for polyp characterisation. Using optical diagnosis alone, 82 of 130 patients could be given a surveillance interval immediately after colonoscopy, and the same interval was found after formal histopathology in 80 patients (98%) using British guidelines and in 78 patients (95%) using US multisociety guidelines.

INTERPRETATION

For polyps less than 10 mm in size, in-vivo optical diagnosis seems to be an acceptable strategy to assess polyp histopathology and future surveillance intervals. Dispensing with formal histopathology for most small polyps found at colonoscopy could improve the efficiency of the procedure and lead to substantial savings in time and cost.

FUNDING

Leigh Family Trust, London, UK.

Hyperplastic polyposis syndrome: a pilot study for the differentiation of polyps by using high-resolution endoscopy, autofluorescence imaging, and narrow-band imaging

BACKGROUND

Endoscopic differentiation and removal of potentially premalignant sessile serrated adenomas (SSAs) may be important steps in preventing the development of colorectal cancer in hyperplastic polyposis syndrome (HPS).

OBJECTIVE

To assess the value of high-resolution endoscopy, autofluorescence imaging (AFI), and narrow-band imaging (NBI) for differentiating polyps in HPS.

DESIGN

A prospective polyp series.

SETTING

Single tertiary referral center.

PATIENTS AND INTERVENTIONS

Seven patients with HPS underwent colonoscopy with endoscopic trimodal imaging, which incorporates high-resolution endoscopy, AFI, and NBI in 1 system. All detected polyps were analyzed with AFI for color and with NBI for Kudo pit pattern and vascular pattern intensity.

MAIN OUTCOME MEASUREMENTS

The accuracy, sensitivity, and specificity of AFI and NBI in differentiating detected polyps were determined by using histology as the criterion standard.

RESULTS

A total of 19 hyperplastic polyps (HPs), 32 SSAs, and 15 adenomas were detected. For differentiating SSAs from HPs, AFI color, Kudo pit pattern, and vascular pattern intensity resulted in a diagnostic accuracy of 55%, 55%, and 52%, respectively. For differentiating adenomas from HPs, the accuracy was 65%, 94%, and 90%, respectively. Macroscopically, the combination of a size of 3 mm or larger and a proximal location resulted in the highest accuracy (76%) for differentiating SSAs from HPs.

LIMITATION

Small sample size.

CONCLUSION

Endoscopic differentiation between HPs and SSAs by using endoscopic trimodal imaging proved unsatisfactory. Differentiation of adenomas from HPs was possible with NBI but not with AFI.

The use of indigocarmine spray increases the colonoscopic detection rate of adenomas

PURPOSE

It remains controversial whether chromocolonoscopy using indigocarmine increases the detection of colorectal polyps. We aimed to assess the impact of indigocarmine dye spray on the detection rate of adenomas and the feasibility of learning the technique in a Western practice.

METHODS

400 patients were prospectively allocated into 2 groups; A (n = 200): indigocarmine chromocolonoscopy was performed by a Japanese colonoscopist with expertise in chromoscopy; B (n = 200): initial 100 patients (B-1), a Western colonoscopist with no previous experience of chromoscopy performed conventional colonoscopy, but with at least 10 min observation during colonoscopy withdrawal. In the next 100 patients (B-2), he performed chromocolonoscopy. All polyps found were resected. Regression analysis was used to compare the numbers of polyps detected in groups A, B-1 and B-2, whilst controlling for gender, age, indication and history of colorectal cancer.

RESULTS

There were significant differences in the numbers of neoplastic polyps and flat adenomas between groups A and B-1 as well as between B-1 and B-2, but not between A and B-2. There was no significant difference in numbers of advanced lesions. Chromocolonoscopy (A and B-2) detected more neoplastic polyps of <or=5 mm.

CONCLUSION

Chromocolonoscopy increases the detection of neoplastic polyps and flat adenomas, particularly diminutive polyps, but does not increase the detection of advanced lesions.

Diagnostic value of image-enhanced video cholangiopancreatoscopy

We summarized past and present results concerning the observation capability of cholangiopancratoscopy using chromoendoscopy, autofluorescence imaging (AFI), and narrow-band imaging (NBI). New generation peroral and percutaneous transhepatic video cholangiopancreatoscopes provide superior quality images. Pilot studies suggest that chromoendocholangioscopy using methylene blue or cholangioscopy using AFI can distinguish benign from malignant bile duct lesions. On the other hand, the NBI system enhances the imaging of certain features such as mucosal structures and microvessels in pancreatobiliary lesions. In patients with main-duct-type intraductal papillary mucinous neoplasm, peroral pancreatoscopy can be used to determine extent of tumor involvement. Although many technical hurdles still need to be overcome, image-enhanced cholangiopancratoscopy appears to be a promising modality to improve diagnostic accuracy of pancreatobiliary diseases, particularly in distinguishing benign from malignant lesions.

High accuracy of narrow band imaging without magnification for the real-time characterization of polyp histology and its comparison with high-definition white light colonoscopy: a prospective study

OBJECTIVES

Standard white light colonoscopy has limited ability to differentiate between polyp types (adenomatous vs. hyperplastic). Narrow band imaging (NBI) highlights the superficial mucosal/vascular patterns on polyps and may facilitate real-time characterization of polyp histology. The aim of this study was to prospectively evaluate and compare the diagnostic characteristics of high-definition white light colonoscopy (HDWL) and NBI without magnification in the real-time prediction of polyp histology (adenomatous vs. hyperplastic) by evaluating the surface mucosal and vascular patterns.

METHODS

We conducted a prospective comparative study in a tertiary referral center. A total of 100 patients referred for screening or surveillance colonoscopy were prospectively enrolled and underwent colonoscopy using a high-definition colonoscope with NBI capability. Every polyp detected was initially evaluated with HDWL followed by NBI for the presence of surface mucosal/vascular patterns. Based on these patterns, polyp histology was predicted by both modalities. The main outcome measurements were: (i) diagnostic characteristics of HDWL and NBI in predicting polyp histology and (ii) impact of polyp size and learning effect (first half of study vs. second half) on the ability of NBI to predict adenomas.

RESULTS

A total of 236 polyps were detected in 100 patients-143 adenomas, 77 hyperplastic, and 16 others. Surface patterns (type A: hyperplastic; type B: adenomatous) were recognized in all polyps with NBI (100%) compared to 45% with HDWL. For predicting adenomas, NBI had a significantly higher sensitivity and greater accuracy (96 and 93% respectively) compared with HDWL (38 and 61% respectively) (all P<0.0001). Although the accuracy of NBI for predicting adenomas improved with increasing polyp size (< or =5 mm; 6-9 mm; > or =10 mm) and in the second half compared with the first half of the study, these differences were not statistically significant.

CONCLUSIONS

Using a simple surface mucosal/vascular pattern classification, NBI without magnification was highly accurate and significantly superior to HDWL for the real-time prediction of adenomas.

[Virtual chromoendoscopy]

Precise endoscopic assessment of gastrointestinal mucosal features is important in order to detect neoplastic lesions at an early stage. Electronic virtual chromoendoscopy markedly improves capillary pattern contrast and is an in vivo method for visualizing microvessel morphological changes in superficial neoplastic lesions. The scientific basis for this technique is that short wavelength light falls within the hemoglobin absorption band, thereby facilitating clearer visualization of vascular structures and pit pattern. Narrow Band Imaging (NBI, Olympus) and Multi-Band Imaging (FICE) are real-time, on-demand endoscopic imaging techniques available with high-definition endoscope. Potential indications include both the detection of premalignant lesions and differentiation between neoplastic and non-neoplastic lesions. The ease and readiness of use and the routine availability of virtual chromoendoscopy will probably contribute to its popularity. This does not alleviate the need to better define the role of these techniques in daily endoscopy practice by conducting well-designed prospective studies.

Diagnosis of colorectal lesions with the magnifying narrow-band imaging system

BACKGROUND

Narrow-band imaging (NBI) emphasizes the surface microvasculature of the GI tract and may help in detecting small neoplasms.

OBJECTIVE

The aim of this study was to clarify the value of the NBI system in tissue characterization and differential diagnosis.

DESIGN

A prospective study.

SETTING

Digestive Disease Center of Showa University Northern Yokohama Hospital.

PATIENTS

The subjects were 495 patients who, from January 2006 to June 2007, underwent a complete colonoscopic examination. A total of 617 lesions were evaluated in the 495 patients (33 hyperplastic polyps, 532 adenomas, 52 submucosally invasive [T1] cancers).

RESULTS

Most hyperplastic polyps showed a faint pattern. The vascular patterns of adenomas were mainly the network pattern or the dense pattern. The major vascular patterns of cancers were the irregular pattern and the sparse pattern. The irregular pattern was characteristic for protruded or flat-elevated cancers, whereas the sparse pattern was unique for depressed cancers. When we assumed that the faint pattern was diagnostic for hyperplastic polyps, we could differentiate between neoplastic and non-neoplastic lesions with a sensitivity of 90.9% and a specificity of 97.1%. Likewise, irregular and sparse patterns were assumed to be indices of massively invasive submucosal cancer, the sensitivity was 100%, the specificity was 95.8%, and the accuracy rate was 96.1%.

LIMITATIONS

This study was performed at a single center.

CONCLUSIONS

The NBI system was valuable for distinguishing between neoplastic and non-neoplastic lesions, as well as between cancers and adenomas. Vascular pattern analysis can also be a promising tool for determining treatment selection, either endoscopy or surgery.

Advances in confocal laser endomicroscopy for the diagnosis of gastrointestinal diseases

BACKGROUND

Confocal laser endomicroscopy (CLE) is a novel technique enabling in vivo microscopy of the human gastrointestinal mucosa. Cellular details even below the tissue surface can be visualized at high resolution during ongoing endoscopy.

OBJECTIVE

This review summarizes the current clinical data on the use of CLE in different disease states and discusses a perspective for future clinical and scientific application of CLE.

METHODS

Review on published literature and meeting abstracts.

RESULTS/CONCLUSION

Confocal laser endomicroscopy covers a growing field of indications in both upper and lower gastrointestinal endoscopy and beyond. It has been shown to reliably predict the presence of neoplastic lesions and inflammatory changes of the gastrointestinal mucosa during endoscopy. With CLE, 'smart' biopsies can be targeted to regions with microscopic alterations rather than having to rely on blind, untargeted sampling. This results in a reduction in the number of biopsies and in an increase in their diagnostic yield at the same time. Dynamic imaging of microscopic events in their natural environment and molecular imaging by CLE will open a door for an advanced understanding of tissue function and microarchitecture in vivo.

Improving visualization techniques by narrow band imaging and magnification endoscopy

Endoscopy plays an important role in the early detection of gastrointestinal tract neoplasms. Using conventional white light or dye-based image enhanced endoscopy, it has been difficult to assess pre-malignant and early neoplastic lesions precisely. However, narrow band imaging (NBI) dramatically improves the detection of these lesions, particularly in combination with magnifying endoscopy. This allows the endoscopist to accomplish accurate diagnosis. Such enhanced detection of pre-malignant and early neoplastic lesions in the gastrointestinal tract should allow better targeting of biopsy, improved and more appropriate treatment, and thereby contribute to optimal quality of life and patient survival.

Gastric mucosal pattern by using magnifying narrow-band imaging endoscopy clearly distinguishes histological and serological severity of chronic gastritis

BACKGROUND

Magnifying narrow-band imaging (NBI) endoscopy clearly visualizes superficial gastric mucosal patterns and capillary patterns.

OBJECTIVE

To investigate gastric mucosal patterns by using magnifying NBI endoscopy and identify any relationship between those patterns and Helicobacter pylori-induced gastritis.

DESIGN

Gastric mucosal patterns seen with magnifying NBI in uninvolved gastric corpus were divided into the following categories: normal--small, round pits with regular subepithelial capillary networks; type 1-slightly enlarged, round pits with unclear or irregular subepithelial capillary networks; type 2--obviously enlarged, oval or prolonged pits with increased density of irregular vessels; and type 3-well--demarcated oval or tubulovillous pits with clearly visible coiled or wavy vessels.

SETTING

Department of Gastroenterology, Fujita Health University.

PATIENTS

This study involved 106 participants undergoing upper endoscopy.

RESULTS

H pylori infection-positive ratios of normal and types 1, 2, and 3 patterns were 7.5%, 92.9%, 94.5%, and 66.7%, respectively. Sensitivity and specificity for types 1 + 2 + 3 for detection of H pylori positivity and type 3 for detection of intestinal metaplasia were 95.2%, 82.2%, 73.3%, and 95.6%, respectively. Development of mucosal patterns from normal to types 1, 2, and 3 was correlated with all histological parameters (P < .0001), lower pepsinogen I/II ratios (P < .0001), and degree of endoscopic atrophy (P < .0001). Sensitivity and specificity of type 3 for the prediction of severe histological atrophy was also better than those of serum pepsinogen level and standard endoscopy.

LIMITATIONS

Only 1 endoscopist performed endoscopic procedures, and interobserver agreement could not be assessed.

CONCLUSIONS

Magnifying NBI endoscopy is useful for predicting H pylori infection and the histological severity of gastritis and is valuable for predicting gastric atrophy in the entire stomach.

Endoscopic mucosal resection for early colorectal neoplasia: pathologic basis, procedures, and outcomes

Open access endoscopy and screening programs enable detection and removal of an increased number of colon polyps in the early stages of neoplastic transformation. Unfortunately, polyps larger than 3 cm, involving more than one-third of circumference or two haustral folds, or with a flat/depressed morphology are more challenging to remove with standard polypectomy techniques. Endoscopic mucosal resection potentiates the removal, in a minimally invasive way, of certain colonic lesions that would otherwise require surgical or ablative treatment. Because the plane of resection during endoscopic mucosal resection is typically the middle to deep submucosal layer, compared with standard polypectomy, which normally provides resection at a mucosal level, endoscopic mucosal resection offers the advantage of providing en bloc resection specimens for histopathologic analysis. Indications to perform endoscopic mucosal resection are adenoma and small, well-differentiated carcinoma, confined to the mucosa or with minimal invasion to submucosa, and without any invasion to lymphatic channels or vessels. The most frequently reported major complications, such as perforation (0-5%) and bleeding (0.5-6%), may be controlled by endoscopic methods and rarely require surgical treatment. Follow-up postendoscopic mucosal resection is essential because of the risk of neoplastic recurrence.

[Colonoscopy: maximizing detection and characterization]

The endoscopic analysis of the colonic lumen with a flexible tube began around1960, at first with a gastrocamera, then with a fibrocolonoscope. After 1990, the electronic imaging brought a three points revolution with increased resolution of the image, transfer of the image on a television monitor giving access to multiple observers, electronic image processing. The recent colonoscopes have an increased resolution with more pixels in the Charged Coupled Device (CCD) sensor, a High Definition Television (HDTV) image and an electronic and/or optical zoom for magnification. Colonoscopy is now often performed in a similar environment to that of surgery. Therapeutic applications justify a strict strategy for endoscopic diagnosis. At first, detection of the lesion in standard vision, then characterization with the help of chromoscopy for the evaluation of morphology and with the help of magnification for the evaluation of the pit pattern. Then, comes the time for treatment decision between abstention, endoscopic resection or surgery. The legitimacy of the management is controlled in retrospective by the analysis of the tissue samples. Recent alternatives to colonoscopy (3D radiological imaging, colon capsule) should not invalidate the priority attributed to colonoscopy which associates treatment to the early detection of colorectal cancer and precursors.

Current status and future perspective of endoscopic diagnosis and treatment for colorectal neoplasia - situation in Taiwan

The incidence of colorectal cancer (CRC) is rising substantially in Taiwan. Hence, both effective screening and management of colorectal neoplasms, including precursor lesions and early cancers, have become critically important. Colorectal cancer is not only curable, but also can be managed endoscopically if detected at the stage of precursor lesions or early cancer. Optimal management of colorectal neoplasia relies largely on accurate evaluation of the characteristics of lesions, including malignant transformation, and the depth of invasion of the malignant lesions. In this context, observation using image enhancing endoscopy (IEE) to magnify the image during colonoscopy is of utmost importance. Polypectomy or endoscopic mucosal resection is now the standard procedure for the treatment of colorectal adenoma or early cancerous lesions in Taiwan. Endoscopic submucosal dissection (ESD) is performed at only a few institutions; its long-term efficacy and cost-effectiveness require further elucidation. More attention from the government, academic societies, and individual clinicians is necessary.

Evaluation of the clinical outcomes associated with EXERA II and LUCERA endoscopes

AIM

Regarding the assessment of colonic lesions, important differences between Japan and the Western world have emerged during the last decade. The aim of this study was to compare the clinical outcomes of the same equipment when used in Japan or in France.

METHOD

Chromoscopy has not been extensively accepted in the West, in contrast to the wide acceptance in Japan which is probably due to the national screening programme for early gastric cancer. With the development of narrow-band imaging (NBI) we might expect a more generalized approach to the clinical use of various classifications. Narrow band imaging might be an important step towards virtual chromoscopy. A total of 48 patients were examined with back-to-back colonoscopy, using a non-sequential (EXERA II, Olympus Medical Systems Corp., Tokyo, Japan) endoscope, and a sequential endoscope (LUCERA, Olympus Medical Systems Corp.).

RESULTS

Education differences also play a role in the evaluation of the clinical outcome of the endoscopy. In Japan, detailed classification of the morphology of the detected lesion is done as a preliminary characterization step before the treatment decision. In the West a treatment decision immediately leads to the therapeutic outcome (non-neoplastic or neoplastic; removed or not). This study showed clearly that, with the same equipment, we obtained identical results for image quality of image in Japan and France. Non-Japanese endoscopists could achieve the same results as Japanese colleagues if knowledge of the minute classification is more widely accepted.

CONCLUSION

While the differences in the evaluation of the clinical outcome are mostly cultural, the analysis of endoscopic imaging indicates that the LUCERA and EXERA series provide the same clinical benefit.

Combining autofluorescence imaging and narrow-band imaging for the differentiation of adenomas from non-neoplastic colonic polyps among experienced and non-experienced endoscopists

OBJECTIVES

Endoscopic tri-modal imaging incorporates high-resolution white-light endoscopy (HR-WLE), narrow-band imaging (NBI), and autofluorescence imaging (AFI). Combining these advanced techniques may improve endoscopic differentiation between adenomas and non-neoplastic polyps. In this study, we aimed to assess the interobserver variability and accuracy of HR-WLE, NBI, and AFI for polyp differentiation and to evaluate the combined use of AFI and NBI.

METHODS

First, still images of 50 polyps (22 adenomas; median 3 mm) were randomly displayed to three experienced and four non-experienced endoscopists. All HR-WLE and NBI images were scored for Kudo classification and AFI images for color. Second, the combined AFI and NBI images were assessed using a newly developed algorithm by six additional non-experienced endoscopists.

RESULTS

The outcomes measured were interobserver agreement and diagnostic accuracy using histopathology as reference standard. Experienced endoscopists had better interobserver agreement for NBI (kappa=0.77) than for AFI (kappa=0.33), whereas non-experienced endoscopists had better agreement for AFI (kappa=0.58) than for NBI (kappa=0.33). The accuracies of HR-WLE, NBI, and AFI among experienced endoscopists were 65, 70, and 74, respectively. Figures among non-experienced endoscopists were 57, 63, and 77. The algorithm was associated with a significantly higher accuracy of 85% among all observers (P<0.023). These figures were confirmed in the second evaluation study.

CONCLUSIONS

Non-experienced endoscopists have better interobserver agreement and accuracy for AFI than for HR-WLE or NBI, indicating that AFI is easier to use for polyp differentiation in non-experienced setting. The newly developed algorithm, combining information of AFI and NBI together, had the highest accuracy and obtained equal results between experienced and non-experienced endoscopists.

Chromoendoscopy, narrow-band imaging colonoscopy, and autofluorescence colonoscopy for detection of diminutive colorectal neoplasia in familial adenomatous polyposis

PURPOSE

This study was designed to compare the diagnostic yield of white light colonoscopy, chromoendoscopy, narrow-band imaging, and autofluorescence imaging in the detection of diminutive lesions.

METHODS

Thirteen patients with adenomatous polyposis were examined by total colonoscopy using an instrument that incorporated both narrow-band and autofluorescence imaging. Colonoscopic images were obtained using white light colonoscopy, autofluorescence imaging, narrow-band imaging, and chromoendoscopy. All images were captured at equivalent angles and distances from the colorectal mucosa.

RESULTS

Chromoendoscopy detected the greatest number of lesions at all sites within the large intestine, and it detected a significantly greater number than the other procedures on the left side of the large intestine. Narrow-band imaging depicted a greater number of lesions than did white light in the transverse colon, descending colon, and rectum. Autofluorescence imaging showed a greater number of lesions than did white light in the rectum. The total number of depicted lesions under chromoendoscopy (43.3 +/- 38.5) was significantly greater than the total number detected with white light (12.2 +/- 13.9, P = 0.005), autofluorescence imaging (21.4 +/- 27.5, P = 0.0006), and narrow-band imaging (20.1 +/- 21.5, P = 0.003). Narrow-band imaging detected a significantly higher total number of lesions than did white light (P = 0.04).

CONCLUSION

Chromoendoscopy is superior to white light colonoscopy, autofluorescence imaging, and narrow-band imaging for detection of diminutive colorectal lesions in adenomatous polyposis.

Prospective study of early detection of pharyngeal superficial carcinoma with the narrowband imaging laryngoscope

BACKGROUND

The newly developed narrowband imaging (NBI) gastrointestinal endoscope makes possible the detection of superficial carcinoma in the oropharynx and hypopharynx, which is difficult with the conventional laryngoscope. Here, we investigated whether the combined use of laryngoscope with NBI allows the detection of superficial carcinoma in this region.

METHODS

A total of 51 superficial, histologically confirmed lesions in 29 patients were studied. The quality of visualization of superficial carcinoma in the oropharynx and hypopharynx using the NBI-equipped laryngoscope was evaluated in comparison with the results by conventional laryngoscopy.

RESULTS

The NBI laryngoscope provided better detection of the irregular microvascular pattern of carcinoma than the conventional laryngoscope (p <.05) and better visualization of the demarcation line (p <.05), and thus significantly better visualization of the lesions.

CONCLUSION

The NBI laryngoscope may play an important role in the diagnosis and treatment of superficial carcinoma in the oropharynx and hypopharynx.

Mucosal vascular pattern in ulcerative colitis: observations using narrow band imaging colonoscopy with special reference to histologic inflammation

BACKGROUND AND AIM

Narrow band imaging (NBI) is a novel endoscopy system, which enables a clear visualization of the mucosal vasculature of the gastrointestinal tract. The aim of this study is to determine whether this system may be of value for assessing the disease severity in ulcerative colitis (UC).

MATERIALS AND METHODS

We observed the mucosal vascular pattern (MVP) in 157 colorectal segments of 30 patients with UC using both conventional and NBI colonoscopy. The MVP was determined to be normal or distorted under conventional colonoscopy and, subsequently, to be clear or obscure under NBI colonoscopy. The histologic variables in each segment were assessed in biopsy specimen. The possible correlation between MVP and the histologic grade of inflammation was evaluated.

RESULTS

The MVP under conventional colonoscopy was normal in 60 segments while it was distorted in 97 segments. In all of the former 60 segments, their MVP was clear under NBI colonoscopy. The MVP in the latter 97 segments were determined to be clear (n = 44) or obscure (n = 53) under NBI colonoscopy. Acute inflammatory cell infiltrates (26% vs. 0%, p = 0.0001), goblet cell depletion (32% vs. 5%, p = 0.0006), and basal plasmacytosis (2% vs. 21%, p = 0.006) were more frequently observed in segments with an obscure MVP than in those with a clear MVP.

CONCLUSION

NBI colonoscopy may be of value for determining the grade of inflammation in patients with quiescent UC.

Narrow-band imaging without optical magnification for histologic analysis of colorectal polyps

BACKGROUND & AIMS

The ability to determine colorectal polyp pathology by endoscopy could reduce the risks of polypectomy and the cost of pathologic evaluation. This study evaluated the ability of the Olympus Exera 180 high-definition colonoscope (Olympus America, Inc, Center Valley, PA), with narrow-band imaging, to predict colorectal polyp histology.

METHODS

A library of 320 endoscopic photographs with correlated histologic information was used to identify endoscopic features associated with adenomatous and hyperplastic histology. These features were tested in a prospective study of 451 consecutively identified colorectal polyps. Polyps were observed endoscopically and assigned a designation of high or low confidence. The primary end points were the predictive value of high-confidence endoscopic interpretations of adenoma and hyperplastic histology for polyps 5 mm and smaller in size.

RESULTS

Endoscopic predictions of adenoma and hyperplastic histology were made with high confidence for 80% and 83% of cases, respectively. High-confidence predictions were more likely than low-confidence predictions to be correct (P<.001). High-confidence predictions of adenoma and hyperplastic histology were correct for 91% and 95%, respectively, of polyps 5 mm and smaller in size.

CONCLUSIONS

Introduction of confidence levels to the endoscopic interpretation of colorectal polyp histology allows sufficient accuracy for the use of the Exera narrow-band imaging system in the identification of distal hyperplastic polyps that do not need resection, as well as to plan postpolypectomy surveillance without pathologic evaluation of polyps 5 mm in size or smaller.

Endoscopic classification of the capillary-vessel pattern of colorectal lesions by spectral estimation technology and magnifying zoom imaging

BACKGROUND

Colonoscopy with spectral estimation technology and magnifying zoom imaging allows the characterization of the fine superficial capillary pattern of normal mucosa and of colorectal lesions. The endoscopic distinction of the capillary pattern of colorectal lesions might contribute to the differential diagnosis among normal, hyperplastic, and neoplastic lesions.

OBJECTIVE

By means of these latest technologic advances, the objective is to define a classification of the capillary-vessel pattern of colorectal lesions diagnosed during routine colonoscopy.

DESIGN

A total of 309 colorectal lesions endoscopically or surgically resected were prospectively examined. The capillary pattern was divided into 5 subtypes according to the number, morphology, and distribution of the fine blood vessels. Capillary patterns types I and II were characterized by a few short, straight, and sparsely distributed vessels; types III to V were of numerous, elongated, and tortuous capillaries irregularly distributed.

RESULTS

The overall accuracy of the capillary-vessel classification in determining the neoplastic or non-neoplastic nature of the colorectal lesions was 98.3% (304/309 lesions). Among 59 non-neoplastic lesions, 56 (94.9%) that showed patterns I or II were diagnosed as normal, inflammatory, or hyperplastic polyps. Of the 250 neoplastic lesions, 248 (99.2%) that had capillary pattern types III, IV, and V were diagnosed as adenomatous or carcinoma. The sensitivity of the capillary pattern classification for distinguishing neoplasia was 99.2% (95% CI, 98.2%-100%), and the specificity was 94.9% (95% CI, 92.5%-97.4%).

LIMITATION

A single-center study.

CONCLUSION

The endoscopic classification of the superficial capillary-vessel pattern of colorectal lesions is an accurate method of predicting the histopathologic findings.

Clinical evaluation of endoscopic trimodal imaging for the detection and differentiation of colonic polyps

BACKGROUND & AIMS

Endoscopic trimodal imaging (ETMI) incorporates high-resolution endoscopy (HRE) and autofluorescence imaging (AFI) for adenoma detection, and narrow-band imaging (NBI) for differentiation of adenomas from nonneoplastic polyps. The aim of this study was to compare AFI with HRE for adenoma detection and to assess the diagnostic accuracy of NBI for differentiation of polyps. This was a randomized trial of tandem colonoscopies. The study was performed at the Academic Medical Center in Amsterdam.

METHODS

One hundred patients underwent colonoscopy with ETMI. Each colonic segment was examined twice for polyps, once with HRE and once with AFI, in random order per patient. All detected polyps were assessed with NBI for pit pattern and with AFI for color, and subsequently removed. Histopathology served as the gold standard for diagnosis. The main outcome measures of this study were adenoma miss-rates of AFI and HRE, and diagnostic accuracy of NBI and AFI for differentiating adenomas from nonneoplastic polyps.

RESULTS

Among 50 patients examined with AFI first, 32 adenomas were detected initially. Subsequent inspection with HRE identified 8 additional adenomas. Among 50 patients examined with HRE first, 35 adenomas were detected initially. Successive AFI yielded 14 additional adenomas. The adenoma miss-rates of AFI and HRE therefore were 20% and 29%, respectively (P = .351). The sensitivity, specificity, and overall accuracy of NBI for differentiation were 90%, 70%, and 79%, respectively; corresponding figures for AFI were 99%, 35%, and 63%, respectively.

CONCLUSIONS

The overall adenoma miss-rate was 25%; AFI did not significantly reduce the adenoma miss-rate compared with HRE. Both NBI and AFI had a disappointing diagnostic accuracy for polyp differentiation, although AFI had a high sensitivity.

Near-infrared narrow-band imaging of gold/silica nanoshells in tumors

Gold nanoshells (GNS) are a new class of nanoparticles that can be optically tuned to scatter or absorb light from the near-ultraviolet to near-infrared (NIR) region by varying the core (dielectric silica)/shell (gold) ratio. In addition to spectral tunability, GNS are inert and bioconjugatable, making them potential labels for in vivo imaging and therapy of tumors. We report the use of GNS as exogenous contrast agents for enhanced visualization of tumors using narrow-band imaging (NBI). NBI takes advantage of the strong NIR absorption of GNS to distinguish between blood and nanoshells in the tumor by imaging in narrow wavelength bands in the visible and NIR, respectively. Using tissue-simulating phantoms, we determined the optimum wavelengths to enhance contrast between blood and GNS. We then used the optimum wavelengths for ex vivo imaging of tumors extracted from human colon cancer xenograft bearing mice injected with GNS. Systemically delivered GNS accumulated passively in tumor xenografts by the enhanced permeability and retention (EPR) effect. Ex vivo NBI of tumor xenografts demonstrated heterogeneous distribution of GNS with a clear distinction from the tumor vasculature. The results of this study demonstrate the feasibility of using GNS as contrast agents to visualize tumors using NBI.

Narrow-band imaging magnification predicts the histology and invasion depth of colorectal tumors

BACKGROUND

There are several reports concerning the differential diagnosis of non-neoplastic and neoplastic colorectal lesions by narrow-band imaging (NBI). However, there are only a few NBI articles that assessed invasion depth.

OBJECTIVE

To determine the clinical usefulness of NBI magnification for evaluating microvessel architecture in relation to pit appearances and in the qualitative diagnosis of colorectal tumors.

DESIGN

A retrospective study.

SETTING

Department of Endoscopy, Hiroshima University, Hiroshima, Japan.

PATIENTS AND MAIN OUTCOME MEASUREMENTS

A total of 289 colorectal lesions were analyzed: 12 hyperplasias (HP), 165 tubular adenomas (TA), 65 carcinomas with intramucosal to scanty submucosal invasion (M-SM-s), and 47 carcinomas with massive submucosal invasion (SM-m). Lesions were observed by NBI magnifying endoscopy and were classified according to microvessel features and pit appearances: type A, type B, and type C. Type C was divided into 3 subtypes (C1, C2, and C3), according to the detailed NBI magnifying findings of pit visibility, vessel diameter, irregularity, and distribution. These were compared with histologic findings.

RESULTS

Histologic findings of HP and TA were seen in 80.0% and 20.0%, respectively, of type A lesions. TA and M-SM-s were found in 79.7% and 20.3%, respectively, of type B lesions. TA, M-SM-s, and SM-m were found in 21.6%, 29.9%, and 48.5, respectively, of type C lesions. HPs were observed significantly more often than TAs in type A lesions, TAs were observed significantly more often than carcinomas in type B lesions, carcinomas were observed significantly more often than TAs in type C (P < .01). TA, M-SM-s, and SM-m were found in 46.7%, 42.2%, and 11.1% of type C1 lesions, respectively. M-SM-s and SM-m were found in 45.5% and 54.5%, respectively, of type C2 lesions. SM-m was found in 100% of type C3 lesions. TAs and M-SM-s were observed significantly more often than SM-m in type C1 lesions, and SM-m were observed significantly more often than TAs and M-SM-s in type C3 lesions (P < .01).

CONCLUSIONS

NBI magnification findings of colorectal lesions were associated with histologic grade and invasion depth.

A comparison of conventional endoscopy, chromoendoscopy, and the optimal-band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps

BACKGROUND

The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye.

OBJECTIVE

To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy.

DESIGN

An open prospective study.

SETTING

Jichi Medical University, Japan.

PATIENTS

A total of 133 colonoscopy cases.

MAIN OUTCOME MEASUREMENT

A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps < or =5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification.

RESULTS

A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy.

CONCLUSIONS

Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.

Meshed capillary vessels by use of narrow-band imaging for differential diagnosis of small colorectal polyps

BACKGROUND

Although microvascular vessels on the surface of colorectal polyps are observed by narrow-band imaging (NBI) with magnification, its clinical usefulness is still uncertain.

OBJECTIVE

Our purpose was to evaluate the usefulness of meshed capillary (MC) vessels observed by NBI magnification for differentiating between nonneoplastic and neoplastic colorectal lesions.

DESIGN

Prospective polyp study.

SETTING

National Cancer Center Hospital East, Chiba, Japan.

PATIENTS

A total of 702 consecutive patients who underwent total colonoscopy between September and December 2004 were prospectively evaluated. Patients with polyps >10 mm and those with polyps previously evaluated by histologic examination or colonoscopy were excluded.

INTERVENTION

Lesions were classified into 2 groups: polyps with invisible or faintly visible MC vessels as nonneoplastic and polyps with clearly visible MC vessels as neoplastic. Lesions judged as nonneoplastic were subjected to biopsy and those as neoplastic were removed endoscopically. Histologic analysis was performed in all lesions.

MAIN OUTCOME MEASUREMENT

Visible or invisible surface MC vessels, prediction of histologic diagnosis.

RESULTS

Of 92 eligible patients enrolled in this study, 150 lesions, including 39 (26%) hyperplastic polyps and 111 (74%) adenomatous polyps, were detected. Observation of MC vessels detected 107 of 111 neoplastic polyps and 36 of 39 nonneoplastic polyps. The overall diagnostic accuracy, sensitivity, and specificity were 95.3%, 96.4%, and 92.3%, respectively.

LIMITATIONS

MC vessel judgment performed by a single colonoscopist with extensive experience in magnifying NBI.

CONCLUSION

Observation of surface MC vessels by magnifying NBI is a useful and simple method for differentiating colorectal nonneoplastic and neoplastic polyps.

Detectability of colorectal neoplastic lesions using a narrow-band imaging system: a pilot study

BACKGROUND AND AIM

Flat and depressed colorectal neoplastic lesions can be difficult to identify using conventional colonoscopy techniques. Narrow-band imaging (NBI) provides unique views especially of mucosal vascular network and helps in visualization of neoplasia by improving contrast. The aim of this study was to assess the feasibility of using NBI for colorectal neoplasia screening.

METHODS

Forty-seven consecutive patients, who underwent high definition colonoscopy (HDC) screening examinations revealing neoplastic lesions, were enrolled in our prospective study. No biopsies or resections were performed during the initial HDC, but patients in whom lesions were detected underwent further colonoscopies using NBI, with the results of the first examination blinded from the colonoscopist. They then received appropriate treatment. We compared diagnostic detection rates of neoplastic lesions for HDC and NBI procedures using total number of all identified neoplastic lesions as reference standard.

RESULTS

Altogether, 153 lesions were detected and analyzed in 43 patients. Mean diagnostic extubation times were not significantly different (P = 0.18), but the total number of lesions detected by NBI was higher (134 vs 116; P = 0.02). Based on macroscopic type, flat lesions were identified more often by NBI (P = 0.04). As for lesion size, only flat lesions < 5 mm were detected more frequently (P = 0.046). Lesions in the right colon were identified more often by NBI (P = 0.02), but NBI missed two flat lesions >or= 10 mm located there.

CONCLUSIONS

Narrow band imaging colonoscopy may represent a significant improvement in the detection of flat and diminutive lesions, but a future multi-center controlled trial should be conducted to fully evaluate efficacy for screening colonoscopies.

Narrow-band imaging without high magnification to differentiate polyps during real-time colonoscopy: improvement with experience

BACKGROUND

There is no widely adopted, easily applied method for distinguishing between adenomatous and nonadenomatous polyps during real-time colonoscopy.

OBJECTIVE

To compare white light (WL) with narrow-band imaging (NBI) for the differentiation of colorectal polyps in vivo and to assess for a learning curve.

DESIGN

A prospective polyp series.

PATIENTS AND SETTING

A total of 302 patients referred for colonoscopy, between August 2006 and July 2007, to a single tertiary-referral center in the United States.

INTERVENTION

Standard WL colonoscopy was performed with Olympus 180-series colonoscopes. Each detected polyp was first characterized by WL and then by NBI. Modified Kudo pit pattern and vascular color intensity (VCI) were recorded, and the histology was predicted. Endoscopists were given feedback every 2 weeks.

MAIN OUTCOME MEASUREMENTS

Overall accuracy and sensitivity and specificity of endoscopic diagnosis by using WL alone and with NBI, as well as improvement in endoscopists' performance.

RESULTS

A total of 265 polyps were found in 131 patients. Diagnostic accuracy was 80% with NBI and 77% with WL (P = .35). NBI performed better than WL in diagnosing adenomas (sensitivity 80% vs 69%, P < .05). Nonadenomatous polyps were more likely to have a "light" VCI compared with adenomas (71% vs 29%, P < .001). During the second half of the study, NBI accuracy improved, from 74% to 87%, and outperformed an unchanged WL accuracy of 79% (P < .05).

CONCLUSIONS

Overall, NBI was not more accurate than WL in differentiating colorectal polyps in vivo; however, once a learning curve was achieved, NBI performed significantly better. Further refinements of an NBI pit-pattern classification and VCI scale are needed before broad application to clinical decisions regarding the necessity of polypectomy.

Meta-analysis: narrow band imaging for lesion characterization in the colon, oesophagus, duodenal ampulla and lung

BACKGROUND

Narrow band imaging is a new endoscopic technology that highlights mucosal surface structures and microcapillaries, which may be indicative of neoplastic change.

AIM

To assess the diagnostic precision of narrow band imaging for the diagnosis of epithelial neoplasia compared to conventional histology both overall and in specific organs.

METHODS

We performed a meta-analysis of studies which compared narow band imaging-based diagnosis of neoplasia with histopathology as the gold standard. Search terms: 'endoscopy' and 'narrow band imaging'.

RESULTS

Five hundred and eighty-two patients and 1108 lesions in 11 studies were included. Overall, sensitivity was 0.94 (95% confidence interval 0.92-0.95), specificity 0.83 (0.80-0.86); weighted area under the curve was 0.96 (standard error 0.02), diagnostic odds ratio (DOR) 72.74 (34.11-155.15). DORs were 66.65 (25.84-171.90), 61.19 (7.09-527.97), 69.74 (8.04-605.24) for colon, oesophagus and lung respectively. Studies with more than 50 patients had higher diagnostic precision, relative DOR 4.96 (1.28-19.27), P = 0.022. There was no difference in accuracy between microvessel and mucosal (pit) pattern based measures, relative DOR 1.29 (0.05-35.16), P = 0.87. There was significant heterogeneity overall between studies, Q = 31.2, P = 0.003.

CONCLUSION

Narrow band imaging is accurate with high diagnostic precision for in vivo diagnosis of neoplasia across a range of organs, using simple microvessel-based measures.

Indications and techniques for lower intestinal endoscopy

The search for inflammatory and neoplastic lesions are the main indications for colonoscopy. A high rate of detection of polyps has become a quality criterion that depends on skilled handling of the colonoscope, on expertise and concentration during the examination, on excellent bowel preparation, and on a high standard of technical equipment. The diagnostic benefits outweigh the risk of bleeding, perforation and infection in almost all situations. Contraindications are signs of perforated intestine or imminent perforation due to deep ulcerations, necroses, or fulminant colitis. The patient's comorbidity must be considered to assess the physical stress of bowel preparation, colonoscopy and sedation. Informed consent is necessary and must be documented in all cases. It is advisable to explain planned therapeutic manoeuvres before the examination, since all non-invasive polyps must be removed completely. Total colonoscopy is possible in 95-99% of cases, but technical efforts are under way to solve the problem of looping and fixed colon angulations. Optimising optical imaging is another main focus of industrial development. The combination of narrow-band imaging, zoom magnification, and high-definition processor technology is currently the most promising tool for identifying small and flat lesions in the colon.