Narrow Band Imaging Technique Research Articles

Assessment of hyperspectral imaging and CycleGAN-simulated narrowband techniques to detect early esophageal cancer

The clinical signs and symptoms of esophageal cancer (EC) are often not discernible until the intermediate or advanced phases. The detection of EC in advanced stages significantly decreases the survival rate to below 20%. This study conducts a comparative analysis of the efficacy of several imaging techniques, including white light image (WLI), narrowband imaging (NBI), cycle-consistent adversarial network simulated narrowband image (CNBI), and hyperspectral imaging simulated narrowband image (HNBI), in the early detection of esophageal cancer (EC). In conjunction with Kaohsiung Armed Forces General Hospital, a dataset consisting of 1000 EC pictures was used, including 500 images captured using WLI and 500 images captured using NBI. The CycleGAN model was used to generate the CNBI dataset. Additionally, a novel method for HSI imaging was created with the objective of generating HNBI pictures. The evaluation of the efficacy of these four picture types in early detection of EC was conducted using three indicators: CIEDE2000, entropy, and the structural similarity index measure (SSIM). Results of the CIEDE2000, entropy, and SSIM analyses suggest that using CycleGAN to generate CNBI images and HSI model for creating HNBI images is superior in detecting early esophageal cancer compared to the use of conventional WLI and NBI techniques.

Retracted: Diagnostic Value of Endoscopic Narrow-Band Imaging Technique in Early Gastric Cancer and Precancerous Lesions.

[This retracts the article DOI: 10.1155/2022/9205150.].

The Effectiveness of White Light Endoscopy Combined With Narrow Band Imaging Technique Using Ni Classification in Detecting Early Laryngeal Carcinoma in 114 Patients: Our Clinical Experience

By displaying tumor-specific neoangiogenesis, narrow band imaging (NBI), a novel imaging approach, enhances the diagnosis of head and neck cancers and makes it more accurate OBJECTIVE: To determine the effect of NBI in combination with white light endoscopy (WLE) for diagnosis of preneoplastic or neoplastic laryngeal cancers according to Ni classification and to conclude if higher Ni classification and tumor stage are related. We enrolled 114 patients with various laryngeal cancer between December 2018 and June 2021. Patients were examined with WLE and NBI. Squamous cell carcinoma (SCC) accounted for 46 cases, benign lesions 30 cases, and nondysplastic, low-grade, and severe dysplasias for 38 cases. Based on characteristics of the intraepithelial papillary capillary loop (IPCL), endoscopic NBI results were divided into five categories (I, II, III, IV, and V). Type I-IV are regarded to be benign, while type V is considered to be cancerous. An incisional biopsy was conducted to assess histopathology, and the histopathology was compared to the NBI results. We assessed the negative predictive value (NPV), positive predictive value (PPV), specificity, and sensitivity for WLE alone and WLE combined with NBI. Analyses were conducted using SPSS software version 26. The WLE combined with NBI showed excellent sensitivity (96%) compared to WLE (86.4%). Specificity was higher in the WLE combined with NBI (96.4%) than WLE alone (91.7%). WLE combined with NBI saw a NPV of 89% as compared with WLE with 88%. WLE and WLEin combination with NBI, recorded a PPV of 90% and 98%, respectively. The accuracy of detecting laryngeal cancer increases when WLE and NBI are combined. Combined NBI with WLE remains highly sensitive to early glottis cancer. Accuracy of preoperative NBI was high. In the diagnosis of laryngeal cancer, a higher Ni classification closely correlates with the late stages of the glottis tumor.

Diagnostic Value of Endoscopic Narrow-Band Imaging Technique in Early Gastric Cancer and Precancerous Lesions.

Objective To investigate the diagnostic value of endoscopic narrow-band imaging technique in early gastric cancer and precancerous lesions. Methods A total of 100 patients with recurrent upper gastrointestinal symptoms in our hospital from January 2017 to January 2022 were selected and divided into group A and group B according to the random number table method, with 50 cases in each group. Group A received white light endoscopy, and group B received narrow-band imaging technology combined with endoscopy. Narrow-band imaging combined with magnifying endoscopy was used to stain the area with suspicious mucosal lesions with indigo carmine and magnified observation. Results The endoscopic image clarity of group B was significantly better than that of group A in terms of lesion outline, gastric pit, and microvascular morphology (P < 0.05). There were 10 cases of early gastric cancer, 18 cases of benign lesions, and 9 cases of gastric cancer (nonearly stage); 17 cases of precancerous lesions, 12 cases of early gastric cancer, 13 cases of benign lesions, and 6 cases of gastric cancer (nonearly stage) were diagnosed by ordinary white light endoscopy. Pathological results confirmed that among the 50 patients in group B, there were 15 cases of precancerous lesions, 11 cases of early gastric cancer, 17 cases of benign lesions, and 7 cases of gastric cancer (nonearly stage). Among the 50 patients in group A, 16 were precancerous lesions, 11 were early gastric cancer, 15 were benign lesions, and 8 were gastric cancer (non early stage). In the diagnosis of precancerous lesions and early gastric cancer, the diagnostic consistency, sensitivity, and specificity of group B were better than those of group A (P < 0.05); NBI combined with endoscopy in the diagnosis of precancerous lesions and early gastric cancer (kappa = 0.860, kappa = 0.883) was more consistent with pathological diagnosis than common white light endoscopy (kappa = 0.433, kappa = 0.535). Conclusion The value of narrow-band imaging technology combined with endoscopy in the diagnosis of precancerous lesions and early gastric cancer is better than that of ordinary white light endoscopy, and it can be widely used in clinical practice.

Obstructive sleep apnoea patients vs laryngopharyngeal reflux disease: Non-invasive evaluation with NBI and pepsin detection in tears.

Obstructive sleep apnea (OSA) and laryngopharyngeal reflux disease (LPR) are two common diseases that lower patients’ quality of life. OSA is defined by cyclic events of airflow obstruction that occurs during sleep, while LPR is characterized by upper airway inflammatory signs and symptoms due to the return of gastroduodenal gaseous and liquid elements. pH-metry is the gold standard in LPR diagnosis, but considering its invasiveness among other negative traits, questionnaires that catalog symptoms and signs of the disease such as reflux symptom index (RSI) and reflux finding score (RFS) are preferred. Moreover, LPR can be evaluated by testing the presence of pepsin in tears, and narrowband imaging (NBI) has been introduced for the early diagnosis of larynx oncological disease. This paper aims to test whether LPR is more frequent in OSA patients than in control ones, performing a non-invasive protocol composed of RSI and RFS test (with light vs. NBI techniques) followed by pepsin detection in tears. Sixty-eight LPR patients were enrolled in the study (45 with OSA and 23 without OSA). A strong linear relationship between apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) was found, and patients who presented pepsin in tears had higher values of AHI and ODI in comparison to patients without it. Pathological RFS and NBI showed higher values of AHI and ODI in comparison to the control group. Furthermore, pathological RSI showed higher values of AHI and ODI in comparison to the control group. In conclusion, this diagnostic combined non-invasive protocol may be a good method to perform an early diagnosis of LPR.

Demographics and targeted biopsy with NBI in head and neck mucosal lesions

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; It is estimated that by the end of year 2020 over 10 million people worldwide would die of cancer every year and about 66% of these would be from developing world like India (WHO-UCC 2003). Our aim in present study was to evaluate the use of targeted biopsy of mucosal lesions of head and neck cancer using narrow band imaging technique, in order to yield more accurate specimen of lesion which will result in correct diagnosis of disease early and to study different demographics of patients.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Patients lesions were examined under NBI endoscope, best site of biopsy were identified on the basis of increase vascularity, neo-angiogenesis and superficial capillary vessels. Biopsy were taken from this site and sent for histopathological examinations. Considering histopathological report as standard, results from NBI endoscopy were compared to the results of previous studies and conclusion was done. We also studied different demographics of these patients under site of lesion, age distribution, sex distribution, and locality, histopathology type. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Maximum lesions were found in oral cavity (56.33%). Malignancy was also more common in oral cavity (63.46%), mostly belong to squamous cell carcinoma on histopathology. Mean age of presentation of head and neck mucosal lesion was found to be 48 year and of malignant lesions is 54 years.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; We conclude that up to an extent with progression of age malignant lesions increase. Male to female ratio of mucosal lesions is 1.7:1 and of malignancy is 2.25:1. Narrow band imaging endoscopy helps us to identify best site of biopsy, helping in early diagnosis of disease and ultimately reducing morbidity and mortality of patient.&lt;/p&gt;

Optimization of Band Selection in Multispectral and Narrow-Band Imaging: An Analytical Approach.

The contrast ratio has been proposed for quantification of image quality of subsurface inhomogeneities in the skin. Based on the two-flux Kubelka-Munk model, we developed an analytical approach which links the contrast ratio with optical tissue parameters. We obtained an explicit analytical solution for the dependence of maximal contrast ratio on optical tissue parameters. Then, we linked the minimally observable contrast ratio (cmin) with the bit depth of the camera, d: cmin=1/(2d-1). Based on this analysis we were able to derive an explicit expression, which links camera properties with the minimally detectable changes in optical tissue parameters (both scattering and absorption). The proposed analytical model can be used for rapid assessment and optimization of multispectral and narrow band imaging techniques and for estimation of the accuracy of imaging techniques. The developed model confirms the utility of the contrast ratio for tissue imaging.

The role of narrow band imaging in colorectal polyp detection.

Colonoscopic detection and removal of polyps represent the most important prevention method for colorectal cancer. We aimed to investigate the diagnostic yield of narrow band imaging (NBI) colonoscopy for polyp detection compared with standard colonoscopy. In this prospective study, 505 patients that underwent total colonoscopy were randomized into two groups: 226 patients in NBI group and 279 in non-NBI group (standard colonoscopy). The primary endpoints were polyp detection rate (PDR) and adenoma detection rate (ADR) in both groups. Polyps detected with NBI technique were characterized according to the NBI International Colorectal Endoscopic (NICE) classification. The total number of polyps detected in NBI group was significantly higher compared with non-NBI group (325 polyps in 226 patients versus 189 polyps in 279 patients, respectively). PDR in NBI group was 55.3%, versus 43.3% in non-NBI group. ADR in NBI group was significantly higher compared with non-NBI group (35.3% versus 20%, respectively). The proportion of detected adenomas in the left-sided colon was significantly higher in NBI group (72.8% versus 61.06% in non-NBI group), which was related to an increased number of small adenomas detected in NBI group. Also, in NBI group, a significant number of flat adenomas were detected (28 versus 9 in non-NBI group). A total of 147 (45.2%) polyps were classified according to the NICE classification, and showed a good correlation with histological analysis. In conclusion, this study demonstrated increased PDR and ADR for NBI colonoscopy. A good correlation between the NICE classification and histological analysis was also observed.

The feasibility of NBI in patients with suspected upper airway lesions: A multicenter study.

Narrow band imaging (NBI) improves diagnosis of laryngopharyngeal cancer, but most reported NBI studies are from experienced centers. Feasibility reports on use at everyday outpatient departments are needed. Researcher-initiated, prospective, multicenter. Participating physicians were instructed in NBI technique during a 4-hour meeting. Patients underwent an examination that included endoscopy with white light (WL) high-definition (HD) TV and NBI filter in the selected time period. All suspicious lesions were biopsied. The medical records of patients with NBI negative findings were evaluated 6 months after the visit to detect all possible malignant lesions coming into view at mucosal sites. These were considered as false-negative cases, enabling long-term assess to the positive predictive value (NPV) of the protocol. We enrolled 125 patients. Of those, 84 (67.2%) were males and the median age was 65 years (range, 35-91). In analysis of the accuracy of WL HD TV and NBI against biopsy, the sensitivity and specificity of WL HD TV were 62% and 81%, respectively; and the sensitivity and specificity of NBI were 100% and 84%, respectively. The diagnostic accuracy of NBI was significantly better (P < 0.05). When analyzing medical records 6 months after the initial examination, we found three patients who had been diagnosed with a malignant lesion (NPV of NBI of 96.8%). Narrow band imaging is readily implemented in an everyday outpatient practice, and there seems to be better detection rates of dysplastic/carcinoma lesions with HD NBI compared to HD WL. 2b. Laryngoscope, 127:1821-1825, 2017.

The diagnostic performance parameters of Narrow Band Imaging: A preclinical and clinical study

ObjectivesThe oral carcinoma is a widespread pathology and still presents poor prognosis. Among the available procedures for its early detection, Narrow Band Imaging technique allows to assess potential vascular network abnormalities. The reliability of this technique in the detection of dysplastic and neoplastic oral lesions was evaluated in a preclinical and clinical study. Materials and methodsIn the preclinical study, a chemical oral carcinogen was administered to 50 mice to induct both dysplastic and neoplastic oral lesions. In the clinical study 91 patients, bearing suspicious premalignant and malignant oral lesions, have been included. Images of animals’ and patients’ lesions were acquired under white and Narrow Band Imaging light prior to biopsy. Two expert raters examined the images and classified lesions, which were eventually compared to the histological diagnosis. The diagnostic performance included sensitivity, specificity, positive likelihood ratio, positive and negative predictive values, accuracy, percentages and degree of agreement between raters’ evaluation and the histological report. ResultsIn the preclinical study sensitivity ranged from 0.57 to 1, specificity from 0.85 to 0.99, positive likelihood ratio from 6.54 to 65.04, positive predictive values from 0.32 to 0.96, negative predictive values from 0.91 to 1 and accuracy from 0.86 to 0.98. In the clinical study sensitivity ranged from 0.63 to 0.99, specificity from 0.89 to 1, positive likelihood ratio from 8.45 to 61.47, positive predictive values from 0.59 to 0.96, negative predictive values from 0.78 to 1 and accuracy from 0.82 to 0.99. ConclusionNarrow Band Imaging is an accurate technique, which holds a great potential for tumour angiogenesis evaluation and for the subsequent early detection of suspicious premalignant and malignant oral lesions.

The Clinical Research Office of the Endourological Society (CROES) Multicentre Randomised Trial of Narrow Band Imaging–Assisted Transurethral Resection of Bladder Tumour (TURBT) Versus Conventional White Light Imaging–Assisted TURBT in Primary Non–Muscle-invasive Bladder Cancer Patients: Trial Protocol and 1-year Results

BackgroundWhite light (WL) is the established imaging modality for transurethral resection of bladder tumour (TURBT). Narrow band imaging (NBI) is a promising addition. ObjectivesTo compare 12-mo recurrence rates following TURBT using NBI versus WL guidance. Design, setting, and participantsThe Clinical Research Office of the Endourological Society (CROES) conducted a prospective randomised single-blind multicentre study. Patients with primary non–muscle-invasive bladder cancer (NMIBC) were randomly assigned 1:1 to TURBT guided by NBI or WL. InterventionTURBT for NMIBC using NBI or WL. Outcome measurements and statistical analysisTwelve-month recurrence rates were compared by chi-square tests and survival analyses. Results and limitationsOf the 965 patients enrolled in the study, 481 patients underwent WL-assisted TURBT and 484 patients received NBI-assisted TURBT. Of these, 294 and 303 patients, respectively, completed 12-mo follow-up, with recurrence rates of 27.1% and 25.4%, respectively (p=0.585, intention-to-treat [ITT] analysis). In patients at low risk for disease recurrence, recurrence rates at 12 mo were significantly higher in the WL group compared with the NBI group (27.3% vs 5.6%; p=0.002, ITT analysis). Although TURBT took longer on average with NBI plus WL compared with WL alone (38.1 vs 35.0min, p=0.039, ITT; 39.1 vs 35.7min, p=0.047, per protocol [PP] analysis), lesions were significantly more often visible with NBI than with WL (p=0.033). Frequency and severity of adverse events were similar in both treatment groups. Possible limitations were lack of uniformity of surgical resection, data on smoking status, central pathology review, and specific data regarding adjuvant intravesical instillation therapy. ConclusionsNBI and WL guidance achieved similar overall recurrence rates 12 mo after TURBT in patients with NMIBC. NBI-assisted TURBT significantly reduced the likelihood of disease recurrence in low-risk patients. Patient summaryUse of a narrow band imaging technique might provide greater detection of bladder tumours and subsequent treatment leading to reduced recurrence in low-risk patients.

Unknown primary: diagnostic issues in the biological endoscopy and positron emission tomography scan era.

There is no general agreement on which diagnostic procedures are required and optimal in searching for primary tumors among patients with cervical metastasis of unknown primary (CUP). Because of the rising incidence of human papillomavirus (HPV)-associated oropharyngeal carcinoma, it is reasonable to assume that the number of small oropharyngeal tumors with neck metastasis will increase. The purpose of this review is to highlight the diagnostic approaches more useful in detecting such lesions. After the introduction of the narrow band imaging technique, positron emission tomography-computed tomography, and transoral diagnostic procedures, the accuracy in discovering the primary lesion is up to 80-90%. By far, most primaries arise in the oropharynx, especially among patients with p16/HPV-positive CUP. The oropharynx is the most likely primary site in patients with CUP, especially in p16/HPV-positive cases. By utilizing recent techniques, a high diagnostic accuracy in detecting the primary tumor is achievable; this may offer better survival rates with cost-effective efforts. We recommend some approaches for the diagnostic protocol used in searching for primary tumors in patients with CUP.

Non-polypoid colorectal neoplasms: Classification, therapy and follow-up.

In the last years, an increasing interest has been raised on non-polypoid colorectal tumors (NPT) and in particular on large flat neoplastic lesions beyond 10 mm tending to grow laterally, called laterally spreading tumors (LST). LSTs and large sessile polyps have a greater frequency of high-grade dysplasia and local invasiveness as compared to pedunculated lesions of the same size and usually represent a technical challenge for the endoscopist in terms of either diagnosis and resection. According to the Paris classification, NPTs are distinguished in slightly elevated (0-IIa, less than 2.5 mm), flat (0-IIb) or slightly depressed (0-IIc). NPTs are usually flat or slightly elevated and tend to spread laterally while in case of depressed lesions, cell proliferation growth progresses in depth in the colonic wall, thus leading to an increased risk of submucosal invasion (SMI) even for smaller neoplasms. NPTs may be frequently missed by inexperienced endoscopists, thus a careful training and precise assessment of all suspected mucosal areas should be performed. Chromoendoscopy or, if possible, narrow-band imaging technique should be considered for the estimation of SMI risk of NPTs, and the characterization of pit pattern and vascular pattern may be useful to predict the risk of SMI and, therefore, to guide the therapeutic decision. Lesions suitable to endoscopic resection are those confined to the mucosa (or superficial layer of submucosa in selected cases) whereas deeper invasion makes endoscopic therapy infeasible. Endoscopic mucosal resection (EMR, piecemeal for LSTs > 20 mm, en bloc for smaller neoplasms) remains the first-line therapy for NPTs, whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory and cannot be achieved by means of EMR. After piecemeal EMR, follow-up colonoscopy should be performed at 3 mo to assess resection completeness. In case of en bloc resection, surveillance colonoscopy should be scheduled at 3 years for adenomatous lesions ≥ 1 cm, or in presence of villous features or high-grade dysplasia patients (regardless of the size), while less intensive surveillance (colonoscopy at 5-10 years) is needed in case of single (or two) NPT < 1 cm presenting tubular features or low-grade dysplasia at histology.

Correlation of narrow band imaging endoscopy and histopathology in the diagnosis of nonerosive reflux disease.

Background /Aim:Narrow band imaging (NBI) is a novel, innovative high-resolution endoscopic technique, which utilizes spectral narrow band filter for the visualization of mucosal patterns and microvasculature. Nonerosive reflux disease (NERD) is a type of gastroesophageal reflux disease (GERD) and it is characterized by reflux symptoms without mucosal breaks on white light endoscopy (WLE). Biopsies from distal esophagus of GERD patients show group of histologic features such as basal cell hyperplasia, elongation of lamina propria papillae, and inflammatory cells. The present study was undertaken to evaluate diagnostic utility of NBI endoscopy and biopsy study in NERD patients and also to correlate NBI endoscopy findings with histologic features of GERD.Patients and Methods:A total of 71 cases of NERD having symptom score more than 10 and those not having erosion on WLE were recruited prospectively and underwent NBI endoscopic examination. Two mucosal biopsies were taken at 3 cm above the squamocolumnar junction.Results:Histologic features of GERD were seen in 50 (70.4%) out of 71 cases. No significant correlation between NBI endoscopic findings with histologic features of GERD was found.Conclusion:The present study showed that histopathologic evaluation of distal esophageal mucosa has promising diagnostic value over NBI endoscopy in NERD patients. Use of newly introduced NBI technique requires tremendous familiarity for the detection of the cases of NERD, which show histologic features of GERD.

Acquisition and visualization techniques for narrow spectral color imaging

This paper introduces a new approach in narrow-band imaging (NBI). Existing NBI techniques generate images by selecting discrete bands over the full visible spectrum or an even wider spectral range. In contrast, here we perform the sampling with filters covering a tight spectral window. This image acquisition method, named narrow spectral imaging, can be particularly useful when optical information is only available within a narrow spectral window, such as in the case of deep-water transmittance, which constitutes the principal motivation of this work. In this study we demonstrate the potential of the proposed photographic technique on nonunderwater scenes recorded under controlled conditions. To this end three multilayer narrow bandpass filters were employed, which transmit at 440, 456, and 470 nm bluish wavelengths, respectively. Since the differences among the images captured in such a narrow spectral window can be extremely small, both image acquisition and visualization require a novel approach. First, high-bit-depth images were acquired with multilayer narrow-band filters either placed in front of the illumination or mounted on the camera lens. Second, a color-mapping method is proposed, using which the input data can be transformed onto the entire display color gamut with a continuous and perceptually nearly uniform mapping, while ensuring optimally high information content for human perception.

Bronchoscopic narrow band imaging technique in diagnosis of lung malignancy

Bronchoscopic narrow band imaging technique in diagnosis of lung malignancy

Time saving with narrow‐band imaging for distinguishing between neoplastic and non‐neoplastic small colorectal lesions

For colonoscopic examinations, the narrow-band imaging (NBI) system is more convenient and timesaving than magnifying chromoendoscopy (MCE). However, the time-saving aspects of NBI techniques have not been assessed. The present study compared interpretation times between NBI and MCE techniques in distinguishing between neoplastic and non-neoplastic small colorectal lesions. Between January and March 2010, 693 consecutive patients who underwent colonoscopy at the National Cancer Center Hospital, Tokyo, Japan, were enrolled. When the first lesion was detected by conventional white-light observation, the patient was randomly assigned to undergo a sequence of NBI and MCE observations (group A: NBI-MCE, group B: MCE-NBI). The time to diagnosis with each modality (NBI, from changing to NBI until diagnosis; MCE, from the start of indigo carmine solution spraying until diagnosis) was recorded by an independent observer. The sensitivity, specificity, and diagnostic accuracy of the first modality used in each group (NBI or MCE) were assessed by referring to the histopathological data. Seventy-one patients with 137 lesions were randomized to group A, and 80 patients with 163 lesions to group B. The median interpretation times were 12 s (interquartile range [IQR]: 7-19 s) in group A, and 17 s (IQR: 12-24 s) in group B, the difference being significant (P < 0.001). No significant differences were observed between NBI and MCE in terms of sensitivity, specificity, and diagnostic accuracy. NBI reduces the interpretation times for distinguishing between neoplastic and non-neoplastic small lesions during colonoscopies, without loss of diagnostic accuracy.

Surgical Devices in Otolaryngology—Present and Future—

Evolution of a surgical device can sometimes set a new trend in the history of surgery. It is well recognized that the development of the surgical microscope generated new fields in surgery, such as neurosurgery, temporal bone surgery, and phonosurgery. Also, the spread of the flexible and rigid endoscope in the 1990s produced functional endoscopic sinus surgery as well as laparoscopic surgery, video-assisted thoracoscopic surgery, and arthroscopic surgery, which enabled early diagnosis and minimally invasive surgery. In this paper, we review recent and novel surgical devices, such as navigation systems, narrow band imaging technique, three-dimensional endoscope systems, and especially, robotic surgical systems, and discuss the future of surgical devices.

Pharyngo-laryngeal examination with the narrow band imaging technology: early experience

The prognosis of cancer patients is highly dependent on the time of diagnosis. Early, stage 1 disease is often curable whereas late stage diseases are usually beyond curable treatments. Therefore, new diagnostic tools for malignancies of the upper aerodigestive tract are developed all the time and narrow band imaging (NBI) is one of these new options for early diagnostics. In this paper, we describe the implementation of NBI technique in our institution. During the first 6 weeks we used NBI to examine 73 patients with different types of pharyngeal or laryngeal problems. Most of the patients (77%) were on follow-up visits after earlier malignant disease. In our series we had 11 NBI-positive patients and the histological diagnosis was carcinoma or dysplasia among 10 of these. Among the NBI negative patients we found four carcinomas. It is notable that NBI affected the decision of a biopsy procedure in three patients, with final diagnosis of dysplasia or carcinoma. In conclusion, we find NBI useful in the diagnostics of malignancies of the upper aerodigestive tract. This is a useful tool in improving the accuracy of the diagnostics. However, it still takes an experienced clinician and a learning curve can be expected.

Utility of narrow band imaging for identification of the orifice of the bile duct during ERCP

Exact identification of the orifice of the bile duct in the major duodenal papilla is required for selective cannulation during endoscopic retrograde cholangiopancreatography (ERCP). However, there are some cases in which the orifice is unclear. The narrow band imaging (NBI) system is an endoscopic imaging technique based on modification of spectral features that enhances visualization of the vascular network. On NBI, bile appears as a bright red fluid, and it is enhanced in the digestive tract. We report two cases in which the NBI was useful for identification of the orifice of the bile duct during ERCP. We recommend the NBI technique before cannulation in cases where the orifice is unclear on the standard image.