Improving visualization techniques by narrow band imaging and magnification endoscopy

Virtual indigo carmine chromoendoscopy images: a novel modality for peroral cholangioscopy using artificial intelligence technology (with video)

BACKGROUND AND AIMS

Accurately diagnosing biliary strictures is crucial for surgical decisions, and although peroral cholangioscopy (POCS) aids in visual diagnosis, diagnosing malignancies or determining lesion margins via this route remains challenging. Indigo carmine is commonly used to evaluate lesions during GI endoscopy. We aimed to establish the utility of virtual indigo carmine chromoendoscopy (VICI) converted from POCS images using artificial intelligence.

METHODS

This single-center, retrospective study analyzed 40 patients with biliary strictures who underwent POCS using white-light imaging (WLI) and narrow-band imaging (NBI). A cycle-consistent adversarial network was used to convert the WLI into VICI of POCS images. Three experienced endoscopists evaluated WLI, NBI, and VICI via POCS in all patients. The primary outcome was the visualization quality of surface structures, surface microvessels, and lesion margins. The secondary outcome was diagnostic accuracy.

RESULTS

VICI showed superior visualization of the surface structures and lesion margins compared with WLI (P < .001) and NBI (P < .001). The diagnostic accuracies were 72.5%, 87.5%, and 90.0% in WLI alone, WLI and VICI simultaneously, and WLI and NBI simultaneously, respectively. WLI and VICI simultaneously tended to result in higher accuracy than WLI alone (P = .083), and the results were not significantly different from WLI and NBI simultaneously (P = .65).

CONCLUSIONS

VICI in POCS proved valuable for visualizing surface structures and lesion margins and contributed to higher diagnostic accuracy comparable to NBI. In addition to NBI, VICI may be a novel supportive modality for POCS.

Assessment of Narrow-Band Imaging Algorithm for Video Capsule Endoscopy Based on Decorrelated Color Space for Esophageal Cancer: Part II, Detection and Classification of Esophageal Cancer

Esophageal carcinoma (EC) is a prominent contributor to cancer-related mortality since it lacks discernible features in its first phases. Multiple studies have shown that narrow-band imaging (NBI) has superior accuracy, sensitivity, and specificity in detecting EC compared to white light imaging (WLI). Thus, this study innovatively employs a color space linked to décor to transform WLIs into NBIs, offering a novel approach to enhance the detection capabilities of EC in its early stages. In this study a total of 3415 WLI along with the corresponding 3415 simulated NBI images were used for analysis combined with the YOLOv5 algorithm to train the WLI images and the NBI images individually showcasing the adaptability of advanced object detection techniques in the context of medical image analysis. The evaluation of the model's performance was based on the produced confusion matrix and five key metrics: precision, recall, specificity, accuracy, and F1-score of the trained model. The model underwent training to accurately identify three specific manifestations of EC, namely dysplasia, squamous cell carcinoma (SCC), and polyps demonstrates a nuanced and targeted analysis, addressing diverse aspects of EC pathology for a more comprehensive understanding. The NBI model effectively enhanced both its recall and accuracy rates in detecting dysplasia cancer, a pre-cancerous stage that might improve the overall five-year survival rate. Conversely, the SCC category decreased its accuracy and recall rate, although the NBI and WLI models performed similarly in recognizing the polyp. The NBI model demonstrated an accuracy of 0.60, 0.81, and 0.66 in the dysplasia, SCC, and polyp categories, respectively. Additionally, it attained a recall rate of 0.40, 0.73, and 0.76 in the same categories. The WLI model demonstrated an accuracy of 0.56, 0.99, and 0.65 in the dysplasia, SCC, and polyp categories, respectively. Additionally, it obtained a recall rate of 0.39, 0.86, and 0.78 in the same categories, respectively. The limited number of training photos is the reason for the suboptimal performance of the NBI model which can be improved by increasing the dataset.

Association between continuous cessation or reduction of drinking alcohol and improvement of multiple dysplastic lesions in patients with esophageal squamous cell carcinoma after endoscopic resection

BACKGROUND

Multiple development of squamous cell carcinoma (SCC) in the upper aerodigestive tract has been explained by the 'field cancerization phenomenon' associated with alcohol drinking. Squamous dysplastic lesion is clinically visualised as a Lugol-voiding lesion (LVL) by chromoendoscopy. Whether cessation or reduction of alcohol drinking improves multiple LVL and reduces the risk of field cancerization has not been elucidated.

METHODS

We analysed 330 patients with newly diagnosed superficial esophageal SCC (ESCC) enrolled in the cohort study. The grade of LVL was assessed in all patients every 6 months. We instructed the patients to stop smoking and drinking and recorded their drinking and smoking status every 6 months.

RESULTS

Among 330 patients, we excluded 98 with no LVL or no drinking habit. Of the remaining 232 patients, 158 continuously ceased or reduced their drinking habit. Patients who ceased or reduced their drinking habit significantly showed improvement in the grade of LVL. Multivariate analysis showed that continuous cessation or reduction of drinking habit improved the grade of LVL (hazard ratio [HR] = 8.5, 95% confidence interval [CI] 1.7-153.8, p = 0.0053). Higher grade of LVL carried a high risk of multiple ESCC and head and neck SCC (HNSCC) (HR = 3.7, 95% CI 2.2-6.4, p < 0.0001). Improvement in LVL significantly decreased the risk of multiple ESCC and HNSCC (HR = 0.2, 95% CI 0.04-0.7, p = 0.009).

CONCLUSIONS

This is the first report indicating that field cancerization was reversible and cessation or reduction of drinking alcohol could prevent multiple squamous dysplastic lesion and multiple ESCC and HNSCC development.

CLINICAL TRIALS REGISTRY NUMBER

UMIN000001676.

Endoscope Capsules: The Present Situation and Future Outlooks

This paper presents new perspectives on photonic technologies for capsule endoscopy. It first presents a review of conventional endoscopy (upper endoscopy and colonoscopy), followed by capsule endoscopy (CE), as well as their techniques, advantages, and drawbacks. The technologies for CEs presented in this paper include integration with the existing endoscopic systems that are commercially available. Such technologies include narrow-band imaging (NBI), photodynamic therapy (PDT), confocal laser endomicroscopy (CLE), optical coherence tomography (OCT), and spectroscopy in order to improve the performance of the gastrointestinal (GI) tract examination. In the context of NBI, two optical filters were designed and fabricated for integration into endoscopic capsules, allowing for the visualization of light centered at the 415 nm and 540 nm wavelengths. These optical filters are based on the principle of Fabry-Perot and were made of thin films of titanium dioxide (TiO2) and silicon dioxide (SiO2). Moreover, strategies and solutions for the adaptation of ECs for PDT are also discussed.

Endoscopic near-infrared photoimmunotherapy in an orthotopic head and neck cancer model

Near-infrared photoimmunotherapy (NIR-PIT) is a cell selective cancer therapy that uses an antibody-photoabsorber (IRDye700DX, IR700) conjugate (APC) and NIR light. NIR-PIT targeting epidermal growth factor receptor (EGFR) in head and neck cancer (HNC) was conditionally approved in Japan in 2020. APC-bound tumors can be detected using endoscopic fluorescence imaging, whereas NIR light can be delivered using endoscopic fiber optics. The aims of this study were: (1) to assess the feasibility of endoscopic NIR-PIT in an orthotopic HNC model using a CD44-expressing MOC2-luc cell line; and (2) to evaluate quantitative fluorescence endoscopic imaging prior to and during NIR-PIT. The results were compared in 3 experimental groups: (1) untreated controls, (2) APC injection without light exposure (APC-IV), and (3) APC injection followed by NIR light exposure (NIR-PIT). APC injected groups showed significantly higher fluorescence signals for IR700 compared with the control group prior to therapeutic NIR light exposure, and the fluorescence signal significantly decreased in the NIR-PIT group after light exposure. After treatment, the NIR-PIT group showed significantly attenuated bioluminescence compared with the control and the APC-IV groups. Histology demonstrated diffuse necrotic death of the cancer cells in the NIR-PIT group alone. In conclusion, endoscopically delivered light combined with quantitative fluorescence imaging can be used to "see and treat" HNC. This method could also be applied to other types of cancer approachable with endoscopy.

Standard vs magnifying narrow-band imaging endoscopy for diagnosis of Helicobacter pylori infection and gastric precancerous conditions

BACKGROUND

Advances in endoscopic imaging enable the identification of patients at high risk of gastric cancer. However, there are no comparative data on the utility of standard and magnifying narrow-band imaging (M-NBI) endoscopy for diagnosing Helicobacter pylori (H. pylori) infection, gastric atrophy, and intestinal metaplasia.

AIM

To compare the diagnostic performance of standard and M-NBI endoscopy for H. pylori gastritis and precancerous conditions.

METHODS

In 254 patients, standard endoscopy findings were classified into mosaic-like appearance (type A), diffuse homogenous redness (type B), and irregular redness with groove (type C). Gastric mucosal patterns visualized by M-NBI were classified as regular round pits with polygonal sulci (type Z-1), more dilated and linear pits without sulci (type Z-2), and loss of gastric pits with coiled vessels (type Z-3).

RESULTS

The diagnostic accuracy of standard and M-NBI endoscopy for H. pylori gastritis was 93.3% and 96.1%, respectively. Regarding gastric precancerous conditions, the accuracy of standard and M-NBI endoscopy was 72.0% vs 72.6% for moderate to severe atrophy, and 61.7% vs. 61.1% for intestinal metaplasia in the corpus, respectively. Compared to type A and Z-1, types B+C and Z-2+Z-3 were significantly associated with moderate to severe atrophy [odds ratio (OR) = 5.56 and 8.67] and serum pepsinogen I/II ratio of ≤ 3 (OR = 4.48 and 5.69).

CONCLUSION

Close observation of the gastric mucosa by standard and M-NBI endoscopy is useful for the diagnosis of H. pylori gastritis and precancerous conditions.

Image-Enhanced Endoscopy in Lower Gastrointestinal Diseases: Present and Future

From dye-assisted conventional chromoendoscopy to novel virtual chromoendoscopy, image-enhanced endoscopy (IEE) is continuously evolving to meet clinical needs and improve the quality of colonoscopy. Dye-assisted chromoendoscopy using indigo carmine or crystal violet, although slightly old-fashioned, is still useful to emphasize the pit patterns of the colonic mucosa and predict the histological structures of relevant lesions. Equipment-based virtual chromoendoscopy has the advantage of being relatively easy to use. There are several types of virtual chromoendoscopy that vary depending on the manufacturer and operating principle. IEE plays distinctive roles with respect to histologic characterization of colorectal polyps and prediction of the invasion depth of colorectal cancers. In addition, the newest models of IEE have the potential to increase adenoma and polyp detection rates in screening colonoscopy.

Usefulness of Narrow-Band Imaging in Endoscopic Submucosal Dissection of the Stomach

There have been many advances in endoscopic imaging technologies. Magnifying endoscopy with narrow-band imaging is an innovative optical technology that enables the precise discrimination of structural changes on the mucosal surface. Several studies have demonstrated its usefulness and superiority for tumor detection and differential diagnosis in the stomach as compared with conventional endoscopy. Furthermore, magnifying endoscopy with narrow-band imaging has the potential to predict the invasion depth and tumor margins during gastric endoscopic submucosal dissection. Classifications of the findings of magnifying endoscopy with narrow-band imaging based on microvascular and pit patterns have been proposed and have shown excellent correlations with invasion depth confirmed by microscopy. In terms of tumor margin prediction, magnifying endoscopy with narrow-band imaging offers superior delineation of gastric tumor margins compared with traditional chromoendoscopy with indigo carmine. The limitations of narrow-band imaging, such as the need for considerable training, long procedure time, and lack of studies about its usefulness in undifferentiated cancer, should be resolved to confirm its value as a complementary method to endoscopic submucosal dissection. However, the role of magnifying endoscopy with narrow-band imaging is expected to increase steadily with the increasing use of endoscopic submucosal dissection for the treatment of gastric tumors.

Prospective Comparative Study of Laparoscopic Narrow Band Imaging (NBI) Versus Standard Imaging in Gynecologic Oncology

BACKGROUND

Narrow band imaging (NBI) is an optic filtration enhancement for endoscopy that uses two wavelengths of light (415 and 540 nm) to highlight superficial microvascular patterns. It has been successfully utilized to improve identification of lesions with abnormal vasculature, which is associated with endometriosis and endometrial cancer. Case studies suggest it may also facilitate surgical staging of gynecologic cancer, which is critical in determining appropriate adjuvant therapies. A technology that enhances the ability to identify metastatic disease during minimally invasive surgery (MIS) could make an important difference in patient outcomes.

METHODS

A prospective comparative study was conducted to evaluate patients with clinical indication for diagnostic or operative laparoscopy. All received white light imaging followed by NBI during the same procedure. Suspicious lesions were examined and photographed, using both modalities, before excision. The two techniques were compared. Positive predictive value, negative predictive value, and diagnostic accuracy in identifying histologically confirmed metastatic lesions were assessed, using appropriate statistical methods.

RESULTS

Of 124 patients enrolled in the study, 94 were evaluable; 30 did not undergo MIS and were therefore excluded. A significantly higher number of peritoneal abnormalities were identified with NBI versus white light imaging (P = 0.0239). However, no statistically significant difference (P = 0.18, patient level) was observed in identification of histologically confirmed metastatic disease.

CONCLUSIONS

NBI imaging provides a unique contrast between peritoneal surface and microvascular patterns. However, the results of this study suggest that NBI-enhanced laparoscopy does not provide superior detection of peritoneal surface malignancy compared with standard white light high-definition laparoscopy.

Expression of methylation-modulated tumor-related genes in endoscopically resected early esophageal squamous neoplasia

Smoking and alcohol consumption are major risk factors for the development of esophageal squamous cell carcinoma (ESCC). Recent studies have demonstrated that smoking and alcohol consumption may be associated with altered DNA methylation in human cancer development. The aim of the present study was to evaluate methylation-modulated protein expression of tumor-related genes (TRGs) in the early stages of esophageal squamous neoplasia (ESN). ESN tissue samples (n=141) comprising 19 cases of low-grade intraepithelial neoplasia (LGIN), 70 of high-grade intraepithelial neoplasia/carcinoma in situ (HGIN/CIS) and 52 of invasive cancer, were endoscopically resected. The methylation-modulated protein expression of 5 TRGs [fragile histidine triad (FHIT), E-cadherin, MutL homolog 1 (MLH1) /MutS homolog 2 (MSH2) and cyclooxygenase-2 (COX-2)] as well as p53 was examined with immunohistochemistry, and their expression was compared with patient clinicopathological characteristics. Reduced or loss of FHIT, E-cadherin, MLH1/MSH2 and COX-2 expression was detected in 26.3 (5/19), 5.3 (1/19), 0 (0/19) and 63.2% (12/19) of LGIN cases, 61.4 (43/70), 18.6 (13/70), 7.1 (5/70) and 65.7% (46/70) of HGIN/CIS cases, and 78.8 (41/52), 50.0 (26/52), 11.5 (6/52) and 59.6% (31/52) of invasive cancer cases, respectively. Reduced or absent expression of FHIT and E-cadherin was significantly associated with neoplastic progression (FHIT, P=0.0007; E-cadherin, P=0.00014). The mean number of TRGs (FHIT, E-cadherin, MLH1/MSH2, and COX-2) that exhibited reduced or absent expression in LGIN, HGIN/CIS and invasive cancer specimens was 1.12±0.61, 1.66±0.93 and 2.09±0.96, respectively, demonstrating a significant stepwise increment from LGIN to HGIN/CIS and then to invasive cancer (P<0.05). p53 overexpression was frequently detected in ESN with head and neck carcinomas. However p53 overexpression was not significantly associated with ESN progression. An increase in the number of the 5 TRG proteins with reduced or loss of expression in the early stages of esophageal tumorigenesis was demonstrated, and their decreased expression was observed to be associated with tumor progression. Therefore, smoking and alcohol drinking may be associated with not only carcinogenesis but also the progression of ESN.

Narrow-band imaging in transoral laser surgery for early glottic cancer in relation to clinical outcome

BACKGROUND

The purpose of this study was to validate the prognostic value of adding narrow-band imaging (NBI) during transoral laser surgery (TLS) for early glottic cancer.

METHODS

In 84 patients, 93 transoral laser resections were performed for carcinoma in situ (Tcis), T1, or T2 glottic cancer. TLS was preceded by intraoperative evaluation using traditional white-light imaging (WLI) in 51 cases. In 42 cases, NBI was used in addition to WLI. Local recurrence rate and recurrence-free survival were retrospectively compared between both groups.

RESULTS

Local recurrences developed in 14% of the 93 cases: 12 of 51 patients (24%) were treated by TLS based on WLI alone, and in 1 of 42 patients (2%) in the NBI group (P < .01). Two-year recurrence-free survival was 82% in the WLI group and 98% in the NBI group (P < .05).

CONCLUSION

Additional use of NBI during TLS for early glottic cancer significantly improves clinical outcome.

Diagnostic accuracy of Narrow Band Imaging for the detection of oral potentially malignant disorders

OBJECTIVE

To determine the clinical diagnostic accuracy of Narrow Band Imaging(™) for the detection of oral potentially malignant disorders in a prospective series of patients.

MATERIALS AND METHODS

New and existing patients referred to an oral medicine and pathology specialist clinic for assessment of at least one white, red or red-white oral mucosal lesion underwent conventional oral examination, followed by examination with the white light mode and then narrow band imaging mode of a Narrow Band Imaging(™) system. The clinical presentation, microvascular architecture and relevant histopathology of all lesions were recorded.

RESULTS

A total of 272 lesions from 95 patients were observed. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the detection of oral potentially malignant disorders or worse by Narrow Band Imaging(™) were 100%, 74.63%, 92.38%, 100% and 93.77%, respectively, when compared with conventional oral examination. Narrow Band Imaging(™) aided the detection of 24 lesions undetected by conventional oral examination and 13 lesions undetected by white light endoscopy.

CONCLUSION

Narrow Band Imaging(™) demonstrates great utility as a visualisation adjunct for detecting and monitoring oral potentially malignant diseases, particularly lesions not identified by conventional oral examination or white light examination alone.

Voice Outcome in Patients Treated With Endoscopic Laryngopharyngeal Surgery for Superficial Hypopharyngeal Cancer

OBJECTIVES

Endoscopic laryngopharyngeal surgery (ELPS) is a minimally invasive transoral surgery that was developed to treat superficial larygo-pharyngeal cancer, in which a mucosal lesion is resected transorally while preserving deeper structures by subepithelial injection. The purpose of this retrospective study is to evaluate voice outcome in patients who underwent ELPS for superficial hypopharyngeal cancer. As important structures in producing voice, such as intrinsic laryngeal muscles, their fascia, and recurrent laryngeal nerve, are located in the medial side of the piriform sinus and the postcricoid region of the hypopharynx, we focused on patients with cancer lesions involving these regions.

METHODS

From April 2010 to March 2011, 25 consecutive patients with superficial laryngopharyngeal cancer were treated with ELPS at Kyoto University Hospital. Among the 25 patients, 11 patients with cancer lesions on the medial side of the piriform sinus or the postcricoid area were studied. Preoperative and postoperative voice functions including maximum phonation time (MPT), mean flow rate (MFR), jitter, shimmer, soft phonation index (SPI), and noise-to-harmonic ratio (NHR), were compared retrospectively.

RESULTS

Five of 11 cancer lesions had submucosal invasion and no lesion had invaded the muscular layer pathologically. T stage was classified as Tis in 5 cases, T1 in 4 cases, and T2 in 2 cases. All lesions involved the medial side of the piriform sinus and 2 also involved the postcricoid area. Vocal fold movement was normal in all cases after the surgery. Average preoperative and postoperative values for MPT, MFR, jitter, shimmer, SPI, and NHR, were 22.7 seconds and 23.4 seconds, 165 mL/sec and 150 mL/sec, 1.53% and 1.77%, 3.82% and 5.17%, 35.5 and 36.6, and 0.13% and 0.14%, respectively. There was no statistical difference between preoperative and postoperative data for all values examined.

CONCLUSION

ELPS is useful in preserving voice function in the treatment of superficial hypopharyngeal cancer. Preserving the deeper structures including intrinsic muscles and their fascia may be important for preserving voice function as long as the lesions are superficial.

Narrow band imaging: clinical applications in oral and oropharyngeal cancer

Narrow Band Imaging (NBI) is an endoscopic optical imaging enhancement technology that improves the contrast of mucosal surface texture, and enhances visualisation of mucosal and submucosal vasculature. White light is filtered to emit two 30-nm narrow bands of blue (415 nm) and green light (540 nm) light simultaneously, the former corresponding to the main peak absorption spectrum of haemoglobin, and the latter allowing visualisation of blood vessels in the deeper mucosal and submucosal layers. NBI has been used to better assess oral potentially malignant disorders (OPMD), identify oral and oropharyngeal squamous cell carcinoma (SCC), and to define surgical margins of head and neck malignancies. NBI shows great potential in improving detection rates of OPMD, facilitating better assessment of oral and oropharyngeal SCC, and reducing the risk of recurrence for oral SCC. Although further research is required to better understand and define intrapapillary capillary loop (IPCL) patterns and to relate these with clinical, histopathological and molecular parameters especially for early mucosal changes, there is building evidence to recommend its use as the new gold standard for endoscopic assessment in head and neck oncology.

Recent Advances From Basic and Clinical Studies of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive squamous cell carcinomas and is highly prevalent in Asia. Alcohol and its metabolite, acetaldehyde, are considered definite carcinogens for the esophagus. Polymorphisms in the aldehyde dehydrogenase 2 gene, which encodes an enzyme that eliminates acetaldehyde, have been associated with esophageal carcinogenesis. Studies of the mutagenic and carcinogenic effects of acetaldehyde support this observation. Several recent large-scale comprehensive analyses of the genomic alterations in ESCC have shown a high frequency of mutations in genes such as TP53 and others that regulate the cell cycle or cell differentiation. Moreover, whole genome and whole exome sequencing studies have frequently detected somatic mutations, such as G:C→A:T transitions or G:C→C:G transversions, in ESCC tissues. Genomic instability, caused by abnormalities in the Fanconi anemia DNA repair pathway, is also considered a pathogenic mechanism of ESCC. Advances in diagnostic techniques such as magnifying endoscopy with narrow band imaging or positron emission tomography have increased the accuracy of diagnosis of ESCC. Updated guidelines from the National Comprehensive Cancer Network standardize the practice for the diagnosis and treatment of esophageal cancer. Patients with ESCC are treated endoscopically or with surgery, chemotherapy, or radiotherapy, based on tumor stage. Minimally invasive treatments help improve the quality of life of patients who undergo such treatments. We review recent developments in the diagnosis and treatment of ESCC and advances gained from basic and clinical research.

Image Quality Analysis of Various Gastrointestinal Endoscopes: Why Image Quality Is a Prerequisite for Proper Diagnostic and Therapeutic Endoscopy

Arising from human curiosity in terms of the desire to look within the human body, endoscopy has undergone significant advances in modern medicine. Direct visualization of the gastrointestinal (GI) tract by traditional endoscopy was first introduced over 50 years ago, after which fairly rapid advancement from rigid esophagogastric scopes to flexible scopes and high definition videoscopes has occurred. In an effort towards early detection of precancerous lesions in the GI tract, several high-technology imaging scopes have been developed, including narrow band imaging, autofocus imaging, magnified endoscopy, and confocal microendoscopy. However, these modern developments have resulted in fundamental imaging technology being skewed towards red-green-blue and this technology has obscured the advantages of other endoscope techniques. In this review article, we have described the importance of image quality analysis using a survey to consider the diversity of endoscope system selection in order to better achieve diagnostic and therapeutic goals. The ultimate aims can be achieved through the adoption of modern endoscopy systems that obtain high image quality.

Transoral surgery for laryngo-pharyngeal cancer - The paradigm shift of the head and cancer treatment

Transoral surgery is a less invasive treatment that is becoming a major strategy in the treatment of laryngo-pharyngeal cancer. It is a minimally invasive approach that has no skin incision and limits the extent of tissue dissection, disruption of speech and swallowing muscles, blood loss, damage to major neurovascular structures, and injury to normal tissue. Transoral approaches to the laryngo-pharynx, except for early glottis cancer, had been limited traditionally to tumors that can be observed directly and manipulated with standard instrumentation and lighting. Since the 1990s, transoral laser microsurgery (TLM) has been used as an organ preservation strategy with good oncological control and good functional results, although it has not been widely used because of its technical difficulty. Recently, transoral robotic surgery (TORS) is becoming popular as a new treatment modality for laryngo-pharyngeal cancer, and surgical robots are used widely in the world since United States FDA approval in 2009. In spite of the global spread of TORS, it has not been approved by the Japan FDA, which has led to the development of other low-cost transoral surgical techniques in Japan. Transoral videolaryngoscopic surgery (TOVS) was developed as a new transoral surgery system for laryngo-pharyngeal lesions to address the problems of TLM. In TOVS, a rigid endoscope is used to visualize the surgical field instead of a microscope and the advantages of TOVS include the wide operative field and working space achieved using the distending laryngoscope and videolaryngoscope. Also, with the spread of narrow band imaging (NBI), endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), which are widely used for superficial cancers in the gastrointestinal tract, have been applied for the superficial laryngo-pharyngeal cancer. Both EMR and ESD are performed mainly by gastroenterologists with a sharp dissector and magnifying endoscopy (ME)-NBI with minimal surgical margin. Endoscopic laryngo-pharyngeal surgery (ELPS) was developed to treat laryngo-pharyngeal superficial cancer by modifying the ESD procedure. The concept of ELPS is the same as that of ESD, however, the resection procedure is performed by a head and neck surgeon with both hands using a ME-NBI and rigid curved laryngo-pharyngoscope. These four procedures are low cost with similar oncological and functional outcomes to TORS. TORS may be less expensive than chemoradiotherapy, but the number of hospitals that can afford da Vinci surgical systems is limited. Even in the era of robotic surgery, these four procedures will be good options for laryngo-pharyngeal cancer.

Diagnostic performance of magnifying narrow-band imaging for early gastric cancer: A meta-analysis

AIM: To investigate the performance of magnifying endoscopy with narrow-band imaging (ME-NBI) in the diagnosis of early gastric cancer (EGC).

METHODS: Systematic literature searches were conducted until February 2014 in PubMed, EMBASE, Web of Science, Ovid, Scopus and the Cochrane Library databases by two independent reviewers. Meta-analysis was performed to calculate the pooled sensitivity, specificity and diagnostic odds ratio and to construct a summary receiver operating characteristic (ROC) curve. Subgroup analyses were performed based on the morphology type of lesions, diagnostic standard, the size of lesions, type of assessment, country and sample size to explore possible sources of heterogeneity. A Deeks’ asymmetry test was used to evaluate the publication bias.

RESULTS: Fourteen studies enrolling 2171 patients were included. The pooled sensitivity, specificity and diagnostic odds ratio for ME-NBI diagnosis of EGC were 0.86 (95%CI: 0.83-0.89), 0.96 (95%CI: 0.95-0.97) and 102.75 (95%CI: 48.14-219.32), respectively, with the area under ROC curve being 0.9623. Among the 14 studies, six also evaluated the diagnostic value of conventional white-light imaging, with a sensitivity of 0.57 (95%CI: 0.50-0.64) and a specificity of 0.79 (95%CI: 0.76-0.81). When using “VS” (vessel plus surface) ME-NBI diagnostic systems in gastric lesions of depressed macroscopic type, the pooled sensitivity and specificity were 0.64 (95%CI: 0.52-0.75) and 0.96 (95%CI: 0.95-0.98). For the lesions with a diameter less than 10 mm, the sensitivity and specificity were 0.74 (95%CI: 0.65-0.82) and 0.98 (95%CI: 0.97-0.98).

CONCLUSION: ME-NBI is a promising endoscopic tool in the diagnosis of early gastric cancer and might be helpful in further target biopsy.

Endocytoscopic observation of various esophageal lesions at ×600: can nuclear abnormality be recognized?

Endocytoscopy (ECS) is a novel endoscopic technique that allows detailed diagnostic examination of the gastrointestinal tract at the cellular level. We previously reported that use of ECS at ×380 magnification (GIF-Y0002) allowed a pathologist to diagnose esophageal squamous cell carcinoma (ESCC) with high sensitivity (94.9%) but considerably low specificity (46.7%) because this low magnification did not reveal information about nuclear abnormality. In the present study, we used the same magnifying endoscope to observe various esophageal lesions, but employed digital 1.6-fold magnification to achieve an effective magnification of ×600, and evaluated whether this improved the diagnostic accuracy in distinguishing neoplastic from non-neoplastic lesions.We examined the morphology of surface cells using vital staining with toluidine blue and compared the histological features of 40 cases, including 19 case of ESCC and 21 non-neoplastic esophageal lesions (18 cases of esophagitis, 1 case of glycogenic acanthosis, 1 case of leiomyoma, and 1 case of normal squamous epithelium). One endoscopist classified the lesions using the type classification, and we consulted one pathologist for judgment of the ECS images as 'neoplastic', 'borderline', or 'non-neoplastic'. At ×600 magnification, the pathologist confirmed that nuclear abnormality became evident, in addition to the information about nuclear density provided by observation at ×380. The overall sensitivity and specificity with which the endoscopist was able to predict neoplastic lesions using the type classification was 100% (19/19) and 90.5% (19/21), respectively, in comparison with values of 94.7% (18/19 cases) and 76.2% (16/21), respectively, for the pathologist using a magnification of ×600. The pathologist diagnosed two non-neoplastic lesions and one case of ESCC showing an apparent increase of nuclear density with weak nuclear abnormality as 'borderline'. Among the 21 non-cancerous lesions, two cases of esophagitis that were misdiagnosed by the endoscopist were also misinterpreted as 'neoplastic' by the pathologist. We have shown, by consultation with a pathologist, that an ECS magnification of ×600 (on a 19-inch monitor) is adequate for recognition of nuclear abnormality. We consider that it is feasible to diagnose esophageal neoplasms on the basis of ECS images, and that biopsy histology can be omitted if a combination of increased nuclear density and nuclear abnormality is observed.

Efficacy of narrow band imaging for detection and surveillance of potentially malignant and malignant lesions in the oral cavity and oropharynx: a systematic review

OBJECTIVE

Narrow band imaging (NBI) is an endoscopic technique that enhances the mucosal surface texture, and mucosal and submucosal vascular morphology. This paper systematically reviews the available literature regarding the efficacy of NBI for the detection and monitoring of potentially malignant and malignant lesions in the oral cavity and oropharynx.

METHODS

Databases searched included PubMed, EMBASE, Web of Science and Scopus (to September 2013). Additional articles were found by conducting an author publication search using PubMed and by scanning the reference lists of relevant articles. Only trials that investigated and evaluated the effectiveness of both white light (WL) and NBI for aiding the detection of only oral potentially malignant lesions, oral squamous cell carcinomas and/or oropharyngeal squamous cell carcinomas were considered for this review. Two reviewers (ANV and CSF) independently assessed retrieved articles against the criteria, and included articles underwent data extraction and risk of bias assessment.

RESULTS

Two studies, one retrospective and one prospective, met the inclusion criteria. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for WL ranged between 56-96%, 60-100%, 33-100%, 87-99% and 66-89% respectively, whereas it was 87-96%, 94-98%, 73-96%, 97-98% and 92-97% respectively for NBI.

CONCLUSION

While more research is required to determine the full value of NBI, it has great potential in accurately aiding the detection and assessment of neoplastic lesions, and influencing how these lesions are managed.

Update on narrow band imaging in disorders of the upper gastrointestinal tract

With the ever-increasing concern regarding morbidity and mortality associated with diseases of the gastrointestinal tract, the importance of an effective and efficient diagnostic tool cannot be overstated. The standard of care currently is an examination using conventional white light endoscopy. This approach may occasionally overlook areas exhibiting a premalignant change. Numerous image-enhanced modalities have been recently introduced. Narrow band imaging (NBI) appears to be the most prominent of these and perhaps the most commonly used. Thepresent review will focus on some of the newer studies on NBI and its utility in the diagnosis of malignant, pre-malignant and chronic inflammatory conditions of the upper gastrointestinal tract.

High definition endoscopy and "narrow band imaging" in the diagnosis of gastroesophageal reflux disease

INTRODUCTION

The gastroesophageal reflux disease is a common condition in the western world but less than half of patients present endoscopic abnormalities, making a standard procedure unsuitable for diagnosis. High definition endoscopy coupled with narrow band imaging has shown potential for differentiation of lesions and possible biopsy, allowing early diagnosis and treatment.

METHODS

This review describes the principles of biotic and their influence in obtaining images with better definition of the vessels in the mucosa, through the narrow band imaging. Selected papers using it in patients with reflux disease and Barrett's esophagus are analyzed in several ways, highlighting the findings and limitations.

CONCLUSION

The meaning of the narrow band imaging in the endoscopic diagnosis of reflux disease will be defined by large scale studies, with different categories of patients, including assessment of symptoms and response to treatment.

Endocytoscopic findings of lymphomas of the stomach

BACKGROUND

The gastric lesions of various lymphomas were observed at the cellular level using endocytoscopy.

METHODS

Endocytoscopy and magnifying endoscopy with narrow band imaging (NBI) were performed in 17 patients with lymphomas of the stomach. The lesions consisted of 7 with low-grade mucosa-associated lymphoid tissue (MALT), 5 with gastric involvement by adult T-cell leukemia/lymphoma (ATLL), 4 with diffuse large B-cell lymphoma (DLBCL), and 1 with peripheral T-cell lymphoma.

RESULTS

On conventional endoscopy, 9 were classified as having superficial spreading type, 7 were mass-forming type, and 1 was diffuse infiltrating type. Anti-H. pylori treatment was given in the 7 MALT lymphoma cases. NBI magnification endoscopy invariably showed dilatation or ballooning and destruction of gastric pits and elongation and distortion in microvessels. Endocytoscopy showed mucosal aggregation of interstitial cellular elements in almost all gastric lymphoma cases. The nuclear diversity in size and configuration was exclusively seen in gastric lymphomas other than MALT lymphoma, whereas the nuclei of MALT lymphoma cells were regular and small to moderate in size. Inter-glandular infiltration by lymphomatous cell elements was frequently observed in MALT lymphoma and DLBCL, but it was uncommon in peripheral gastric T-cell malignancies. Endocytoscopy could identify the disease-specific histology, the lymphoepithelial origin, as inter-glandular infiltration of cellular components in MALT lymphoma and the possibly related DLBCL cases. Complete regression (CR) was observed in 2 of the 7 MALT lymphoma patients. In the 2 patients with CR who underwent repeat endocytoscopy, the ultra-high magnification abnormalities returned to normal, while they were unchanged in those without tumor regression.

CONCLUSIONS

On endocytoscopy, intra-glandular aggregation of cellular components was invariably identified in lymphomas of the stomach. Nuclear regularity in size and configuration may indicate the cytological grade, differentiating the indolent low-grade from aggressive lymphoproliferative diseases. The inter-glandular infiltration seen on endocytoscopy can indicate the lymphoepithelial lesions seen in MALT lymphoma and related DLBCL. Endocytoscopy would be applicable for virtual histopathological diagnosis of different lymphoproliferative disorders and their clinical assessment during ongoing endoscopy.

Review article: newer optical and digital chromoendoscopy techniques vs. dye-based chromoendoscopy for diagnosis and surveillance in inflammatory bowel disease

BACKGROUND

Recent innovations in gastrointestinal endoscopy have changed our traditional approach to diagnosis and therapy in patients with inflammatory bowel diseases (IBD). While traditionally used dye-based chromoendoscopy (DBC) techniques suffer from several limitations that reduce their utility in daily routine practice, newer 'dye-less' chromoendoscopy (DLC) techniques offer a great potential to overcome most of these limitations.

AIM

To review available optical and digital chromoendoscopy techniques, by critically discussing their potential for diagnostic and surveillance colonoscopy in patients with IBD.

METHODS

A literature search on the use of dye-less and dye-based chromoendoscopy in IBD patients was performed.

RESULTS

In long-standing IBD, DBC improves detection of dysplasia (diagnostic odds ratio = 17.5, 95% CI = 1.2-247.1) as well as prediction of inflammatory disease activity and extent of disease compared with standard video-colonoscopy. Narrow band imaging (NBI) shows no improvement in dysplasia detection rates compared with white-light endoscopy and DBC (P = 0.6). Moreover, NBI results in a suboptimal differentiation of dysplastic from nondysplastic lesions. No data regarding digital DLC techniques (i.e. FICE, i-scan) for dysplasia detection in IBD are yet available. Both NBI and i-scan are superior to white-light endoscopy in assessing the activity and extent of colorectal IBD.

CONCLUSIONS

Although the potential benefits of newer optical and digital dye-less chromoendoscopy techniques over traditionally used DBC are substantial, only DBC can currently be recommended to improve dysplasia detection in long-standing IBD. In contrast, DLC has the potential to quantify disease activity and mucosal healing in IBD.

Advances in optical adjunctive AIDS for visualisation and detection of oral malignant and potentially malignant lesions

Traditional methods of screening for oral potentially malignant disorders and oral malignancies involve a conventional oral examination with digital palpation. Evidence indicates that conventional examination is a poor discriminator of oral mucosal lesions. A number of optical aids have been developed to assist the clinician to detect oral mucosal abnormalities and to differentiate benign lesions from sinister pathology. This paper discusses advances in optical technologies designed for the detection of oral mucosal abnormalities. The literature regarding such devices, VELscope and Identafi, is critically analysed, and the novel use of Narrow Band Imaging within the oral cavity is also discussed. Optical aids are effective in assisting with the detection of oral mucosal abnormalities; however, further research is required to evaluate the usefulness of these devices in differentiating benign lesions from potentially malignant and malignant lesions.

Magnified and enhanced computed virtual chromoendoscopy in gastric neoplasia: A feasibility study

AIM: To evaluate the feasibility of a new computed virtual chromoendoscopy (CVC) device (M i-scan) in the diagnosis of gastric neoplasia.

METHODS: Patients with superficial lesions no larger than 1.0 cm found during high definition endoscopy were included. Those with advanced or obviously protruded or depressed lesions, lesions larger than 1.0 cm and/or lesions which were not amenable to observation by zoom function were excluded. The endoscopist was required to give the real-time descriptions of surface pit patterns of the lesions, based on surface pattern classification of enhanced magnification endoscopy. According to previous reports, types I-III represent non-neoplastic lesions, and types IV-V represent neoplastic lesions. Diagnosis with M i-scan and biopsy was performed before histopathological diagnosis. Magnified images of gastric lesions with and without enhancement were collected for further analysis. The diagnostic yield of real-time M i-scan and effects on magnification image quality by tone enhancement (TE), surface enhancement (SE) and color enhancement (CE) were calculated. The selected images were sent to another endoscopist. The endoscopist rated the image quality of each lesion at 3 levels. Ratings of image quality were based on visualization of pit pattern, vessel and demarcation line.

RESULTS: One hundred and eighty-three patients were recruited. Five patients were excluded for advanced gastric lesions, 1 patient was excluded for poor preparation and 2 patients were excluded for superficial lesions larger than 1.0 cm; 132 patients were excluded for no lesions found by high definition endoscopy. In the end, 43 patients with 43 lesions were included. Histopathology revealed 10 inflammation, 14 atrophy, 10 metaplasia, 1 low grade dysplasia (LGD), 5 high grade dysplasia (HGD) and 3 cancers. For 7 lesions classified into type I, histopathology revealed 6 atrophy and 1 metaplasia; for 10 lesions classified into type II, histopathology revealed 2 inflammation, 7 atrophy and 1 metaplasia; for 10 lesions classified into type III, histopathology revealed 1 inflammation, 8 metaplasia and 1 LGD; for 9 lesions classified into type IV, histopathology revealed 4 inflammation, 1 atrophy and 4 HGD; for 7 lesions classified into type V, histopathology revealed 3 inflammation, 1 HGD and 3 cancers. A total of 172 still images, including 43 images by white light (MWL) and 129 images by M i-scan (43 with TE, 43 with SE and 43 with CE), were selected and sent to the endoscopist who did the analysis. General image quality of M i-scan with TE and SE was significantly better than that of MWL (TE, 4.55 ± 1.07; SE, 4.30 ± 1.02; MWL, 3.25 ± 0.99; P < 0.001). Visualization of pit pattern was significantly improved by M i-scan with SE (1.93 ± 0.25 vs 1.50 ± 0.50, P < 0.001). Microvessel visualization was significantly improved by M i-scan with TE (1.23 ± 0.78 vs 0.76 ± 0.73, P < 0.001). Demarcation line visualization was improved by M i-scan with both TE and SE (TE, 1.75 ± 0.52; SE, 1.56 ± 0.59; MWL, 0.98 ± 0.44; P < 0.001). M i-scan with CE did not show any significant improvements of image quality in general or in the 3 key parameters. Although M i-scan with TE and SE slightly increased the diagnostic yield of MWL, there was no significant difference (P > 0.1).

CONCLUSION: Although digital enhancement improves the image quality of magnification endoscopy, its value in improving the diagnostic yield seems to be limited.

Screening for gastric premalignant lesions with narrow band imaging, white light and updated Sydney protocol or both?

BACKGROUND

Narrow band imaging (NBI) can accurately discriminate gastritis but premalignant lesions (PMLs) are difficult to detect.

AIMS

The purpose of this study was to compare white light endoscopy (WLE) and histopathologic findings using the updated Sydney protocol (USP) with NBI and targeted biopsies (TB).

METHODS

One hundred nineteen symptomatic patients referred for upper GI endoscopy were included in this prospective open study. All patients were assessed for gastritis and PMLs using WLE and NBI by two endoscopists selected in a random manner. Biopsies were taken according to USP and targeted from any area suspicious for PML. Imaging and histological findings between protocols were compared.

RESULTS

In total 45 patients (38 %) had atrophy of whom 39 (32.7 %) were detected with WLE-USP and 28 (23.5 %) with NBI-TB (p = 0.03), 25 (21 %) had intestinal metaplasia (IM) of whom 19 (16 %) were detected with WLE-USP and 18 (15.1 %) with NBI-TB (p = 0.7) and 14 (12 %) had dysplasia of whom 12 (10 %) were detected with WLE-USP and 7 (7 %) with NBI-TB (p = 0.5), and 1 (0.8 %) case of gastric cancer only detected with WLE-USP. Accuracies for atrophy and IM were 93 and 90 % for the WLE-USP and 80 and 82 % for NBI-TB. The NBI-TB detected six cases of atrophy (13 %), 5 (20 %) of IM, and 2 (14 %) of dysplasia missed by WLE-USP as agreement was moderate. Accuracies of the NBI patterns for body and antral gastritis were 80 and 84 %.

CONCLUSIONS

In a non high-risk population NBI-TB has less accuracy in detecting premalignant lesions compared to WLE-USP. However, it may be used as an important and easy-to-use complementary method which increases overall detectability for gastric premalignant lesions.

Screening for precancerous lesions of upper gastrointestinal tract: from the endoscopists' viewpoint

Upper gastrointestinal tract cancers are one of the most important leading causes of cancer death worldwide. Diagnosis at late stages always brings about poor outcome of these malignancies. The early detection of precancerous or early cancerous lesions of gastrointestinal tract is therefore of utmost importance to improve the overall outcome and maintain a good quality of life of patients. The desire of endoscopists to visualize the invisibles under conventional white-light endoscopy has accelerated the advancements in endoscopy technologies. Nowadays, image-enhanced endoscopy which utilizes optical- or dye-based contrasting techniques has been widely applied in endoscopic screening program of gastrointestinal tract malignancies. These contrasting endoscopic technologies not only improve the visualization of early foci missed by conventional endoscopy, but also gain the insight of histopathology and tumor invasiveness, that is so-called optical biopsy. Here, we will review the application of advanced endoscopy technique in screening program of upper gastrointestinal tract cancers.

Novel serine/threonine kinase 11 gene mutations in Peutz-Jeghers syndrome patients and endoscopic management

AIM: To explore mutations in serine/threonine kinase 11 (STK11) gene in Peutz-Jeghers syndrome (PJS) with gastrointestinal (GI) hamartomatous polyps.

METHODS: Six Japanese PJS patients in 3 families were enrolled in this study. Each of the cases had hamartomatous polyposis in the gastrointestinal tract, including the small intestine, along with mucocutaneous hyperpigmentation. Narrow-band imaging (NBI)-magnification endoscopy was employed to detect microvascular and microsurface irregularities in the GI lesions. NBI magnification findings could be classified into three groups (type A, type B, or type C). Endoscopic polypectomy was performed using double-balloon enteroscopy or colonoscopy. Genomic DNA was extracted from a whole blood sample from each subject. All of the coding exons of STK11 gene, its boundary regions, and the promoter region containing the polymorphic regions were amplified by polymerase chain reaction, and direct sequencing was performed to assess the germline mutations.

RESULTS: NBI-magnification endoscopic observation could detect the abnormalities in microvessels and microsurface structures of GI polyps. Overall, we found 5 cases of type A and one case without the examination for the gastric polyps, while there were 4 cases of type B and 2 case of type A for the colorectal polyps. Seventy-nine small-bowel and 115 colorectal polyps over 27 sessions for each were resected endoscopically without significant complications. The only delayed complication included the occurrence of bleeding in a case, and this was successfully managed with hemoclips. Resected polyps contained no malignant components. Based on mutation analysis, all 3 cases in Family I exhibited the +658C>T nonsense mutation in exon 5, which resulted in the production of a truncated protein (Q220X). In Family II, a case had -252C>A and -193C>A in the promoter region. In Family III, a case was found to have the +1062C>G (F342L) mutation in exon 8.

CONCLUSION: We found two novel mutations of STK11 in association with PJS. Endoscopic polypectomy of GI polyps in PJS patients appears to be useful to prevent emergency laparotomies and reduce the cancer risk.

Magnifying endoscopy for intestinal follicular lymphoma is helpful for prompt diagnosis

The representative endoscopic features of primary intestinal follicular lymphoma are well known as small whitish polypoid nodules, but a magnified view has only been described in a few case reports. Herein, we report a case with intestinal follicular lymphoma in which magnifying endoscopy with narrow band imaging was helpful for prompt diagnosis. A 57-year-old Japanese woman underwent surveillance esophagogastroduodenoscopy. The endoscopic examination revealed confluent whitish granules in the duodenum, distinct from the nodules or polyps that are typical findings of intestinal follicular lymphoma. Magnifying endoscopy visualized whitish enlarged villi, and narrow band imaging emphasized an elongated and coiled vascular pattern. Based on these features, intestinal follicular lymphoma was highly suspected, and subsequent histological study confirmed the diagnosis. This case demonstrates that magnifying endoscopy with narrow band imaging was useful for the detection and prompt diagnosis of intestinal follicular lymphoma. The pathological features of intestinal follicular lymphoma are also discussed.

Endoscopic diagnostic strategy of superficial esophageal squamous cell carcinoma

The prognosis of the esophageal squamous cell carcinoma is still poor. Early detection is ideal to improve patient survival. In particular, superficial cancer limited within the mucosal layer is a good candidate for minimally invasive treatment by endoscopic resection with curative intent. However, an effective endoscopic diagnostic strategy is not established worldwide. Herein, we review the published papers on this subject.

The Usefulness of Magnifying Endoscopy and Narrow-Band Imaging in Measuring the Depth of Invasion before Endoscopic Submucosal Dissection

With the widespread application of endoscopic submucosal dissection for the treatment of gastrointestinal neoplasms, accurate determination of the invasion depth prior to intervention has become an indispensable part of treatment planning. Narrow-band imaging (NBI) is a novel endoscopic technique that may enhance the accuracy of diagnosis. Magnifying endoscopy with NBI has been shown to be effective for determining invasion depth for intrapapillary capillary loop classification of esophageal cancer and microvascular pattern of stomach cancer. Such precise pre-treatment staging of early neoplastic lesions in the gastrointestinal tract warrants timely initiation of disease-tailored treatment and, ultimately, better quality of life and improved patient survival.

Advances in endoscopic diagnosis of early esophageal cancer

Esophageal cancer is one of the most common malignancies in China. The prognosis of esophageal carcinoma is closely related to the stage of the disease at the time of detection. Patients with early lesions have an excellent prognosis, whereas those with more advanced stages of the disease usually have a poor prognosis. Therefore, the early detection of these lesions is of the greatest importance for treatment. Recently, many endoscopic methods have been developed, such as fluorescence endoscopy, confocal endoscopy, optical coherence tomography (OCT), and electronic staining imaging technology which includes narrow band imaging (NBI), Fujinon intelligent chromoendoscopy (FICE) and I-Scan. However, the clinical value of these techniques needs to be ascertained in the coming years. This paper reviews the progress of endoscopic diagnosis of early esophageal cancer.

Confocal laser endomicroscopy and narrow-band imaging-aided endoscopy for in vivo imaging of colitis and colon cancer in mice

New endoscopic techniques such as narrow-band imaging (NBI) and confocal laser endomicroscopy (CLE) have improved the in vivo diagnosis of human gastrointestinal diseases in the colon. Whereas NBI may facilitate the identification of neoplastic lesions, CLE permits real-time histology of the inflamed or neoplastic colonic mucosa through the use of fluorescent dyes. These techniques have been recently adopted for use during ongoing endoscopy in mice. This protocol, which can be completed in 2 h, provides a detailed description of NBI and CLE in the mouse colon. In contrast to other techniques, this approach does not require laparotomy, and it allows direct CLE analysis of lesions identified by NBI. Mice exposed to models of colitis or colorectal cancer are anesthetized and examined with a miniaturized NBI endoscope, which provides an increased contrast of the vasculature. Upon identification of suspicious areas by NBI and the administration of fluorescent dyes, a confocal laser probe can be directed to the area of interest through the endoscope and confocal images can be obtained. Through the use of various fluorescent dyes, different aspects of the mucosa can be assessed. In addition, fluorescence-labeled antibodies can be used for molecular imaging of mice in vivo. Mouse NBI endoscopy and CLE represent reliable and fast high-quality techniques for the endoscopic characterization and molecular imaging of the mucosa in colitis and colon cancer.

Proceedings of a preliminary workshop at Gastro 2009--narrow banding imaging in digestive endoscopy: clinical outcome of classification (Omed-Jges Educational Meeting held on 22 November, 2009)

This publication reports the proceedings of the preliminary meeting of the working party that met at Gastro 2009 during the World Congress in London. The purpose of the preliminary meeting was to consider the areas that require attention, to discuss some of the findings that have already been published and to agree on the way forward. Our reason for publishing these proceedings is to stimulate interest in this venture and to provide the opportunity for input from the endoscopy community worldwide. The next meeting of the working party will be at the JGES Society meeting in Aomori in April 2011 when we hope to prepare a preliminary classification. This will be presented for general discussion and debate at the International Congress of Endoscopy (ICE) in Los Angeles in September 2011.

Non-sequential narrow band imaging for targeted biopsy and monitoring of gastric intestinal metaplasia

AIM: To evaluate the efficacy of non-sequential narrow band imaging (NBI) for a better recognition of gastric intestinal metaplasia (GIM).

METHODS: Previously diagnosed GIM patients underwent targeted biopsy from areas with and without GIM, as indicated by NBI, twice at an interval of 1 year. The authors compared the endoscopic criteria such as light blue crest (LBC), villous pattern (VP), and large long crest (LLC) with standard histology. The results from two surveillance endoscopies were compared with histology results for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratio of positive test (LR+). The number of early gastric cancer cases detected was also reported.

RESULTS: NBI targeted biopsy was performed in 38 and 26 patients during the first and second surveillance endoscopies, respectively. There were 2 early gastric cancers detected in the first endoscopy. No cancer was detected from the second study. Surgical and endoscopic resections were successfully performed in each patient. Sensitivity, specificity, PPV, NPV, and LR+ of all 3 endoscopic criteria during the first/second surveillances were 78.8%/91.3%, 82.5%/89.1%, 72.8%/77.8%, 86.8%/96.1, and 4.51/8.4, respectively. LBC provided the highest LR+ over VP and LLC.

CONCLUSION: Non-sequential NBI is useful for GIM targeted biopsy. LBC provides the most sensitive reading. However, the optimal duration between two surveillances requires further study.

Narrow-band imaging endoscopy with and without magnification in diagnosis of colorectal neoplasia

AIM: To evaluate the diagnostic efficacies of narrow-band imaging (NBI) endoscopy with and without high magnification in distinguishing neoplasia from non-neoplasia colorectal lesions.

METHODS: A total of 118 patients with 123 colorectal lesions examined by NBI endoscopy in the Zhejiang Provincial People’s Hospital from September 2008 to April 2010 were enrolled in this study. These lesions were classified by pit pattern and capillary pattern, and then assessed by histopathology.

RESULTS: Ten lesions not meeting the diagnostic criteria were excuded, the overall diagnostic accuracy of NBI endoscopy in distinguishing neoplasia from non-neoplasia colorectal lesions was 91.2% (103/113), and that of NBI endoscopy with and without high magnification was 93.0% (40/43) and 90.0% (63/70), respectively. Both were significantly higher than that of conventional colonoscopy reported in the literature (P < 0.05), but there was no significant difference between the two groups (P > 0.05).

CONCLUSION: Besides NBI magnifying endoscopy, NBI endoscopy without magnification may also be used to distinguish neoplasia from non-neoplasia colorectal lesions.

Prospective replacement of magnifying endoscopy by a newly developed endocytoscope, the 'GIF-Y0002'

Endocytoscopy has the potential to reduce the need for histologic examination of biopsy specimens in cases of esophageal squamous cell carcinoma. Up to now, two types of endocytoscope have been used: the probe type and the integrated type. In this study we examined the utility of a newly developed endocytoscope, the 'GIF-Y0002,' which has a single lens allowing consecutive magnification from the conventional endoscopy level up to ×380. Using the GIF-Y0002, we examined 24 examples of normal esophageal mucosa to clarify the appearance of the microvasculature of the normal squamous epithelium in vivo. We also examined 11 cases of esophageal cancer in the same way, employing methylene blue as a vital dye to stain the surface cells. In normal squamous epithelium, we clarified the relationship between the subepithelial capillary network, IPCLs and subepithelial venules. With methylene blue staining, we observed typical squamous cells (low nuclear density and low N/C ratio without nuclear abnormality). When cancerous lesions were observed using lower-power magnification, we were able to visualize their microvascular architecture to the same extent as when conventional magnifying endoscopy was used. Furthermore, at higher magnification, we were able to visualize the features of blood flow in both superficial and advanced cancer. Methylene blue staining revealed an increase of nuclear density in all cases of cancer. The pathologist agreed to omit biopsy histology in 81.8% (9/11) of cancer cases considering the nuclear density and nuclear abnormality. The GIF-Y0002 provides information on cell abnormality in addition to the features revealed by currently available magnifying endoscopy.

Angiogenesis in superficial esophageal squamous cell carcinoma: magnifying endoscopic observation and molecular analysis

Observations of esophageal squamous cell carcinoma using magnifying endoscopy have now been carried out extensively and, as a result, it has become clear that the morphology of the microvessels evident at the tumor surface reflects the depth of tumor invasion. In M1 and M2 cancer, the surface microvasculature reveals dilation and elongation of the intrapapillary capillary loops (IPCL). However, at this stage, some immature capillaries resembling IPCL also arise inside the tumor and, therefore, the view of the microvasculature should be described as one showing 'intermixing of modified IPCL and IPCL-like immature capillaries (IPCL-like abnormal capillary)'. As cancer invades into the muscularis mucosa (M3 or deeper), an obviously dilated and irregularly branched tumor-specific vasculature, more accurately described as 'neovasculature', can be observed. From our magnifying endoscopy observations and studies of the molecular profile of early esophageal cancer, we conclude that two major angiogenic steps exist in precancerous and M3 lesions in the early phase of cancer progression. In addition, it is now possible to study cell morphology using an endocytoscope with a much higher magnification (×400-×1000) than magnifying endoscopes currently on the market. The histology revealed in this way may reduce the need for conventional biopsy histology in the future.

Early detection of superficial squamous cell carcinoma in the head and neck region and esophagus by narrow band imaging: a multicenter randomized controlled trial

PURPOSE

Most of the esophageal squamous cell carcinomas (ESCCs) and cancers of the head and neck (H&N) region are diagnosed at later stages. To achieve better survival, early detection is necessary. We compared the real-time diagnostic yield of superficial cancer in these regions between conventional white light imaging (WLI) and narrow band imaging (NBI) in high-risk patients.

PATIENTS AND METHODS

In a multicenter, prospective, randomized controlled trial, 320 patients with ESCC were randomly assigned to primary WLI followed by NBI (n = 162) or primary NBI followed by WLI (n = 158) in a back-to-back fashion. The primary aim was to compare the real-time detection rates of superficial cancer in the H&N region and the esophagus between WLI and NBI. The secondary aim was to evaluate the diagnostic accuracy of these techniques.

RESULTS

NBI detected superficial cancer more frequently than did WLI in both the H&N region and the esophagus (100% v 8%, P < .001; 97% v 55%, P < .001, respectively). The sensitivity of NBI for diagnosis of superficial cancer was 100% and 97.2% in the H&N region and the esophagus, respectively. The accuracy of NBI for diagnosis of superficial cancer was 86.7% and 88.9% in these regions, respectively. The sensitivity and accuracy were significantly higher using NBI than WLI in both regions (P < .001 and P = .02 for the H&N region; P < .001 for both measures for the esophagus, respectively).

CONCLUSION

NBI could be the standard examination for the early detection of superficial cancer in the H&N region and the esophagus.