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ESD is an excellent therapy, because it allows en bloc resections of targeted lesions. However, if preoperative determination of lateral extensions is inaccurate, postoperative pathological evaluation may result in positive lateral margins. Therefore, accurate preoperative diagnosis of lateral extensions is imperative. It is possible to observe surface and microvascular patterns in detail by combination of narrow band imaging (NBI) and magnified endoscopy. NBI magnified endoscopy is useful for diagnosis of lateral extensions of cancerous lesions [1, 2]. Diagnosis of lateral extensions by white light (WL) endoscopy, chromoendoscopy using indigo carmine, chromoendoscopy with acetic acid-indigo carmine mixture (AIM), and NBI magnified endoscopy are explained next. Limitations of NBI magnified endoscopy are discussed also.

Narrow band imaging (NBI) is a method of image enhancement [1, 2]. Although it is classified as an “optical digital method,” it enhances images using optical technology, processing them in a different way to previous optical digital methods [3]. An understanding of the optical properties of living tissue was deeply involved in the development of NBI.

In this chapter, I will present early gastric epithelial neoplasias (differentiated gastric cancer and adenoma), stratified for Paris classification of macroscopic appearance, and their characteristic magnifying endoscopy (ME) findings. I will explain how to read and interpret ME findings using the VS classification, with reference to the pathohistological findings. The Paris classification is usually applied to early gastric cancers, but for convenience’s sake I will use it for adenomas as well in this chapter. First table of this chapter shows the macroscopic classification of the presented cases and the characteristic ME findings I wish to highlight. In particular, I will summarize the ME findings of the “background mucosa,” “marginal area,” and “lesion” and add an explanation for each.

Anatomical components of morphological analyses using the VS classification system V components: regular, irregular, or absent Capillaries Collecting venules (CVs) Microvessels (cannot be identified as capillaries or CVs) S components: regular, irregular, or absent Marginal crypt epithelium (MCE) (surface epithelium lining the gastric crypts) Surface epithelium covering the intervening part (IP) (usually not visualized, recognized as the area between MCE and MCE) Crypt openings (COs) Light blue crest (LBC) (brush border) White opaque substance (WOS) Interpretation integrating the combined morphology of V and S components Concordance between V and S: concordant, discordant, or indeterminate

With an understanding of the theoretical background from Chap. 7, I would now like to explain the phenomena that occur when we employ magnifying endoscopy with narrow band imaging (M-NBI) in examining glandular epithelium in the stomach, and the anatomical markers we visualize. Glandular epithelium is a semitransparent mucosa with glandular crypts and other irregularities in its surface. Even more complicated phenomena occur than those seen when light is projected onto a flat semitransparent surface, such as the stratified squamous epithelium of the esophagus, and attempting to interpret the images obtained can be most confusing. In this chapter, I will explain how the findings with M-NBI are derived, using diagrams and illustrations of mucosal microanatomical structures (microvascular architecture and microsurface structure) I produced after close discussions with Olympus engineers.

Narrow band imaging (NBI) is a new electronic endoscopy system ideally suited to the observation of surface structures, including capillaries. With NBI, shortwavelength light radiated through a narrow band filter is strongly absorbed by hemoglobin, thereby allowing surface vascular structures to be distinctly visualized (1).

Narrow band imaging (NBI) was developed by Gono et al. (1) and has been applied widely for the diagnosis of cancer by gastrointestinal endoscopy. In cases of colorectal tumors, in particular, a number of reports have demonstrated the potential utility of NBI for: 1) detecting lesions at screening colonoscopy (2, 3); 2) qualitative diagnosis based on pit patterns and tumor surface vessels (4, 5, 6, 7, 8); and 3) predicting invasion depth. No dye is used for the NBI observation, and digital NBI images (image-enhanced endoscopy) can be obtained easily at the touch of a button on the electronic endoscope. With no requirement for troublesome procedures such as dye spraying and rinsing of the lesion, NBI has been accepted with ease by endoscopists worldwide.

Clearly, colorectal cancer lesions do not suddenly appear at a size of 10–20 mm in diameter. Instead, they arise from minute cancers (≤5 mm) that grow into small cancers (>5 to 10 mm). Clinically, the probability of detecting a minute cancer is low (1). Small lesions such as adenomas and hyperplastic polyps account for an overwhelmingly large proportion of those detected by endoscopy (2). Hence, it is difficult to find such cancers with ordinary observation.

We investigated the efficacy of surveillance colonoscopy using narrowband imaging as a handy method of optical pancolonic chromoendoscopy, and the potential of autofluorescence imaging colonoscopy for patients with ulcerative colitis.

We review the clinical application of magnification endoscopy with white light imaging and narrow-band imaging in the stomach. Basically, the microvascular architecture is visualized by magnification endoscopy with white light imaging; in addition, the microsurface structure can be visualized by magnification, endoscopy. The basic principles for the analysis of magnification endoscopy are that we should describe the magnification endoscopy findings independently based on the two distinct microanatomies, that is, the microvascular architecture (V) and the microsurface structure (S). Then, we should integrate these two findings into various categories to enable a correct diagnosis of gastrointestinal pathology. Based on these principles, for the new diagnostic system produced by magnification endoscopy and narrowband imaging, we propose a simple classification system for making a correct diagnosis between cancerous and noncancerous pathology. The criterion for cancerous pathology is the presence of either an irregular microvascular pattern or an irregular microsurface pattern. Such a simple classification system is mandatory for the establishment of a scientific diagnostic system, which can be successfully utilized by all endoscopists.

Barrett’s esophagus (BE) is the premalignant lesion for the majority of patients with esophageal and gastroesophageal junction adenocarcinoma, a cancer rapidly rising in incidence in the United States and western Europe. Endoscopic diagnosis of BE and neoplasia arising from within a BE segment continues to be a challenge and is typically dependent on random biopsies. Because of the focal and patchy nature of intestinal metaplasia and neoplasia, novel endoscopic approaches aimed at improving current screening and surveillance strategies have been explored. Narrow-band imaging (NBI) with or without magnification endoscopy is a new endoscopic technique that changes the optical filters of the current sequential lighting video endoscopes to spectral narrow-band filters. Use of a higher intensity of blue light with narrow-band filters allows detailed imaging of mucosal and vascular surface patterns with a high degree of resolution. Studies to date have yielded promising results for NBI alone or in combination with other advanced endoscopic techniques in the detection and surveillance of patients with BE.

Narrow-band imaging (NBI) makes it possible to emphasize the imaging of certain features such as mucosal structures and mucosal microvessels in gastrointestinal tract diseases. Recently, video peroral cholangioscopy (POCS) and pancreatoscopy (POPS) have been developed as diagnostic endoscopy for better observation of pancreaticobiliary lesions. Herein, we describe the clinical usefulness of POCS/ POPS using NBI for the diagnosis of pancreaticobiliary diseases. In all pancreaticobiliary lesions, identification of the surface structure and vessels of the lesions by NBI observation was significantly better than with conventional observation. In conclusion, although maneuverability and fragility of POCS/POPS are limited and the current POCS/POPS is not equipped with magnification, POCS/POPS using NBI may be helpful for the observation of both fine mucosal structures and tumor vessels, resulting in correct target biopsy in patients with pancreaticobiliary diseases.

Barrett’s esophagus (BE) is a condition of the distal esophagus involving columnar-lined epithelium (CLE) with intestinal metaplasia (IM). During conventional endoscopy, IM in CLE is not clearly identifiable. Here we describe a technique of magnifying endoscopy (ME) using narrow-band imaging (NBI) in combination with acetic acid institllation in the diagnosis of BE. Within 10–20 s after acetic acid instillation, the mucosal surfaces whiten and fine mucosal surface patterns become clearer with ME emphasized with NBI.

New techniques such as magnifying endoscopy and narrow-band imaging (NBI) are being accepted for diagnosis in esophageal fields. Especially, magnifying endoscopic examination with the NBI system is used to examine suspicious areas of mucosa not visible during conventional endoscopic examination. These endoscopic techniques are also used for diagnosis for nonmalignant disease. Because NBI accurately identifies the microvascular architecture of the surface mucosa, it clearly detects dyspepsia and carcinoma as a brownish area. Conventional endoscopy with NBI is useful for screening examinations in esophagus and pharynx. The advantage of the NBI system is that dye is not required. The main advantage of magnifying endoscopy with NBI is the improved visualization of intrapapillary capillary loops (IPCL). Morphological change and irregular arrangement of IPCLs are associated with inflammation and neoplasia of the esophagus. The characteristic changes of magnified appearance in squamous cell carcinoma are dilation, weaving, and variation in size and shape of IPCL. Magnifying endoscopic observation with NBI of IPCLs in esophageal epithelium is useful for diagnosis of nonerosive reflux disease, which cannot be visualized with conventional endoscopy. The patterns of IPCL in inflammatory mucosa are simply dilation and elongation with regular arrangement. Assessment of the IPCL pattern using magnifying endoscopy with NBI is important for diagnosis of esophageal squamous neoplasia and esophageal inflammatory disease.

Narrow-band imaging (NBI) and autofluorescence imaging (AFI) colonoscopy are procedures which show gastrointestinal neoplasia and inflammation as colored areas distinctive from the surrounding normal tissue. By means of NBI colonoscopy, colorectal mucosa of ulcerative colitis (UC), especially in apparently inactive disease, is classified into two types according to the mucosal vascular pattern. In contrast, AFI colonoscopy can divide active mucosa under conventional colonoscopy into high-AF and low-AF patterns. When compared with histology, the vascular pattern under NBI colonoscopy is representative of epithelial damage, and the AF pattern is representative of inflammatory infiltrates. It is, therefore, suggested that the severity of UC can be classified by NBI and AFI colonoscopy. The procedures also seem to be applicable to cancer surveillance for UC, because the tortuous pattern determined by magnifying NBI colonoscopy and the sharply demarcated dark purple areas shown under AFI colonoscopy are suggestive of dysplastic lesions. Based on these findings, it is suggested that NBI and AFI colonoscopy are promising procedures for the diagnosis and management of UC.

Molecular imaging has been formally defined as the detection, spatial localization, and quantification of specific molecular targets and events that form the basis of various pathologies. Cancer is the greatest target in the short-term tasks of molecular imaging, and molecular imaging is important in various aspects of tackling this target. As image-enhanced endoscopy, narrow-band imaging (NBI) can provide morphological data to show changes in the morphology of the target and is particularly useful for obtaining images of the mucous surface layer with enhanced microvascular structures. Autofluorescence imaging (AFI) allows observation of morphological changes in terms of fluorescence intensity. Ultrahigh-magnification endoscopy such as the microscopic or confocal method allows real-time observation and diagnosis of changes in cellular structure within the body. In contrast, endoscopic molecular imaging is a procedure by which changes in quality, in terms of fluorescence intensity, are observed, and which allows acquisition of higher-level information in a simple form. As for endoscopic molecular imaging, exploration of markers, development of probes, and adequate imaging devices are three keys to clinical application. Not only molecular biological findings but also points of contact with various engineering techniques are extremely important for making progress in molecular imaging. Cooperation among the medical, engineering, and industrial fields has been advocated. In addition, cooperation with the fields of pharmaceutical sciences and biology is also necessary.