Shu Kiyotoki

Usefulness of magnifying endoscopy with narrow-band imaging for determining gastric tumor margin.

Background and Aim:u2002 Magnifying endoscopy with narrow‐band imaging (ME‐NBI) enhances images of the irregular mucosal structures and microvessels of gastric carcinoma, and could be useful for determining the margin between cancerous and non‐cancerous mucosa. We evaluated the usefulness of ME‐NBI for determining the tumor margin compared with indigocarmine chromoendoscopy (ICC).

Role of DNA methylation in the development of Epstein–Barr virus-associated gastric carcinoma†

The frequencies of DNA methylation of certain tumor‐related genes are higher in Epstein–Barr virus (EBV)‐associated gastric carcinomas than in EBV‐negative gastric carcinomas. EBV‐associated gastric carcinomas have distinct clinicopathological features; however, there are no case‐control studies comparing methylation frequency between EBV‐associated gastric carcinomas and controls that have been adjusted according to the clinicopathological features of EBV‐associated gastric carcinomas. This study evaluated 25 EBV‐associated gastric carcinomas that were positive for EBV‐encoded small RNA 1 (EBER‐1) by in situ hybridization and 50 EBV‐negative gastric carcinomas that were matched with the EBV‐associated gastric carcinomas by age, sex, histology, depth of tumor invasion, and stage. Methylation status of 16 loci associated with tumor‐related genes was analyzed by methylation‐specific polymerase chain reaction (PCR) to identify genes in which DNA methylation specifically occurred in EBV‐associated gastric carcinomas. Methylation frequencies of 12 of the 16 genes were higher in EBV‐associated gastric carcinomas than in EBV‐negative controls, and the frequency of methylation of 6 specific loci (MINT2, MINT31, p14, p16, p73, and RUNX3) was significantly higher in EBV‐associated gastric carcinomas than in EBV‐negative controls. There were no significant differences in the methylation frequencies of the other genes. The mean methylation index in EBV‐associated gastric carcinomas was significantly higher than that in EBV‐negative controls. DNA methylation of tumor suppressor genes that regulate the cell cycle and apoptosis specifically occurred in EBV‐associated gastric carcinomas. Aberrant DNA methylation might lead to the development and progression of EBV‐associated gastric carcinoma. J. Med. Virol. 85:121–127, 2012.

Risk factors for delayed bleeding from endoscopic submucosal dissection of gastric neoplasms

Abstract Objective. Delayed bleeding is a major complication of endoscopic submucosal dissection (ESD) of gastric neoplasms. We aimed to clarify risk factors for delayed bleeding from ESD. Material and methods. This study included 447 patients in whom 544 gastric neoplasms were resected by ESD between April 2006 and March 2011 in Yamaguchi University Hospital. We analyzed risk factors for delayed bleeding from ESD in relation to various clinical and pathological factors. Results. En bloc resection rate was 95.4% (519/544), and curative resection rate was 87.8% (477/544). Delayed bleeding occurred in 7.0% (38/544) and perforation occurred in 1.8% (10/544) of patients. Univariate analysis revealed platelet count (Plt) <15 × 104/μl (p = 0.013), prothrombin time (PT) <70% (p = 0.044), resected size ≥50 mm (p = 0.038), and positive/indeterminate lateral margin (p = 0.012) to be risk factors for delayed bleeding. Multivariate analysis showed that Plt <15 × 104/μl (odds ratio [OR], 2.62; 95% confidence interval [CI]: 1.17–5.53, p = 0.020) and positive/indeterminate lateral margin (OR, 5.45; 95% CI: 1.39–17.95, p = 0.018) were independent risk factors for delayed bleeding. Conclusions. Low Plt, low PT, large resected size, and positive/indeterminate lateral margin were significant risk factors for delayed bleeding from ESD. Patients with these risk factors must be carefully observed for signs of delayed bleeding.

Use of hyperspectral imaging technology to develop a diagnostic support system for gastric cancer

Abstract. Hyperspectral imaging (HSI) is a new technology that obtains spectroscopic information and renders it in image form. This study examined the difference in the spectral reflectance (SR) of gastric tumors and normal mucosa recorded with a hyperspectral camera equipped with HSI technology and attempted to determine the specific wavelength that is useful for the diagnosis of gastric cancer. A total of 104 gastric tumors removed by endoscopic submucosal dissection from 96 patients at Yamaguchi University Hospital were recorded using a hyperspectral camera. We determined the optimal wavelength and the cut-off value for differentiating tumors from normal mucosa to establish a diagnostic algorithm. We also attempted to highlight tumors by image processing using the hyperspectral camera’s analysis software. A wavelength of 770 nm and a cut-off value of 1/4 the corrected SR were selected as the respective optimal wavelength and cut-off values. The rates of sensitivity, specificity, and accuracy of the algorithm’s diagnostic capability were 71%, 98%, and 85%, respectively. It was possible to enhance tumors by image processing at the 770-nm wavelength. HSI can be used to measure the SR in gastric tumors and to differentiate between tumorous and normal mucosa.

Fine-tuning the criteria for strip biopsy and endoscopic submucosal dissection improves the outcome of early gastric carcinoma treatment

Background and Aim:u2002 Strip biopsy and endoscopic submucosal dissection (ESD) have been developed as a local treatment for early gastric cancer (EGC). However, the lesion criteria for the use of ESD, rather than strip biopsy, remain to be elucidated.

Use of the light-emitting diode-illuminated endoscope for upper gastrointestinal endoscopy

ting diode (LED)-illuminated endoscopes and previously reported our preliminary experiments with the prototype LED endoscope in the beagle [1]. Authors in Nature noted that the white LEDs we employed have been used for illuminating paintings in fine art museums, as they emit white light with good color rendering and homogeneous light distribution [2, 3]. This supports the notion that these LEDs may also be suitable for use in gastrointestinal endoscopes, as these instruments must be able to indicate subtle changes in the color and mucosal structure of the gastrointestinal tract. The prototype LED endoscopes were based on conventional endoscopes for studies in humans (Fujifilm Corporation, Saitama, Japan), and white LEDs were mounted on their tip (l Fig. 1). After obtaining Institutional Review Board approval, a patient with an early gastric carcinoma underwent endoscopy using this new endoscope. We found that the white LEDs did not provide sufficient illumination for distant observation in the stomach. However, our prototype LED endoscope allowed clear visualization of the early gastric cancer by close observation. The LED endoscope showed a flat lesion, which was located at the anterior wall of the mid-gastric body and had ill-defined margins accompanied by slightly reddish or focally pale mucosa (l Fig. 2 a). Indigo carmine chromoendoscopy emphasized the redness of the lesion and delineated the demarcation between the cancerous and non-cancerous mucosa (l Fig. 2 b). These findings corresponded to those from an examination with a conventional endoscope (l Fig. 2 c, d). We then subjected the lesion to endoscopic submucosal dissection using a conventional endoscope. Pathological evaluation of the excised tissue revealed that the lesion was an intramucosal differentiated adenocarcinoma and that both its lateral and vertical margins were free of carcinoma cells (l Fig. 3 a, b). In conclusion, our observations show that our prototype LED-illuminated endoscope can clearly visualize early gastric cancers upon close observation.

Current state of practice for colonic diverticular bleeding in 37 hospitals in Japan: A multicenter questionnaire study

AIM To clarify the current state of practice for colonic diverticular bleeding (CDB) in Japan. METHODS We conducted multicenter questionnaire surveys of the practice for CDB including clinical settings (8 questions), diagnoses (8 questions), treatments (7 questions), and outcomes (4 questions) in 37 hospitals across Japan. The answers were compared between hospitals with high and low number of inpatient beds to investigate which factor influenced the answers. RESULTS Endoscopists at all 37 hospitals answered the questions, and the mean number of endoscopists at these hospitals was 12.7. Of all the hospitals, computed tomography was performed before colonoscopy in 67% of the hospitals. The rate of bowel preparation was 46.0%. Early colonoscopy was performed within 24 h in 43.2% of the hospitals. Of the hospitals, 83.8% performed clipping as first-line endoscopic therapy. More than half of the hospitals experienced less than 20% rebleeding events after endoscopic hemostasis. No significant difference was observed in the annual number of patients hospitalized for CDB between high- (≥ 700 beds) and low-volume hospitals. More emergency visits (P = 0.012) and endoscopists (P = 0.015), and less frequent participation of nursing staff in early colonoscopy (P = 0.045) were observed in the high-volume hospitals. CONCLUSION Some practices unique to Japan were found, such as performing computed tomography before colonoscopy, no bowel preparation, and clipping as first-line therapy. Although, the number of staff differed, the practices for CDB were common irrespective of hospital size.

Image quality of a novel light-emitting diode (LED)-illuminated colonoscope

BACKGROUND AND STUDY AIMSnLight-emitting diodes (LEDs) are used widely for their high luminous efficiency and durability. We developed a novel prototype high definition endoscope with white LEDs and evaluated the image quality it produced against a commercial endoscope with conventional light source.nnnPATIENTS AND METHODSnThe specifications of both colonoscopes were identical, except for the LED light source at the tip of the prototype. We examined 20 patients with rectal or sigmoid colon lesions and the image quality was evaluated in 40 images (one image from the LED colonoscope and one from the conventional colonoscope for each lesion) by three endoscopists. We additionally evaluated the 17 videos recorded with the LED colonoscope that were available. Image quality, mucosal and vascular color, and luminous distribution and intensity were scored on a 5-point scale.nnnRESULTSnThe mean score for vascular color given by one evaluator was significantly higher using the LED colonoscope than using the conventional colonoscope. The mean scores for mucosal color and luminous intensity from another evaluator were significantly lower with the LED colonoscope than with the conventional colonoscope. There were no significant differences in the luminous distribution scores for any of the evaluators. The image quality of the videos was evaluated as being similar with both colonoscopes.nnnCONCLUSIONSnImage quality from the LED and conventional colonoscopes were similar, although the luminous intensity of the LEDs is inferior to that of the conventional light source at the present time.

A multicenter, randomized controlled trial comparing the identification rate of stigmata of recent hemorrhage and rebleeding rate between early and elective colonoscopy in outpatient-onset acute lower gastrointestinal bleeding: study protocol for a randomized controlled trial

BackgroundThe clinical benefit of early colonoscopy within 24 h of arrival in patients with severe acute lower gastrointestinal bleeding (ALGIB) remains controversial. This trial will compare early colonoscopy (performed within 24 h) versus elective colonoscopy (performed between 24 and 96 h) to examine the identification rate of stigmata of recent hemorrhage (SRH) in ALGIB patients. We hypothesize that, compared with elective colonoscopy, early colonoscopy increases the identification of SRH and subsequently improves clinical outcomes.MethodsThis trial is an investigator-initiated, multicenter, randomized, open-label, parallel-group trial examining the superiority of early colonoscopy over elective colonoscopy (standard therapy) in ALGIB patients. The primary outcome measure is the identification of SRH. Secondary outcomes include 30-day rebleeding, success of endoscopic treatment, need for additional endoscopic examination, need for interventional radiology, need for surgery, need for transfusion during hospitalization, length of stay, 30-day thrombotic events, 30-day mortality, preparation-related adverse events, and colonoscopy-related adverse events. The sample size will enable detection of a 9% SRH rate in elective colonoscopy patients and a SRH rate of ≥u200926% in early colonoscopy patients with a risk of type I error of 5% and a power of 80%.DiscussionThis trial will provide high-quality data on the benefits and risks of early colonoscopy in ALGIB patients.Trial registrationUMIN-CTR Identifier, UMIN000021129. Registered on 21 February 2016; ClinicalTrials.gov Identifier, NCT03098173. Registered on 24 March 2017.

A novel imaging system of optical detection on cancers and tissues in gastrointestinal endoscope using high-color-rendering white and color tunable LEDs

The use of white or color tunable LEDs (light-emitting diodes), which can replace a large light source apparatus and light-guiding fiber bundle, enable the miniaturization of the whole endoscope system and remove constraints on the design of its shape. We have developed a novel white LED for a new experimental prototype LED-illuminated gastrointestinal endoscope having the color rendering in the clinically important red range at around 600 nm.