Ryohei Hirose

Improvement in the visibility of colorectal polyps by using blue laser imaging (with video)

BACKGROUND Fujifilm developed blue laser imaging (BLI) via a laser light source with a narrow-band light observation function. It has a brighter BLI bright mode for tumor detection. OBJECTIVE To investigate whether the BLI bright mode can improve the visibility of colorectal polyps compared with white light (WL). DESIGN We studied 100 colorectal polyps (protruding, 42; flat, 58; size, 2-20 mm) and recorded videos of the polyps by using the BLI bright mode and WL at Kyoto Prefectural University of Medicine and Fukuoka Chikushi University Hospital. The videos were evaluated by 4 expert endoscopists and 4 nonexperts. Each endoscopist evaluated the videos in a randomized order. Each polyp was assigned a visibility score from 4 (excellent visibility) to 1 (poor visibility). SETTING Japanese academic units. MAIN OUTCOME MEASUREMENTS The visibility scores in each mode and their relationship to the clinical characteristics were analyzed. RESULTS The mean visibility scores of the BLI bright mode were significantly higher than those of WL for both experts and nonexperts (experts, 3.10 ± 0.95 vs 2.90 ± 1.09; P = .00013; nonexperts, 3.04 ± 0.94 vs 2.78 ± 1.03; P < .0001). For all nonexperts, the visibility scores of the BLI bright mode were significantly higher than those of WL; however, these scores were significantly higher in only 2 experts. For experts, the mean visibility scores of the BLI bright mode was significantly higher than those of WL for flat polyps, neoplastic polyps, and polyps located on the left side of the colon and the rectum. LIMITATIONS Small sample size and review of videos. CONCLUSIONS Our study showed that polyps were more easily visible with the BLI bright mode compared with WL. ( CLINICAL TRIAL REGISTRATION NUMBER UMIN000013770.).

Risk of lens cloudiness during colorectal endoscopic submucosal dissection and ability of a novel lens cleaner to maintain and restore endoscopic view.

Generally, colorectal endoscopic submucosal dissection (ESD) cannot be carried out with severe lens cloudiness. We examined the occurrence of lens cloudiness during ESD as well as the efficacy of a novel cleaner for it.

Linked color imaging improves the visibility of colorectal polyps: a video study

Background/study aim  Linked color imaging (LCI) by a laser endoscope (Fujifilm Co, Tokyo, Japan) is a novel narrow band light observation. In this study, we aimed to investigate whether LCI could improve the visibility of colorectal polyps using endoscopic videos. Patients and methods  We prospectively recorded videos of consecutive polyps 2 – 20 mm in size diagnosed as neoplastic polyps. Three videos, white light (WL), blue laser imaging (BLI)-bright, and LCI, were recorded for each polyp by one expert. After excluding inappropriate videos, all videos were evaluated in random order by two experts and two non-experts according to a published polyp visibility score from four (excellent visibility) to one (poor visibility). Additionally, the relationship between polyp visibility scores in LCI and various clinical characteristics including location, size, histology, morphology, and preparation were analyzed compared to WL and BLI-bright. Results  We analyzed 101 colorectal polyps (94 neoplastic) in 66 patients (303 videos). The mean polyp size was 9.0 ± 8.1 mm and 54 polyps were non-polypoid. The mean polyp visibility scores for LCI (2.86 ± 1.08) were significantly higher than for WL and BLI-bright (2.53 ± 1.15, P  < 0.001; 2.73 ± 1.47, P  < 0.041). The ratio of poor visibility (score 1 and 2) was significantly lower in LCI for experts and non-experts (35.6 %, 33.6 %) compared with WL (49.6 %, P  = 0.015, 50.5 %, P  = 0.046). The polyp visibility scores for LCI were significantly higher than those for WL for all of the factors. With respect to the comparison between BLI-bright and WL, the polyp visibility scores for BLI-bright were not higher than WL for right-sided location, < 10 mm size, sessile serrated adenoma and polyp histology, and poor preparation. For those characteristics, LCI improved the lesions with right-sided location, SSA/P histology, and poor preparation significantly better than BLI. Conclusions  LCI improved polyp visibility compared to WL for both expert and non-expert endoscopists. It is useful for improving polyp visibility in any location, any size, any morphology, any histology, and any preparation level.

Histopathological analysis of cold snare polypectomy and its indication for colorectal polyps 10–14 mm in diameter

Cold snare polypectomy (CSP) is commonly used for treating colorectal polyps <10 mm in diameter. We evaluated the analysis and safety of CSP for larger polyps.

Mechanism of Human Influenza Virus RNA Persistence and Virion Survival in Feces: Mucus Protects Virions From Acid and Digestive Juices

Although viral RNA or infectious virions have been detected in the feces of individuals infected with human influenza A and B viruses (IAV/IBV), the mechanism of viral survival in the gastrointestinal tract remains unclear. We developed a model that attempts to recapitulate the conditions encountered by a swallowed virus. While IAV/IBV are vulnerable to simulated digestive juices (gastric acid and bile/pancreatic juice), highly viscous mucus protects viral RNA and virions, allowing the virus to retain its infectivity. Our results suggest that virions and RNA present in swallowed mucus are not inactivated or degraded by the gastrointestinal environment, allowing their detection in feces.

Efficacy of a Novel Narrow Knife with Water Jet Function for Colorectal Endoscopic Submucosal Dissection

Backgrounds With respect to the knifes design in colorectal endoscopic submucosal dissection (ESD), diameter, water jet function, and electric power are important because these relate to efficient dissection. In this study, we analyzed a novel, narrow ball tip-typed ESD knife with water jet function (Flush knife BT-S, diameter: 2.2 mm, length: 2000 mm, Fujifilm Co., Tokyo, Japan) compared to a regular diameter knife (Flush knife BT, diameter: 2.6 mm, length: 1800 mm). Methods In laboratory and clinical research, electric power, knife insertion time, vacuum/suction amount with knife in the endoscopic channel, and water jet function were analyzed. We used a knife 2.0 mm long for BT-S and BT knives. Results The BT-S showed faster mean knife insertion time (sec) and better vacuum amount (ml/min) compared to the BT (insertion time: 16.7 versus 21.6, p < 0.001, vacuum amount: 38.0 versus 14.0, p < 0.01). Additionally, the water jet function of the BT-S was not inferior. In 39 colorectal ESD cases in two institutions, there were mean 4.7 times (range: 1–28) of knife insertion. Suction under knife happened 59% (23/39) and suction of fluid could be done in 100%. Conclusions Our study showed that the narrow knife allows significantly faster knife insertion, better vacuum function, and effective clinical results.

High incidence of postoperative hemorrhage in colorectal endoscopic submucosal dissection during anticoagulant therapy

Dear Editor: Endoscopic submucosal dissection (ESD) is useful for resecting large early colorectal cancers. Postoperative hemorrhage is one of the complications for colorectal ESD. Patients with antithrombotic drug such as antiplatelet and anticoagulant are not uncommonly encountered during colorectal ESD because the number of silver generation grows; patients with multiple co-morbidities and polypharmacy also become more prevalent. Due to the importance of antithrombotic drug, many countries had developed their own clinical guidelines advising whether to continue or withhold antithrombotic drug during a certain procedure. To our knowledge, there are no detail reports about postoperative hemorrhage after colorectal ESD in patients with anticoagulant. In this report, we aimed to compare the status of postoperative hemorrhage for colorectal ESD cases with antithrombotic (anticoagulant or antiplatelet) and those without. Consecutive patients who underwent colorectal ESD at the Kyoto Prefectural University of Medicine from November 2008 to April 2015 were retrospectively reviewed. Indication for ESD included (1) tumors that cannot be resected with EMR, as well as those that are diagnosed as (2) intramucosal cancer (Tis) and part of T1 cancer without risk of lymph node metastasis by magnifying endoscopic examination. We analyzed various clinicopathological outcomes in all ESD cases and all included cases were divided into three groups: group A, cases with antiplatelet; group B, cases with anticoagulant (±antiplatelet); and group C, cases without antithrombotic drug. Characteristics of patients and tumors (age, sex, tumor size, location) as well as procedural record and complications (en bloc resection, procedure time, postoperative hemorrhage, perforation, blood transfusion, thrombosis and etc.) were also examined. We followed the Japanese Gastroenterological Endoscopy Society (JGES) on the management of patients on antithrombotic drugs during endoscopy published in 2005 and 2010. Regularly, antiplatelet drugs including aspirin were withdrawn for 1 to 7 days and restarted 1–3 days after ESD. In patients with high embolic risk, aspirin was continued before and after ESD. With respect to anticoagulants, warfarin was regularly replaced with subcutaneous heparin (20,000 units/day) 3 days before ESD. Heparin was stopped 6 h before ESD. Both heparin and warfarin were re-prescribed 1 day after ESD and were continued 4–14 days until the prothrombin times-international normalized ratio (PT-INR) was recovered. However, in some patients, warfarin was withdrawn 3 days before ESD without heparin replacement and was restarted 2 days after ESD until 2010. Dabigatran was withdrawn 1 day before ESD and restarted 1 day after ESD. This study was approved by the ethics committees of Kyoto Prefectural University of Medicine. This study was carried out in accordance with the World Medical Association Helsinki Declaration and was a part of sub-analysis of the study registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) as number UMIN000013772. With respect to overall 678 ESD cases, mean age of patients was 68.2 ± 10.3 years. Three hundred fifty-three * Naohisa Yoshida naohisa@koto.kpu-m.ac.jp

High incidence of metachronous advanced adenoma and cancer after endoscopic resection of colon polyps ≥20 mm in size.

There are limited studies on incidence rates of metachronous neoplastic lesions after resecting large colorectal polyps. In the present study, we analyzed metachronous lesions after endoscopic resection of colorectal polyps ≥20 mm in size.

Identification of the critical viscoelastic factor in the performance of submucosal injection materials

High-performance submucosal injection materials (SIMs) contribute to the success of endoscopic therapy for early-stage gastrointestinal neoplasms. This study aimed to identify the most important factor (viscoelastic parameter) that determines SIM performance and the ease of injection. To determine the ideal viscoelastic parameters of SIMs, submucosal elevation heights (SEHs) and the ease of submucosal injection [characterized by injection pressures (IPs)] were evaluated using a newly developed ex vivo model, in which a constant tension was applied to the studied specimen. The strongest positive correlation was observed between the loss modulus determined at an oscillation frequency of 0.1 rad/s and SEH (correlation coefficient > 0.9) and between the loss modulus at 10 rad/s and IP (correlation coefficient > 0.9). SIMs with high loss moduli (0.1 rad/s) also contributed to maintenance of the submucosal elevation. Moreover, the SEHs of pseudoplastic fluid SIMs (whose loss moduli increased slightly with increasing angular frequency) were greater than those of Newtonian fluid SIMs (whose loss modulus increased drastically with increasing angular frequency). In this study, the ideal viscoelastic SIM parameters were clarified. The loss modulus (0.1 rad/s) was the most important viscoelastic factor affecting SIM performance. Additionally, the development of pseudoplastic fluid SIMs may lead to the creation of next-generation SIMs, with a performance superior to that of sodium hyaluronate, which is currently used widely in endoscopic treatments.

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential to establish an ex vivo model that can evaluate SIM performance accurately, for developing high-performance SIMs. In our previous study, we developed a new ex vivo model that can be used to evaluate the performance of various SIMs in detail by applying constant tension to the specimens ends. We also confirmed that the proposed new ex vivo model allows accurate submucosal elevation height (SEH) measurement under uniform conditions and detailed comparisons of the performances of various types of SIMs. Here, we describe the new ex vivo model and explain the detailed setup methodology of this model. Since all parts of the new model were easy to obtain, the setup of the new model could be completed quickly. SEH of various SIMs could be measured more accurately by using the new model. The critical factor that determines SIM performance can be identified using the new model. SIM development speed will drastically increase after the factor has been identified.