Autofluorescence imaging with a transparent hood for detection of colorectal neoplasms: a prospective, randomized trial.

BACKGROUND: Colonoscopy is one of the most reliable methods for detection of colorectal neoplasms, but conventional colonoscopy can miss some lesions. OBJECTIVE: To evaluate the efficacy of autofluorescence imaging (AFI) with a transparent hood (TH) for detection of colorectal neoplasms. DESIGN: A 2 × 2 factorial designed, prospective, randomized, controlled trial. SETTING: This study was conducted at the Osaka Medical Center for Cancer and Cardiovascular Diseases, a tertiary cancer center. PATIENTS: A total of 561 patients. INTERVENTIONS: Patients were allocated to 1 of 4 groups: (1) white light imaging (WLI) alone--colonoscopy using WLI without a TH; (2) WLI+TH--colonoscopy using WLI with a TH; (3) AFI alone--colonoscopy using AFI without a TH; and (4) AFI+TH--colonoscopy using AFI with a TH. Eight colonoscopists used each allocated method. MAIN OUTCOME MEASUREMENT: The difference in neoplasm detection rate (number of detected neoplasms per patient) between the WLI alone and AFI+TH groups. RESULTS: Neoplasm detection rate (95% confidence interval) in the AFI+TH group was significantly higher than in the WLI alone group (1.96 [1.50-2.43] vs 1.19 [0.93-1.44]; P = .023, Tukey-Kramer multiple comparison test). Relative detection ratios (95% confidence interval) for polypoid neoplasms based on Poisson regression model were significantly increased by mounting a TH (1.69 [1.34-2.12], P < .001), and relative detection ratios for flat neoplasms were significantly increased by AFI observation (1.83 [1.24-2.71], P = .002). LIMITATIONS: Open trial performed in single cancer referral center. CONCLUSION: AFI colonoscopy with a TH detected significantly more colorectal neoplasms than did conventional WLI colonoscopy without a TH.

Surveillance colonoscopy using a transparent hood and image-enhanced endoscopy.

Colonoscopists can miss adenomas during colonoscopy screening. A transparent hood attached to the tip of the colonoscope helps detection of colorectal adenomas, but as far as we are aware, there has been no trial indicating its statistically significant effectiveness. Total colonic dye spray might improve the adenoma detection rate but it is complicated and time-consuming for routine clinical usage. Moreover, the efficacy of narrow band imaging for detection of colorectal adenoma is controversial and is still under debate. Autofluorescence imaging (AFI) might be better able to detect flat lesions than white light imaging (WLI), but its ability is influenced easily by the area of the observation. Therefore, we have attached a transparent hood to the tip of an AFI colonoscope during colonoscopy screening in clinical usage. AFI can detect a flat lesion, which is difficult to detect using WLI. A transparent hood can help to detect lesions behind the folds by pushing the colonic fold. We expect that mounting a transparent hood would work complimentary to AFI. Further improvements, including a combination of AFI and a transparent hood, are needed and they would provide optimal surveillance intervals.

Prospective evaluation of narrow-band imaging endoscopy for screening of esophageal squamous mucosal high-grade neoplasia in experienced and less experienced endoscopists.

Narrow-band imaging (NBI) is a novel, noninvasive optical technique that uses reflected light to visualize the organ surface. However, few prospective studies that examine the efficacy of NBI screening for esophageal cancer have been reported. To compare the diagnostic yield of NBI endoscopy for screening of squamous mucosal high-grade neoplasia of the esophagus between experienced and less experienced endoscopists. Patients with a history of esophageal neoplasia or head and neck cancer received NBI endoscopic screening for esophageal neoplasia followed by chromoendoscopy using iodine staining. Biopsy specimens were taken from iodine-unstained lesions and the histological results of mucosal high-grade neoplasias served as the reference standard. The primary outcome was the sensitivity of NBI for detecting new lesions. The secondary outcome was the positive predictive value of NBI and the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of NBI in a per lesion basis. A total of 350 patients (170 by experienced endoscopists and 180 by less experienced endoscopists) underwent endoscopic examination. A total of 42 new mucosal high-grade neoplastic lesions (25 in the experienced endoscopist group and 17 in the less experienced endoscopist group) were detected. In the per-lesion-based analysis, the sensitivity was significantly higher in the experienced endoscopist group (100%; 25/25) compared with the less experienced endoscopist group (53%; 9/17) (P < 0.001). The positive predictive value of NBI was higher in the experienced endoscopist group than in the less experienced endoscopist group (45%, 25/55 vs. 35%, 9/26), although the difference was not significant (P = 0.50). The sensitivity of NBI in the less experienced endoscopist group was 43% in the former half of patients, and increased to 60% in the latter half of patients. In the per-patient-based analysis, the sensitivity of NBI was significantly higher in the experienced endoscopist group (100%) than in the less experienced endoscopist group (100 vs. 69%, respectively; P = 0.04). The positive predictive values of the experienced endoscopist group and the less experienced endoscopist group were similar, and were 48 and 47%, respectively. In conclusion, compared with the gold standard of chromoendoscopy with iodine staining, the sensitivity of NBI for screening of mucosal high-grade neoplasia was 100% with the experienced endoscopists but was low with the less experienced endoscopists. Electronic chromoendoscopy with NBI is a promising screening tool in these high-risk patients with esophageal mucosal high-grade neoplasia, particularly when performed by endoscopists with experience of using NBI.

Autofluorescence imaging videoendoscopy in the diagnosis of chronic atrophic fundal gastritis.

PURPOSE: Diagnosis of chronic atrophic fundal gastritis (CAFG) is important to understand the pathogenesis of gastric diseases and assess the risk of gastric cancer. Autofluorescence imaging videoendoscopy (AFI) may enable the detection of mucosal features not apparent by conventional white-light endoscopy. The purpose of this study was to estimate the diagnostic ability of AFI in CAFG. METHODS: A total of 77 patients were enrolled. Images of the gastric body in AFI and white-light mode were taken to assess the extent of gastritis, and biopsies were taken from green (n = 119) and purple (n = 146) mucosa in AFI images. The diagnostic accuracy of green mucosa for CAFG was investigated according to the Sydney system. RESULTS: In per-patient analysis, the accuracy of green mucosa in patients with activity, inflammation, atrophy and intestinal metaplasia was 64, 93, 88 and 81%, respectively. In per-biopsy analysis, the accuracy for activity, inflammation, atrophy and intestinal metaplasia was 55, 62, 76 and 76%, respectively. Green areas in the gastric body exhibited more inflammation (p < 0.001), atrophy (p < 0.001) and intestinal metaplasia (p < 0.001), whereas purple areas rarely contained atrophy or intestinal metaplasia. The kappa statistics for inter- and intra-observer agreement of AFI on assessing the extent of CAFG were 0.66 and 0.47, while those for white-light endoscopy were 0.56 and 0.39. CONCLUSIONS: AFI could diagnose the extent of CAFG as a green area in the gastric body, with higher reproducibility compared with white-light endoscopy. Therefore, AFI may be a useful adjunct to endoscopy to identify patients at high risk of developing gastric cancer.

Efficacy of an endo-knife with a water-jet function (Flushknife) for endoscopic submucosal dissection of superficial colorectal neoplasms.

OBJECTIVES: Endoscopic submucosal dissection (ESD) is currently not a common treatment for colorectal neoplasms because it is time consuming and technically difficult. Flushknife--an electrosurgical endo-knife with a water-jet function--is expected to reduce the difficulty of colorectal ESD. The objective of this study was to investigate the efficacy of a water-jet function for colorectal ESD. METHODS: This study was a prospective randomized controlled trial, which was conducted at a cancer referral center. A total of 49 patients, with a total of 51 superficial colorectal neoplasms (median tumor size of 30 mm), were enrolled and randomly assigned to undergo ESD using either the Flexknife (electrosurgical endo-knife without a water-jet function) or the Flushknife. Tumors were resected by ESD using each endo-knife. The procedures were conducted by two endoscopists. Operation time was defined as the main outcome measure. RESULTS: En bloc resection was achieved in 23 out of 26 (88%) lesions in the Flexknife group and in 24 out of 24 (100%) lesions in the Flushknife group. The mean operation time (95% confidence interval) was 87.3 (71.3-103.4) min in the Flexknife group and 61.0 (49.3-72.7) min in the Flushknife group (P=0.02). The Flushknife reduced the number of endoscopic device changes (P=0.001), the number of submucosal injections (P=0.001), and the mean amount of injected hyaluronate sodium (P=0.001) compared with the Flexknife. No severe adverse events were observed in either group. CONCLUSIONS: Without increasing adverse events, the endo-knife with a water-jet function efficiently reduced the operation time of colorectal ESD in patients with large superficial colorectal neoplasms. (University hospital Medical Information Network Clinical Trials Registry number UMIN000001302).

Analysis of the color patterns of early gastric cancer using an autofluorescence imaging video endoscopy system.

BACKGROUND: Using a novel autofluorescence imaging video endoscopy system (AFI), tumors in the esophagus and the colon appeared purple in a green background, but the color patterns of early gastric cancer (EGC) were found to vary. Factors associated with these patterns remain unknown. The aims of the present study were to classify the color patterns of EGCs and to investigate the correlation between the patterns and clinicopathological features. METHODS: A total of 107 EGCs that had been evaluated by AFI endoscopy, prior to endoscopic or surgical resection, were included. The color patterns of EGCs in AFI images and the association between tumor color and clinicopathological factors were evaluated. These factors included tumor morphology, location, size, background color, histological type, depth of invasion, lymphatic or vessel permeation, and ulceration. RESULTS: The color patterns of EGCs were classified into the following four groups: purple tumors in a green background (52%); green tumors with a purple margin in a green background (21%); green tumors in a purple background (17%); and purple tumors in a purple background (10%). Univariate analysis showed that macroscopic type, histological type, ulceration, and background AFI color were significantly associated with tumor color, whereas multivariate analysis revealed that macroscopic type was the only independent contributor to tumor color. CONCLUSION: The present study has enabled a clearer understanding of the significance of tumor color in relation to the AFI imaging of EGCs. Recognition of the color patterns in AFI images should help in the diagnosis of EGCs.