ORIGINAL ARTICLE ISSN 1738-3331, http://dx.doi.org/10.7704/kjhugr.2015.15.1.39 The Korean Journal of Helicobacter and Upper Gastrointestinal Research, 2015;15(1):39-43 Comparison of the Diagnostic Usefulness of Conventional Magnification and Near-focus Methods with Narrow-band Imaging for Gastric Epithelial Tumors Hee Yoon Jang, Su Jin Hong, Jae Pil Han, Se Kyung Park, Han Kyeol Yun, Bong Jin Ko Digestive Disease Center and Research Institute, Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon, Korea Background/Aims: Dual-focus two-stage optical lens technology has been introduced recently. In near-focus mode (NFM), endoscopists can easily examine the mucosal tissue and capillary networks. This study compared the magnified images obtained using NFM and the conventional magnification (CMM) under narrow-band imaging in patients with gastric epithelial tumors. Materials and Methods: An experienced endoscopist performed endoscopy using NFM and CMM in patients with gastric epithelial tumors. We studied 40 images from 40 endoscopy sessions in 20 selected patients. Ten endoscopists rated the image quality independently on a 5-point Likert scale (from poor=1 to excellent=5) in terms of microsurface structure, microvascular structure, and the demarcation line. Results: The gastric epithelial tumors comprised 10 cases of early gastric cancer, 2 of high-grade dysplasia, and 8 of low-grade dysplasia. The median number of magnified images for each was 11. The mean observation time (±SD) for magnification was 99.9±64.1 s in NFM and 91.5±64.6 s in CMM (P=0.54). The image quality score for the microsurface structure was higher with NFM than CMM (4.09±0.39 vs. 3.73±0.40, P=0.015), while that for microvascular structure was lower with NFM than in CMM (3.53±0.45 vs. 4.29±0.45, P=0.001). Conclusions: Magnification using NFM provides higher-quality images of the microsurface structure, although its optical zoom is limited compared with CMM. Since NFM can obtain magnified images easily by pushing a button on the scope, it is useful for evaluating gastric epithelial tumors. (Korean J Helicobacter Up Gastrointest Res 2015;15:39-43) Key Words: Magnification; Epithelial tumor; Diagnosis, s; Stomach INTRODUCTION Early detection and curative treatment are the best strategies for improving survival in patients with gastric cancer. 1-3 New techniques has been applied to endoscopy to enhance the visualization of the gastrointestinal mucosa. 4-9 With no image deterioration after magnification, the optical zoom obtained by moving the lens in the tip of the scope enables close-up observation of the microsurface and microvascular structure. Magnifying endoscopy (ME) using the conventional magnification (CMM) is used widely as a diagnostic in hollow organs, including the stomach. 1,10-14 Recently, magnification using near-focus mode (NFM) has been introduced to enable Received: August 26, 2014 Accepted: November 7, 2014 Corresponding author: Su Jin Hong Digestive Disease Center and Research Institute, Soonchunhyang University Bucheon Hospital, 170, Jomaru-ro, Wonmi-gu, Bucheon 420-767, Korea Tel: +82-32-621-5087, Fax: +82-32-621-5080, E-mail: sjhong@schmc.ac.kr close examination under the control of a single button. 15-17 As no trials have compared NFM with CMM, we compared the magnified images between NFM and CMM under narrow-band imaging (NBI) in gastric epithelial tumors. MATERIALS AND METHODS ME under NBI was performed in patients with gastric epithelial tumors from July 2013 to September 2013. Magnified images were retrieved from the institution s endoscopy database. Inclusion criteria were patients with gastric dysplasia or early gastric cancer (EGC) who underwent ME using both magnification s under NBI. After the endoscopic evaluation, all lesions were treated with endoscopic submucosal dissection (ESD). Exclusion criteria were tumors present with an ulcer or minute tumors that were difficult to demarcate. We used a GIF-H260Z (Olympus, Tokyo, Japan) and a Copyright 2015 Korean College of Helicobacter and Upper Gastrointestinal Research The Korean Journal of Helicobacter and Upper Gastrointestinal Research is an Open-Access Journal. All articles are distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Korean J Helicobacter Up Gastrointest Res: Vol 15, No 1, March 2015 19-inch high-definition television (Olympus) for the CMM and a GIF-HQ290 (Olympus) and OEV-261H for the NFM Table 1. Characteristics of the Gastroscopes Used for the Magnifying Methods Characteristic Conventional magnification Near-focus Scope model GIF-H260Z GIF-HQ290 Working length (mm) 1,030 1,030 Insertion tube OD (mm) 10.5 9.9 Channel diameter (mm) 2.8 2.8 Zoom magnification 85 45 a Resolution HD HD Processor/light source CV-260SL/260 CLV-290SL/290 Monitor 19 HDTV OEV-261H OD, outer diameter; HD, high definition. a 90 with 2 electronic zoom. (Table 1). All images were taken by an experienced endoscopist (SJ Hong). Conventional magnifications were obtained using the zoom lever. In NFM, the magnification was controlled using two buttons: one for moving the lens and one that provided up to twofold electronic magnification of the image. Structure enhancement type A mode was used to enhance the contrast of the fine patterns in the image, and no other enhancement mode such as structure enhancement type B, edge enhancement, or color enhancement was used. Fig. 1 shows examples of magnified images of a case of EGC. We selected 40 magnified images from 40 endoscopy sessions in 20 patients with gastric epithelial tumors. Ten endoscopists rated the image quality independently in terms of the microsurface structure, microvascular structure, and demarcation line in the endoscopic images (Fig. 2). These Fig. 1. Examples of magnified images of a case of early gastric cancer. (A) White-light endoscopy image, (B) conventional magnification with narrow-band imaging (NBI) image, and (C) near-focus mode with NBI image. Fig. 2. (A, B) Magnifying endoscopy with narrow-band imaging for gastric epithelial tumors. The microsurface structure, microvascular structure, and demarcation line were evaluated in the magnified images. 40
Hee Yoon Jang, et al: CMM and NFM with NBI for Gastric Epithelial Tumors Table 2. Baseline Characteristics of the Enrolled Patients Characteristic Value Number of patients 20 Mean age (yr) 65.7 (49 81) Male 15 (75) Final diagnosis Early gastric cancer 10 (50) High-grade dysplasia 2 (10) Low-grade dysplasia 8 (40) Values are presented as number only, mean (range), or n (%). Table 3. Comparison of the Endoscopic Procedures and Image-quality Scores between Magnifying Methods Variable Conventional Near-focus magnification P value Observation time (s) 91.5±64.6 99.9±64.1 0.54 No. of magnified images 11 11 (median) Microsurface structure 3.73±0.40 4.09±0.39 0.015 Microvascular structure 4.29±0.45 3.53±0.45 0.001 Demarcation line 3.61±0.54 3.91±0.41 0.089 Values are presented as mean±sd or number only. subjective ratings were based on a 5-point Likert scale: 1=poor, 2=fair, 3=good, 4=very good, 5=excellent. Statistical analysis was performed using SPSS ver. 14.0 (SPSS, Chicago, IL, USA). The Stuart-Maxwell test was used to compare the mean Likert scores between CMM and NFM. Statistical significance was established at P< 0.05. The interobserver agreement was assessed using the intraclass correlation coefficient (ICC), which was interpreted as follows: 0 0.20, poor; 0.21 0.40, fair; 0.41 0.60, moderate; 0.61 0.80, good; and 0.81 1.00, excellent. 18 RESULTS The mean age of the enrolled patients was 65.7 years and 75% were male. The final diagnosis after ESD revealed 10 cases (50%) of EGC, 2 cases (10%) of high-grade dysplasia, and 8 cases of low-grade dysplasia (Table 2). The mean observation time (±SD) was 91.5±64.6 s for CMM and 99.9±64.1 s for NFM (P=0.54). Each produced a median of 11 magnified images (Table 3). Based on the 10 endoscopists subjective ratings, the mean image quality scores for the microsurface structure were 4.09±0.39 in NFM and 3.73±0.40 in CMM (P= 0.015). The mean image quality scores for the microvascular structure were 3.53±0.45 in NFM and 4.29±0.45 in CMM (P=0.001). The mean image quality scores for the demarcation line were 3.91±0.41 in NFM and 3.61±0.54 in CMM (P=0.089; Table 3). The ICC for CMM was 0.252 (95% CI, 0.165 0.363) and that for NFM was 0.171 (95% CI, 0.103 0.267); these values imply poor interobserver agreement. DISCUSSION Our study showed that ME using NFM provided clearer images of the microsurface structure than CMM under NBI. However, CMM was more useful for observing the microvascular structure than was NFM. New endoscopic s have been developed to improve diagnostic sensitivity by enhancing the detection of suspicious lesions, followed by targeted biopsies. 6 While white light endoscopy uses the visible spectrum of light to form an image, NBI utilizes specific blue and green bands that are strongly absorbed by hemoglobin in the blood vessels. This enhances the visualization of the capillary network and mucosal morphology in a similar way to chromoendoscopy. ME with NBI was reported to be useful for the accurate diagnosis of gastric abnormalities, such as cancers, adenomas, and intestinal metaplasia. 10-14,19-21 In CMM, the endoscopist needs to move the scope close to the lesion to acquire a clear magnified image because the depth of field is 1.5 3.0 mm. The scope must be held steady due to the narrow range of distance at which a clear image can be maintained during ME with CMM. To maintain a consistent distance of about 2 mm from the mucosa, the mount of the soft black hood at the tip of the endoscope can be helpful. 22 If the scope cannot approach within the depth of field, no clear magnified image is acquired. Compared to CMM, the depth of field of NFM is relatively wide (3.0 7.0 mm) and a magnified image can be observed easily with the simple push of a scope button. Moreover, the combination of the improved scope and 41
Korean J Helicobacter Up Gastrointest Res: Vol 15, No 1, March 2015 system provides a brighter endoscopic view. We postulated that the score of image quality for microsurface structure would be higher given the higher resolution of ME using NFM. Using optical zoom, the magnification can reach 85- and 45-fold for CMM and NFM, respectively. When the endoscopist applies twofold electronic magnification, a total of 90-fold magnification is achieved using the specific monitor provided for NFM. However, electronic zoom can also reduce image quality. In our study, the image quality score for the microvascular structure was higher with CMM than NFM. This might have resulted from the larger image magnification without deterioration in CMM. Our study had several limitations. First, it was performed at a single center and a small number of gastric epithelial tumors were assessed. Further study using more tumors should yield clearer results in terms of the comparison of the two magnifying s. Second, the independent endoscopists could determine which imaging modality was used, as the NFM images were brighter than the CMM images because of the improved light source and different NBI filter design. Third, the interobserver agreement was poor because each endoscopist scored both s subjectively. These results suggest individual variation in evaluation of the image quality of CMM and NFM under NBI. In conclusion, magnification using NFM under NBI provides high-quality images of the microsurface structures in gastric epithelial tumors. Using this magnifying, magnified images can be acquired by simply pushing a button on the scope. REFERENCES 1. Ezoe Y, Muto M, Uedo N, et al. Magnifying narrowband imaging is more accurate than conventional white-light imaging in diagnosis of gastric mucosal cancer. Gastroenterology 2011; 141:2017-2025.e3. 2. Uedo N, Yao K, Ishihara R. Screening and treating intermediate lesions to prevent gastric cancer. Gastroenterol Clin North Am 2013;42:317-335. 3. Yao K, Nagahama T, Matsui T, Iwashita A. Detection and characterization of early gastric cancer for curative endoscopic submucosal dissection. Dig Endosc 2013;25(Suppl 1):44-54. 4. Kim KO, Ku YS. Is image-enhanced endoscopy useful for the diagnosis and treatment of gastrointestinal tumor? Clin Endosc 2013;46:248-250. 5. Wanders LK, East JE, Uitentuis SE, Leeflang MM, Dekker E. Diagnostic performance of narrowed spectrum endoscopy, autofluorescence imaging, and confocal laser endomicroscopy for optical diagnosis of colonic polyps: a meta-analysis. Lancet Oncol 2013;14:1337-1347. 6. Coda S, Thillainayagam AV. State of the art in advanced endoscopic imaging for the detection and evaluation of dysplasia and early cancer of the gastrointestinal tract. Clin Exp Gastroenterol 2014;7:133-150. 7. Kodashima S, Fujishiro M, Ono S, et al. Evaluation of a new image-enhanced endoscopic technology using band-limited light for detection of esophageal squamous cell carcinoma. Dig Endosc 2014;26:164-171. 8. Singh R, Lee SY, Vijay N, Sharma P, Uedo N. Update on narrow band imaging in disorders of the upper gastrointestinal tract. Dig Endosc 2014;26:144-153. 9. Tao G, Xing-Hua L, Ai-Ming Y, et al. Enhanced magnifying endoscopy for differential diagnosis of superficial gastric lesions identified with white-light endoscopy. Gastric Cancer 2014; 17:122-129. 10. Nakayoshi T, Tajiri H, Matsuda K, Kaise M, Ikegami M, Sasaki H. Magnifying endoscopy combined with narrow band imaging system for early gastric cancer: correlation of vascular pattern with histopathology (including video). Endoscopy 2004;36: 1080-1084. 11. Uedo N, Ishihara R, Iishi H, et al. A new of diagnosing gastric intestinal metaplasia: narrow-band imaging with magnifying endoscopy. Endoscopy 2006;38:819-824. 12. Yao K, Iwashita A, Tanabe H, et al. White opaque substance within superficial elevated gastric neoplasia as visualized by magnification endoscopy with narrow-band imaging: a new optical sign for differentiating between adenoma and carcinoma. Gastrointest Endosc 2008;68:574-580. 13. Kaise M, Kato M, Urashima M, et al. Magnifying endoscopy combined with narrow-band imaging for differential diagnosis of superficial depressed gastric lesions. Endoscopy 2009;41: 310-315. 14. Ezoe Y, Muto M, Horimatsu T, et al. Magnifying narrow-band imaging versus magnifying white-light imaging for the differential diagnosis of gastric small depressive lesions: a prospective study. Gastrointest Endosc 2010;71:477-484. 15. Ikematsu H, Matsuda T, Osera S, et al. Usefulness of narrow-band imaging with dual-focus magnification for differential diagnosis of small colorectal polyps. Surg Endosc 2014. [Epub ahead of print] 16. Tontini GE, Lindner A, Vieth M, Vecchi M, Neurath MF, Neumann H. Dual-focus narrow band imaging for the detection of intestinal metaplasia and atrophic gastritis. Endoscopy 2014;46 Suppl 1 UCTN:E47-48. 17. Wallace MB, Crook JE, Coe S, et al. Accuracy of in vivo colorectal polyp discrimination by using dual-focus high-definition nar- 42
Hee Yoon Jang, et al: CMM and NFM with NBI for Gastric Epithelial Tumors row-band imaging colonoscopy. Gastrointest Endosc 2014. [Epub ahead of print] 18. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics 1977;33:159-174. 19. Yao K, Iwashita A, Tanabe H, et al. Novel zoom endoscopy technique for diagnosis of small flat gastric cancer: a prospective, blind study. Clin Gastroenterol Hepatol 2007;5:869-878. 20. Kato M, Kaise M, Yonezawa J, et al. Magnifying endoscopy with narrow-band imaging achieves superior accuracy in the differential diagnosis of superficial gastric lesions identified with white-light endoscopy: a prospective study. Gastrointest Endosc 2010;72:523-529. 21. Tamai N, Kaise M, Nakayoshi T, et al. Clinical and endoscopic characterization of depressed gastric adenoma. Endoscopy 2006;38:391-394. 22. Yao K, Anagnostopoulos GK, Ragunath K. Magnifying endoscopy for diagnosing and delineating early gastric cancer. Endoscopy 2009;41:462-467. 43