The Experts below are selected from a list of 35646 Experts worldwide ranked by ideXlab platform
Hiroyuki Osawa - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of elevated-type early gastric cancers by the Optimal Band imaging system
Gastrointestinal endoscopy, 2009Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Masato Shigemori, Kentaro SuganoAbstract:Background The endoscopic diagnosis of an elevated-type early gastric cancer is often difficult. The Optimal Band imaging (OBI) system can reconstruct the best spectral images decomposed from ordinary endoscopic images with free selection of 3 wavelengths and provide unmagnified images with high light intensity as well as magnified images. Objective To evaluate whether the OBI system facilitates detection of the demarcation lines between an elevated-type early gastric cancer and surrounding tissue and thus is more helpful for performing endoscopic therapy. Design A prospective study. Setting Jichi Medical University, Japan. Patients Seventy-five patients, 81 lesions with an elevated-type early gastric cancer. Main Outcome Measurements A comparison between OBI images and conventional endoscopic images in the identification of the demarcation lines of an elevated-type early gastric cancer without magnification and the rate of success in identifying the abnormal surface structure of cancer by using low-magnified OBI images. Results Demarcation lines were easily identified in OBI images, even without magnification, because such cancers could be clearly distinguished from the surrounding whitish atrophic mucosa. Inexperienced endoscopists could determine demarcation lines with significantly greater accuracy with unmagnified OBI images than with conventional images. With 40-fold magnification, irregular microstructural or nonstructural patterns were also found within cancer lesions in all cases studied but in none of the cases in the surrounding noncancerous mucosa. Conclusions The new contrast images obtained with the OBI system enable better determination of the demarcation lines of elevated-type early gastric cancers, and this system may be useful for performing endoscopic therapy of this type of cancer as a new endoscopic modality.
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A comparison of conventional endoscopy, chromoendoscopy, and the Optimal-Band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps.
Gastrointestinal endoscopy, 2009Co-Authors: Kazutomo Togashi, Hiroyuki Osawa, Koji Koinuma, Yoshikazu Hayashi, Tomohiko Miyata, Keijiro Sunada, Mitsuhiro Nokubi, Hisanaga Horie, Hironori YamamotoAbstract:The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal Band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye. To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy. An open prospective study. Jichi Medical University, Japan. A total of 133 colonoscopy cases. A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps < or =5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification. A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy. Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.
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A comparison of conventional endoscopy, chromoendoscopy, and the Optimal-Band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps
Gastrointestinal Endoscopy, 2009Co-Authors: Kazutomo Togashi, Hiroyuki Osawa, Koji Koinuma, Yoshikazu Hayashi, Tomohiko Miyata, Keijiro Sunada, Mitsuhiro Nokubi, Hisanaga Horie, Hironori YamamotoAbstract:Background The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal Band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye. Objective To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy. Design An open prospective study. Setting Jichi Medical University, Japan. Patients A total of 133 colonoscopy cases. Main Outcome Measurement A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps ≤5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification. Results A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy. Conclusions Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.
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NEWLY DEVELOPED Optimal Band IMAGING SYSTEM FOR THE DIAGNOSIS OF EARLY GASTRIC CANCER
Digestive Endoscopy, 2008Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Kentaro SuganoAbstract:Background: Magnifying narrow Band imaging system is useful for the diagnosis of early gastric cancer. However, it is difficult for the operator of the scope to maintain the correct distance between the tip of the endoscope and the gastric mucosa for appropriate visualization. The newly developed Optimal Band imaging system can reconstruct good spectral images derived from ordinary endoscopic images and enhance the mucosal surface without magnification as well as with low magnification. This imaging technique is based on narrowing the Bandwidth of the conventional image arithmetically, using spectral estimation technology. Methods: We evaluated endoscopic features of 30 lesions with elevated-type, 32 lesions with depressed-type and two lesions with flat-type early gastric cancer using this new system. Results: We found the best images in all cases of early gastric cancers by using a specific combination of the following three wavelengths available in this system: 470 nm for blue, 500 nm for green and 550 nm for red. The Optimal Band images showed the depressed-type early gastric cancer as reddish lesions distinct from the surrounding yellowish non-cancerous area, leading to a clear demarcation line between the cancerous and non-cancerous mucosa without magnification. Moreover, 30–40-fold magnified Optimal Band images showed a clearly irregular microvascular pattern or a microstructure pattern of the mucosal surface in all types of gastric cancers. Conclusion: This new system can provide useful information for diagnosing various types of early gastric cancers without and with low magnification.
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Optimal Band imaging system can facilitate detection of changes in depressed-type early gastric cancer.
Gastrointestinal endoscopy, 2007Co-Authors: Hiroyuki Osawa, Mitsuyo Yoshizawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hirohide Ohnishi, Hidetoshi Nakano, Masahiro Wada, Masayuki Arashiro, Mamiko TsukuiAbstract:Background The endoscopic diagnosis of depressed-type early gastric cancers is difficult because these cancers manifest as subtle changes in color and shape. The newly developed Optimal Band imaging (OBI) system can reconstruct the best spectral images derived from ordinary endoscopic images and enhances the mucosal surface without the use of dyes. This imaging technique is based on narrowing the Bandwidth of conventional image arithmetically by using spectral estimation technology. Objective Evaluation of the usefulness of the OBI system for identifying the demarcation line of depressed-type early gastric cancers. Design Prospective study. Setting Jichi Medical University in Japan. Patients Twenty-seven cases with depressed-type early gastric cancer. Main Outcome Measurement Comparative study for the success rate of identifying the demarcation line of depressed-type early gastric cancer by using Optimal Band images and conventional endoscopic images. Results Demarcation of the depressed-type early gastric cancer was easily identified by Optimal Band images without magnification in 26 of 27 cases (96%), because distinct demarcation was observed endoscopically between the reddish images of the cancerous lesion and the yellowish images of the surrounding noncancerous area. With 40-fold magnification of Optimal Band images, the demarcation was also clearly recognized in all cases. Medical students could point out the demarcation line with significantly greater accuracy by observing the new nonmagnified Optimal Band images than by the conventional images ( P Limitation Small sample size. Conclusions The new contrasting images of the OBI system can delineate the depressed-type early gastric cancer more easily than conventional endoscopy.
Mamiko Tsukui - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of elevated-type early gastric cancers by the Optimal Band imaging system
Gastrointestinal endoscopy, 2009Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Masato Shigemori, Kentaro SuganoAbstract:Background The endoscopic diagnosis of an elevated-type early gastric cancer is often difficult. The Optimal Band imaging (OBI) system can reconstruct the best spectral images decomposed from ordinary endoscopic images with free selection of 3 wavelengths and provide unmagnified images with high light intensity as well as magnified images. Objective To evaluate whether the OBI system facilitates detection of the demarcation lines between an elevated-type early gastric cancer and surrounding tissue and thus is more helpful for performing endoscopic therapy. Design A prospective study. Setting Jichi Medical University, Japan. Patients Seventy-five patients, 81 lesions with an elevated-type early gastric cancer. Main Outcome Measurements A comparison between OBI images and conventional endoscopic images in the identification of the demarcation lines of an elevated-type early gastric cancer without magnification and the rate of success in identifying the abnormal surface structure of cancer by using low-magnified OBI images. Results Demarcation lines were easily identified in OBI images, even without magnification, because such cancers could be clearly distinguished from the surrounding whitish atrophic mucosa. Inexperienced endoscopists could determine demarcation lines with significantly greater accuracy with unmagnified OBI images than with conventional images. With 40-fold magnification, irregular microstructural or nonstructural patterns were also found within cancer lesions in all cases studied but in none of the cases in the surrounding noncancerous mucosa. Conclusions The new contrast images obtained with the OBI system enable better determination of the demarcation lines of elevated-type early gastric cancers, and this system may be useful for performing endoscopic therapy of this type of cancer as a new endoscopic modality.
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NEWLY DEVELOPED Optimal Band IMAGING SYSTEM FOR THE DIAGNOSIS OF EARLY GASTRIC CANCER
Digestive Endoscopy, 2008Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Kentaro SuganoAbstract:Background: Magnifying narrow Band imaging system is useful for the diagnosis of early gastric cancer. However, it is difficult for the operator of the scope to maintain the correct distance between the tip of the endoscope and the gastric mucosa for appropriate visualization. The newly developed Optimal Band imaging system can reconstruct good spectral images derived from ordinary endoscopic images and enhance the mucosal surface without magnification as well as with low magnification. This imaging technique is based on narrowing the Bandwidth of the conventional image arithmetically, using spectral estimation technology. Methods: We evaluated endoscopic features of 30 lesions with elevated-type, 32 lesions with depressed-type and two lesions with flat-type early gastric cancer using this new system. Results: We found the best images in all cases of early gastric cancers by using a specific combination of the following three wavelengths available in this system: 470 nm for blue, 500 nm for green and 550 nm for red. The Optimal Band images showed the depressed-type early gastric cancer as reddish lesions distinct from the surrounding yellowish non-cancerous area, leading to a clear demarcation line between the cancerous and non-cancerous mucosa without magnification. Moreover, 30–40-fold magnified Optimal Band images showed a clearly irregular microvascular pattern or a microstructure pattern of the mucosal surface in all types of gastric cancers. Conclusion: This new system can provide useful information for diagnosing various types of early gastric cancers without and with low magnification.
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Optimal Band imaging system can facilitate detection of changes in depressed-type early gastric cancer.
Gastrointestinal endoscopy, 2007Co-Authors: Hiroyuki Osawa, Mitsuyo Yoshizawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hirohide Ohnishi, Hidetoshi Nakano, Masahiro Wada, Masayuki Arashiro, Mamiko TsukuiAbstract:Background The endoscopic diagnosis of depressed-type early gastric cancers is difficult because these cancers manifest as subtle changes in color and shape. The newly developed Optimal Band imaging (OBI) system can reconstruct the best spectral images derived from ordinary endoscopic images and enhances the mucosal surface without the use of dyes. This imaging technique is based on narrowing the Bandwidth of conventional image arithmetically by using spectral estimation technology. Objective Evaluation of the usefulness of the OBI system for identifying the demarcation line of depressed-type early gastric cancers. Design Prospective study. Setting Jichi Medical University in Japan. Patients Twenty-seven cases with depressed-type early gastric cancer. Main Outcome Measurement Comparative study for the success rate of identifying the demarcation line of depressed-type early gastric cancer by using Optimal Band images and conventional endoscopic images. Results Demarcation of the depressed-type early gastric cancer was easily identified by Optimal Band images without magnification in 26 of 27 cases (96%), because distinct demarcation was observed endoscopically between the reddish images of the cancerous lesion and the yellowish images of the surrounding noncancerous area. With 40-fold magnification of Optimal Band images, the demarcation was also clearly recognized in all cases. Medical students could point out the demarcation line with significantly greater accuracy by observing the new nonmagnified Optimal Band images than by the conventional images ( P Limitation Small sample size. Conclusions The new contrasting images of the OBI system can delineate the depressed-type early gastric cancer more easily than conventional endoscopy.
Kentaro Sugano - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of elevated-type early gastric cancers by the Optimal Band imaging system
Gastrointestinal endoscopy, 2009Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Masato Shigemori, Kentaro SuganoAbstract:Background The endoscopic diagnosis of an elevated-type early gastric cancer is often difficult. The Optimal Band imaging (OBI) system can reconstruct the best spectral images decomposed from ordinary endoscopic images with free selection of 3 wavelengths and provide unmagnified images with high light intensity as well as magnified images. Objective To evaluate whether the OBI system facilitates detection of the demarcation lines between an elevated-type early gastric cancer and surrounding tissue and thus is more helpful for performing endoscopic therapy. Design A prospective study. Setting Jichi Medical University, Japan. Patients Seventy-five patients, 81 lesions with an elevated-type early gastric cancer. Main Outcome Measurements A comparison between OBI images and conventional endoscopic images in the identification of the demarcation lines of an elevated-type early gastric cancer without magnification and the rate of success in identifying the abnormal surface structure of cancer by using low-magnified OBI images. Results Demarcation lines were easily identified in OBI images, even without magnification, because such cancers could be clearly distinguished from the surrounding whitish atrophic mucosa. Inexperienced endoscopists could determine demarcation lines with significantly greater accuracy with unmagnified OBI images than with conventional images. With 40-fold magnification, irregular microstructural or nonstructural patterns were also found within cancer lesions in all cases studied but in none of the cases in the surrounding noncancerous mucosa. Conclusions The new contrast images obtained with the OBI system enable better determination of the demarcation lines of elevated-type early gastric cancers, and this system may be useful for performing endoscopic therapy of this type of cancer as a new endoscopic modality.
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NEWLY DEVELOPED Optimal Band IMAGING SYSTEM FOR THE DIAGNOSIS OF EARLY GASTRIC CANCER
Digestive Endoscopy, 2008Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Kentaro SuganoAbstract:Background: Magnifying narrow Band imaging system is useful for the diagnosis of early gastric cancer. However, it is difficult for the operator of the scope to maintain the correct distance between the tip of the endoscope and the gastric mucosa for appropriate visualization. The newly developed Optimal Band imaging system can reconstruct good spectral images derived from ordinary endoscopic images and enhance the mucosal surface without magnification as well as with low magnification. This imaging technique is based on narrowing the Bandwidth of the conventional image arithmetically, using spectral estimation technology. Methods: We evaluated endoscopic features of 30 lesions with elevated-type, 32 lesions with depressed-type and two lesions with flat-type early gastric cancer using this new system. Results: We found the best images in all cases of early gastric cancers by using a specific combination of the following three wavelengths available in this system: 470 nm for blue, 500 nm for green and 550 nm for red. The Optimal Band images showed the depressed-type early gastric cancer as reddish lesions distinct from the surrounding yellowish non-cancerous area, leading to a clear demarcation line between the cancerous and non-cancerous mucosa without magnification. Moreover, 30–40-fold magnified Optimal Band images showed a clearly irregular microvascular pattern or a microstructure pattern of the mucosal surface in all types of gastric cancers. Conclusion: This new system can provide useful information for diagnosing various types of early gastric cancers without and with low magnification.
Mitsuyo Yoshizawa - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of elevated-type early gastric cancers by the Optimal Band imaging system
Gastrointestinal endoscopy, 2009Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Masato Shigemori, Kentaro SuganoAbstract:Background The endoscopic diagnosis of an elevated-type early gastric cancer is often difficult. The Optimal Band imaging (OBI) system can reconstruct the best spectral images decomposed from ordinary endoscopic images with free selection of 3 wavelengths and provide unmagnified images with high light intensity as well as magnified images. Objective To evaluate whether the OBI system facilitates detection of the demarcation lines between an elevated-type early gastric cancer and surrounding tissue and thus is more helpful for performing endoscopic therapy. Design A prospective study. Setting Jichi Medical University, Japan. Patients Seventy-five patients, 81 lesions with an elevated-type early gastric cancer. Main Outcome Measurements A comparison between OBI images and conventional endoscopic images in the identification of the demarcation lines of an elevated-type early gastric cancer without magnification and the rate of success in identifying the abnormal surface structure of cancer by using low-magnified OBI images. Results Demarcation lines were easily identified in OBI images, even without magnification, because such cancers could be clearly distinguished from the surrounding whitish atrophic mucosa. Inexperienced endoscopists could determine demarcation lines with significantly greater accuracy with unmagnified OBI images than with conventional images. With 40-fold magnification, irregular microstructural or nonstructural patterns were also found within cancer lesions in all cases studied but in none of the cases in the surrounding noncancerous mucosa. Conclusions The new contrast images obtained with the OBI system enable better determination of the demarcation lines of elevated-type early gastric cancers, and this system may be useful for performing endoscopic therapy of this type of cancer as a new endoscopic modality.
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NEWLY DEVELOPED Optimal Band IMAGING SYSTEM FOR THE DIAGNOSIS OF EARLY GASTRIC CANCER
Digestive Endoscopy, 2008Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Kentaro SuganoAbstract:Background: Magnifying narrow Band imaging system is useful for the diagnosis of early gastric cancer. However, it is difficult for the operator of the scope to maintain the correct distance between the tip of the endoscope and the gastric mucosa for appropriate visualization. The newly developed Optimal Band imaging system can reconstruct good spectral images derived from ordinary endoscopic images and enhance the mucosal surface without magnification as well as with low magnification. This imaging technique is based on narrowing the Bandwidth of the conventional image arithmetically, using spectral estimation technology. Methods: We evaluated endoscopic features of 30 lesions with elevated-type, 32 lesions with depressed-type and two lesions with flat-type early gastric cancer using this new system. Results: We found the best images in all cases of early gastric cancers by using a specific combination of the following three wavelengths available in this system: 470 nm for blue, 500 nm for green and 550 nm for red. The Optimal Band images showed the depressed-type early gastric cancer as reddish lesions distinct from the surrounding yellowish non-cancerous area, leading to a clear demarcation line between the cancerous and non-cancerous mucosa without magnification. Moreover, 30–40-fold magnified Optimal Band images showed a clearly irregular microvascular pattern or a microstructure pattern of the mucosal surface in all types of gastric cancers. Conclusion: This new system can provide useful information for diagnosing various types of early gastric cancers without and with low magnification.
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Optimal Band imaging system can facilitate detection of changes in depressed-type early gastric cancer.
Gastrointestinal endoscopy, 2007Co-Authors: Hiroyuki Osawa, Mitsuyo Yoshizawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hirohide Ohnishi, Hidetoshi Nakano, Masahiro Wada, Masayuki Arashiro, Mamiko TsukuiAbstract:Background The endoscopic diagnosis of depressed-type early gastric cancers is difficult because these cancers manifest as subtle changes in color and shape. The newly developed Optimal Band imaging (OBI) system can reconstruct the best spectral images derived from ordinary endoscopic images and enhances the mucosal surface without the use of dyes. This imaging technique is based on narrowing the Bandwidth of conventional image arithmetically by using spectral estimation technology. Objective Evaluation of the usefulness of the OBI system for identifying the demarcation line of depressed-type early gastric cancers. Design Prospective study. Setting Jichi Medical University in Japan. Patients Twenty-seven cases with depressed-type early gastric cancer. Main Outcome Measurement Comparative study for the success rate of identifying the demarcation line of depressed-type early gastric cancer by using Optimal Band images and conventional endoscopic images. Results Demarcation of the depressed-type early gastric cancer was easily identified by Optimal Band images without magnification in 26 of 27 cases (96%), because distinct demarcation was observed endoscopically between the reddish images of the cancerous lesion and the yellowish images of the surrounding noncancerous area. With 40-fold magnification of Optimal Band images, the demarcation was also clearly recognized in all cases. Medical students could point out the demarcation line with significantly greater accuracy by observing the new nonmagnified Optimal Band images than by the conventional images ( P Limitation Small sample size. Conclusions The new contrasting images of the OBI system can delineate the depressed-type early gastric cancer more easily than conventional endoscopy.
Hironori Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of elevated-type early gastric cancers by the Optimal Band imaging system
Gastrointestinal endoscopy, 2009Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Masato Shigemori, Kentaro SuganoAbstract:Background The endoscopic diagnosis of an elevated-type early gastric cancer is often difficult. The Optimal Band imaging (OBI) system can reconstruct the best spectral images decomposed from ordinary endoscopic images with free selection of 3 wavelengths and provide unmagnified images with high light intensity as well as magnified images. Objective To evaluate whether the OBI system facilitates detection of the demarcation lines between an elevated-type early gastric cancer and surrounding tissue and thus is more helpful for performing endoscopic therapy. Design A prospective study. Setting Jichi Medical University, Japan. Patients Seventy-five patients, 81 lesions with an elevated-type early gastric cancer. Main Outcome Measurements A comparison between OBI images and conventional endoscopic images in the identification of the demarcation lines of an elevated-type early gastric cancer without magnification and the rate of success in identifying the abnormal surface structure of cancer by using low-magnified OBI images. Results Demarcation lines were easily identified in OBI images, even without magnification, because such cancers could be clearly distinguished from the surrounding whitish atrophic mucosa. Inexperienced endoscopists could determine demarcation lines with significantly greater accuracy with unmagnified OBI images than with conventional images. With 40-fold magnification, irregular microstructural or nonstructural patterns were also found within cancer lesions in all cases studied but in none of the cases in the surrounding noncancerous mucosa. Conclusions The new contrast images obtained with the OBI system enable better determination of the demarcation lines of elevated-type early gastric cancers, and this system may be useful for performing endoscopic therapy of this type of cancer as a new endoscopic modality.
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A comparison of conventional endoscopy, chromoendoscopy, and the Optimal-Band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps.
Gastrointestinal endoscopy, 2009Co-Authors: Kazutomo Togashi, Hiroyuki Osawa, Koji Koinuma, Yoshikazu Hayashi, Tomohiko Miyata, Keijiro Sunada, Mitsuhiro Nokubi, Hisanaga Horie, Hironori YamamotoAbstract:The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal Band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye. To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy. An open prospective study. Jichi Medical University, Japan. A total of 133 colonoscopy cases. A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps < or =5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification. A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy. Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.
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A comparison of conventional endoscopy, chromoendoscopy, and the Optimal-Band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps
Gastrointestinal Endoscopy, 2009Co-Authors: Kazutomo Togashi, Hiroyuki Osawa, Koji Koinuma, Yoshikazu Hayashi, Tomohiko Miyata, Keijiro Sunada, Mitsuhiro Nokubi, Hisanaga Horie, Hironori YamamotoAbstract:Background The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal Band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye. Objective To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy. Design An open prospective study. Setting Jichi Medical University, Japan. Patients A total of 133 colonoscopy cases. Main Outcome Measurement A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps ≤5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification. Results A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy. Conclusions Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.
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NEWLY DEVELOPED Optimal Band IMAGING SYSTEM FOR THE DIAGNOSIS OF EARLY GASTRIC CANCER
Digestive Endoscopy, 2008Co-Authors: Mitsuyo Yoshizawa, Hiroyuki Osawa, Hironori Yamamoto, Kiichi Satoh, Hidetoshi Nakano, Mamiko Tsukui, Kentaro SuganoAbstract:Background: Magnifying narrow Band imaging system is useful for the diagnosis of early gastric cancer. However, it is difficult for the operator of the scope to maintain the correct distance between the tip of the endoscope and the gastric mucosa for appropriate visualization. The newly developed Optimal Band imaging system can reconstruct good spectral images derived from ordinary endoscopic images and enhance the mucosal surface without magnification as well as with low magnification. This imaging technique is based on narrowing the Bandwidth of the conventional image arithmetically, using spectral estimation technology. Methods: We evaluated endoscopic features of 30 lesions with elevated-type, 32 lesions with depressed-type and two lesions with flat-type early gastric cancer using this new system. Results: We found the best images in all cases of early gastric cancers by using a specific combination of the following three wavelengths available in this system: 470 nm for blue, 500 nm for green and 550 nm for red. The Optimal Band images showed the depressed-type early gastric cancer as reddish lesions distinct from the surrounding yellowish non-cancerous area, leading to a clear demarcation line between the cancerous and non-cancerous mucosa without magnification. Moreover, 30–40-fold magnified Optimal Band images showed a clearly irregular microvascular pattern or a microstructure pattern of the mucosal surface in all types of gastric cancers. Conclusion: This new system can provide useful information for diagnosing various types of early gastric cancers without and with low magnification.
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Optimal Band imaging system can facilitate detection of changes in depressed-type early gastric cancer.
Gastrointestinal endoscopy, 2007Co-Authors: Hiroyuki Osawa, Mitsuyo Yoshizawa, Hironori Yamamoto, Hiroto Kita, Kiichi Satoh, Hirohide Ohnishi, Hidetoshi Nakano, Masahiro Wada, Masayuki Arashiro, Mamiko TsukuiAbstract:Background The endoscopic diagnosis of depressed-type early gastric cancers is difficult because these cancers manifest as subtle changes in color and shape. The newly developed Optimal Band imaging (OBI) system can reconstruct the best spectral images derived from ordinary endoscopic images and enhances the mucosal surface without the use of dyes. This imaging technique is based on narrowing the Bandwidth of conventional image arithmetically by using spectral estimation technology. Objective Evaluation of the usefulness of the OBI system for identifying the demarcation line of depressed-type early gastric cancers. Design Prospective study. Setting Jichi Medical University in Japan. Patients Twenty-seven cases with depressed-type early gastric cancer. Main Outcome Measurement Comparative study for the success rate of identifying the demarcation line of depressed-type early gastric cancer by using Optimal Band images and conventional endoscopic images. Results Demarcation of the depressed-type early gastric cancer was easily identified by Optimal Band images without magnification in 26 of 27 cases (96%), because distinct demarcation was observed endoscopically between the reddish images of the cancerous lesion and the yellowish images of the surrounding noncancerous area. With 40-fold magnification of Optimal Band images, the demarcation was also clearly recognized in all cases. Medical students could point out the demarcation line with significantly greater accuracy by observing the new nonmagnified Optimal Band images than by the conventional images ( P Limitation Small sample size. Conclusions The new contrasting images of the OBI system can delineate the depressed-type early gastric cancer more easily than conventional endoscopy.