Visualization of Laterally Spreading Colorectal Tumors by Using Image-Enhanced Endoscopy

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Colonoscopy is considered the gold standard for detecting colorectal tumors; however, conventional colonoscopy can miss flat tumors. We aimed to determine whether visualization of colorectal flat lesions was improved by autofluorescence imaging and narrow-band imaging image analysis in conjunction with a new endoscopy system. Eight physicians compared autofluorescent, narrow-band, and chromoendoscopy images to 30 corresponding white-light images of flat tumors. Physicians rated tumor visibility from each image set as follows: +2 (improved), +1 (somewhat improved), 0 (equivalent to white light), −1 (somewhat decreased), and −2 (decreased). The eight scores for each image were totalled and evaluated. Interobserver agreement was also examined. Autofluorescent, narrow-band, and chromoendoscopy images showed improvements of 63.3% (19/ 30), 6.7% (2/30), and 73.3% (22/30), respectively, with no instances of decreased visibility. Autofluorescence scores were generally greater than narrow-band scores. Interobserver agreement was 0.65 for autofluorescence, 0.80 for narrow-band imaging, and 0.70 for chromoendoscopy. In conclusion, using a new endoscopy system in conjunction with autofluorescent imaging improved visibility of colorectal flat tumors, equivalent to the visibility achieved using chromoendoscopy.

Section: Discussionmentioning

confidence: 99%

Improved visibility of colorectal flat tumors using image‐enhanced endoscopy

Oka

Tamai

Ikematsu

et al. 2015

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“…Tamai et al . reported that significantly better visualization of non‐polypoid colorectal lesions was provided by AFI than by WL when used by less‐experienced endoscopists . On the assumption that better differentiation and visualization may enable improved detection, we carried out the present pilot study to evaluate whether the AFI system is useful for trainees with an initial brief training session.…”

Section: Discussionmentioning

confidence: 99%

“…This means that the identification of smaller neoplasms when reviewed by trainees was similar between the two systems. The AFI system has been shown to provide significantly better visualization and differentiation of non‐polypoid colorectal neoplasms than that provided by WL colonoscopy, which is an advantage of the AFI system . Any type of IEE, including AFI and NBI, has its own special characteristics.…”

Section: Discussionmentioning

confidence: 99%

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What is the accuracy of autofluorescence imaging in identifying non‐polypoid colorectal neoplastic lesions when reviewed by trainees? A pilot study

Odagaki

Sakamoto

Sekiguchi

et al. 2012

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False-positive results tended to be more frequent for the AFI images than for the WL images. Further improvements in the technology and resolution are necessary for the AFI system to be useful for the detection of colorectal neoplasms. At present, clinical application of the AFI system may require more extensive structured training to improve its accuracy in the identification of non-polypoid colorectal neoplasms.

“…In several reports, the effectiveness of AFI systems for detecting colorectal neoplasia has been evaluated using first-generation AFI systems (EVIS LUCERA CLV-260SL, EVIS LUCERA CV-260S; Olympus Medical Systems, Tokyo, Japan); however, these results are controversial. [1][2][3][4] Recently, second-generation AFI systems have been developed (EVIS LUCERA ELITE CLV-290SL, EVIS LUCERA ELITE CV-290; Olympus Medical Systems) that have a brighter lamp and an improved image-processing algorithm that results in a higher frame rate and higher resolution images compared to those of the first-generation systems. According to a recent report, the second-generation AFI systems allow higher color contrast between colorectal neoplasia and the surrounding mucosa than white light imaging (WLI) and narrow band imaging.…”

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confidence: 99%

Second‐generation autofluorescence imaging for colorectal neoplasia

Tamai

Takeuchi

Tajiri

2015

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In autofluorescence imaging (AFI) systems, white light from a light source is separated with a filter into an excitation light and a green light, and irradiated onto an object. After blocking the reflection of excitation light, a false color image is produced on a monitor based on the balance of autofluorescence intensity and green light intensity. Finally, AFI systems enable visualization of colorectal neoplasia with magenta. In several reports, the effectiveness of AFI systems for detecting colorectal neoplasia has been evaluated using first-generation AFI systems (EVIS LUCERA CLV-260SL, EVIS LUCERA CV-260S; Olympus Medical Systems, Tokyo, Japan); however, these results are controversial. [1][2][3][4] Recently, second-generation AFI systems have been developed (EVIS LUCERA ELITE CLV-290SL, EVIS LUCERA ELITE CV-290; Olympus Medical Systems) that have a brighter lamp and an improved image-processing algorithm that results in a higher frame rate and higher resolution images compared to those of the first-generation systems. According to a recent report, the second-generation AFI systems allow higher color contrast between colorectal neoplasia and the surrounding mucosa than white light imaging (WLI) and narrow band imaging. Based on results from an objective questionnaire given to endoscopists, these systems also have better visualization scores than WLI in still images. These results may suggest that higher color contrast corresponds to better visibility of colorectal lesions. 5In WLI, the color contrast between a flat lesion and surrounding mucosa is occasionally low. Therefore, it is often difficult to clearly visualize flat lesions (Fig. 1a). Conversely, AFI provides higher color contrast of flat lesions that allows better visibility and better delineation of flat lesions than WLI (Fig. 1b).Although it seems promising that second-generation AFI systems may increase the adenoma detection rate compared to WLI, prospective studies are needed to confirm whether they are effective for the detection of colorectal neoplasia in clinical practice. CONFLICT OF INTERESTSA UTHORS DECLARE no conflict of interests for this article. In WLI, the lesion is visualized as being almost the same color as the surrounding mucosa. In AFI, the lesion is observed with higher color contrast than in WLI.