Linked color imaging enhances endoscopic detection of sessile serrated adenoma/polyps

Linked color imaging improves colorectal lesion detection especially for low performance endoscopists: An international trial in Asia

BACKGROUND AND AIM

Linked color imaging (LCI) is an image-enhanced endoscopy technique that accentuates the color difference between red and white, potentially improving the adenoma detection rate (ADR). However, it remains unclear whether LCI performance in detecting colorectal lesions differs based on endoscopists' experience levels. We aimed to evaluate the differences in LCI efficacy based on the experience levels of endoscopists by conducting an exploratory analysis.

METHODS

In this post hoc analysis of an international randomized controlled trial comparing the detection of adenoma and other lesions using colonoscopy with LCI and high-definition white light imaging (WLI), we included patients from 11 institutions across four countries/regions: Japan, Thailand, Taiwan, and Singapore. We retrospectively reviewed differences in the lesion detection of LCI according to endoscopists' colonoscopy history or ADR.

RESULTS

We included 1692 and 1138 patients who underwent colonoscopies performed by 54 experts (experience of ≥ 5000 colonoscopies) and by 43 non-experts (experience of < 5000 colonoscopies), respectively. Both expert and non-expert groups showed a significant improvement in ADR with LCI compared to WLI (expert, 61.7% vs 46.4%; P < 0.001; non-expert, 56.6% vs 46.4%; P < 0.001). LCI had no effect on sessile serrated lesion detection rate in non-experts (3.1% vs 2.5%; P = 0.518). LCI significantly improved detection rates in endoscopists with relatively low detection performance, defined as an ADR < 50%.

CONCLUSIONS

This exploratory study analyzed data from a previous trial and revealed that LCI is useful for both experts and non-experts and is even more beneficial for endoscopists with relatively low detection performance using WLI.

Comparison of LED and LASER Colonoscopy About Linked Color Imaging and Blue Laser/Light Imaging of Colorectal Tumors in a Multinational Study

INTRODUCTION

In light-emitting diode (LED) and LASER colonoscopy, linked color imaging (LCI) and blue light/laser imaging (BLI) are used for lesion detection and characterization worldwide. We analyzed the difference of LCI and BLI images of colorectal lesions between LED and LASER in a multinational study.

METHODS

We prospectively observed lesions with white light imaging (WLI), LCI, and BLI using both LED and LASER colonoscopies from January 2020 to August 2021. Images were graded by 27 endoscopists from nine countries using the polyp visibility score: 4 (excellent), 3 (good), 2 (fair), and 1 (poor) and the comparison score (LED better/similar/LASER better) for WLI/LCI/BLI images of each lesion.

RESULTS

Finally, 32 lesions (polyp size: 20.0 ± 15.2 mm) including 9 serrated lesions, 13 adenomas, and 10 T1 cancers were evaluated. The polyp visibility scores of LCI/WLI for international and Japan-expert endoscopists were 3.17 ± 0.73/3.17 ± 0.79 (p = 0.92) and 3.34 ± 0.78/2.84 ± 1.22 (p < 0.01) for LED and 3.30 ± 0.71/3.12 ± 0.77 (p < 0.01) and 3.31 ± 0.82/2.78 ± 1.23 (p < 0.01) for LASER. Regarding the comparison of lesion visibility about between LED and LASER colonoscopy in international endoscopists, a significant difference was achieved not for WLI, but for LCI. The rates of LED better/similar/LASER better for brightness under WLI were 54.5%/31.6%/13.9% (International) and 75.0%/21.9%/3.1% (Japan expert). Those under LCI were 39.2%/35.4%/25.3% (International) and 31.3%/53.1%/15.6% (Japan expert). There were no significant differences in the diagnostic accuracy and the comparison score of BLI images between LED and LASER.

CONCLUSIONS

The differences of lesion visibility for WLI/LCI/BLI between LED and LASER in international endoscopists could be compared to those in Japanese endoscopists.

Image enhanced colonoscopy: updates and prospects-a review

Colonoscopy has been proven to be a successful approach in both identifying and preventing colorectal cancer. The incorporation of advanced imaging technologies, such as image-enhanced endoscopy (IEE), plays a vital role in real-time diagnosis. The advancements in endoscopic imaging technology have been continuous, from replacing fiber optics with charge-coupled devices to the introduction of chromoendoscopy in the 1970s. Recent technological advancements include "push-button" technologies like autofluorescence imaging (AFI), narrowed-spectrum endoscopy, and confocal laser endomicroscopy (CLE). Dye-based chromoendoscopy (DCE) is falling out of favor due to the longer time required for application and removal of the dye and the difficulty of identifying lesions in certain situations. Narrow band imaging (NBI) is a technology that filters the light used for illumination leading to improved contrast and better visibility of structures on the mucosal surface and has shown a consistently higher adenoma detection rate (ADR) compared to white light endoscopy. CLE has high sensitivity and specificity for polyp detection and characterization, and several classifications have been developed for accurate identification of normal, regenerative, and dysplastic epithelium. Other IEE technologies, such as blue laser imaging (BLI), linked-color imaging (LCI), i-SCAN, and AFI, have also shown promise in improving ADR and characterizing polyps. New technologies, such as Optivista, red dichromatic imaging (RDI), texture and color enhancement imaging (TXI), and computer-aided detection (CAD) using artificial intelligence (AI), are being developed to improve polyp detection and pathology prediction prior to widespread use in clinical practice.

Effect of real-time computer-aided detection of colorectal adenoma in routine colonoscopy (COLO-GENIUS): a single-centre randomised controlled trial

BACKGROUND

Artificial intelligence systems have been developed to improve polyp detection. We aimed to evaluate the effect of real-time computer-aided detection (CADe) on the adenoma detection rate (ADR) in routine colonoscopy.

METHODS

This single-centre randomised controlled trial (COLO-GENIUS) was done at the Digestive Endoscopy Unit, Pôle Digestif Paris-Bercy, Clinique Paris-Bercy, Charenton-le-Pont, France. All consecutive individuals aged 18 years or older who were scheduled for a total colonoscopy and had an American Society of Anesthesiologists score of 1-3 were screened for inclusion. After the caecum was reached and the colonic preparation was appropriate, eligible participants were randomly assigned (1:1; computer-generated random numbers list) to either standard colonoscopy or CADe-assisted colonoscopy (GI Genius 2.0.2; Medtronic). Participants and cytopathologists were masked to study assignment, whereas endoscopists were not. The primary outcome was ADR, which was assessed in the modified intention-to-treat population (all randomly assigned participants except those with misplaced consent forms). Safety was analysed in all included patients. According to statistical calculations, 20 endoscopists from the Clinique Paris-Bercy had to include approximately 2100 participants with 1:1 randomisation. The trial is complete and registered with ClinicalTrials.gov, NCT04440865.

FINDINGS

Between May 1, 2021, and May 1, 2022, 2592 participants were assessed for eligibility, of whom 2039 were randomly assigned to standard colonoscopy (n=1026) or CADe-assisted colonoscopy (n=1013). 14 participants in the standard group and ten participants in the CADe group were then excluded due to misplaced consent forms, leaving 2015 participants (979 [48·6%] men and 1036 [51·4%] women) in the modified intention-to-treat analysis. ADR was 33·7% (341 of 1012 colonoscopies) in the standard group and 37·5% (376 of 1003 colonoscopies) in the CADe group (estimated mean absolute difference 4·1 percentage points [95% CI 0·0-8·1]; p=0·051). One bleeding event without deglobulisation occurred in the CADe group after a large (>2 cm) polyp resection and resolved after a haemostasis clip was placed during a second colonoscopy.

INTERPRETATION

Our findings support the benefits of CADe, even in a non-academic centre. Systematic use of CADe in routine colonoscopy should be considered.

FUNDING

None.

Colorectal sessile serrated lesion detection using linked-color imaging versus narrow-band imaging: a parallel randomized controlled trial

BACKGROUND

 Previous studies have reported the effectiveness of narrow-band imaging (NBI) and linked-color imaging (LCI) in improving the detection of colorectal neoplasms. There has however been no direct comparison between LCI and NBI in the detection of colorectal sessile serrated lesions (SSLs). The present study aimed to compare the effectiveness of LCI and NBI in detecting colorectal SSLs.

METHODS

 A prospective, parallel, randomized controlled trial was conducted. The participants were randomly assigned to the LCI or NBI arms. The primary end point was the SSL detection rate (SDR).

RESULTS

 406 patients were involved; 204 in the LCI arm and 202 in the NBI arm. The total polyp detection rate, adenoma detection rate, and SDR were 54.2 %, 38.7 %, and 10.8%, respectively. The SDR was not significantly different between the LCI and NBI arms (12.3 % vs. 9.4 %; P = 0.36). The differences in the detection rate and the per-patient number of polyps, adenomas, diminutive lesions, and flat lesions between LCI and NBI also were not statistically significant. Multivariate analysis showed that LCI and NBI were not independent factors associated with SDR, whereas Boston Bowel Preparation Scale score (odds ratio [OR] 1.35, 95 %CI 1.03-1.76; P = 0.03), withdrawal time (OR 1.13, 95 %CI 1.00-1.26; P = 0.04), and operator experience (OR 3.73, 95 %CI 1.67-8.32; P = 0.001) were independent factors associated with SDR.

CONCLUSIONS

 LCI and NBI are comparable for SSL detection, as well as for the detection of polyps and adenomas.

Colorectal Sessile Serrated Lesion Detection Using Linked Color Imaging: A Multicenter, Parallel Randomized Controlled Trial

BACKGROUND & AIMS

Linked color imaging (LCI) is a novel technology that improves the color differences between colorectal lesions and the surrounding mucosa. The present study aims to compare the detection of colorectal sessile serrated lesions (SSL) using LCI with white light imaging (WLI).

METHOD

A large-scale, multicenter, parallel prospective randomized controlled trial was conducted in 4 hospitals in China. The participants were randomly assigned to the LCI group and WLI group. The primary endpoint was the SSL detection rate (SDR).

RESULTS

A total of 884 patients were involved in the intention-to-treat analysis, with 441 patients in the LCI group and 443 patients in the WLI group. The total polyp detection rate, adenoma detection rate, and SDR were 51.8%, 35.7%, and 8.6%, respectively. The SDR was significantly higher in the LCI group than in the WLI group (11.3% vs 5.9%, P = .004). Furthermore, LCI significantly increased the number of polyps and adenomas detected per patient, when compared with WLI (P < .05). In addition, there was higher detection rate of diminutive and flat lesions in the LCI group (P < .05). Multivariate analysis revealed that LCI is an independent factor associated with SDR (hazard ratio, 1.990; 95% confidence interval, 1.203-3.293; P = .007), along with withdrawal time (hazard ratio, 1.157; 95% confidence interval, 1.060-1.263; P = .001) and operator experience (hazard ratio, 1.850; 95% confidence interval, 1.045-3.273; P = .035).

CONCLUSIONS

LCI is significantly superior to WLI for SSL detection, and may improve polyp and adenoma detection. LCI can be recommended as an appropriate method for routine inspection during colonoscopy (http://www.chictr.org.cn number, ChiCTR2000035705).

Evaluation of the detection rate of high‑grade gastric intraepithelial neoplasia using linked color imaging and white light imaging

As an endoscopic technology for the enhancement of images, linked color imaging (LCI) performs well when used for the early detection and diagnosis of gastrointestinal cancer. However, literature data are lacking for LCI in the detection of high-grade gastric intraepithelial neoplasia. Therefore, the aim of the present study was to investigate the efficacy of LCI compared with traditional white light imaging (WLI) in the detection of high-grade gastric intraepithelial neoplasia via the comparison of detection rates between senior and junior endoscopists using both techniques. Overall, 84 lesions from 81 patients with high-grade gastric intraepithelial neoplasia diagnosed between January 2017 and December 2017 were considered. Following the exclusion of three patients with two lesions, 78 patients who had only one lesion were enrolled. The two types of endoscopy, WLI and LCI, were performed in the same patients under the same conditions. Four senior and four junior endoscopists retrospectively compared the images. The detection rate of high-grade gastric intraepithelial neoplasia was significantly higher with LCI than with WLI when performed by senior and junior endoscopists. With WLI, the detection rate obtained by senior endoscopists was significantly higher than that obtained by junior endoscopists. However, for LCI, the detection rates for junior and senior endoscopists were comparable. Interobserver agreement was good to satisfactory. These findings indicate that LCI is superior to WLI in the detection and identification of gastric cancer and provides highly accurate diagnostic results from endoscopic examinations, regardless of the experience of the endoscopist. LCI may be used to narrow the gap in the detection rate of high-grade gastric intraepithelial neoplasia between junior and senior endoscopists.

Comparison of Linked Color Imaging and White Light Imaging Colonoscopy for Detection of Colorectal Adenoma Requiring Endoscopic Treatment: A Single-Center Randomized Controlled Trial

BACKGROUND

Linked color imaging (LCI) improves detection of colorectal neoplastic lesions during colonoscopy. However, polyps <5 mm in diameter often do not require resection, and the benefits of LCI are unclear for detection of colorectal polyps ≥5 mm that are indicated for endoscopic resection in clinical practice. This randomized controlled trial compared rates of detection of adenoma polyps, stratified by size, for LCI and white light imaging (WLI).

METHODS

We compared ADR (5 mm-) and PDR (5 mm-), which were defined as the proportion of patients with at least one adenoma or polyp with a diameter of 5 mm or larger in the LCI and WLI groups. Moreover, we estimated ADR and PDR for diameters between 5 and 10 mm (ADR (5-9 mm), PDR (5-9 mm) ) and for diameters larger than 10 mm (ADR (10 mm-), PDR (10 mm-) ).

RESULTS

Data from 594 patients (LCI, n=305; WLI, n=289) were analyzed. ADR (5 mm-) and PDR (5 mm-) were significantly higher in the LCI group than in the WLI group (ADR (5 mm-): P=0.016, PDR (5 mm-): P=0.020). In the assessment of adenoma and polyp size, ADR (5-9 mm) and PDR (5-9 mm) were significantly higher in the LCI group than in the WLI group, although no significant differences were seen in ADR (10 mm-) and PDR (10 mm-) between these groups.

CONCLUSIONS

Polyps ≥5 mm, which are indicated for endoscopic treatment, were more easily visualized with LCI mode than with WLI mode. The improvement in detection rate was obvious for polyps <10 mm, which are easier to miss.

Detection of colorectal adenomas with texture and color enhancement imaging: Multicenter observational study

OBJECTIVES

We aimed to evaluate the efficacy of texture and color enhancement imaging (TXI), which allows the acquisition of brighter images with enhanced color and surface structure in colorectal polyp detection compared to white light imaging.

METHODS

Patients who underwent colonoscopy with repeated ascending colon observation using TXI and white light imaging between August 2020 and January 2021 were identified in three institutions. The outcomes included the mean number of adenomas detected per procedure (MAP), adenoma detection rate (ADR), and ascending colonic adenoma miss rate (Ac-AMR). Logistic regression was used to determine the effects of the variables on the outcomes.

RESULTS

We included 1043 lesions from 470 patients in the analysis. The MAP, ADR, flat polyp detection rate, and Ac-AMR in TXI and white light imaging were 1.5% (95% confidence interval 1.3-1.6%) vs. 1.0% (0.9-1.1%), 58.2% (51.7-64.6%) vs. 46.8% (40.2-53.4%), 66.2% (59.8-72.2%) vs. 49.8% (43.2-56.4%), and 17.9% (12.1-25.2%) vs. 28.2% (20.0-37.6%), respectively. TXI, age, withdrawal time, and endoscopy type were identified as significant factors affecting the MAP and the ADR using multivariate regression analysis.

CONCLUSIONS

Our study indicates that TXI improve the detection of colorectal neoplastic lesions. However, prospective randomized trials are required to confirm these findings.

Linked color imaging improves visibility of colorectal serrated lesion by high color contrast to surrounding mucosa

OBJECTIVES

This study aimed to objectively evaluate the efficacy of linked color imaging (LCI) in diagnosing colorectal serrated lesions by utilizing visibility scores and color differences.

METHODS

We examined 89 serrated lesions, including 36 hyperplastic polyps (HPs), 47 sessile serrated lesions (SSLs), and six traditional serrated adenomas (TSAs). Visibility changes were scored by six endoscopists as follows: 4, excellent; 3, good; 2, fair; and 1, poor. Furthermore, images obtained by white-light imaging (WLI) or LCI were assessed using the CIELAB color space in the lesion and adjacent mucosa. We calculated the mean color values (L*, a*, and b*) measured at five regions of interest of the sample lesion and surrounding mucosa and derived the color difference (ΔE*).

RESULTS

The visibility scores of both HPs and SSLs in LCI were significantly higher than that in WLI (HPs, 3.67/2.89, P < 0.001; SSLs, 3.07/2.36, P < 0.001). Furthermore, SSLs showed a significantly higher L* value and significantly lower a* and b* values in LCI than the adjacent mucosae (L*, 61.76/58.23, P = 0.016; a*, 14.91/17.58, P = 0.019; b*, 20.42/24.21, P = 0.007), while WLI produced no significant difference in any color value. A similar trend was apparent in HPs. In all serrated groups, LCI revealed significantly greater ΔE* values between the lesion and adjacent mucosa than WLI (HPs, 11.54/6.12; SSLs, 13.43/7.67; TSAs, 35.00/22.48).

CONCLUSION

Linked color imaging showed higher color contrast between serrated lesions and the surrounding mucosae compared with WLI, indicating improved visibility of colorectal serrated lesion using LCI.

Images of laser and light-emitting diode colonoscopy for comparing large colorectal lesion visibility with linked color imaging and white-light imaging

OBJECTIVES

In light-emitting diode (LED) and laser colonoscopy, linked color imaging (LCI) superiority to white-light imaging (WLI) for polyp detection is shown separately. We analyzed the noninferiority of LCI between LED and laser colonoscopy and that of WLI (LECOL study).

METHODS

We prospectively collected nonpolypoid lesions with WLI and LCI using LED and laser colonoscopy from January 2021 to August 2021. All images were evaluated randomly by 12 endoscopists (six nonexperts and six experts in three institutions) using the polyp visibility score: 4, excellent; 3, good; 2, fair; and 1, poor. The comparison score (LED better/similar/laser better) for redness and brightness was evaluated for WLI and LCI pictures of each lesion.

RESULTS

Finally, 63 nonpolypoid lesions were evaluated, and the mean polyp size was 24.5 ± 13.4 mm. Histopathology revealed 13 serrated lesions and 50 adenomatous/cancerous lesions. The mean polyp visibility scores of LCI pictures were significantly higher than those of WLI in the LED (3.35 ± 0.85 vs. 3.08 ± 0.91, P < 0.001) and the laser (3.40 ± 1.71 vs. 3.05 ± 0.97, P < 0.001) group, and the noninferiority of LCI pictures between LED and laser was significant (P < 0.001). The comparison scores revealed that the evaluation of redness and brightness (LED better/similar/laser better) were 26.8%/40.1%/33.1% and 43.5%/43.5%/13.0% for LCI pictures (P < 0.001) and 20.6%/44.3%/35.1% and 60.3%/31.7%/8.0% for WLI pictures (P < 0.001), respectively.

CONCLUSION

The noninferiority of polyp visibility with WLI and LCI in LED and laser colonoscopy was shown. WLI and LCI of LED tended to be brighter and less reddish than those of laser.

Usefulness of linked color imaging for the detection of obscure early gastric cancer: Multivariate analysis of 508 lesions

OBJECTIVES

Early gastric cancers (EGCs) of the elevated type or with submucosal invasion are easily found by routine endoscopy. However, most early cancers are challenging to detect because of subtle morphological or color differences from surrounding atrophic mucosa and intestinal metaplasia. Linked color imaging (LCI) enhances mucosal color difference, making it easier to detect EGCs. The aim of this study is to clarify the advantages and possible disadvantages of LCI for screening for obscure EGC.

METHODS

A total of 665 malignant gastric lesions resected using endoscopic submucosal dissection between January 2015 and April 2018 were retrospectively reviewed. Obviously detectable lesions were not included in the main analysis when determining the target lesion. White light imaging (WLI)/LCI images of 508 endoscopically obscure malignant lesions were included in the final analysis and evaluated by three non-expert and three expert endoscopists using visibility scores for detection and extent.

RESULTS

The detection visibility scores using LCI were significantly higher than those using WLI regardless of lesion characteristics including location, size, histological type, depth of invasion, and Helicobacter pylori status. The detection score improved in 46.4% cases and deteriorated in 4.9% when the modality changed from WLI to LCI. A mixed-effects multivariate logistic regression analysis showed that use of LCI (odds ratio [OR] 2.57), elevated type (OR 1.92), invasion to submucosa (OR 2.18) were significantly associated with improved visibility of EGC.

CONCLUSIONS

Linked color imaging significantly improves visibility of EGC regardless of differences in lesion morphology, histology, location, depth of invasion, and H. pylori status compared to conventional WLI.

Detecting colon polyps in endoscopic images using artificial intelligence constructed with automated collection of annotated images from an endoscopy reporting system

BACKGROUND

Artificial intelligence (AI) has made considerable progress in image recognition, especially in the analysis of endoscopic images. The availability of large-scale annotated datasets has contributed to the recent progress in this field. Datasets of high-quality annotated endoscopic images are widely available, particularly in Japan. A system for collecting annotated data reported daily could aid in accumulating a significant number of high-quality annotated datasets.

AIM

We assessed the validity of using daily annotated endoscopic images in a constructed reporting system for a prototype AI model for polyp detection.

METHODS

We constructed an automated collection system for daily annotated datasets from an endoscopy reporting system. The key images were selected and annotated for each case only during daily practice, not to be performed retrospectively. We automatically extracted annotated endoscopic images of diminutive colon polyps that had been diagnosed (study period March-September 2018) using the keywords of diagnostic information, and additionally collect the normal colon images. The collected dataset was devised into training and validation to build and evaluate the AI system. The detection model was developed using a deep learning algorithm, RetinaNet.

RESULTS

The automated system collected endoscopic images (47,391) from colonoscopies (745), and extracted key colon polyp images (1356) with localized annotations. The sensitivity, specificity, and accuracy of our AI model were 97.0%, 97.7%, and 97.3% (n = 300), respectively.

CONCLUSION

The automated system enabled the development of a high-performance colon polyp detector using images in endoscopy reporting system without the efforts of retrospective annotation works.

Visibility evaluation of colorectal lesion using texture and color enhancement imaging with video

Objective

Methods

Results

Conclusions

Detection of colorectal lesions during colonoscopy

Owing to its high mortality rate, the prevention of colorectal cancer is of particular importance. The resection of colorectal polyps is reported to drastically reduce colorectal cancer mortality, and examination by endoscopists who had a high adenoma detection rate was found to lower the risk of colorectal cancer, highlighting the importance of identifying lesions. Various devices, imaging techniques, and diagnostic tools aimed at reducing the rate of missed lesions have therefore been developed to improve detection. The distal attachments and devices for improving the endoscopic view angle are intended to help avoid missing blind spots such as folds and flexures in the colon, whereas the imaging techniques represented by image‐enhanced endoscopy contribute to improving lesion visibility. Recent advances in artificial intelligence‐supported detection systems are expected to supplement an endoscopist's eye through the instant diagnosis of the lesions displayed on the monitor. In this review, we provide an outline of each tool and assess its impact on the reduction in the incidence of missed colorectal polyps by summarizing previous clinical research and meta‐analyses. Although useful, the many devices, image‐enhanced endoscopy, and artificial intelligence tools exhibited various limitations. Integrating these tools can improve their shortcomings. Combining artificial intelligence‐based diagnoses with wide‐angle image‐enhanced endoscopy may be particularly useful. Thus, we hope that such tools will be available in the near future.

Evaluation of the visibility of bleeding points using red dichromatic imaging in endoscopic hemostasis for acute GI bleeding (with video)

BACKGROUND AND AIMS

We aimed to clarify whether red dichromatic imaging (RDI), a new type of image-enhanced endoscopy, improves the visibility of bleeding points in acute GI bleeding (AGIB) compared with white-light imaging (WLI).

METHODS

Images and videos of bleeding points acquired with WLI and RDI during endoscopic hemostasis for AGIB were retrospectively compared. In images, the color difference between bleeding points and surrounding blood was analyzed. In videos, 4 expert and 4 trainee endoscopists evaluated the visibility on a scale of 1 (undetectable) to 4 (easily detectable). Furthermore, the correlation between the color difference and visibility score was evaluated.

RESULTS

We analyzed 64 lesions. The color difference was significantly higher in RDI (13.11 ± 4.02) than in WLI (7.38 ± 3.68, P < .001). The mean visibility score for all endoscopists was significantly higher in RDI (3.12 ± .51) compared with WLI (2.72 ± .50, P < .001); this was also observed in experts (3.18 ± .51 vs 2.79 ± .54, P < .001) and trainees (3.05 ± .54 vs 2.64 ± .47, P < .001). The color difference and visibility score were moderately correlated for all endoscopists (γ = .56, P < .001) and for experts (γ = .53, P < .001) and trainees (γ = .57, P < .001).

CONCLUSIONS

RDI improves the visibility of bleeding points in AGIB compared with WLI. RDI can help endoscopists at all levels of experience to recognize bleeding points by enhancing the color contrast relative to surrounding blood.

Effect of Linked-color Imaging on the Detection of Adenomas in Screening Colonoscopies

OBJECTIVES

Linked-color imaging (LCI) is a new image-enhancement option that emphasizes mucosal surface contrast, facilitating the differentiation between colorectal lesions and normal mucosa. This study aimed to evaluate the potential of LCI to increase the detection of colorectal adenomas in screening colonoscopies.

METHODS

A prospective randomized study was conducted using white-light imaging (WLI), blue-laser imaging (BLI)-bright and LCI. The outcome measures were adenoma detection rate (ADR), mean number of adenomas per patient, and withdrawal time. Lesion characteristics such as size, morphology, location, and histology were also evaluated.

RESULTS

A total of 205 patients were randomized, and 251 adenomas were detected. The overall ADR was 62%. The ADR was 52.9% for WLI, 62.1% for BLI-bright, and 71% for LCI, and was significantly higher in the LCI group than in the WLI group (P=0.04). No significant difference was observed between LCI and BLI-bright (P=0.28) or BLI-bright and WLI (P=0.30). The mean number of adenomas per patient was 1.01, 1.03, and 1.62 for WLI, BLI-bright, and LCI, respectively, with a significant difference (P=0.02). Withdrawal time did not differ among the groups. A total of 71 adenomas were detected by WLI, 68 by BLI-bright, and 112 by LCI. There was no difference in the size and morphology of the adenomas detected, nor in the diagnosis of sessile serrated adenomas/polyps.

CONCLUSION

LCI significantly increased the detection of adenomas in screening colonoscopies.

Linked Colour imaging for the detection of polyps in patients with Lynch syndrome: a multicentre, parallel randomised controlled trial

OBJECTIVE

Despite regular colonoscopy surveillance, colorectal cancers still occur in patients with Lynch syndrome. Thus, detection of all relevant precancerous lesions remains very important. The present study investigates Linked Colour imaging (LCI), an image-enhancing technique, as compared with high-definition white light endoscopy (HD-WLE) for the detection of polyps in this patient group.

DESIGN

This prospective, randomised controlled trial was performed by 22 experienced endoscopists from eight centres in six countries. Consecutive Lynch syndrome patients ≥18 years undergoing surveillance colonoscopy were randomised (1:1) and stratified by centre for inspection with either LCI or HD-WLE. Primary outcome was the polyp detection rate (PDR).

RESULTS

Between January 2018 and March 2020, 357 patients were randomised and 332 patients analysed (160 LCI, 172 HD-WLE; 6 excluded due to incomplete colonoscopies and 19 due to insufficient bowel cleanliness). No significant difference was observed in PDR with LCI (44.4%; 95% CI 36.5% to 52.4%) compared with HD-WLE (36.0%; 95% CI 28.9% to 43.7%) (p=0.12). Of the secondary outcome parameters, more adenomas were found on a patient (adenoma detection rate 36.3%; vs 25.6%; p=0.04) and a colonoscopy basis (mean adenomas per colonoscopy 0.65 vs 0.42; p=0.04). The median withdrawal time was not statistically different between LCI and HD-WLE (12 vs 11 min; p=0.16).

CONCLUSION

LCI did not improve the PDR compared with HD-WLE in patients with Lynch syndrome undergoing surveillance. The relevance of findings more adenomas by LCI has to be examined further.

TRIAL REGISTRATION NUMBER

NCT03344289.

Irrigating Acetic Acid Solution During Colonoscopy for the Detection of Sessile Serrated Neoplasia: A Randomized Controlled Trial

BACKGROUND

Misdiagnosed sessile serrated lesions (SSLs) are important precursors for interval colorectal cancers.

AIMS

We investigated the usage of acetic acid (AA) solution for improving the detection of SSLs in the right colon in a randomized controlled trial.

METHODS

A tandem observation of the right colon was performed in 412 consecutive patients. A first inspection was performed under white light high-definition endoscopy. In the AA group, a low concentration vinegar solution (AA: 0.005%) irrigated by a water pump in the right colon was compared with a plain solution of normal saline (NS) in the diagnostic yield of SSLs during the second inspection. Secondary outcomes in overall polyp detection were measured.

RESULTS

Qualitative comparisons showed significant differences in the detection rates of all polyps except adenomas, with remarkable improvement in the demonstration of advanced (> 20 mm), SSLs, and hyperplastic polyps during the second inspection of the right colon using the AA solution. Significant improvement was also noted in the AA group, as far as the mean number of polyps/patient detected, not only in SSLs (AA group: 0.14 vs. NS group: 0.01, P < 0.001), but also in all histological types and all size-categories in the right colon. Small (≤ 9 mm) polyps were detected at a higher rate in the sigmoid colon expanding the effect of the method in the rest of the colon.

CONCLUSION

AA-assisted colonoscopy led to a significant increase in SSLs detection rate in the right colon in a safe, quick, and effective manner.

TXI (Texture and Color Enhancement Imaging) for Serrated Colorectal Lesions

Background and aim: Olympus Corporation released the texture and color enhancement imaging (TXI) technology as a novel image-enhancing endoscopic technique. We investigated the effectiveness of TXI in the imaging of serrated colorectal polyps, including sessile serrated lesions (SSLs). Methods: Serrated colorectal polyps were observed using white light imaging (WLI), TXI, narrow-band imaging (NBI), and chromoendoscopy with and without magnification. Serrated polyps were histologically confirmed. TXI was compared with WLI, NBI, and chromoendoscopy for the visibility of the lesions without magnification and for that of the vessel and surface patterns with magnification. Three expert endoscopists evaluated the visibility scores, which were classified from 1 to 4. Results: Twenty-nine consecutive serrated polyps were evaluated. In the visibility score without magnification, TXI was significantly superior to WLI but inferior to chromoendoscopy in the imaging of serrated polyps and the sub-analysis of SSLs. In the visibility score for vessel patterns with magnification, TXI was significantly superior to WLI and chromoendoscopy in the imaging of serrated polyps and the sub-analysis of SSLs. In the visibility score for surface patterns with magnification, TXI was significantly superior to WLI but inferior to NBI in serrated polyps and in the sub-analysis of SSLs and hyperplastic polyps. Conclusions: TXI provided higher visibility than did WLI for serrated, colorectal polyps, including SSLs.

Enhancing polyp detection: technological advances in colonoscopy imaging

The detection and removal of polyps at colonoscopy is core to the current colorectal cancer (CRC) prevention strategy. However, colonoscopy is flawed with a well described miss rate and variability in detection rates associated with incomplete protection from CRC. Consequently, there is significant interest in techniques and technologies which increase polyp detection with the aim to remedy colonoscopy's ills. Technologic advances in colonoscope imaging are numerous and include; increased definition of imaging, widening field of view, virtual technologies to supplant conventional chromocolonoscopy (CC) and now computer assisted detection. However, despite nearly two decades of technologic advances, data on gains in detection from individual technologies have been modest at best and heterogenous and conflicted as a rule. This state of detection technology science is exacerbated by use of relatively blunt metrics of improvement without consensus, the myopic search for gains over single generations of technology improvement and an unhealthy focus on adenomatous lesions. Yet there remains cause for optimism as detection gains from new technology, while small, may still improve CRC prevention. The technologies are also readily available in current generation colonoscopes and have roles beyond simply detection such as lesion characterization, further improving their worth. Coupled with the imminent expansion of computer assisted detection the detection future from colonoscope imaging advances looks bright. This review aims to cover the major imaging advances and evidence for improvement in polyp detection.

Linked color imaging versus white light imaging colonoscopy for colorectal adenoma detection: A randomized controlled trial

BACKGROUND AND AIM

The adenoma detection rate is an important indicator of colonoscopy quality and colorectal cancer incidence. We compared the adenoma detection rates between white light imaging (WLI) and linked color imaging (LCI) colonoscopy.

METHODS

Patients undergoing colonoscopy for positive fecal immunochemical tests, follow-up of colon polyps, and abdominal symptoms at three institutions were randomly assigned to the LCI or WLI groups. Mean adenoma number per patient (including based on endoscopists' experience), adenoma detection rate, cecal intubation time, withdrawal time, mean adenoma number per location, and adenoma size were compared.

RESULTS

The LCI and WLI groups comprised 494 and 501 patients, respectively. No significant differences in the cecal intubation rate (LCI vs WLI: 99.5% vs 99.4%), cecal intubation time, and withdrawal time were noted between groups. The mean adenoma number per patient was significantly higher in the LCI group than in the WLI group (1.07 vs 0.88, P = 0.04), particularly in the descending [0.12 (58/494) vs 0.07 (35/501), P = 0.01] and sigmoid colon [0.41 (201/494) vs 0.30 (149/501), P ≤ 0.001]. However, the adenoma detection rate was 47.1% in the LCI group and 46.9% in the WLI group, with no significant difference (P = 0.93). The total number of sessile-type adenomas was significantly higher in the LCI group than in the WLI group (346/494 vs 278/501, P = 0.04). As for polyp size, small polyps (≤ 5 mm) were detected at a significantly higher rate in the LCI group (271/494 vs 336/501, P = 0.04).

CONCLUSION

Linked color imaging is significantly superior to WLI in terms of mean adenoma number per patient.

Detection of Colorectal Neoplasms Using Linked Color Imaging: A Prospective, Randomized, Tandem Colonoscopy Trial

BACKGROUND AND AIMS

A higher adenoma detection rate (ADR) has been shown to be related to a lower incidence and mortality of colorectal cancer. We analyzed the efficacy of linked color imaging (LCI) by assessing the detection, miss, and visibility of various featured adenomas as compared with white light imaging (WLI).

METHODS

This was a prospective, randomized, tandem trial. The participants were randomly assigned to 2 groups: first observation by LCI, then second observation by WLI (LCI group); or both observations by WLI (WLI group). Suspected neoplastic lesions were resected after magnifying image-enhanced endoscopy. The primary outcome was to compare the ADR during the first observation. Secondary outcomes included evaluation of adenoma miss rate (AMR) and visibility score.

RESULTS

A total of 780 patients were randomized, 700 of whom were included in the final analysis. The ADR was 69.6% and 63.2% in the LCI and WLI groups, respectively, with no significant difference. However, LCI improved the average ADR in low-detectors compared with high-detectors (76.0% vs 55.1%; P < .001). Total AMR was 20.6% in the LCI group, which was significantly lower than that in the WLI group (31.1%) (P < .001). AMR in the LCI group was significantly lower, especially for diminutive adenomas (23.4% vs 35.1%; P < .001) and nonpolypoid lesions (25.6% vs 37.9%; P < .001) compared with the WLI group.

CONCLUSION

Although both methods provided a similar ADR, LCI had a lower AMR than WLI. LCI could benefit endoscopists with lower ADR, an observation that warrants additional study. (UMIN Clinical Trials Registry, Number: UMIN000026359).

Linked colour imaging versus white-light colonoscopy for the detection of flat colorectal lesions: A randomized controlled trial

AIM

Linked colour imaging is an image-enhanced endoscopy system that emphasizes the red portion of the mucosa's colour. Our aim was to compare the effectiveness of linked colour imaging with white-light colonoscopy for the detection of flat-type colorectal polyps.

METHOD

This was a single-centre, randomized controlled trial. Enrolled patients were those aged ≥50 years undergoing cap-assisted colonoscopy for colorectal cancer screening. They were randomized in a 1:1 ratio for observation using linked colour imaging or white-light colonoscopy. All colorectal polyps detected were removed or biopsied. The primary outcome was the number of flat-type polyps per patient in patients in whom flat polyps were detected. Secondary outcomes included adenoma and polyp detection rates.

RESULTS

There were 302 subjects randomized: 152 to linked colour imaging and 150 to white-light colonoscopy. There were no differences in the clinical features between the two arms. The number of flat polyps detected per patient using linked colour imaging was approximately twice that with white light (2.9 ± 3.0 vs 1.2 ± 1.6, p = 0.045). Linked colour imaging also proved superior to white-light colonoscopy in terms of adenoma and polyp detection rates [adenomas 66% (101/152) vs 49% (73/150), p = 0.0024; polyps 69% (105/152) vs 55% (82/150), p = 0.013]. The ratio of polyps detected in the right colon compared with those detected in the left colon was significantly greater using linked colour than white-light imaging (168/64 vs 93/84; p < 0.001).

CONCLUSION

Compared with white-light colonoscopy, linked colour imaging improved adenoma and polyp detection rates, including detection of flat-type colorectal polyps.

TXI: Texture and Color Enhancement Imaging for Endoscopic Image Enhancement

Recognition of lesions with subtle morphological and/or color changes during white light imaging (WLI) endoscopy remains a challenge. Often the endoscopic image suffers from nonuniform illumination across the image due to curvature in the lumen and the direction of the illumination light of the endoscope. We propose an image enhancement technology to resolve the drawbacks above called texture and color enhancement imaging (TXI). TXI is designed to enhance three image factors in WLI (texture, brightness, and color) in order to clearly define subtle tissue differences. In our proposed method, retinex-based enhancement is employed in the chain of endoscopic image processing. Retinex-based enhancement is combined with color enhancement to greatly accentuate color tone differences of mucosal surfaces. We apply TXI to animal endoscopic images and evaluate the performance of TXI compared with conventional endoscopic enhancement technologies, conventionally used techniques for real-world image processing, and newly proposed techniques for surgical endoscopic image augmentation. Our experimental results show that TXI can enhance brightness selectively in dark areas of an endoscopic image and can enhance subtle tissue differences such as slight morphological or color changes while simultaneously preventing over-enhancement. These experimental results demonstrate the potential of the proposed TXI algorithm as a future clinical tool for detecting gastrointestinal lesions having difficult-to-recognize tissue differences.

Duodenal sessile serrated adenoma/polyp with characteristic endoscopic and pathologic features

Sessile serrated adenomas/polyps (SSA/Ps), recently called sessile serrated lesions, have a neoplastic pathway in the large intestine and are treated as lesions with malignant potential. There are a few reports of traditional serrated adenomas in the duodenum but no reports of duodenal SSA/Ps. A 66-year-old man underwent screening upper gastrointestinal endoscopy and was found to have a white elevated lesion in the second portion of the duodenum. Magnifying blue laser imaging showed various sized villous-like structures with dilated crypt openings in the white surface mucosa, similar to a SSA/P. Based on these images, a duodenal adenoma was suspected at the time of endoscopic resection. Pathological findings of the resected specimen showed a saw-tooth structure corresponding to basal crypt dilatation and branching with mucus and positive immunostaining for MUC6 and MUC2, similar to a colonic SSA/P. MUC5AC did not stain the glandular crypt cells. KRAS mutation was detected. Immunohistochemical expression of Annexin A10 was clearly identified in the lesion. Although not all of molecular biological features were satisfied, these findings were similar to a colonic SSA/P which has malignant potential. This is the first report of a duodenal SSA/P which should be considered when evaluating elevated duodenal lesions.

Linked Color Imaging Focused on Neoplasm Detection in the Upper Gastrointestinal Tract : A Randomized Trial

BACKGROUND

Linked color imaging (LCI) is a new image-enhanced endoscopy technique that allows users to recognize slight differences in mucosal color.

OBJECTIVE

To compare the performance of LCI with white light imaging (WLI) in detecting neoplastic lesions in the upper gastrointestinal tract.

DESIGN

A controlled, multicenter trial with randomization using minimization. (University Hospital Medical Information Network Clinical Trials Registry: UMIN000023863).

SETTING

16 university hospitals and 3 tertiary care hospitals in Japan.

PATIENTS

1502 patients with known previous or current cancer of the gastrointestinal tract and undergoing surveillance for gastrointestinal cancer.

INTERVENTION

WLI followed by LCI examination (WLI group) or LCI followed by WLI examination (LCI group).

MEASUREMENTS

Diagnosis of 1 or more neoplastic lesions in the pharynx, esophagus, or stomach in the first examination (primary outcome) and 1 or more neoplastic lesions overlooked in the first examination (secondary outcome).

RESULTS

752 patients were assigned to the WLI group and 750 to the LCI group. The percentage of patients with 1 or more neoplastic lesions diagnosed in the first examination was higher with LCI than with WLI (60 of 750 patients or 8.0% [95% CI, 6.2% to 10.2%] vs. 36 of 752 patients or 4.8% [CI, 3.4% to 6.6%]; risk ratio, 1.67 [CI, 1.12 to 2.50; P = 0.011]). The proportion with overlooked neoplasms was lower in the LCI group than in the WLI group (5 of 750 patients or 0.67% [CI, 0.2% to 1.6%] vs. 26 of 752 patients or 3.5% [CI, 2.3% to 5.0%]; risk ratio, 0.19 [CI, 0.07 to 0.50]).

LIMITATION

Endoscopists were not blinded.

CONCLUSION

LCI is more effective than WLI for detecting neoplastic lesions in the pharynx, esophagus, and stomach.

PRIMARY FUNDING SOURCE

Fujifilm Corporation.

Colon polyp detection using linked color imaging compared to white light imaging: Systematic review and meta-analysis

BACKGROUND AND AIM

Linked color imaging (LCI) is a novel image-enhancing technology which enhances color differences between a colorectal lesion and surrounding mucosa with enough brightness to illuminate the wide colorectal lumen. The aim of this study is to compare colorectal polyp detection using LCI with that using white light imaging (WLI).

METHODS

Randomized controlled trials and prospective studies comparing LCI with WLI for colorectal polyp detection were selected. Outcomes included overall polyp/adenoma detection and additional polyp detection at a second observation. Outcomes were documented by pooled risk ratios (RR) with 95% confidence interval (CI) using the Mantel-Haenszel random effect model.

RESULTS

Seven studies were included. LCI showed significant superiority for polyp and adenoma detection compared with WLI (RR 1.16, 95% CI 1.09-1.25, P < 0.001 for polyp detection; RR 1.26, 95% CI 1.14-1.39 P < 0.001 for adenoma detection). LCI significantly increased the number of polyps detected per patient compared with WLI (mean difference 0.27, 95% CI 0.01-0.53, P = 0.040). LCI significantly increased the number of adenomas detected per patient compared with WLI (mean difference 0.22, 95% CI 0.08-0.36, P = 0.002). LCI significantly increased the number of flat polyps detected per patient compared with WLI (mean difference 0.14, 95% CI 0.01-0.27, P = 0.040). LCI had a significantly higher rate of additional polyp detection compared with WLI in the right colon (RR 2.68, 95% CI 1.71-4.19, P < 0.001).

CONCLUSIONS

Linked color imaging has significantly greater polyp and adenoma detection rates and detection rate of previously missed polyps compared with WLI. We recommend the initial use of LCI for routine colonoscopy.

Linked-color imaging versus white-light colonoscopy in an organized colorectal cancer screening program

BACKGROUND AND AIMS

Linked-color imaging (LCI), a new image-enhancing technology emphasizing contrast in mucosal color, has been demonstrated to substantially reduce polyp miss rate as compared with standard white-light imaging (WLI) in tandem colonoscopy studies. Whether LCI increases adenoma detection rate (ADR) remains unclear.

METHODS

Consecutive subjects undergoing screening colonoscopy after fecal immunochemical test (FIT) positivity were 1:1 randomized to undergo colonoscopy with LCI or WLI, both in high-definition systems. Insertion and withdrawal phases of each colonoscopy were carried out using the same assigned light. Experienced endoscopists from 7 Italian centers participated in the study. Randomization was stratified by gender, age, and screening round. The primary outcome measure was represented by ADR.

RESULTS

Of 704 eligible subjects, 649 were included (48.9% men, mean age ± standard deviation, 60.8 ± 7.3 years) and randomized to LCI (n = 326) or WLI (n = 323) colonoscopy. The ADR was higher in the LCI group (51.8%) than in the WLI group (43.7%) (relative risk, 1.19; 95% confidence interval, 1.01-1.40). The proportions of patients with advanced adenomas and sessile serrated lesions were, respectively, 21.2% and 8.6% in the LCI arm and 18.9% and 5.9% in the WLI arm (not significant for both comparisons). At multivariate analysis, LCI was independently associated with ADR, along with male gender, increasing age, and adequate (Boston Bowel Preparation Scale score ≥6) bowel preparation. At per-polyp analysis, the mean ± standard deviation number of adenomas per colonoscopy was comparable in the LCI and WLI arms, whereas the corresponding figures for proximal adenomas was significantly higher in the LCI group (.72 ± 1.2 vs .55 ± 1.07, P = .05) CONCLUSIONS: In FIT-positive patients undergoing screening colonoscopy, the routine use of LCI significantly increased the ADR. (Clinical trial registration number: NCT03690297.).

Bile pigment in small-bowel water content may reflect bowel habits: a retrospective analysis of a capsule endoscopy imaging series

Background

Pigmented bile salts darken the small-bowel lumen and are present with bile acid, which is involved in the development of bowel habits. The small-bowel water content (SBWC) in the ileum could represent the colonic environment, but no studies have focused on this feature. However, measurement of crude SBWC can be challenging because of the technical difficulty of the endoscopic approach without preparation. Our aim was to evaluate optically active bile pigments in the SBWC of patients with abnormal bowel habits using capsule endoscopy (CE) to investigate the impact of bile acid on bowel habits.

Methods

The study population included 37 constipated patients, 20 patients with diarrhea, and 77 patients with normal bowel habits who underwent CE between January 2015 and May 2018. Patients with secondary abnormal bowel habits were excluded. In addition to conventional imaging, we used flexible spectral imaging color enhancement (FICE) setting 1 imaging, in which the effects of bile pigments on color are suppressed. Intergroup color differences of SBWC in the ileum (ΔE) were evaluated from conventional and FICE setting 1 images. Color values were assessed using the CIE L*a*b* color space. Differences in SBWC lightness (black to white, range 0–100) were also evaluated.

Results

The ΔE values from the comparison of conventional images between patients with constipation and with normal bowel habits and between patients with diarrhea and with normal bowel habits were 12.4 and 11.2, respectively. These values decreased to 4.4 and 3.3, respectively, when FICE setting 1 images were evaluated. Patients with constipation and diarrhea had significantly brighter (34.4 versus 27.6, P < .0001) and darker (19.6 versus 27.6, P < .0001) SBWC lightness, respectively, than patients with normal bowel habits. The FICE setting 1 images did not reveal significant differences in SBWC lightness between those with constipation and with normal bowel habits (44.1 versus 43.5, P = .83) or between those with diarrhea and with normal bowel habits (39.1 versus 43.5, P = .20).

Conclusions

Differences in SBWC color and darkness in the ileum appear to be attributable to bile pigments. Therefore, bile pigments in SBWC may reflect bowel habits.

Improved adenoma detection with linked color imaging technology compared to white-light colonoscopy

OBJECTIVES

Linked color imaging (LCI) is a new endoscopic technology that may increase colorectal adenoma detection rate (ADR) and polyp detection rate (PDR) by virtual chromoendoscopy. Aim of the present study was to evaluate the effectiveness of LCI in ADR and PDR compared to the HD white-light colonoscopy (WLC) technique.

MATERIALS AND METHODS

Between October 2016 and June 2018, we enrolled consecutive outpatients prospectively. Eligible patients allocated randomly to undergo HD WLC or LCI colonoscopy technique during instrument withdrawal. Each colonoscopy was performed in a single center by the same three expert endoscopists (with expertise more than 5000 colonoscopies).

RESULTS

A total of 1278 patients underwent colonoscopy in the study period. ADR and PDR were significantly higher in the LCI group compared to the WLC group (34.4% vs. 26.8%; p = .007; and 53.3% vs 46.4%; p = .023, respectively). Similarly, the mean number of adenomas per patient (MAP) was significantly higher with the LCI than WLC (0.64 vs 0.44, respectively; p = .002). The mean age of patients at the time of colonoscopy was 51.95 years (SD = 13.861) in the LCI group and 51.96 years (SD = 14.028) in the WLC group. No significant differences observed in patient demographic characteristics (there was no difference in gender and age distribution, p = .986), quality of colonoscopy preparation and withdrawal times (WT) between the two groups (WLC and the LCI groups, 493.9 (SD: 143.5) and 514.0 (SD: 139.5) sec, respectively).

CONCLUSIONS

According to our results, LCI virtual chromoendoscopic technology was superior compared to conventional HD WLC in detecting colorectal polyps and adenomas.

Blue laser imaging and linked color imaging improve the color difference value and visibility of colorectal polyps in underwater conditions

BACKGROUND AND AIM

Underwater endoscopic mucosal resection (UEMR) has become widespread for treating colorectal polyps. However, which observational mode is best suited for determining polyp margins underwater remains unclear. To determine the best mode, we analyzed three imaging modes: white light imaging (WLI), blue laser imaging (BLI) and linked color imaging (LCI).

METHODS

Images of consecutive colorectal polyps previously examined by these three modes before UEMR were analyzed according to the degree of underwater turbidity (transparent or cloudy). Color differences between the polyps and their surroundings were calculated using the Commission Internationale d'Eclairage Lab color space in which 3-D color parameters were expressed. Eight evaluators, who were blinded to the histology, scored the visibility from one (undetectable) to four (easily detectable) in both underwater conditions. The color differences and visibility scores were compared.

RESULTS

Seventy-three polyps were evaluated. Sixty-one polyps (44 adenomatous, 17 serrated) were observed under transparent conditions, and 12 polyps (seven adenomatous, five serrated) were observed under cloudy conditions. Under transparent conditions, color differences for the BLI (8.5) and LCI (7.9) were significantly higher than that of WLI (5.7; P < 0.001). Visibility scores for BLI (3.6) and LCI (3.4) were also higher than that of WLI (3.1; P < 0.0001). Under cloudy conditions, visibility scores for LCI (2.9) and WLI (2.7) were significantly higher than that of BLI (2.2; P < 0.0001 and P = 0.04, respectively).

CONCLUSIONS

BLI and LCI were better observational modes in transparent water; however, BLI was unsuitable for cloudy conditions.

Comparison Between Linked Color Imaging and Blue Laser Imaging for Improving the Visibility of Flat Colorectal Polyps: A Multicenter Pilot Study

INTRODUCTION

Linked color imaging (LCI) and blue laser imaging-bright (BLI-b) improve the visibility of gastrointestinal lesions. In this multicenter study, we compared the effects of LCI and BLI-b on the visibility of flat polyps with visibility scores and color difference (CD) values, including fast-withdrawal and large-monitor observation.

METHODS

We recorded 120 videos of 40 consecutive flat polyps (2-20 mm), adenoma, and sessile serrated adenoma and polyp (SSA/P), using white light imaging (WLI), BLI-b, and LCI from July 2017 to December 2017. All videos were evaluated by eight endoscopists according to a published polyp visibility score of 4 (excellent) to 1 (poor). Additionally, 1.5 ×faster and 1.7 ×sized videos were evaluated. Moreover, we calculated the CD values for each polyp in three modes.

RESULTS

The mean LCI scores (3.1 ± 0.9) were significantly higher than the WLI scores (2.5 ± 1.0, p < 0.001) but not significantly higher than the BLI-b scores (3.0 ± 1.0). The scores of faster videos on LCI (3.0 ± 1.1) were significantly higher than WLI (2.0 ± 1.0, p < 0.001) and BLI-b (2.8 ± 1.1, p = 0.03). The scores of larger-sized videos on LCI were not significantly higher than those of WLI or BLI-b. The CD value of LCI (18.0 ± 7.7) was higher than that of WLI (11.7 ± 7.0, p < 0.001), but was not significantly higher than that of BLI-b (16.6 ± 9.6). The CD value of LCI was significantly higher than that of BLI-b for adenoma, but the CD value of BLI-b was significantly higher than that of LCI for SSA/P.

CONCLUSIONS

The superiority of LCI to BLI-b was proven for the visibility of adenoma and fast observation.

The efficacy of tumor characterization and tumor detectability of linked color imaging and blue laser imaging with an LED endoscope compared to a LASER endoscope

OBJECTIVES

An endoscope with a light-emitting diode (LED) light source which has a 2-mm close-distance observation function without magnification, has been marketed, enabling linked color imaging (LCI) and blue laser imaging (BLI) for tumor detection and characterization. We analyzed the efficacy of a LED endoscope compared to a LASER endoscope.

METHODS

We retrospectively reviewed 272 lesions observed using the LED endoscopic system (Fujifilm Co., Tokyo, Japan) from May 2018 to September 2019. The Japanese NBI Classification was used for tumor characterization. We analyzed the diagnostic accuracy and confidence level. Sixty-one lesions observed with both the LED and magnified LASER endoscopes were also analyzed to compare the diagnostic accuracy. Regarding the tumor detectability, we calculated color difference values (CDVs) and brightness values (BVs) of white-light imaging, BLI, and LCI modes between the two endoscopes for each tumor.

RESULTS

The mean polyp size was 9.2 ± 11.3 mm. Histology showed 71 sessile serrated lesions, 193 adenoma and high-grade dysplasias, and 8 T1 cancers. The diagnostic accuracy of tumors ≥ 10 and < 10 mm was 72.0% and 92.9% (p < 0.001), respectively and the high confidence rate was 93.8%. The diagnostic accuracy of LED (77.0%) was a little higher than that of LASER without magnification (65.6%, p = 0.16) but was not inferior to that of LASER with magnification (82.0%, p = 0.50). The respective CDVs of LED and LASER endoscopes were 20.6 ± 11.2 and 21.6 ± 11.2 for LCI (p = 0.30), and the respective BVs were 210.0 ± 24.2 and 175.9 ± 21.1 (p < 0.001).

CONCLUSIONS

A LED endoscope with close-distance observation improved tumor detection and characterization due to high brightness.

Significance of Linked Color Imaging for Predicting the Risk of Clinical Relapse in Ulcerative Colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with unknown etiology. Recently, mucosal healing has emerged as an important therapeutic endpoint in UC. Linked color imaging (LCI) is a novel endoscopic system that enhances the color differences of the gastrointestinal mucosa. Our previous study emphasized the redness and yellowness of the lesion using LCI observation, which was useful for the evaluation of histological mucosal activity in UC. In this study, we aimed to evaluate the correlation between LCI observation and clinical relapse rate in UC patients. We retrospectively analyzed UC patients who underwent total colonoscopy between August 2016 and October 2018 at our facility with Mayo endoscopic scores of 0 or 1. We assessed the correlation between orange-like color lesion (defined as LCI-scarlet color lesions) and clinical relapse rate (requiring additional treatment for UC) during the 1-year follow-up period. Fifty-eight patients (22 female, 36 male; median age at diagnosis, 47.2 (18–80) years) who underwent colonoscopy were analyzed. During the 1-year follow-up period, clinical relapse was observed in 12 patients (20.1%) among which ten patients (83.3%) had an LCI-scarlet color lesions recognized by LCI. By contrast, 29 patients (63%) had no LCI-scarlet color lesions in the clinical remission group (n = 46). There was a significant difference in LCI-scarlet color between the clinical relapse and remission groups, remaining significantly associated with clinical relapse. LCI findings, including an orange-like color lesion, have diagnostic implications for predicting the risk of clinical relapse in UC during the 1-year follow-up period.

Advanced Endoscopic Imaging in Colonic Neoplasia

Background

Endoscopic imaging is a rapidly evolving field with a constant influx of new concepts and technologies. Since the introduction of video endoscopy and subsequently high-definition imaging as the first revolutions in gastrointestinal endoscopy, several technologies of virtual chromoendoscopy have been developed and brought to the market in the past decade, which have shaped and revolutionized for a second time our approach to endoscopic imaging. In parallel to these developments, microscopic imaging technologies, such as endomicroscopy and endocytoscopy, allow us to examine single cells within the mucosa in real time, thereby enabling histological diagnoses during ongoing endoscopy.

Summary

In this review, we provide an overview on the technical background of different technologies of advanced endoscopic imaging, and then review and discuss their role and applications for the diagnosis and management of colorectal neoplasms as well as limitations and challenges that exist despite all technological improvements.

Key Messages

Technologies of advanced endoscopic imaging have profound impact not only on our imaging capabilities, they are also about to fundamentally change our approach to managing lesions in the gastrointestinal tract: not every lesion found during colonoscopy has to be excised or sent for histopathologic evaluation. However, before this becomes widespread reality, major obstacles such as patient acceptance, adoption by less trained endoscopists, and also legal aspects need to carefully addressed. The development of computer-aided diagnosis and artificial intelligence algorithms hold the potential to overcome the obstacles associated with the concept of optical biopsy and will most likely fundamentally facilitate, shape, and change decision making in the management of colorectal lesions.

Linked color imaging versus narrow-band imaging for colorectal polyp detection: a prospective randomized tandem colonoscopy study

BACKGROUND AND AIMS

Linked color imaging (LCI) is a newly available image-enhanced endoscopy (IEE) system that emphasizes the red mucosal color. No study has yet compared LCI with other available IEE systems. Our aim was to investigate polyp detection rates using LCI compared with narrow-band imaging (NBI).

METHODS

This is a prospective randomized tandem colonoscopy study. Eligible patients who underwent colonoscopy for symptoms or screening/surveillance were randomized in a 1:1 ratio to receive tandem colonoscopy with both colonoscope withdrawals using LCI or NBI. The primary outcome was the polyp detection rate.

RESULTS

Two hundred seventy-two patients were randomized (mean age, 62 years; 48.2% male; colonoscopy for symptoms, 72.8%) with 136 in each arm. During the first colonoscopy, the polyp detection rate (71.3% vs 55.9%; P = .008), serrated lesion detection rate (34.6% vs 22.1%; P = .02), and mean number of polyps detected (2.04 vs 1.35; P = .02) were significantly higher in the NBI group than in the LCI group. There was also a trend of higher adenoma detection rate in the NBI group compared with the LCI group (51.5% vs 39.7%, respectively; P = .05). Multivariable analysis confirmed that use of NBI (adjusted odds ratio, 1.99; 95% confidence interval, 1.09-3.68) and withdrawal time >8 minutes (adjusted odds ratio, 5.11; 95% confidence interval, 2.79-9.67) were associated with polyp detection. Overall, 20.5% of polyps and 18.1% of adenomas were missed by the first colonoscopy, but there was no significant difference in the miss rates between the 2 groups.

CONCLUSION

NBI was significantly better than LCI for colorectal polyp detection. However, both LCI and NBI missed 20.5% of polyps. (Clinical trial registration number: NCT03336359.).

Improving serrated adenoma detection rate in the colon by electronic chromoendoscopy and distal attachment: systematic review and meta-analysis

BACKGROUND AND AIMS

The evidence for modification of conventional colonoscopy using either "distal attachments" (DAs; endocap, endocuff, and endoring) or "electronic chromoendoscopy" (EC; narrow-band imaging [NBI], iScan, blue-light imaging, autofluorescence imaging, and linked-color imaging) to improve the detection of serrated adenomas during colonoscopy has shown conflicting results.

METHODS

A comprehensive literature search was performed using Medline, Google Scholar, Embase, and Cochrane Library based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials (RCTs) comparing any DA or EC with high-definition white-light colonoscopy for detection of serrated adenomas (sessile serrated adenoma/polyp and traditional serrated adenoma) were included. The primary outcome was serrated adenoma detection rate (SADR) defined as the number of patients with at least 1 serrated adenoma of total patients in that group. The secondary outcome was the number of serrated adenomas per subject. Pooled rates were reported using risk ratio (RR) with 95% confidence interval.

RESULTS

Seventeen studies with 13,631 patients (56% men; age range, 50-66 years) met the inclusion criteria. The use of DAs (RR, 1.21; P = .45) and EC (RR, 1.29; P = .09) during colonoscopy did not show a significant improvement in SADR. The SADR using EC was 6.9% (4 studies) and that with NBI alone was 3.7% (3 studies).

CONCLUSIONS

The results indicate that, except for NBI, the use of DAs or EC during colonoscopy does not improve detection of serrated adenomas in the colon. More RCTs evaluating NBI are needed to explore the effect.

Impact of linked-color imaging on colorectal adenoma detection

BACKGROUND AND AIMS

Linked-color imaging (LCI) is a new technology that emphasizes changes in mucosal color by providing clearer and brighter images, thus allowing red and white areas to be visualized more clearly. We investigated whether LCI increases the detection of colorectal adenomas compared with white-light imaging (WLI) and blue-laser imaging (BLI)-bright.

METHODS

Consecutive patients undergoing colonoscopy were randomized (1:1:1) into examination by WLI, BLI-bright, or LCI during withdrawal of the colonoscope. The adenoma detection rate (ADR), mean number of adenomas per patient, and withdrawal time were evaluated. The lesions were evaluated according to size, morphology, location, and histology.

RESULTS

A total of 379 patients were randomized, and 412 adenomas were detected. The ADR was 43.2%, 54.0%, and 56.9% for WLI, BLI-bright, and LCI, respectively, and was significantly higher in the LCI group than in the WLI group (P = .03). No significant difference was observed between LCI and BLI-bright (P = .71) or BLI-bright and WLI (P = .09). The mean number of adenomas per patient was 0.82, 1.06, and 1.38 for WLI, BLI-bright, and LCI, respectively, with a significant difference between LCI and WLI (P = .03). Withdrawal time did not differ among the groups. A total of 102 adenomas were detected by WLI, 131 by BLI-bright, and 179 by LCI. LCI provided a higher rate of detection of adenomas ≤5 mm in size than WLI (P = .02), with a borderline significance for a higher detection of sessile serrated adenomas (P = .05). Nonpolypoid adenomas were more commonly located in the right colon segment and polypoid adenomas in the left colon segment, with a significant difference only between BLI-bright (P < .01) and LCI (P = .03).

CONCLUSIONS

Our findings show that LCI increases the detection of colorectal adenomas during colonoscopy. (Clinical trial registration number: RBR-9xg6dx.).

A comparison of 2 distal attachment mucosal exposure devices: a noninferiority randomized controlled trial

BACKGROUND AND AIMS

Endocuff (Arc Medical Design, Leeds, UK) and Endocuff Vision (Arc Medical Design, Leeds, UK) are effective mucosal exposure devices for improving polyp detection during colonoscopy. AmplifEYE (Medivators Inc, Minneapolis, Minn, USA) is a device that appears similar to the Endocuff devices but has received minimal clinical testing.

METHODS

We performed a randomized controlled clinical trial using a noninferiority design to compare Endocuff Vision with AmplifEYE.

RESULTS

The primary endpoint of adenomas per colonoscopy was similar in AmplifEYE at 1.63 (standard deviation 2.83) versus 1.51 (2.29) with Endocuff Vision (P = .535). The 95% lower confidence limit was 0.88 for ratio of means, establishing noninferiority of AmplifEYE (P = .008). There was no difference between the arms for mean insertion time, and mean inspection time (withdrawal time minus polypectomy time and time for washing and suctioning) was shorter with AmplifEYE (6.8 minutes vs 6.9 minutes, P = .042).

CONCLUSIONS

AmplifEYE is noninferior to Endocuff Vision for adenoma detection. The decision on which device to use can be based on cost. Additional comparisons of AmplifEYE with Endocuff by other investigators are warranted. (Clinical trial registration number: NCT03560128.).

Linked color imaging for the detection of early gastrointestinal neoplasms

In routine upper and lower gastrointestinal endoscopy, overlooking neoplastic lesions is inevitable even for well-trained endoscopists. Various methods have been reported to improve the detection of gastrointestinal neoplasms including chromoendoscopy, special endoscopes, and processor and image enhanced technologies. Equipment-based image enhanced endoscopy (e-IEE) using narrow band imaging (NBI) and blue laser imaging (BLI) is useful to characterize known lesions with magnification at a close-up view. However, they are not useful for the early detection of superficial, pale neoplasms, or both because of the weak image at a distant view in a wide lumen such as the stomach or colon. Linked color imaging (LCI) is a novel pre- and post-processing technology developed by Fujifilm Corporation that has sufficient brightness to illuminate a wide lumen. LCI delineates early gastric cancers as orange-red and intestinal metaplasia as purple. LCI improves the adenoma detection rate in the colon and decreases the polyp miss rate. LCI contributes to the detection of superficial lesions throughout the gastrointestinal tract by enhancing the color contrast between the neoplasm and the surrounding mucosa. LCI can distinguish them by their specific color allocation based mainly on the distribution of capillaries. The authors believe that moving forward, LCI should be used in routine upper and lower gastrointestinal endoscopy.

Blue Laser Imaging, Blue Light Imaging, and Linked Color Imaging for the Detection and Characterization of Colorectal Tumors

A laser endoscopy system was developed in 2012. The system allows blue laser imaging (BLI), BLI-bright, and linked color imaging (LCI) to be performed as modes of narrow-band light observation; these modes have been reported to be useful for tumor detection and characterization. Furthermore, an innovative endoscopy system using four-light emitting diode (LED) multilight technology was released in 2016 to 2017 in some areas in which laser endoscopes have not been approved for use, including the United States and Europe. This system enables blue light imaging (this is also known as BLI) and LCI with an LED light source instead of a laser light source. Several reports have shown that these modes have improved tumor detection. In this paper, we review the efficacy of BLI and LCI with laser and LED endoscopes in tumor detection and characterization.

A Review of New and Emerging Techniques For Optical Diagnosis of Colonic Polyps

BACKGROUND AND AIMS

Endoscopic imaging is a rapidly progressing field and benefits from miniaturization of advanced imaging technologies, which may allow accurate real-time characterization of lesions. The concept of the "optical biopsy" to predict polyp histology has gained prominence in recent years and may become clinically applicable with the advent of new imaging technology. This review aims to discuss current evidence and examine the emerging technologies as applied to the optical diagnosis of colorectal polyps.

METHODS

A structured literature search and review has been carried out of the evidence for diagnostic accuracy of image-enhanced endoscopy and emerging endoscopic imaging technologies. The image-enhanced endoscopy techniques are reviewed, including their basic scientific principles and current evidence for effectiveness. These include the established image-enhancement technologies such as narrow-band imaging, i-scan, and Fuji intelligent chromoendoscopy. More recent technologies including optical enhancement, blue laser imaging, and linked color imaging are discussed. Adjunctive imaging techniques in current clinical use are discussed, such as autofluorescence imaging and endocytoscopy. The emerging advanced imaging techniques are reviewed, including confocal laser endomicroscopy, optical coherence tomography, and Raman spectroscopy.

CONCLUSIONS

Large studies of the established image-enhancement techniques show some role for the optical diagnosis of polyp histology, although results have been mixed, and at present only the technique of narrow-band imaging is appropriate for the diagnosis of low-risk polyps when used by an expert operator. Other image-enhancement techniques will require further study to validate their accuracy but show potential to support the use of a "resect-and-discard" approach to low-risk polyps. New technologies show exciting potential for real-time diagnosis, but further clinical studies in humans have yet to be performed.

Diagnostic utility of linked color imaging in the evaluation of colonic mucosal inflammation in ulcerative colitis: a pilot study

Background and aims  Recent studies recommend histological mucosal healing of intestinal tissue as a treatment goal in ulcerative colitis (UC). Linked-color imaging (LCI) is a new endoscopy system that enhances the color differences of the gastrointestinal mucosa. We investigated the efficacy of LCI in the evaluation of intestinal activity, including the histological activity in UC. Method  A total of 21 UC patients who were evaluated by the LASEREO system (FUJIFILM Co., Tokyo, Japan) were enrolled from August to December in 2016. All of the target points were observed by conventional white-light imaging (WLI) and LCI and biopsied from the region of interest in each view. We quantified the color tones of 73 biopsied points on WLI and LCI using the L*a*b* color value (WLI-L, WLI-a, WLI-b, and LCI-L, LCI-a, LCI-b). We then investigated the relationships among the L*a*b* color values, endoscopic findings, and histological healing. Results  The average LCI-a and LCI-b values of patients with high mucosal activity disease were significantly higher than in those with mucosal healing ( P  < 0.01), and only LCI-a was significantly correlated with the score for histological healing. With regard to the other color values (LCI-L and all WLI values), there were no statistically significant differences in terms of average color value and correlation between patients with high mucosal activity and those with mucosal healing. In addition, the difference in the average color values with LCI and WLI was 7.1 and 3.1, respectively. Conclusion  LCI is more useful than WLI for the visualization and evaluation of mucosal inflammation in UC.