Diagnostic performance of linked color imaging for gastric cancer by Helicobacter pylori infection status: A subanalysis of the large-scale, multicenter randomized controlled trial LCI-FIND

BACKGROUND

Linked color imaging (LCI) is a new image enhancement technology that facilitates the recognition of subtle differences in mucosal color. In the large-scale, multicenter randomized controlled trial LCI-FIND, LCI demonstrated good diagnostic performance for the detection of tumor lesions in the upper gastrointestinal tract. The aim of the present study was to exploratively evaluate the diagnostic performance of LCI according to H. pylori infection status as a subanalysis of LCI-FIND trial.

METHODS

The patients were randomly allocated to receive white light imaging (WLI) first, followed by LCI (WLI group), or vice versa (LCI group), and the two groups were compared for the detection of tumors. Data from this trial were analyzed by the presence/absence of H. pylori infection and further analyzed by successful or unsuccessful eradication in the H. pylori infection group.

RESULTS

The 752 patients in the WLI group and 750 patients in the LCI group who had participated in the LCI-FIND trial were included. In the successful eradication group, more gastric lesions were detected by primary mode in the LCI group than in the WLI group, indicating that more lesions were missed by WLI. Fisher's exact probability test for the comparison of the WLI and LCI groups yielded a p-value of 0.0068, with missed gastric lesions being detected 0.136 times (95% confidence interval: 0.020-0.923), significantly less with LCI than with WLI.

CONCLUSION

The current study suggests that LCI should be used for gastric cancer screening, particularly in patients with successful H. pylori eradication.

Texture and color enhancement imaging improves the visibility of gastric neoplasms: clinical trial with image catalogue assessment using conventional and newly developed endoscopes

BACKGROUND

Texture and color enhancement imaging (TXI) enhances the changes in endoscopic features caused by gastric neoplasms, such as redness/whiteness and elevation/depression. This study aimed to demonstrate the effectiveness of TXI in improving the visibility of gastric neoplasms compared with white light imaging (WLI) using conventional (CE) and newly developed endoscopes (NE).

METHODS

We recruited patients who were histologically diagnosed with gastric neoplasms; endoscopy was performed, and gastric neoplasms photographed using three imaging modalities, including WLI, TXI mode 1 (TXI-1) and TXI mode 2 (TXI-2). Two different endoscopes (CE and NE) were used for the same patients. Six endoscopists provided the visibility scale scores ranging from 1 (poor) to 4 (excellent) for gastric neoplasms. The primary outcome was the visibility scale scores based on each modality and endoscope. The secondary outcome was the identification of factors including H. pylori infection, atrophy, location, size, morphology, histological diagnosis and intestinal metaplasia that affect the differences in visibility scale scores between TXI-1/TXI-2 and WLI.

RESULTS

Fifty-two gastric neoplasms were analyzed. The mean visibility scale scores with the NE were 2.79 ± 1.07, 3.23 ± 0.96 and 3.14 ± 0.92 for WLI, TXI-1 and TXI-2, respectively. The mean visibility scales with the CE were 2.53 ± 1.10, 3.04 ± 1.05 and 2.96 ± 1.92 for WLI, TXI-1 and TXI-2, respectively. For both endoscopes, significant differences were observed in visibility scale scores between WLI and TXI-1 (p < 0.001) and between WLI and TXI-2 (p < 0.001). The visibility scale scores of NE were superior to those of CE in all modalities. In the secondary outcome, there was no factor affected the differences of visibility scale scores between TXI-1/TXI-2 and WLI.

CONCLUSIONS

This study demonstrated that TXI-1 and TXI-2 enhanced the visibility scale scores of gastric neoplasms compared with that of WLI. Moreover, newly developed endoscope has the potential to improve visibility compared to conventional endoscope.

TRIAL REGISTRATION

This study was registered with the University Hospital Medical Information Network (UMIN000042429, 16/11/2020).

Usefulness of Acetic Acid Spray with Narrow-Band Imaging for Identifying the Margin of Sessile Serrated Lesions

BACKGROUND

Sessile serrated lesions (SSLs) are precursors of colon cancer, especially in cases of large, right colon. However, they are difficult to not only detect, but only clarify the margin of the lesion, which can lead to the poor endoscopic treatment outcomes.

AIMS

This study evaluated the usefulness of acetic acid spray with narrow-band imaging (A-NBI) for the better visualization of the margin of SSLs.

METHODS

From January 2013 to March 2022, patients with superficial elevated polyps suspected of being SSLs ≥ 10 mm with an endoscopic diagnosis that had been endoscopically resected at Hiroshima City Hiroshima Citizens Hospital were enrolled. Endoscopic images with white-light imaging (WLI), narrow-band imaging (NBI), indigo-carmine (IC), and A-NBI were recorded in each lesion and were randomly arranged and assessed by 10 endoscopists. We compared the visibility score (1 to 4) and color differences (ΔE) between inside and outside of the lesions among WLI, NBI, IC, and A-NBI.

RESULTS

Forty-one lesions in 33 cases were included, and a total of 164 images were evaluated. As for the visibility score, most of the lesions were scored as 1 or 2 on WLI, whereas most were scored 4 on A-NBI. The median ΔE of A-NBI was also significantly higher than that of WLI, NBI, or IC (20.5 vs. 8.3 vs. 8.2 vs. 12.3, P < 0.01). A significant correlation was observed between the color difference and visibility score (r = 0.53, P < 0.01).

CONCLUSIONS

A-NBI may be a useful modality for identifying the margin of SSLs.

Kyoto classification of gastritis, virtual chromoendoscopy and artificial intelligence: Where are we going? What do we need?

Chronic gastritis (CG) is a widespread and frequent disease, mainly caused by Helicobacter pylori infection, which is associated with an increased risk of gastric cancer. Virtual chromoendoscopy improves the endoscopic diagnostic efficacy, which is essential to establish the most appropriate therapy and to enable cancer prevention. Artificial intelligence provides algorithms for the diagnosis of gastritis and, in particular, early gastric cancer, but it is not yet used in practice. Thus, technological innovation, through image resolution and processing, optimizes the diagnosis and management of CG and gastric cancer. The endoscopic Kyoto classification of gastritis improves the diagnosis and management of this disease, but through the analysis of the most recent literature, new algorithms can be proposed.

Endoscopic three-categorical diagnosis of Helicobacter pylori infection using linked color imaging and deep learning: a single-center prospective study (with video)

BACKGROUND

Helicobacter pylori (H. pylori) eradication is required to reduce incidence related to gastric cancer. Recently, it was found that even after the successful eradication of H. pylori, an increased, i.e., moderate, risk of gastric cancer persists in patients with advanced mucosal atrophy and/or intestinal metaplasia. This study aimed to develop a computer-aided diagnosis (CAD) system to classify the status of H. pylori infection of patients into three categories: uninfected (with no history of H. pylori infection), currently infected, and post-eradication.

METHODS

The CAD system was based on linked color imaging (LCI) combined with deep learning (DL). First, a validation dataset was formed for the CAD systems by recording endoscopic movies of 120 subjects. Next, a training dataset of 395 subjects was prepared to enable DL. All endoscopic examinations were recorded using both LCI and white-light imaging (WLI). These endoscopic data were used to develop two different CAD systems, one for LCI (LCI-CAD) and one for WLI (WLI-CAD) images.

RESULTS

The diagnostic accuracy of the LCI-CAD system was 84.2% for uninfected, 82.5% for currently infected, and 79.2% for post-eradication status. Comparisons revealed superior accuracy of diagnoses based on LCI-CAD data relative based on WLI-CAD for uninfected, currently infected, and post-eradication cases. Furthermore, the LCI-CAD system demonstrated comparable diagnostic accuracy to that of experienced endoscopists with the validation data set of LCI.

CONCLUSIONS

The results of this study suggest the feasibility of an innovative gastric cancer screening program to determine cancer risk in individual subjects based on LCI-CAD.

New Diagnostic Approach for Esophageal Squamous Cell Neoplasms Using Linked Color Imaging and Blue Laser Imaging Combined with Iodine Staining

A 62-year-old man with a flat early esophageal cancer was referred for endoscopic treatment. White light imaging revealed a pale red lesion, whereas linked color imaging (LCI) and blue laser imaging (BLI) yielded purple and brown images, respectively. Iodine staining demonstrated a large unstained area with a homogenous but very weak pink-color sign. This area appeared more clearly as purple and green on LCI and BLI, respectively; however, a different colored portion was observed at the 4 o’clock position inside the iodineunstained area. Histopathology findings of the resected specimen revealed squamous intraepithelial neoplasia at the 4 o’clock position and an esophageal squamous cell carcinoma in the remaining iodine-unstained area. LCI and BLI combined with iodine staining produce characteristic images that overcomes the pink-color sign, reflecting the histological features of a flat esophageal neoplasm. This new method is useful for detailed evaluation of early flat squamous cell neoplasms.

Endoscopic diagnosis and treatment of early esophageal squamous neoplasia

Esophageal cancer is one of the leading causes of cancer-related death and is associated with high morbidity and mortality. It carries a poor prognosis as more than half of patients present with advanced and unresectable disease. One contributing factor is the increased risk of lymph node metastases at early stages of disease. As such, it is essential to detect squamous cell neoplasia (SCN) at an early stage. In order to risk stratify lesions, endoscopists must be able to perform image enhanced endoscopy including magnification and Lugol’s chromoendoscopy. The assessment of both the horizontal extent and depth of any lesion is also of utmost importance prior to treatment. Endoscopic mucosal resection and submucosal dissection remain the standard of care with literature supportive their respective use. Radiofrequency ablation and other endoscopic treatments are currently available although should not be considered first line at this time. Our objective is to review the current options for the endoscopic diagnosis and treatment of esophageal SCN.

Evidence based review of the impact of image enhanced endoscopy in the diagnosis of gastric disorders

Gastric cancer is the third most common cause of cancer-related death. Advanced stages of gastric cancers generally have grim prognosis. But, good prognosis can be achieved if such cancers are detected, diagnosed and resected at early stages. However, early gastric cancers and its precursors often produce only subtle mucosal changes and therefore quite commonly remain elusive at the conventional examination with white light endoscopy. Image-enhanced endoscopy makes mucosal lesions more conspicuous and can therefore potentially yield earlier and more accurate diagnoses. Recent years have seen growing work of research in support of various types of image enhanced endoscopy (IEE) techniques (e.g., dye-chromoendoscopy; magnification endoscopy; narrow-band imaging; flexible spectral imaging color enhancement; and I-SCAN) for a variety of gastric pathologies. In this review, we will examine the evidence for the utilization of various IEE techniques in the diagnosis of gastric disorders.

Narrow Band Imaging: Technology Basis and Research and Development History

The first launch of narrow band imaging (NBI) was in 2005. Since then, in most countries where gastrointestinal endoscopies are performed, NBI is the most commonly used optical digital method of performing image-enhanced endoscopy. Thanks to the outstanding efforts of many endoscopists, many clinical studies have been performed and clinical evidence has been gathered. In Japan, since 2010, NBI has been reimbursed under the Japanese national health insurance system. This is owing to the establishment of clinical evidence by physicians. However, even though endoscope systems with NBI function have been widely used outside of Japan, dissemination of knowledge on how to use NBI is insufficient. In this review paper, the technology basis of NBI and its research and development history are described. I hope this information will be helpful for updating physicians’ knowledge of NBI.

Image-enhanced endoscopy technology in the gastrointestinal tract: what is available?

Gastrointestinal malignancy accounts for approximately a fifth of all cancer deaths in the United Kingdom. By the time patients are symptomatic, lesions are often advanced, with limited treatment options available. The development of effective endoscopic therapies means that neoplastic lesions can now be treated with improved patient outcomes. This has led to a paradigm shift, whereby the aim of digestive endoscopy is to identify premalignant conditions or early neoplastic change, in order to make an impact on their natural history. This has necessitated an improvement in imaging techniques in order to identify subtle mucosal changes that may harbour precancerous cells. At present there is an array of available imaging modalities, each with implications on cost, training and lesion detection. Here we describe the scientific rationale behind the major commercially available techniques as well as offering a glimpse at possible future directions.

Serrated polyps of the colon and rectum: Endoscopic features including image enhanced endoscopy

In this review, I outline the characteristic endoscopic findings of serrated lesions of the colorectum based on image enhanced endoscopy (IEE). Histopathologically, lesions with serrated structures are typically classified into the following three types based: hyperplastic polyps (HPs), traditional serrated adenomas (TSAs), and sessile serrated adenoma/polyps (SSA/Ps). Both HP and SSA/P often present as dark-green colors on auto fluorescence imaging (AFI) colonoscopy that are similar to the normal surrounding mucosa. In contrast, TSAs often have elevated shapes and present as magenta colors that are similar to the tubular adenomas. The superficial type of TSA also includes many lesions that present as magenta colors. When SSA/Ps are associated with cytological dysplasia, many lesions present with magenta colors, whereas lesions that are not associated with cytological dysplasia present with dark-green colors. When observed via narrow band imaging (NBI), many SSA/P include lesions with strong mucous adhesions. Because these lesions are observed with reddish mucous adhesions, we refer to them as “red cap sign” and place such signs among the typical findings of SSA/P. Because the dilatation of the pit in SSA/P is observed as a round/oval black dot on magnified observations, we refer to this finding as II-dilatation pit (II-D pit) and also positioned it as a characteristic finding of SSA/P. In contrast, dilatations of the capillary vessels surrounding the glands, such as those that occur in tubular adenoma, are not considered to be useful for differentiating HPs from SSA/Ps. However, in cases in which SSA/P is associated with cytological dysplasia, the dilatation of capillary vessels is observed in the same area. When submucosal layer invasion occurs in the same area, the blood flow presents with irregularities that are similar to those of common colorectal cancer at an early stage and disappears as the invasion proceeds deeply. The surface pattern of invasive cancer that is observed at the tumor surface is also likely to disappear. Based on the above results, we considered that the differentiations between HP and TSA, between TSA and SSA/P, and between HP and SSA/P might become easier due to the concomitant use of white light observation and IEE. We also concluded that AFI and NBI can be useful modalities for SSA/P lesions associated with cytological dysplasia.

Is image-enhanced endoscopy useful for the diagnosis and treatment of gastrointestinal tumor?

Since the introduction of endoscopic submucosal dissection method for the treatment of early gastric cancer, endoscopic treatment of early gastric cancer has increased exponentially. Accordingly, early diagnosis of cancerous or precancerous lesion has become one of the most important missions for endoscopists. The desire to improve diagnostic capability of white light endoscopy led to the development of new imaging techniques called "image enhanced endoscopy." The usefulness of these image enhanced endoscopy has not been proven yet, although there are several studies reporting diagnostic superiority of these new imaging methods over white light endoscopy. Among these new imaging modalities, narrow band image (NBI) with magnification endoscopy has been most widely used and studied. This manuscript will be focused on the NBI with magnification endoscopy.

Role of enhanced visibility in evaluating polyposis syndromes using a newly developed contrast image capsule endoscope

Background/Aims

A flexible spectral imaging color enhancement system was installed in new capsule software for video capsule endoscopy. Contrast image capsule endoscopy (CICE) is a novel technology using light-emitting diodes selected for the main absorption range of hemoglobin. We assessed the feasibility and diagnostic effi cacy for small bowel surveillance in patients with polyposis syndromes.

Methods

Six patients with polyposis syndromes, four with familial adenomatous polyposis and one each with Cowden syndrome (CS) and Cronkhite-Canada syndrome (CCS) were examined using CICE. We conducted three evaluations to assess the effect on the numbers of the detected polyps; compare polyp diagnostic rates between adenoma and hamartoma; and assess polyp visibility.

Results

The numbers of detected polyps and diagnostic accuracy did not differ signifi cantly between pre-contrast and contrast images. However, 50% of the adenomatous polyps displayed enhanced visibility on contrast images. CICE contrast images exhibited clearly demarcated lesions and improved the visibility of minute structures of adenomatous polyps. Hamartomatous polyp micro-structures in patients with CS and CCS were more clearly visualized on contrast than pre-contrast images.

Conclusions

CICE is an effective tool for enhancing the visibility of polyps in patients with polyposis syndrome.