Standard White Light Endoscopy Research Articles

Development of a Low-Cost Gastroscope Prototype (GP) for Potential Cost-Effective Gastric Cancer Screening in Prevalent Regions

Abstract Background Screening for gastric cancer is known to be associated with reduced mortality in populations with high prevalence. However, many countries with high prevalence do not screen, with high costs being a significant reason for this. Aims To describe, develop, and assess the potential for a low-cost gastroscope for early cancer screening and patient risk stratification. Methods Our interdisciplinary team used both off-the-shelf and fabricated components to create multiple gastroscope prototypes (GP) in iterative fashion based off clinician feedback. Clinician endoscopists were surveyed using Likert scales regarding device potential, video quality, and handling when testing on a GI training device. Video quality comparison to clinically standard high-definition white light endoscopy (HD-WLE) was done using the absolute categorical ratings (ACR) method. Results A candidate cost-effective GP with clinical potential was developed. Although initial versions were scored as inferior via ACR on all views tested when compared to HD-WLE (p < 0.001), participants agreed the concept may be beneficial (M = 4.52/5, SD = 0.72). In testing improved versions, participants agreed the device had the ability to identify discrete (M = 4.62/5, SD = 0.51) and subtle lesions (M = 4/5, SD = 0.7) but most felt video quality, although improved, was still less than HD-WLE. Sufficiency of maneuverability of device to visualize gastric views was rated as equivocal (M = 2.69/5, SD = 1.25). Conclusion The presented low-cost gastroscopic devices have potential for clinical application. With further device development and refinement including the possible addition of technologies in telemedicine and artificial intelligence, we hope the GP can help expand gastric cancer screening for populations in need.

Confocal Endomicroscopy Monitoring of Tumor Formation.

The utilization of preclinical murine models of colorectal cancer (CRC) has been essential to our understanding of the onset and progression of disease. As the genetic complexity of these models evolves to better recapitulate emerging CRC subtypes, our ability to utilize these models to discover and validate novel therapeutic targets will also improve. This will be aided, in part, by the development of live animal imaging techniques, including confocal endomicroscopy for mice. Here in this chapter, we describe the combined use of standard white light endoscopy and confocal endomicroscopy thereby providing a method to rapidly image and assess changes in the colon of an individual live mouse in real time. These methods permit the generation of high-resolution cross-sectional images of the tumor microenvironment for immediate visualization of cells of interest, avoiding the need for euthanasia and tissue collection across multiple cohorts of mice.

Fusion of colour contrasted images for early detection of oesophageal squamous cell dysplasia from endoscopic videos in real time

Standard white light (WL) endoscopy often misses precancerous oesophageal changes due to their only subtle differences to the surrounding normal mucosa. While deep learning (DL) based decision support systems benefit to a large extent, they face two challenges, which are limited annotated data sets and insufficient generalisation. This paper aims to fuse a DL system with human perception by exploiting computational enhancement of colour contrast. Instead of employing conventional data augmentation techniques by alternating RGB values of an image, this study employs a human colour appearance model, CIECAM, to enhance the colours of an image. When testing on a frame of endoscopic videos, the developed system firstly generates its contrast-enhanced image, then processes both original and enhanced images one after another to create initial segmentation masks. Finally, fusion takes place on the assembled list of masks obtained from both images to determine the finishing bounding boxes, segments and class labels that are rendered on the original video frame, through the application of non-maxima suppression technique (NMS). This deep learning system is built upon real-time instance segmentation network Yolact. In comparison with the same system without fusion, the sensitivity and specificity for detecting early stage of oesophagus cancer, i.e. low-grade dysplasia (LGD) increased from 75% and 88% to 83% and 97%, respectively. The video processing/play back speed is 33.46 frames per second. The main contribution includes alleviation of data source dependency of existing deep learning systems and the fusion of human perception for data augmentation.

Advanced Endoscopy for Benign Esophageal Disease: A Review Focused on Non-Erosive Reflux Disease and Eosinophilic Esophagitis.

Advanced endoscopy (AVE) techniques include image-enhanced endoscopy methods, such as narrow-band imaging (NBI), and types of microscopic endoscopy, such as endocytoscopy. In the esophagus, AVE first showed diagnostic utility in the diagnosis of superficial esophageal cancer and was then applied to inflammatory disease. This review focuses on non-erosive reflux disease (NERD) and eosinophilic esophagitis (EoE), which sometimes show no abnormal findings on standard white light endoscopy alone. Studies have demonstrated that advanced endoscopy, including NBI magnification endoscopy and endocytoscopy, improved the diagnostic performance of white-light endoscopy alone for NERD and EoE. In this review, we explain why advanced endoscopy is needed for the diagnosis of these esophageal inflammatory diseases, summarize the study results, and discuss future perspectives.

Can Chromoendoscopy Improve the Early Diagnosis of Gastric Carcinoma in Dogs?

Simple SummaryCurrently, canine gastric carcinoma is mainly diagnosed in its late, incurable phase, and strategies for early diagnosis are lacking. In human medicine, chromoendoscopic (CE) methods such as staining the gastric mucosal surface with indigo carmine (IC), and narrow band imaging (NBI), have improved the diagnosis of precancerous gastric mucosal changes and early gastric carcinoma. This study aimed at investigating whether IC-CE and NBI-CE can improve the diagnostic yield of endoscopy in dogs. Belgian Shepherd dogs are predisposed to gastric carcinoma; thus, 30 dogs of the breed served as the study population. As a result, the study revealed that especially the combination of standard white light endoscopy (WLE) with NBI-CE allows better recognition of gastric mucosal structural changes than WLE alone. However, CE assessment templates used to predict the type of mucosal change in humans were not applicable in dogs. The value of the study lies in providing evidence that CE can improve the diagnosis of precancerous changes and early gastric carcinoma in dogs. However, current image assessment templates from human medicine need major adjustments to comprehend canine gastric mucosal conditions.Chromoendoscopy has improved the early diagnosis of gastric cancer in humans but its usefulness in dogs is unknown. This study aimed at assessing whether adding narrow band imaging (NBI) or indigo carmine (IC) chromoendoscopy (CE) can improve the diagnostic yield of standard white light endoscopy (WLE). We compared the real-time findings of canine WLE, NBI-CE, and IC-CE and corresponding histology reports with endoscopic mucosal pattern assessment templates used in human medicine. Belgian Shepherd dogs are predisposed to gastric carcinoma. Therefore, 30 dogs of this breed served as the study population. According to histology, 17/30 dogs had mucosal changes (mucous metaplasia, glandular dysplasia, and gastric carcinoma). Diagnostic yield was best when targeted biopsies were taken with WLE and NBI-CE combined (15/17 cases). WLE alone positively identified only 8/17 cases and missed a gastric carcinoma in 3/6 cases. CE assessment templates based on macroscopic mucosal patterns, broadly used in human medicine, were not readily applicable in dogs. In conclusion, the study provides evidence that using CE in dogs has the potential to improve the diagnosis of precancerous gastric mucosal pathology and early gastric carcinoma. However, current image assessment templates from human medicine need major adjustments to the patterns of canine gastric mucosa.

A computer-aided diagnosis system using white-light endoscopy for the prediction of conventional adenoma with high grade dysplasia

ObjectivesWe developed a computer-aided diagnosis system called ECRCCAD using standard white-light endoscopy (WLE) for predicting conventional adenomas with high-grade dysplasia (HGD) to optimise the patients' management decisions during colonoscopy. MethodsPretraining model was used to fine-tune the model parameters by transfer learning. 2,397 images of HGD and 2,487 low-grade dysplasia (LGD) images were randomly assigned (8:1:1) to the training, optimising, and internal validation dataset. The prospective validation dataset is the frames accessed from colonoscope videoes. One independent rural hospital provided an external validation dataset. Histopathological diagnosis was used as the standard criterion. The capability of the ECRCCAD to distinguish HGD was assessed and compared with two expert endoscopists. ResultsThe accuracy, sensitivity and specificity for diagnosis of HGD in the internal validation set were 90.5%, 93.2%, 87.9%, respectively. While 88.2%, 85.4%, 89.8%, respectively, for the external validation set. For the prospective validation set, ECRCCAD achieved an AUC of 93.5% in diagnosing HGD. The performance of ECRCCAD in diagnosing HGD was better than that of the expert endoscopist in the external validation set (88.2% vs. 71.5%, P < 0.0001). ConclusionECRCCAD had good diagnostic capability for HGD and enabled a more convenient and accurate diagnosis using WLE.

Advanced Endoscopic Imaging and Interventions in GERD: An Update and Future Directions

Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal diseases encountered in primary care and gastroenterology clinics. Most cases of GERD can be diagnosed based on clinical presentation and risk factors; however, some patients present with atypical symptoms, which can make diagnosis difficult. An esophagogastroduodenoscopy can be used to assist in diagnosis of GERD, though only half of these patients have visible endoscopic findings on standard white light endoscopy. This led to the development of new advanced endoscopic techniques that enhanced the diagnosis of GERD and related complications like squamous cell dysplasia, Barrett's esophagus, and early esophageal adenocarcinoma. This is conducted by improved detection of subtle irregularities in the mucosa and vascular structures through optical biopsies in real-time. Management of GERD includes lifestyle modifications, pharmacological therapy, endoscopic and surgical intervention. Minimally invasive endoscopic intervention can be an option in selected patients with small hiatal hernia and without complications of GERD. These endoscopic interventions include endoscopic fundoplication, endoscopic mucosal resection techniques, ablative techniques, creating mechanical barriers, and suturing and stapling devices. As these new advanced endoscopic techniques are emerging, data surrounding the indications, advantages and disadvantages of these techniques need a thorough understanding.

Chromoendoscopy Is Not Superior to White Light Endoscopy in Improving Adenoma Detection in Lynch Syndrome Cohort Undergoing Surveillance with High-Resolution Colonoscopy: A Real-World Evidence Study

Background: Endoscopic surveillance in patients with Lynch syndrome (LS) is crucial due to a genetically based high risk of colorectal cancer (CRC). We aimed to compare the adenoma detection rate (ADR) between high-resolution white light endoscopy (WLE) alone and WLE plus dye chromoendoscopy (CE) in a cohort of LS patients. Methods: In a context of real-world data, we retrospectively enrolled 50 LS patients who had non-randomly undergone WLE versus CE surveillance examinations from 2007 to 2019. The 2 groups were compared at baseline (BL) in terms of the rate of patients with lesions and the number of lesions, and at follow-up (FU), to evaluate a possible enhanced detection rate. Longitudinal analysis of the effect of the endoscopy type on the main outcomes was performed by generalized linear mixed models. Results: Forty-two patients had undergone at least one diagnostic colonoscopy. At BL and at FU analysis, we found no significant differences in detection rates and clinical-pathological features between WLE and CE groups. At the longitudinal analysis, an increase in the endoscopy rank (i.e., the position of each colonoscopy for all the colonoscopies that a patient had undergone) was associated with an increase in polyp detection rate (p = 0.006) and ADR (p = 0.005), while a trend toward significance (p = 0.069) was found for endoscopy type (CE vs. WLE) in the detection of serrated lesions. Conclusions: CE is not superior to high-resolution WLE in increasing the ADR. Even under standard WLE, an active and careful endoscopic surveillance of LS patients can prevent CRC.

S0677 An Indian National Survey of Gastroenterologists' Views on Dysplasia Surveillance and Chromoendoscopy in IBD

INTRODUCTION: International societal guidelines support use of chromoendoscopy (CE) for dysplasia surveillance in patients with inflammatory bowel disease (IBD). Our objective was to assess current dysplasia surveillance practices among gastroenterologists in India, which has the second highest number of patients with IBD after the USA. METHODS: A 31-question survey was distributed to members of the Indian Society of Gastroenterology. RESULTS: A total of 128 participated (94.5% male) with 87.5% consultant gastroenterologists (GI), 6.25% clinicians with GI interest & 6.25% GI trainees. Of these, 117 (91.4%) participants agreed that IBD patients in India require colonoscopic surveillance, 100 (78.2%) carried out surveillance colonoscopies. The 3 most common reasons for not performing IBD surveillance were lack of local guidelines (78.6%), cost constraints (78.6%) and perceived low-risk of colorectal cancer from IBD in Indians compared to the West (75%). Information on the practice of surveillance colonoscopy was available for 89/100 (89%). The preferred surveillance modality was standard white light endoscopy (WLE) by 38.2%, high definition WLE by 24.7%, narrow band imaging by 27% & dye-based (DB) chromo-endoscopy (CE) by 10.1%. 41.6% did not feel confident using CE, 44.9% felt confident using dye-less CE and 16.8% were confident of using DB CE. Random biopsies were considered an effective method of detecting neoplasia by 41 (46.1%) 65 (73%) were aware of recommendations from major organisations endorsing use of CE over random biopsies. The average number of biopsies performed at surveillance was 13 (median 10, IQR 10.25) with 16.7% performing quadrantic biopsies at 10 cm intervals in >50% of patients. The biggest barrier considered for using newer endoscopic modalities was financial constraints (77.1%) and 69.9% felt patients would receive better care with availability of novel endoscopic tools. The need for local IBD dysplasia surveillance guidelines was suggested by 79.8%. CONCLUSION: We noted a high level of awareness regarding dysplasia surveillance but considerable variation in practice amongst GI clinicians in India. Cost constraints and lack of local guidelines were deemed significant barriers for modern dysplasia surveillance. The rising incidence and prevalence of IBD in India emphasises an urgent need for training and pragmatic guidelines to improve surveillance strategies.

Topical application of Chlorin e6-PVP (Ce6-PVP) for improved endoscopic detection of neoplastic lesions in a murine colitis-associated cancer model

Screening colonoscopy is crucial in reducing the mortality of colorectal cancer. However, detecting adenomas against the backdrop of an inflamed mucosa (e.g. in ulcerative colitis) remains exceedingly difficult. Therefore, we aimed to improve neoplastic lesion detection by employing a fluorescence-based endoscopic approach. We used the well-established murine AOM/DSS model to induce inflammation-driven carcinogenesis in the colon. In our diagnostic approach, we evaluated Chlorin e6 polyvinylpyrrolidone (Ce6-PVP)-based fluorescence endoscopy in comparison to standard white-light endoscopy. A specialized pathologist then analyzed the histology of the detected lesions. Complementary in vitro studies were performed using human cell lines and a murine organoid system. Ce6-PVP-based fluorescence endoscopy had an improved detection rate of 100% (8/8) in detecting high-grade dysplasias and carcinomas over white-light detection alone with 75% (6/8). Trade-off for this superior detection rate was an increased rate of false positive lesions with an increase in the false discovery rate from 45% for white-light endoscopy to 81% for fluorescence endoscopy. We demonstrate in a proof-of-concept study that Ce6-PVP-based fluorescence endoscopy is a highly sensitive red flag technology to identify biopsy-worthy lesions in the colon.

Meta-analysis of Virtual-based Chromoendoscopy Compared With Dye-spraying Chromoendoscopy Standard and High-definition White Light Endoscopy in Patients With Inflammatory Bowel Disease at Increased Risk of Colon Cancer.

Patients with inflammatory bowel disease (IBD) have an increased risk of colorectal cancer. We sought to assess the comparative efficacy of virtual chromoendoscopy (VCE) vs high definition white light endoscopy (HDWLE) or dye-spraying chromoendoscopy (DCE) through a meta-analysis and rating the quality of evidence. A systematic review of the literature was performed through February 15, 2019. Primary outcomes were number of patients in whom dysplasia was identified and number of dysplastic lesions identified in these patients. We included only randomized control trials (RCTs) and performed meta-analysis using RevMan5.3. Of the 3205 studies identified, 11 RCTs were included, with a total of 1328 patients. Per patient analysis, VCE was not statistically different compared with DCE (risk ratio [RR] 0.77; 95% CI, 0.55-1.08) or HDWLE (RR 0.72; 95% CI, 0.45-1.15). However, per dysplasia analysis, VCE was not statistically different compared with DCE (RR 0.72; 95% CI, 0.47-1.11) and inferior compared with HDWLE (RR 0.62; 95% CI, 0.44-0.88). The quality of evidence was moderate in the HDWLE and low to moderate in the DCE studies. Based on this meta-analysis, VCE was as good as HDWLE and DCE in identifying dysplasia per patient analysis. However, per dysplasia analysis, VCE was inferior compared with HDWLE and no different from DCE. Further studies need to examine the efficacy of each individual VCE technique.

Artificial Intelligence Assisted Standard White Light Endoscopy Accurately Characters Early Colorectal Cancer: A Multicenter Diagnostic Study

Background: Early detection and treatment under endoscopy have effectively decreased the mortality of colorectal cancer (CRC). But it is difficult to detect early CRC under white light endoscopy (WLE). Artificial intelligence (A.I.) assisted diagnose system are accumulated, but early CRC assisting diagnosis system is lack due to clinical design and sample size limitation. We propose to establish a propagable AI-assisted early CRC diagnosis and characterization system (ECRC-CAD). Methods: Establishing algorithms were implemented in four (i.e., municipal, provincial, rural) hospitals of China. All patients who completed WLE from January 2016 to July 2019 were enrolled. Early CRC is diagnosed by pathological examination. Images of intraepithelial neoplasm (IN-ECRC) were included in the case group, and precancerous conditions and serrate lesion without intraepithelial neoplasm (NIN-ECRC) were randomly sampled in corresponding quantity included to control group. These images were randomly assigned (8:1:1) to the training, optimizing datasets and internal datasets. The evaluating indexes of diagnostic performance include sensitivity, specificity, positive predictive value, and negative predictive value. Findings: The largest new CRC endoscopic image database to date were established, which included 4,390 images of IN-ECRC. The diagnostic accuracy was 0·963 (95% CI, 0·941-0·978) in the internal validation set, and 0·835 (95% CI, 0·805-0·862) of identifying IN-ECRC in external datasets. ECRC-CAD achieved better diagnostic accuracy than the expert endoscopist (0·885 [95% CI, 0·859-0·907] vs 0.505 [95% CI, 0·411–0·598]; p<0.0001). The sensitivity, specificity, positive, and negative predictive value were significantly higher for ECRC-CAD than the expert endoscopist (p<0.0001). Interpretation: ECRC-CAD can identify early CRC and characterize neoplasms with high malignant potential; the performance is better comparing with expert endoscopists. Spreading of ECRC-CAD to regions with different medical levels can assist in CRC screening and prevention. Funding Statement: This research was supported by Major Science and Technology Project of Zhejiang Provincial (2020C03030), Natural Science Foundation of Fujian Province (2019-CXB-31), Science and technology program of Guangdong Province (2016A020213002), and National Natural Science Foundation of China (81773956). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: Each participating institute has ethical approval by independent ethics Committee according to the Helsinki declaration. The informed consent of retrospective cohort was exempted by the institutional review boards as the secondary use of clinical data without any intervention. In the prospective study, each patient was informed and signed informed consent.

Artificial Intelligence Assisted Standard White Light Endoscopy Accurately Characters Early Colorectal Cancer: A Multicenter Diagnostic Study

Artificial Intelligence Assisted Standard White Light Endoscopy Accurately Characters Early Colorectal Cancer: A Multicenter Diagnostic Study

Accuracy of endoscopic staging and targeted biopsies for routine gastric intestinal metaplasia and gastric atrophy evaluation study protocol of a prospective, cohort study: the estimate study

IntroductionPatients with chronic atrophic gastritis (CAG) and intestinal metaplasia (IM) are at risk of developing gastric adenocarcinoma. Their diagnosis and management currently rely on histopathological guidance after random endoscopic biopsy...

Endocuff Vision is safe to use for dysplasia surveillance in patients with ulcerative colitis: a feasibility study.

Background and study aims Endocuff Vision improves adenoma detection rates in patients without inflammatory bowel disease. This study aimed to investigate the safety and feasibility of Endocuff Vision-assisted high-definition white light endoscopy (HDWLE) with dye-spray chromoendoscopy for detection of dysplasia in patients with ulcerative colitis. Patients and methods Patients with clinically inactive ulcerative colitis due for dysplasia surveillance were recruited. Procedural endpoints included safety, cecal intubation rate (CIR), terminal ileum intubation rate (TIR), withdrawal time, polyp detection rate, dysplasia detection rate (DDR), and sessile serrated lesion detection rate. Results Twenty-five patients (9 female, median age 57 [range 28 – 82] years) were studied. Endocuff Vision-assisted HDWLE was completed in all participants, with a CIR of 100 %, in a median 4 minutes (range 2 – 16), and a TIR of 88% in a median of 6.5 minutes (range 3 – 19). Median withdrawal time was 18 minutes (range 10 – 55), including application of dye-spray, biopsies and polypectomy. The Mayo Endoscopic subscore was 0 in 11, 1 in 9, and 2 in 5 patients. The DDR was 24 % (6 patients had a total of 12 dysplastic lesions) and sessile serrated lesion detection rate was 12 % (3 patients had a total of 4 sessile serrated polyps). No serious adverse events occurred, with one patient developing clinically insignificant minor mucosal bleeding. Conclusion Endocuff Vision-assisted HDWLE is feasible and safe in patients with ulcerative colitis undergoing dysplasia surveillance. Further studies are required to assess superiority of this technique compared with standard high-definition white light endoscopy with chromoendoscopy.

Evaluation of confocal endoscopic microscopy for detection of early-stage gastric cancer in hereditary diffuse gastric cancer (HDGC) syndrome.

Hereditary diffuse gastric cancer (HDGC) syndrome results most often from a mutation in the CDH1 tumor suppressor gene and confers a 56-70% lifetime risk of gastric cancer. In asymptomatic carriers HDGC is characterized by multiple foci of signet ring cancer cells (SRCC) throughout the gastric mucosa. Because SRCC foci are less than 1 mm in diameter, and often make up less than 2% of the gastric mucosa, they are undetectable on standard screening endoscopy. International consensus guidelines recommend thorough white light endoscopic gastric mapping with a systematic method for gastric biopsies. Despite a painstaking approach to gastric mapping, retrospective analyses have demonstrated a low rate of detection and poor sensitivity of standard white light endoscopy for detecting occult cancer cells. Therefore, a more sensitive cancer screening tool is needed for these high-risk patients. Confocal endoscopic microscopy (CEM) allows for real-time, in vivo histologic imaging of gastrointestinal mucosa during upper endoscopy. Clinical application has demonstrated the ability of CEM to differentiate normal mucosal cells and cancer cells. A phase II clinical trial is currently underway to compare CEM to standard endoscopic gastric mapping in an effort to reduce the false negative detection rate of SRCC in patients diagnosed with HDGC. After an upper endoscopy with gastric mapping is performed, patients will undergo probe-based CEM. The endoscopist will scan the anatomic zones of the stomach in a similar fashion to the systematic gastric mapping approach. Any abnormal areas visualized with the CEM probe will be biopsied and sent for permanent pathologic analysis. The primary endpoint is to determine if CEM affords a higher sensitivity for detection of SRCC in CDH1 germline mutation carriers compared to white light endoscopy with gastric mapping. This novel screening technique is expected to provide greater sensitivity for detecting occult cancer in patients with HDGC, thereby improving cancer risk-assessment and overall cancer care. ClinicalTrials.gov NCT03648879 (registration date: August 28, 2018, clinicaltrials.gov).

Usefulness of confocal laser endomicroscopy for predicting postoperative recurrence in patients with Crohn’s disease: a pilot study

Confocal laser endomicroscopy (CLE) has been shown to predict relapse in inflammatory bowel disease, but its value in the detection of postoperative recurrence in Crohn's disease (CD) is unknown. The aims of this pilot study performed in patients with CD after ileocolonic resection were to compare the macroscopic appearance of the neoterminal ileum, according to the endoscopic Rutgeerts score, with the microscopic findings provided by CLE 6 to 12 months after surgery and to assess the predictive values of CLE-generated parameters for predicting further recurrence in patients with postoperative endoscopic remission. In 25 consecutive patients with CD within 6 to 12 months of surgery, the neoterminal ileum was examined by standard white-light endoscopy (Rutgeerts scale) followed by CLE (Watson grade). Only patients without endoscopic recurrence (Rutgeerts i0 and i1) were then followed endoscopically and clinically (median follow-up 38 months). At the time of the first postoperative colonoscopy, 18 patients (72%) were in endoscopic remission, and 7 (28%) experienced an endoscopic recurrence (Rutgeerts≥i2). The Rutgeerts score was significantly correlated with the Watson score (ρ= 0 .73; P< .0001). The Watson scores at baseline were significantly higher in patients with further endoscopic recurrence (median 2.0; interquartile range [IQR] 1.5-2.0) than in those with endoscopic remission (median 1.0; IQR 1.0-1.0; P= .032) and were significantly higher in patients with clinical relapse (medium 2.0, IQR 2.0-2.0) compared with those in clinical remission (median 1.0; IQR 1.0-1.0; P= .036). CLE could be useful in monitoring patients with CD after intestinal resection. Further studies with a larger population are necessary to confirm these preliminary results.

Bimodal reflectance and fluorescence multispectral endoscopy based on spectrally resolving detector arrays.

.Emerging clinical interest in combining standard white light endoscopy with targeted near-infrared (NIR) fluorescent contrast agents for improved early cancer detection has created demand for multimodal imaging endoscopes. We used two spectrally resolving detector arrays (SRDAs) to realize a bimodal endoscope capable of simultaneous reflectance-based imaging in the visible spectral region and multiplexed fluorescence-based imaging in the NIR. The visible SRDA was composed of 16 spectral bands, with peak wavelengths in the range of 463 to 648 nm and full-width at half-maximum (FWHM) between 9 and 26 nm. The NIR SRDA was composed of 25 spectral bands, with peak wavelengths in the range 659 to 891 nm and FWHM 7 to 15 nm. The spectral endoscope design was based on a “babyscope” model using a commercially available imaging fiber bundle. We developed a spectral transmission model to select optical components and provide reference endmembers for linear spectral unmixing of the recorded image data. The technical characterization of the spectral endoscope is presented, including evaluation of the angular field-of-view, barrel distortion, spatial resolution and spectral fidelity, which showed encouraging performance. An agarose phantom containing oxygenated and deoxygenated blood with three fluorescent dyes was then imaged. After spectral unmixing, the different chemical components of the phantom could be successfully identified via majority decision with high signal-to-background ratio (). Imaging performance was further assessed in an ex vivo porcine esophagus model. Our preliminary imaging results demonstrate the capability to simultaneously resolve multiple biological components using a compact spectral endoscopy system.

Volumetric Laser Endomicroscopy for Barrett's Esophagus - Looking at the Fine Print.

Barrett's esophagus (BE) is a premalignant condition. The incidence of adenocarcinoma in BE has been reported to be between 0.1-3%. Dysplasia in BE is patchy and extensive biopsy sampling is labor intensive, low yield and does not eliminate the sampling error completely. Volumetric laser endomicroscopy (VLE) is expected to enable endoscopists to do targeted biopsy of dysplastic/cancerous lesions (not visible on white light endoscopy) among patients with BE. We reviewed 7 studies with a total of 62 subjects who had undergone VLE. Of 34 patients with available data, VLE correlated with histology in 17 subjects (50%). It missed the underlying diagnosis in one subject (2.9%). VLE led to inadvertent biopsy in 16 patients (47.1%), and led or would have led to upstaging of disease in 11 subjects (32.4%). In the entire cohort, the sensitivity, specificity, positive predictive value and negative predictive value (NPV) of VLE for diagnosis of dysplasia, buried Barrett's or intramucosal carcinoma was 92.3%, 23.8%, 42.9% and 83.3%, respectively. High sensitivity and NPV can potentially help space out the surveillance intervals. Low specificity does lead to a high number of biopsies, which are likely less than non targeted biopsies. Volumetric laser endomicroscopy is a safe and sensitive test to identify mucosal lesions in patients with BE which are invisible under standard white light endoscopy.

Follow-up of oral and oropharyngeal cancer using narrow-band imaging and high-definition television with rigid endoscope to obtain an early diagnosis of second primary tumors: a prospective study.

Narrow-band imaging (NBI) is an optical technique enhancing mucosal vasculature. The aim of this study is to assess the effectiveness of rigid NBI endoscopy in the early detection of second primaries or local recurrences after treatment for oral (OSCC) and oropharyngeal squamous cell carcinoma (OPSCC), its advantage over standard white-light (WL) endoscopy, and the influence of previous radiotherapy, the learning curve, and lesion site. Between January 2013 and June 2015, 195 patients treated for OSCC or OPSCC with surgery alone (group A) or radiotherapy with or without surgery and/or chemotherapy (group B) underwent additional follow-up assessments using NBI. Sensitivity, specificity, positive/negative predictive values (PPV and NPV), and accuracy for detecting second primaries or local recurrences were calculated for patients with at least two NBI assessments. The effect of previous radiotherapy was determined by test of proportions and that of the learning curve and lesion site with Fisher's exact test. 138/195 patients were included in the analysis. NBI sensitivity, specificity, PPV, NPV, and accuracy for groups A and B were 89.5 vs 100%, 85.2 vs 81.5%, 65.4 vs 69.7%, 96.3 vs 100%, and 86.3 vs 87%, respectively. The diagnostic gain of NBI was 88.2% in group A and 69.6% in group B. The learning curve was the main source of false positives (p = 0.025), whereas radiotherapy and lesion site were uninfluential (p = NS). NBI appears useful for follow-up after treatment for OSCC or OPSCC, its performance being affected only by the learning curve and not by previous treatment or lesion site.