High Resolution White Light Endoscopy Research Articles

Surveillance in Barrett’s Esophagus: Challenges, Progress, and Possibilities

Endoscopic surveillance of Barrett's esophagus, aiming to detect prevalent dysplasia and adenocarcinoma, followed by effective endoscopic treatment, is an integral part of the esophageal adenocarcinoma prevention paradigm. However, several limitations, such as the subtle appearance of dysplasia, sampling error (inherent in current surveillance protocols), and noncompliance with surveillance recommendations, lead to missed dysplasia and neoplasia, reducing the effectiveness of surveillance as currently practiced. Careful endoscopic assessment with high-resolution white-light endoscopy, dye-based or electronic chromoendoscopy, and comprehensive sampling of the BE mucosa, remains the cornerstone of endoscopic surveillance. Emerging innovations in this area span the gamut of more efficient sampling methods, advanced imaging tools, artificial intelligence, and molecular marker-powered approaches as adjuncts, to identify prevalent and predict incident dysplasia or adenocarcinoma. Development and implementation of validated quality indicators will allow additional advancement of this critical field. These approaches will hopefully enable efficient and effective cancer prevention and treatment.

Image-Enhanced Endoscopy and Molecular Biomarkers Vs Seattle Protocol to Diagnose Dysplasia in Barrett’s Esophagus

Dysplasia in Barrett's esophagus often is invisible on high-resolution white-light endoscopy (HRWLE). We compared the diagnostic accuracy for inconspicuous dysplasia of the combination of autofluorescence imaging (AFI)-guided probe-based confocal laser endomicroscopy (pCLE) and molecular biomarkers vs HRWLE with Seattle protocol biopsies. Barrett's esophagus patients with no dysplastic lesions were block-randomized to standard endoscopy (HRWLE with the Seattle protocol) or AFI-guided pCLE with targeted biopsies for molecular biomarkers (p53 and cyclin A by immunohistochemistry; aneuploidy by image cytometry), with crossover to the other arm after 6 to 12 weeks. The primary end point was the histologic diagnosis from all study biopsies (trial histology). A sensitivity analysis was performed for overall histology, which included diagnoses within 12 months from the first study endoscopy. Endoscopists were blinded to the referral endoscopy and histology results. The primary outcome was diagnostic accuracy for dysplasia by real-time pCLE vs HRWLE biopsies. Of 154 patients recruited, 134 completed both arms. In the primary outcome analysis (trial histology analysis), AFI-guided pCLE had similar sensitivity for dysplasia compared with standard endoscopy (74.3%; 95% CI, 56.7-87.5 vs 80.0%; 95% CI, 63.1-91.6; P= .48). Multivariate logistic regression showed pCLE optical dysplasia, aberrant p53, and aneuploidy had the strongest correlation with dysplasia (secondary outcome). This 3-biomarker panel had higher sensitivity for any grade of dysplasia than the Seattle protocol (81.5% vs 51.9%; P < .001) in the overall histology analysis, but not in the trial histology analysis (91.4% vs 80.0%; P= .16), with an area under the receiver operating curve of 0.83. Seattle protocol biopsies miss dysplasia in approximately half of patients with inconspicuous neoplasia. AFI-guided pCLE has similar accuracy to the current gold standard. The addition of molecular biomarkers could improve diagnostic accuracy.

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.

Proton Pump Inhibitors and Radiofrequency Ablation for Treatment of Barrett's Esophagus.

Gastroesophageal Reflux Disease (GERD) is characterized by acid and bile reflux in the distal oesophagus, and this may cause the development of reflux esophagitis and Barrett's oesophagus (BE). The natural histological course of untreated BE is non-dysplastic or benign BE (ND), then lowgrade (LGD) and High-Grade Dysplastic (HGD) BE, with the expected increase in malignancy transfer to oesophagal adenocarcinoma (EAC). The gold standard for BE diagnostics involves high-resolution white-light endoscopy, followed by uniform endoscopy findings description (Prague classification) with biopsy performance according to Seattle protocol. The medical treatment of GERD and BE includes the use of proton pump inhibitors (PPIs) regarding symptoms control. It is noteworthy that long-term use of PPIs increases gastrin level, which can contribute to transfer from BE to EAC, as a result of its effects on the proliferation of BE epithelium. Endoscopy treatment includes a wide range of resection and ablative techniques, such as radio-frequency ablation (RFA), often concomitantly used in everyday endoscopy practice (multimodal therapy). RFA promotes mucosal necrosis of treated oesophagal region via high-frequency energy. Laparoscopic surgery, partial or total fundoplication, is reserved for PPIs and endoscopy indolent patients or in those with progressive disease. This review aims to explain distinct effects of PPIs and RFA modalities, illuminate certain aspects of molecular mechanisms involved, as well as the effects of their concomitant use regarding the treatment of BE and prevention of its transfer to EAC.

Reliability of Paris Classification for superficial neoplastic gastric lesions improves with training and narrow band imaging.

Background and study aims Paris Classification is used to classify gastrointestinal superficial neoplastic lesions and to predict presence of submucosal invasion. We aimed to evaluate interobserver reliability and agreement for this classification among Western endoscopists. Methods A total of 54 superficial gastric lesions were independently classified according to Paris classification by eight endoscopists (4 experts and 4 non-experts). Observers were asked to classify two sets of images – first, obtained with high-resolution white light (HR-WL) endoscopy and secondly, with the same HR-WL images paired with images obtained with high-resolution Narrow Band Imaging (HR-NBI) – HR-WL + NBI image group. Results Overall interobserver reliability when asked to classify in I, II or III was good both using HR-WL images and HR-WL + NBI images (wK of 0.65 and 0.70, respectively). The proportion of agreement for type III lesions was 0.48 for HR-WL images increasing to 0.74 in the HR-WL + NBI group. Interobserver reliability for identification of a IIc component was only moderate (wK 0,47). NBI improves both sensitivity and interobserver reliability among trainees (from wK 0.19 to 0.47). Specificity was higher than sensitivity in predicting submucosal invasion. Conclusion Overall, the reliability of Paris classification is moderate to good. Training on this classification or its revision and use of technology such as NBI may improve not only reliability and agreement but also accuracy.

Endoscopic submucosal dissection using a novel endoscopic articulating knife for clinical staging of early esophageal neoplasia.

114 Background: Clinical staging of early esophageal neoplasia traditionally involves histological confirmation and imaging with endoscopic ultrasound (EUS), CT, and PET which have low sensitivity and specificity for staging esophageal cancer (EC). Endoscopic submucosal dissection (ESD) therapy is traditionally used for treatment, but not diagnosis as it is felt to be technically challenging and have a high risk for complications. We applied a new articulating endoscopic knife that permits safe ESD (ESD-CC) to evaluate early neoplasia with potential curative resection. Methods: We performed a retrospective study of patients undergoing ESD to stage or treat suspected early EC (cT1-T2). Clinical stage was done by EUS, CT, and PET. Two expert GI pathologists reviewed all histology. Lesions were examined with high resolution white light endoscopy and narrow band imaging. ESD was done with 1:200,000 epinephrine and methylene blue dye injection for lifting and staining the submucosal space. A 5mm, scissors-like articulated knife was used to perform ESD and hemostasis. Complications during post-ESD observation or follow-up were recorded. Results: A total of 35 patients who underwent ESD-CC were included with median age 70 (IQR 12), 26 males (74%), and followed for a median 3.4 months (IQR 6.4). This group consisted of 32 potential adenocarcinomas and 3 squamous cell cancers. The clinical Pre-ESD diagnoses were cT1 EC (24, 69%) and suspected EC in Barrett’s esophagus (BE) (11, 31%). The cT1 EC cases had ESD staged at least T1b (5, 21%), T1a (11, 46%), EC in situ (1, 4%), and dysplastic BE (7, 29%). The suspected EC cases had ESD staged at least T1b (1, 9%), T1a (2, 18%), and DBE (8, 73%). ESD-CC up-staged 4 (11%), down-staged 10 (29%), and confirmed prior diagnosis in 21 (60%). No complications including bleeding, perforation, or stricture formation regardless of size of ESD, age of patient, or co-morbidities. Conclusions: Staging of early esophageal cancer can be improved using ESD with an articulating knife, without increase in complications. ESD may be used as a staging modality in early esophageal cancer.

Therapeutic endoscopic strategies in early esophageal cancer and dysplastic Barrett’s epithelium

Endoscopic therapy is the gold standard for curative treatment of early esophageal adenocarcinoma (EAC) including dysplastic Barrett´s epithelium (BE) and very early squamous cell carcinoma (SCC) because it is superior to surgery in regard to morbidity, mortality and cost effectiveness while yielding excellent results and low complication rates. Tumor detection at an early stage is often challenging and a multimodal approach using high resolution white light endoscopy, virtual chromoendoscopy (e.g. narrow band imaging, NBI) and endoscopic ultrasonography (EUS) is recommended. Importantly, histological diagnosis and EUS guided tumor staging should be performed before endoscopic tumor resection, although EUS validity has its limitations in terms of superficial mucosal and submucosal tumor invasion. In early esophageal adenocarcinoma, endoscopic mucosal resection (EMR) is considered the first line therapy and endoscopic submucosal dissection (ESD) is recommended only in special cases. In contrast, in very early squamous cell carcinoma, ESD is superior to EMR. This is mainly caused by a lower risk for lymphatic metastases in adenocarcinoma compared to squamous cell carinoma. If endoscopic resection is not curative or not feasible, surgery is the treatment of choice - assuming the patient´s comorbidities and performance status are no exclusion criteria.

Chromoendoscopy in combination with random biopsies does not improve detection of gastric cancer foci in CDH1 mutation positive patients.

Background and study aims: Hereditary diffuse gastric cancer (HGGC), an autosomal dominant tumor-syndrome, accounts for 1 % to 3 % of gastric cancers worldwide. Presumably 30 % to 40 % of all patients fulfilling the clinical guidelines for HDGC are carriers of a pathogenic mutation in the CDH1 gene. Patients often show multiple foci of signet ring cell carcinoma at early age and are advised to undergo prophylactic total gastrectomy (PTG). Our aim was to improve the endoscopic detection of HDGC by using an enhanced endoscopic protocol. Patient and methods: Patients with a proven CDH1 germline mutation identified in our institute were prospectively included. Patients were advised to undergo PTG and offered a baseline endoscopic examination prior surgery. Examination was performed by using high-resolution white-light endoscopy and pan-gastric chromoendoscopy with indigo carmine as dye combined with targeted and multiple random biopsies assessed by an expert histopathologist. Postoperative histopathology was compared with results from endoscopic biopsies. Results: Between September 2012 and November 2014 8 patients with a proven CDH1 germline mutation were included. We conducted 44 targeted (6.3/patient) and 225 random (32.1/patient) biopsies in 7 patients. We detected 1 gastric cancer by random biopsy (14 %). All other examinations showed no signs of cancer. Histopathology of gastrectomy specimen revealed multiple foci of gastric carcinoma in 6 patients (86 %) with a total number of 27 cancer foci. Conclusions: Examination with targeted and random biopsies combined with chromoendoscopy is not able to detect small foci of gastric cancer in CDH1 mutation carriers. Therefore PTG is advocated in these patients.

PWE-080 Eosinophilic Oesophagitis: Improving Diagnosis and Optimising Therapy

Introduction Eosinophilic oesophagitis (EoE) is a chronic condition of the oesophagus characterised by a dense eosinophilic infiltrate defined as >15 eosinophils/high power field (eos/hpf). The aim of this study was to capture the prevalence of EoE in a tertiary referral centre in London, to identify factors associated with a positive diagnosis and interrogate optimal response to therapy. Methods From February 2013 to November 2015, all patients presenting with solid food dysphagia to University College Hospital had a high resolution white light endoscopy. Those with cancer, achalasia, postoperative stricture or endotherapy for Barrett’s were excluded. Endoscopy, histology and clinical data were collected. >15 oes/hpf were defined as positive for EoE. A separate histopathology search identified patients with >15 eos/hpf and no dysphagia. A prospective follow-up was conducted in focusing on therapy and response in those with >15 eos/hpf. Results Out of the 1566 patients with dysphagia, 524 were excluded for reasons stated. 736/1042 (71%) had oesophageal biopsies. Of those, 67 (9.1%) had more than 15 eos/hpf. Another 14 patients with >15 eos/hpf with symptoms other than dysphagia were identified from histology records, making the total number with eosiniphilia 81. The mean number of biopsies taken in those with >15 eos/hpf (6.3) was greater than those with Conclusion A higher number of biopsies taken raises the diagnostic yield; however still up to 1/3 patients in a modern referral centre have no biopsies taken. EoE should be excluded in those with no dysphagia and refractory reflux symptoms. Although PPIs are provided as first-line therapy, a positive response to steroids is more likely in those with higher numbers eos/hpf, while those with fewer numbers and no endoscopic features could be considered for PPI therapy first. Such findings might be a useful tool to help tailor therapy. Disclosure of Interest None Declared

Narrow-band imaging for the detection of polyps in patients with serrated polyposis syndrome: a multicenter, randomized, back-to-back trial

Serrated polyposis syndrome (SPS) is characterized by the presence of multiple serrated polyps spread throughout the colon. Patients with SPS are considered to be at risk of colorectal cancer and are advised to undergo endoscopic surveillance. Narrow-band imaging (NBI) may improve the detection of polyps during these surveillance colonoscopies. To compare polyp miss rates between NBI and high-resolution white-light endoscopy (HR-WLE). Multicenter, randomized, crossover study. Four tertiary referral institutions. A total of 52 patients with SPS undergoing surveillance colonoscopy. All patients underwent back-to-back colonoscopies with HR-WLE and NBI in a randomized order. Polyp miss rates of HR-WLE and NBI. In the HR-WLE group, 116 polyps were detected during the first inspection. A second inspection with NBI added 47 polyps, resulting in an overall polyp miss rate of 29% with HR-WLE (95% confidence interval, 22-36). In the NBI group, a total of 128 polyps were detected during the first inspection. Subsequent inspection with HR-WLE added 32 polyps, resulting in an overall polyp miss rate of NBI of 20% (95% confidence interval, 15-27). Comparison of the overall polyp miss rates of HR-WLE and NBI showed no significant difference (P= .065). Small sample size; second inspection was performed by the same endoscopist. The results of our study suggest that NBI does not reduce polyp miss rates in patients with SPS compared with HR-WLE. Further multinational studies with larger numbers of patients are warranted to verify these results. ( NTR2497.).

Prospective cohort study assessing outcomes of patients from families fulfilling criteria for hereditary diffuse gastric cancer undergoing endoscopic surveillance

Prophylactic total gastrectomy is performed in hereditary diffuse gastric cancer (HDGC) patients carrying the CDH1 mutation because endoscopic surveillance often fails to detect microscopic disease. The aim of this study was to determine the natural history and outcomes of patients with HDGC undergoing endoscopy. Prospective, cohort observational study. Tertiary referral center. Patients fulfilling criteria for HDGC who opted to undergo endoscopy. Research surveillance program using high-resolution white-light endoscopy with autofluorescence and narrow-band imaging combined with targeted and multiple random biopsies assessed by an expert histopathologist for the presence of signet ring cell carcinoma. The primary endpoint was the endoscopic yield of microscopic signet ring cell carcinoma according to patient mutation status and subsequent decision to undergo surgery. The secondary endpoint was the additional yield of targeted biopsies compared with random biopsies. Between September 2007 and March 2013, 29 patients from 17 families underwent 70 surveillance endoscopies. Signet ring cell carcinoma foci were identified in 14 of 22 (63.6%) patients with confirmed CDH1 germline mutations and 2 of 7 (28.6%) with no pathogenic mutation identified. Eleven of 16 (9 CDH1-positive) patients proceeded to gastrectomy in a median 5.7 months. Five patients delayed surgery. In 1 patient, advanced gastric cancer developed 40.2 months after the first endoscopic findings. No control group. Careful white-light examination with targeted and random biopsies combined with detailed histopathology can identify early lesions and help to inform decision making with regard to gastrectomy. Autofluorescence and narrow-band imaging are of limited utility. Delaying gastrectomy in individuals with signet ring cell carcinoma foci carries a high risk and has to be weighed carefully.

Endoscopic Tri-Modal Imaging Improves Detection of Gastric Intestinal Metaplasia Among a High-Risk Patient Population in Singapore

Detection of pre-neoplastic gastric mucosal changes and early gastric cancer (EGC) by white-light endoscopy (WLE) is often difficult. In this study we investigated whether combined autofluorescence imaging (AFI) and narrow band imaging (NBI) can improve detection of pre-neoplastic lesions and early gastric cancer in high-risk patients. Chinese patients who were 50-years-old or above with dyspepsia were examined by both high-resolution WLE and combined AFI followed by NBI (AFI-NBI), consecutively in a prospective randomized cross-over setting, by two experienced endoscopists. The primary outcome was diagnostic ability of the two methods for patients with pre-neoplastic lesions such as intestinal metaplasia (IM) and mucosal atrophy. Sixty-five patients were recruited. One patient with large advanced gastric cancer was found and excluded from the analysis. Among the remaining 64 patients, 38 (59%) had IM; of these, 26 (68%) were correctly identified by AFI-NBI (sensitivity 68%, specificity 23%) and only 13 (34%) by WLE (sensitivity 34%, specificity 65%). AFI-NBI detected more patients with IM than did WLE (p=0.011). Thirty-one patients (48%) had mucosal atrophy. Ten patients (32%) were identified by AFI-NBI (sensitivity 32%, specificity 79%) and four patients (13%) by WLE (sensitivity 13%, specificity 88%) (p=0.100). No dysplasia or EGC was found. AFI-NBI identified significantly more patients with IM than did WLE. Our result warrants further studies to define the role of combined AFI-NBI endoscopy for detection of precancerous conditions.

Advanced Imaging in the Diagnosis of Gastric Intestinal Metaplasia: The Expert's Approach

Gastric intestinal metaplasia (IM) is associated with a risk for development of differentiated-type gastric cancers. The diagnosis of IM is currently based on the histology of biopsy specimens because IM usually appears in flat mucosa and has few morphologic changes, and identification of IM by conventional endoscopy has high interobserver variability and a poor correlation with histological findings. Autofluorescence imaging (AFI) produces real-time images from natural tissue fluorescence from endogenous fluorophores with light excitation. Narrow band imaging (NBI) uses two specific narrow banded lights (400–430 nm and 525–555 nm) to accentuate the contrast in surface structure and microvascular architecture of the superficial mucosa. With magnification, NBI enables a detailed observation of the morphological features of the epithelium corresponding to histology. Currently, AFI and NBI are incorporated with high-resolution white-light video endoscopy in one system (tri-modal imaging). To diagnose gastric IM, selection of Helicobacter pylori positive patients is important because it increases pretest probability. For an endoscopic procedure, areas with H. pylori associated mucosal atrophy or IM are identified as areas that increase visibility of mucosal vessels and lose gastric folds in the white-light image; greenish mucosa in the gastric corpus in AFI imagery; and whitish patchy areas in NBI imagery. When the magnifying NBI is applied in the areas, IM can be diagnosed as mucosa with ridged, papillary or villiform surface structure in the corpus or mucosa, with whitish papillary or villiform surface structure in the antrum, with the light blue crest sign (white-bluish lines of light on the epithelial crests). This article is part of an expert video encyclopedia.

Nodular Gastritis

High-resolution white-light endoscopy showed nodular gastritis (NG). NG is an endoscopic indicator of Helicobacter pylori infection, particularly in young women. NG is characterized by unique small protruding lesions with a uniform distribution within the antrum. Biopsy specimens of these lesions reveal lymphoid follicles with active and chronic inflammation. As NG may be associated with diffuse-type gastric cancer, detailed observation at the time or future screening endoscopy should be considered when NG is encountered on endoscopy. This article is part of an expert video encyclopedia.

Endoscopic features of sessile serrated adenomas: validation by international experts using high-resolution white-light endoscopy and narrow-band imaging

Sessile serrated adenomas/polyps (SSAs/Ps) are premalignant lesions susceptible to being easily overlooked by endoscopists. A detailed description of the endoscopic appearance of SSAs/Ps might help endoscopists to recognize these lesions to improve the effectiveness of colonoscopy. To identify various endoscopic features of SSAs/Ps using high-resolution white-light endoscopy (HR-WLE) and narrow-band imaging (NBI). Retrospective image evaluation study. Single tertiary referral center. Forty-5 patients with serrated polyposis syndrome undergoing surveillance colonoscopies. HR-WLE and NBI images of 150 polyps (50 SSAs/Ps, 50 hyperplastic polyps [HPs], and 50 adenomas) were systematically assessed by 5 experts using various endoscopic descriptors. The prevalence of specific endoscopic features observed in SSAs/Ps versus HPs. Multivariate analysis demonstrated that indistinct borders (OR, 3.11; 95% CI, 1.57-6.15) and a cloud-like surface (OR, 2.65; 95% CI, 1.21-5.78) were associated with SSA/P histology on HR-WLE. On NBI, a cloud-like surface (OR, 4.91; 95% CI, 2.42-9.97), indistinct borders (OR, 2.38; 95% CI, 1.14-4.96), irregular shape (OR, 3.17; 95% CI, 1.59-6.29), and dark spots inside the crypts (OR, 2.05; 95% CI, 1.02-4.11) were found to be endoscopic predictors of SSA/P histology. The sensitivity, specificity, and accuracy of NBI for differentiating serrated polyps containing either none or all 4 endoscopic SSA/P features were, respectively, 89%, 96%, and 93%. Retrospective, image evaluation analysis. The current study demonstrates that SSAs/Ps possess several specific endoscopic features compared with HPs. Recognition of these characteristics might assist endoscopists in the differentiation of these lesions and could possibly facilitate endoscopic detection of these rather subtle lesions.

Endotherapy for Barrett's Esophagus

Endotherapy is now the mainstay of therapy for Barrett's associated neoplasia. The approach should begin with confirmation of neoplasia by a gastrointestinal pathologist, patient counseling, and appropriate endoscopic work up. Detailed examination with high-resolution white light endoscopy is the most important tool for detection of neoplasia. Further validation studies are needed for many enhanced imaging modalities before being recommended as part of the standard work up and assessment of patients with Barrett's esophagus (BE). Endoscopic mucosal resection is required for any visible lesion in the setting of dysplasia for accurate histological diagnosis. The remainder of the epithelium may be treated with resection or ablative therapy, followed by adequate surveillance. Patients with nondysplastic Barrett's require further risk stratification before incorporation of ablative therapy for this population. The future will fortify the endoscopic role in Barrett's with validation trials for endoscopic assessment, further long-term results for each of the treatment modalities, potential risk stratification for patients with BE, and improved guidelines for surveillance after therapy.

Tu1588 Comparison of Narrow Band Imaging With High Resolution White Light Endoscopy for the Assessment of Non Steroidal Anti-Inflammatory Drug Induced Gastroduodenal Injury

The diagnosis of NSAID induced gastro-duodenal injury is often associated with difficulties in determination of the degree of injury. The Lanza score and its many modifications are commonly used in clinical trials, but are considered subjective and susceptible to errors in interpretation. The aim of this study was to determine the inter-observer variability in assessing NSAID induced gastro-duodenal injury among endoscopists with and without experience in narrow band imaging (NBI) using both high resolution white light endoscopy (HR-WLE) and NBI. Corresponding NBI and HR-WLE images were taken during endoscopy from healthy volunteers taking different NSAID preparations. Six blinded endoscopists (3 experts in NBI imaging) counted the number of ulcers, erosions and hemorrhagic lesions to derive a 5 point modified Lanza scale and evaluated image quality on a 10 point visual analogue score (VAS). Overall agreement and kappa value with bias corrected 95% confidence intervals using bootstrapping techniques were calculated to assess inter-observer reliability. The inter-observer agreement (κ) with HR-WLE among all 6 endoscopists was 0.62 (95% CI 0.52-0.72), which improved significantly with NBI to 0.76(95% CI 0.69-0.84, p=0.02). The inter-observer agreement among expert endoscopists with HR-WLE was “substantial” (κ=0.75, 95% CI 0.63-0.87) and improved with NBI to “almost perfect agreement (κ= 0.87, 95% CI 0.78-0.95, p=0.06) which almost reached statistical significance. The inter-observer agreement among non-expert endoscopists with HR-WLE was “moderate” (κ=0.54, 95% CI 0.42-0.67) and significantly improved with NBI to “substantial” (κ=0.72, 95% CI 0.60-0.82, p=0.02). Non-expert endoscopists found significantly higher number of mucosal hemorrhages on NBI images (p=0.03). VAS scores for NBI images were higher than HR-WLE for experts while the opposite was true for non-experts. VAS scores for NBI images were however consistently higher than HR-WLE when the paired images were presented side by side. Inter-observer reliability between both expert and non-expert endoscopists for assessment of NSAID induced injury is better with NBI than HR-WLE images. NBI imaging improves the visualization of mucosal hemorrhages especially in non-expert endoscopists.

Comparison of narrow band imaging with high resolution white light endoscopy for the assessment of non-steroidal anti-inflammatory drug induced gastroduodenal injury

IntroductionThe diagnosis of NSAID induced gastroduodenal injury is often associated with difficulties in determination of the degree of injury. The Lanza score and its many modifications are commonly used in...

Su1478 An Inter-Observer Agreement Study of Autofluorescence Endoscopy in Barrett's Oesophagus Among Expert Endoscopists

Autofluorescence imaging (AFI) is used as a ‘red flag' technique during Barrett's surveillance to identify subtle abnormal lesions which are not evident in high resolution white light endoscopy (HRE). This technique was found to have significant false positive results, but the sensitivity remains high. The aim of this study was to assess the interobserver agreement in detecting dysplastic lesions and to assess the overall accuracy of AFI among expert endoscopists. Anonymised AFI and HRE images were prospectively collected from patients undergoing Barrett's surveillance and dysplasia work-up. The AFI images were presented on power point in random order, followed by corresponding HRE and AFI images in a second folder. Three expert endoscopists (>150 AF endoscopies) scored the work sheet on separate occasions after an automated training presentation. The inter-observer agreement was calculated using kappa values (bias corrected) and the accuracy was calculated with histology as gold standard. 74 sets of anonymised white light and AFI images were prospectively collected from 63 patients (48 males, mean age 69). The inter-observer agreement for number of AF lesions noted was fair with a Kappa value of 0.39 (95% CI 0.28-0.52) for AFI images which improved significantly (p=0.04) to moderate kappa (0.57 and 95% CI 0.44-0.7) when corresponding AFI and HRE images are presented side by side. The inter-observer agreement for the quadrant with most significant AF lesion was moderate with a kappa of 0.48 (95% CI 0.37-0.6) which improved (p=0.08) to substantial kappa 0.62 (95% CI 0.50-0.72) when corresponding images were presented. The sensitivity for dysplasia detection was 0.75 (95% CI-0.68-0.81) and 0.84 (95% CI 0.78-0.89) using AFI images alone and using corresponding images respectively. Similarly, the specificity was 0.76 (95% CI 0.71-0.81) and 0.85 (95% CI 0.8-0.89). The overall accuracy of detecting dysplasia was 0.76 (95% CI 0.7-0.81) using AFI images alone and 0.85 (95% CI 0.79-0.89) using corresponding HRE and AFI images. The inter-observer agreement for dysplasia detection in Barrett's oesophagus using AFI images alone is only moderate among expert endoscopists, although it improved with addition of HRE. The overall accuracy of dysplasia using AF imaging was reasonable. Better understanding and recognition of what constitutes an AF positive signal on the endoscopic images is needed to improve this technique.

* An interobserver agreement study of autofluorescence endoscopy in barrett's oesophagus among expert endoscopists

IntroductionAutofluorescence imaging (AFI) is used as a Șred flag’ technique during Barrett's surveillance to identify subtle abnormal lesions which are not evident in high resolution white light endoscopy (HRE). This...