Optical biopsy strategy for the assessment of atrophic gastritis, intestinal metaplasia, and dysplasia.

BACKGROUND AND AIMS: The pathogenesis of gastric cancer involves premalignant changes of the gastric mucosa. An accurate estimation of the topography and severity of these lesions represents an important step in detecting premalignant lesions, thereby classifying patients into low or high risk of developing gastric cancer. We prospectively analyzed the diagnostic performance of narrow-band imaging with magnification endoscopy (NBI-ME) for assessing premalignant gastric lesions during real-time examination. PATIENTS, MATERIALS AND METHODS: A total number of 59 patients were examined by NBI-ME and target biopsies of the antrum, corporeal, and incisura angularis levels. Modified endoscopic patterns were classified into three groups: type A [tubulo-villous mucosal pattern with regular microvessels, or the light blue crest (LBC) sign], type B [disappearance of normal subepithelial capillary network (SECN) pattern], and type C [irregular mucosal pattern (IMP) and∕or irregular vascular pattern (IVP)]. The endoscopic diagnosis was compared to histological findings (the gold standard). The NBI-ME results were assessed for accuracy, sensitivity, specificity, and negative and positive predictive values in detecting intestinal metaplasia, atrophic gastritis and dysplasia. RESULTS: Analysis of endoscopic patterns showed a good correlation with premalignant lesions (p<0.05). Type A pattern showed 80.2% accuracy, 80.43% sensitivity and 80% specificity [area under receiver operating characteristic (AUROC) of 0.8] in detecting intestinal metaplasia. Diagnostic performance for assessment of atrophic gastritis was not ideal (69.5% accuracy, 83.72% sensitivity, 56.04% specificity, AUROC 0.69). Pattern C represents a reliable endoscopic marker for the diagnosis of dysplasia (91.1% accuracy, 83.3% sensitivity, 91.81% specificity, AUROC 0.87). The extension of precancerous lesions was estimated during endoscopic examination. CONCLUSIONS: NBI-ME represents a valuable tool in the assessment of premalignant gastric lesions, thereby categorizing patients into low and high risks of developing gastric cancer. The applicability of the method in routine practice is promising, as it helps shape the follow up protocol of patients with premalignant lesions of the stomach. It is worth mentioning that, this method requires standardization, additional training, and expertise.

A multicenter prospective study of the real-time use of narrow-band imaging in the diagnosis of premalignant gastric conditions and lesions.

BACKGROUND AND AIM: Some studies suggest that narrow-band imaging (NBI) can be more accurate at diagnosing gastric intestinal metaplasia and dysplasia than white-light endoscopy (WLE) alone. We aimed to assess the real-time diagnostic validity of high resolution endoscopy with and without NBI in the diagnosis of gastric premalignant conditions and to derive a classification for endoscopic grading of gastric intestinal metaplasia (EGGIM). METHODS: A multicenter prospective study (five centers: Portugal, Italy, Romania, UK, USA) was performed involving the systematic use of high resolution gastroscopes with image registry with and without NBI in a centralized informatics platform (available online). All users used the same NBI classification. Histologic result was considered the diagnostic gold standard. RESULTS: A total of 238 patients and 1123 endoscopic biopsies were included. NBI globally increased diagnostic accuracy by 11 percentage points (NBI 94 % vs. WLE 83 %; P < 0.001) with no difference in the identification of Helicobacter pylori gastritis (73 % vs. 74 %). NBI increased sensitivity for the diagnosis of intestinal metaplasia significantly (87 % vs. 53 %; P < 0.001) and for the diagnosis of dysplasia (92 % vs. 74 %). The added benefit of NBI in terms of diagnostic accuracy was greater in OLGIM III/IV than in OLGIM I/II (25 percentage points vs. 15 percentage points, respectively; P < 0.001). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve for EGGIM in the identification of extensive metaplasia was 0.98. CONCLUSIONS: In a real-time scenario, NBI demonstrates a high concordance with gastric histology, superior to WLE. Diagnostic accuracy higher than 90 % suggests that routine use of NBI allows targeted instead of random biopsy samples. EGGIM also permits immediate grading of intestinal metaplasia without biopsies and merits further investigation.

A preliminary feasibility study: Narrow-band imaging targeted versus standard white light endoscopy non-targeted biopsies in a surveillance Barrett's population.

BACKGROUND: Narrow band imaging (NBI) is used in the detection of intestinal metaplasia (IM) and dysplasia in patients with Barrett's oesophagus (BE). AIMS: The study compared the usefulness of NBI with white-light standard endoscopy (WLSE) for the detection of dysplasia and IM in BE and determined the prediction of the histological diagnosis according to the mucosal and vascular patterns obtained by NBI. PATIENTS AND METHODS: A total of 84 patients were prospectively enrolled in the study. Every patient underwent a WLSE with random biopsies and after 4-6 weeks, a NBI examination was performed. RESULTS: NBI detected significant more IM positive biopsies than WLSE (74.5% vs. 35.9%; p<0.0001) and significant more patients with low grade dysplasia (LGD) (7.1% vs. 0%; p=0.03). Taking biopsy samples from the villous pattern determined the diagnosis of IM (80%) and biopsies from the area covered by the irregular pattern lead to the identification of LGD in 45.4% of the cases and indefinite dysplasia (ID) in 18.2% of the cases. CONCLUSION: A thorough analysis of NBI patterns may lead to real-time IM diagnosis in the absence of the histological examination and may require targeted biopsies from the areas with an irregular pattern for diagnosing dysplasia.

Narrow-band imaging with magnifying endoscopy for the evaluation of gastrointestinal lesions.

Narrow band imaging (NBI) endoscopy is an optical image enhancing technology that allows a detailed inspection of vascular and mucosal patterns, providing the ability to predict histology during real-time endoscopy. By combining NBI with magnification endoscopy (NBI-ME), the accurate assessment of lesions in the gastrointestinal tract can be achieved, as well as the early detection of neoplasia by emphasizing neovascularization. Promising results of the method in the diagnosis of premalignant and malignant lesions of gastrointestinal tract have been reported in clinical studies. The usefulness of NBI-ME as an adjunct to endoscopic therapy in clinical practice, the potential to improve diagnostic accuracy, surveillance strategies and cost-saving strategies based on this method are summarized in this review. Various classification systems of mucosal and vascular patterns used to differentiate preneoplastic and neoplastic lesions have been reviewed. We concluded that the clinical applicability of NBI-ME has increased, but standardization of endoscopic criteria and classification systems, validation in randomized multicenter trials and training programs to improve the diagnostic performance are all needed before the widespread acceptance of the method in routine practice. However, published data regarding the usefulness of NBI endoscopy are relevant in order to recommend the method as a reliable tool in diagnostic and therapy, even for less experienced endoscopists.