Narrow band imaging for detection of gastric intestinal metaplasia and dysplasia: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Gastric intestinal metaplasia (GIM), a precursor of gastric adenocarcinoma, is challenging to diagnose with white light endoscopy (WLE) and can be missed by random gastric biopsies. Narrowband imaging (NBI) may potentially improve the detection of GIM. However, pooled estimates from prospective studies are lacking. METHODS: Electronic databases were searched for studies comparing NBI and WLE alone for detection of GIM and synchronous dysplasia. Primary outcome was pooled detection rate of GIM by NBI compared with WLE in prospective studies. The secondary outcome was concurrent dysplasia detection. RESULTS: Ten studies were found eligible from 306 articles screened. Eight prospective studies were found eligible for primary endpoint of GIM detection. Two other retrospective studies were included for dysplasia detection. A total of 1366 subjects (694 males, 54.4 ± 5.08 years) underwent upper endoscopy. GIM was detected in 482 (35.3%) subjects. NBI detected GIM in 32% additional subjects (70% vs 38%, RR 1.79; 95% CI 1.34-2.37; P < 0.01). Subgroup analysis revealed newer NBI scopes (GIF260) detected significantly more GIM than WLE (RR 2.47; 95% CI 1.63-3.76; P < 0.01) but not the older (H180) NBI endoscopes (RR 1.33; 95% CI 0.93-1.88; P = 0.11). There was moderate heterogeneity between the studies (I2  = 63%). In five studies (n = 628) that reported dysplasia, there was no significant difference between NBI and WLE in dysplasia detection (RR 1.09; 95% CI 0.81-1.47; P = 0.58). CONCLUSION: Narrowband imaging can significantly increase the detection of GIM when used in addition to standard white light exam during an upper endoscopy.

Preliminary feasibility study using a novel narrow-band imaging system with dual focus magnification capability in Barrett's esophagus: is the time ripe to abandon random biopsies?

This preliminary feasibility study assessed the utility of a novel narrow-band imaging (NBI) system (Olympus Exera III; 190 series) both as a detection and as a characterization tool in patients undergoing surveillance endoscopy for Barrett's esophagus (BE). Two hundred and twenty-one areas in 40 patients with BE were examined prospectively. The BE segment was initially evaluated with NBI overview as a 'red flag' technique. Abnormal areas identified with NBI overview were then further interrogated with NBI and a dual focus (DF) magnification system (NBI-DF) in order to aid characterization. Normal areas on NBI overview were also systematically assessed with NBI-DF systematically (four quadrants every 2 cm). A confidence system was utilized when each area was assessed with NBI-DF. All areas on NBI-DF were classified into three easily distinguishable mucosal patterns: (i) regular pits with regular microvasculature (no dysplasia); (ii) irregular pits with irregular microvasculature (early cancer/high-grade dysplasia [HGD]); and (iii) equivocal, where the endoscopist was not sure about the pattern (this could be areas with increased brownish discoloration on NBI overview and dilated vasculature but no change in caliber on NBI-DF [likely inflammation or low-grade dysplasia: LGD]). Corresponding biopsies of each area were then taken. The sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of both modes (NBI overview and NBI-DF) were then compared with the final histopathological diagnosis. One hundred and eighty-three of 221 areas (82.8%) did not exhibit any dysplasia on final histopathological assessment. NBI overview and NBI-DF accurately called all these areas as non-dysplastic. The 38 areas that appeared suspicious on NBI overview were also further assessed with NBI-DF: seven of seven were accurately predicted as harboring no dysplasia; nine areas were predicted as irregular, of which four harbored early cancer, one HGD, three LGD and one inflammation on final histopathology assessment. Twenty-two areas were deemed to be equivocal (final histology: 18 LGD and four inflammation). The Sn, Sp, PPV and NPV for the prediction of dysplasia/early cancer using NBI overview and NBI-DF were thus 100%, 93.8%, 68.6%, 100% and 100%, 86.2%, 73.3%, 100%, respectively. If NBI-DF was used in addition to NBI overview, biopsies would have been avoided in 190 areas (86%). In addition, all early cancers and HGD could be accurately identified.