A comparative study of magnifying blue laser imaging and magnifying narrow-band imaging system for endoscopic diagnosis of Helicobacter pylori infection

Helicobacter pylori (Hp) infection is a major cause of gastric cancer. The use of proton-pump inhibitors, anti-platelet and anti-coagulant has become widespread in the clinic. Thus, it would be clinically useful to distinguish Hp-positive stomachs by endoscopic findings alone. Blue laser imaging (BLI) is a new image-enhanced endoscopy technique that utilizes a laser light source developed for narrow-band light observation. We investigated the diagnostic ability of magnifying BLI endoscopy to distinguish Hp-positive stomach in cancer free subjects. The data were also compared to the diagnostic ability of magnifying narrow-band imaging (NBI) endoscopy. In total, 215 participants were randomly assigned to the NBI (n=112) and BLI (n=113) groups. The greater curvature of the gastric middle and upper corpus were carefully evaluated with magnifying NBI or BLI. Small, round pits, accompanied with regular honeycomb-like subepithelial capillary networks (SECNs), being regularly interspersed with collecting venules were considered as Hp infection negative, while enlarged or elongated pits with unclear SECNs or dense fine irregular vessels were considered as Hp infection positive. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the diagnosis of Hp infection for the NBI group was 0.97, 0.81, 0.87 and 0.95, respectively. Sensitivity, specificity, PPV and NPV for the BLI group was 0.98, 0.92, 0.93 and 0.98, respectively. There was no significant difference among the values for the NBI and BLI groups (all P>0.2). In conclusion, the diagnostic ability of magnifying BLI is acceptable, since it is similar to that of magnifying NBI.