Enhanced magnifying endoscopy for differential diagnosis of superficial gastric lesions identified with white-light endoscopy.

Background: Various techniques using magnifying endoscopy (ME) and chromoendoscopy are being developed to enhance images of gastrointestinal tumor. The aim of this study was to evaluate the diagnostic performance of ME enhanced by acetic acid-indigo carmine mixture (ME-AIM) and ME enhanced with narrow-band imaging (ME-NBI) for differential diagnosis of superficial gastric lesions identified with conventional white-light endoscopy (WLE).

Methods: Patients with superficial gastric lesions picked up with WLE were enrolled in the study. ME-NBI and ME-AIM were used to further characterize the lesions. All images of the lesions were evaluated by four skilled endoscopists blinded to the clinical data. The microarchitectural patterns in the lesions were analyzed with reference to the "VS classification" system.

Results: A total of 643 lesions (mean diameter, 7 mm) from 508 patients (316 men, 192 women; mean age, 63 years) were evaluated. Pathologically, 24 of the 643 lesions were diagnosed as gastric cancer; the others were noncancerous lesions. For diagnosis of gastric cancer, the negative predictive value of each of the three magnified findings (irregular microvascular pattern, irregular microsurface pattern, and demarcation line) was high (nearly 100 %). According to the "VS classification" system, either ME-NBI or ME-AIM had a higher specificity (99.5 % or 99.4 % vs. 89.5 %, P < 0.001) and accuracy (99.2 % or 98.9 % vs. 89.0 %, P < 0.001) than WLE, and ME-AIM was not superior to ME-NBI for identifying carcinoma.

Conclusions: Enhanced ME is useful for correctly diagnosing early gastric cancer, and in contrast with ME-AIM, ME-NBI is a more feasible and efficient method for clinical practice.