A Randomized Crossover Study Comparing Video Endoscopic Autofluorescence Imaging Followed By Narrow Band Imaging With Standard Endoscopy For The Detection Of High Risk Lesions In Stomach

Video endoscopic Autofluorescence Imaging (AFI) and Narrow Band Imaging (NBI) are new imaging techniques for detecting early neoplasia by endoscopy. A recent study showed that these 2 techniques are complementary to each other in detection of dysplasia in Barrett's esophagus. Aims: To determine whether combined AFI and NBI examinations improves the detection of preneoplastic lesions in the stomach in a high risk population. Methods: Patients aged 50 or above with dyspepsia were examined by both standard endoscopy (SE) and combined AFI/NBI techniques consecutively in a randomized sequence by two independent endoscopists at the same session. In the combined technique, the stomach was first examined by AFI followed by NBI. Lesion biopsies and random biopsies were obtained and reported by pathologists in a blinded fashion. Results: 65 patients were recruited, 46.2% of whom were male. Mean (sd) age 61.7(9.9), 50 - 91 years. One case was diagnosed to have advanced gastric cancer by both methods. The number of targeted biopsy was 146 by combined AFI/NBI, compared to 82 by white light endoscopy (p < 0.001). Out of these, pathology was confirmed in 94.5% and 90.2% respectively. Analysis of the results by per-biopsy protocol showed that combined AFI/NBI method diagnosed significantly more intestinal metaplasia (n = 80) than SE (n = 26, p = 0.001). The sensitivity and positive predictive value of correct endoscopic diagnosis of intestinal metaplasia was 67.7% and 55% for combined method and 51.7% and 58% respectively for SE (p = ns). One case of atypia was diagnosed by combined method, but missed by SE. The combined AFI/NBI examination prolonged the endoscopic procedure by an average of 14.5 minutes (SD; 6 minutes). Conclusion: Combined AFI/NBI examination detects more mucosal abnormalities than standard endoscopy, of which premalignant lesions, such as intestinal metaplasia has clinical significance. This method can be used to identify high risk patients for surveillance.