“Eye-tracking” for assessment of image perception in gastrointestinal endoscopy with narrow-band imaging compared with white-light endoscopy

Background and study aims: Narrow-band imaging (NBI) is a new imaging methodology for improving the detection rate of gastrointestinal lesions. We aimed to evaluate perception of images by NBI and corresponding standard white-light-endoscopy (WLE) using a computer-guided eye-tracking system.

Methods: A total of 23 NBI images of various lesions with the 23 corresponding WLE images were assessed in random order by 18 subjects with various endoscopy experience. Before evaluation, a teaching set of three NBI and corresponding WLE images was shown to highlight the characteristics of lesions. An eye-tracking system (Tobii X series with integrated 17-inch monitor) was used to record the eye movements of the subjects while they examined respective images. The following parameters were measured: total time spent on image, time until first fixation of lesion, total number of fixations per image and per lesion, and number of fixations until finding the lesion.

Results: In total, 828 experiments were conducted. Lesions could not be detected in 6.5 % (NBI) and 4.1 % (WLE) of images (P = NS). The total number of fixations and total time spent on respective figures as a whole were significantly greater for NBI images compared with WLE images (P < 0.003). However, the number of fixations until the lesion was found, the number of fixations on the lesion, and the time until first fixation of the lesion did not differ between the two image groups (P > 0.1).

Conclusion: This is the first study using eye tracking to evaluate image perception in gastrointestinal endoscopy. Significant differences in the interpretation of NBI and WLE images were observed, which may be relevant for the detection and characterization of lesions during endoscopy.

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