Video clips compared with high-definition still images for characterization of colorectal neoplastic lesions: a randomized comparative prospective study.

 Accurate real-time characterization of colorectal neoplastic lesions (CNLs) during colonoscopy is important for deciding appropriate treatment. No studies have evaluated whether still images or video clips are better for characterization. We compared histological predictions and size estimations of CNLs between two groups of gastroenterologists: one viewing still images and the other viewing video clips.  Participants were shown 20 CNLs as either 3-5 still images or a video clip. Three endoscopy experts obtained the images using high-definition white light and virtual chromoendoscopy without magnification. Stratified randomization was performed according to experience. For each lesion, participants assessed the size and histological subtype according to the CONECCT classification (hyperplastic polyp [IH], sessile serrated lesion [IS], adenoma [IIA], high-risk adenoma or superficial adenocarcinoma [IIC], or deeply invasive adenocarcinoma [III]). The correct histological status and size were defined by the pathology reports or combined criteria between histology and expert opinion for high-risk adenoma or superficial adenocarcinoma (CONECCT IIC).  332 participants were randomized and 233 performed the characterization. Participants comprised 118 residents, 75 gastroenterologists, and 40 endoscopy experts; 47.6 % were shown still images and 52.4 % viewed video clips. There was no statistically significant difference between the two groups in histological prediction, our primary end point. However, the lesion size was better assessed using still images than video clips (  = 0.03).  Video clips did not improve the histological prediction of CNLs compared with still images. Size was better assessed using still images.