Increasing Navigation Speed at Endoluminal CT Colonography Reduces Colonic Visualization and Polyp Identification.
Radiology. 2017 Mar 10:162037. doi: 10.1148/radiol.2017162037. [Epub ahead of print] Plumb AA1, Phillips P1, Spence G1, Mallett S1, Taylor SA1, Halligan S1, Fanshawe T1.
Purpose: To investigate the effect of increasing navigation speed on the visual search and decision making during polyp identification for computed tomography (CT) colonography
Materials and Methods: Institutional review board permission was obtained to use deidentified CT colonography data for this prospective reader study. After obtaining informed consent from the readers, 12 CT colonography fly-through examinations that depicted eight polyps were presented at four different fixed navigation speeds to 23 radiologists. Speeds ranged from 1 cm/sec to 4.5 cm/sec. Gaze position was tracked by using an infrared eye tracker, and readers indicated that they saw a polyp by clicking a mouse. Patterns of searching and decision making by speed were investigated graphically and by multilevel modeling.
Results: Readers identified polyps correctly in 56 of 77 (72.7%) of viewings at the slowest speed but in only 137 of 225 (60.9%) of viewings at the fastest speed (P = .004). They also identified fewer false-positive features at faster speeds (42 of 115; 36.5%) of videos at slowest speed, 89 of 345 (25.8%) at fastest, P = .02). Gaze location was highly concentrated toward the central quarter of the screen area at faster speeds (mean gaze points at slowest speed vs fastest speed, 86% vs 97%, respectively).
Conclusion: Faster navigation speed at endoluminal CT colonography led to progressive restriction of visual search patterns. Greater speed also reduced both true-positive and false-positive colorectal polyp identification. © RSNA, 2017 Online supplemental material is available for this article.