Visual search in angiograms: does geometry play a role in saliency?
Jannick P. Rolland, Christopher S. Helvig · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1996
Quantifying and modeling how the human eye searches medical images is important. Equally detectable lesions may not be equally salient in a visual search. This research investigates the effect of geometry on the saliency of stenoses in angiograms. A previous experiment suggested that stenoses located in areas of high curvature along vessels would be less salient. In this paper, we measure the saliency of stenoses in two steps: first, we measure stenoses amplitude detection thresholds for stenoses at three values of curvature along vessels; second, after adjusting the degree of stenosis at these curvatures to multiples of the measured thresholds to achieve equal detectability, we measure the saliency of the stenoses in a visual search experiment. Median reaction time is used as a measure of saliency. We found that thresholds increase as curvature increases. This finding explains the decrease in saliency found in a previous investigation. Results also show that median reaction time is constant across different curvatures for 70% and higher degrees of stenosis, indicating that saliency is independent of geometry for clinically significant angiographic lesions.