Researchers at Washington University in St. Louis have shown that a simple visual technique called “subtle gaze direction,” in which gentle visual cues are used to guide a viewer’s gaze, can be an effective technique to help radiology students learn how to study a mammogram.
The technique takes advantage of our vision’s quick response to brightness, color, and contrast changes in the periphery, which almost forces the eye to move toward the changing scene. By recording an experienced radiologist’s eye movements and using those to steer the gaze of novices, the researchers were able to show that the newbies improved their accuracy in detecting potential tumors better than the control group.
For the study, Grimm and her colleagues used a database of images provided by the Mammographic Image Analysis Society that includes both images and text files that contains coordinates of abnormalities and their size.
“Expert diagnostic radiologists have a particular search pattern that is not the same as that of a novice,” Grimm says. “We don’t know exactly what they’re doing, but they tend to do a fairly broad scan and then fixate on parts of the image that have a tumor-like texture. A novice might instead attend to brighter spots in the image or fail to scan all of it.”
Bailey hired an expert radiologist at the Rochester Institute of Technology to view and mark 65 images from the database. The expert’s scanpath was recorded during this process by an eye-tracking system.
During the experiment, subtle gaze direction was used to guide a group of novices along the expert scanpath. A control group viewed the mammograms without gaze manipulation.
Novices who were guided were significantly more accurate than the control group or a third group guided along a random path. Moreover, even though the training session was brief, the effect lingered even after gaze manipulation was disabled.
Here’s is the slide presentation from the study:
Press release: Visual nudge improves accuracy of mammogram readings