Informatics in Radiology: What Can You See in a Single Glance and How Might This Guide Visual Search in Medical Images?

Abstract

Diagnostic accuracy for radiologists is above that expected by chance when they are exposed to a chest radiograph for only one-fifth of a second, a period too brief for more than a single voluntary eye movement. How do radiologists glean information from a first glance at an image? It is thought that this expert impression of the gestalt of an image is related to the everyday, immediate visual understanding of the gist of a scene. Several high-speed mechanisms guide our search of complex images. Guidance by basic features (such as color) requires no learning, whereas guidance by complex scene properties is learned. It is probable that both hardwired guidance by basic features and learned guidance by scene structure become part of radiologists' expertise. Search in scenes may be best explained by a two-pathway model: Object recognition is performed via a selective pathway in which candidate targets must be individually selected for recognition. A second, nonselective pathway extracts information from global or statistical information without selecting specific objects. An appreciation of the role of nonselective processing may be particularly useful for understanding what separates novice from expert radiologists and could help establish new methods of physician training based on medical image perception.

Eye-Tracking in the Study of Visual Expertise: Methodology and Approaches in Medicine

“…As a method of assessing gaze patterns during task execution, eye-tracking has been used to understand which parts of an image are important to medical decision-making, and also the process which experts adopt to analyze these images. To date, the majority of the published eyetracking studies involving medical expertise are naturally in the fields requiring extensive visual training, such as radiology (Drew, Evans, Vo, Jacobson, & Wolfe, 2013;Kundel, Nodine, Krupinski, & MelloThoms, 2008;G. Tourassi, Voisin, Paquit, & Krupinski, 2013;G.…”

“…Radiology is the most extensively studied field of medicine in relation to visual expertise, and it is not surprising that a significant literature involving eye-tracking has arisen in relation to this specialty (Drew, Evans, et al, 2013;Kundel et al, 2008;G. Tourassi et al, 2013;G.…”

“…At this level of visual processing, the radiologist guides attention toward a mental representation of the features and potential location of a target (Wen et al, 2016). Top-down processing is also employed at the point of diagnosis, when the visual item is matched to both a mental depiction of the target, and general medical knowledge (Drew, Evans, et al, 2013;Drew, Vo, Olwal, et al, 2013). Wolfe et al (1994) summarize this process in the "Guided Search Model," in which bottom-up attention to distracters is at least partially suppressed by the top-down effects of visual expertise.…”

Attention and the Cognitive Penetrability of Perception

“…For example, radiologists reliably identify abnormalities in rapidly presented (200ms) chest radiographs. Eyetracking studies corroborate these results by revealing substantially different scan patterns between experts and controls: expert radiologists make fewer total saccadic eye-movements and fixate more quickly on abnormalities [Drew et al 2013;Evans et al 2013]. These and many other cases of empirically studied perceptual expertise are candidate examples of epistemically enhancing cognitive penetration.…”

The influence of automation on tumor contouring

“…Another aspect that can be measured is the amount of time spent on inspecting data as shown in the Familiarizing and Evaluating steps of the workflow. However, increased time does not necessarily correlate with the quality of contours as physicians are capable of detecting abnormalities rather rapidly (Drew et al 2013).…”