Abstract TP64: Visual Perception, Cognition, and Non-Contrast CT Aspects

Introduction: As image interpretation is a visual perception task, it is affected by context and task structure. The non-contrast CT Alberta Stroke Program Early CT Score (ASPECTS) is considered an objective radiologic measure of the extent of ischemic change in cases of acute ischemic stroke. We hypothesize that variability in ASPECTS reading is because readers are susceptible to interplay between higher-order, top-down information (clinical background or other imaging) and bottom-up sensory information, and that experts are more resistant to being swayed by these factors than novices. Methods: We tested the effect of three top-down background-information conditions (no information; clinical information with affected side; clinical information plus CT angiography (CTA)) and three environment/task conditions (daylight, core lab, time pressure) on the inter-rater reliability (IRR) of NCCT ASPECTS. Three raters (trainee, fellow, neuro-radiologist) independently scored 150 NCCT scans from acute ischemic stro...