Eye tracking reveals expertise-related differences in the time-course of medical image inspection and diagnosis

Abstract. Purpose: Physicians’ eye movements provide insights into relative reliance on different visual features during medical image review and diagnosis. Current theories posit that increasing expertise is associated with relatively holistic viewing strategies activated early in the image viewing experience. This study examined whether early image viewing behavior is associated with experience level and diagnostic accuracy when pathologists and trainees interpreted breast biopsies. Approach: Ninety-two residents in training and experienced pathologists at nine major U.S. medical centers interpreted digitized whole slide images of breast biopsy cases while eye movements were monitored. The breadth of visual attention and frequency and duration of eye fixations on critical image regions were recorded. We dissociated eye movements occurring early during initial viewing (prior to first zoom) versus later viewing, examining seven viewing behaviors of interest. Results: Residents and faculty pathologists were similarly likely to detect critical image regions during early image viewing, but faculty members showed more and longer duration eye fixations in these regions. Among pathology residents, year of residency predicted increasingly higher odds of fixating on critical image regions during early viewing. No viewing behavior was significantly associated with diagnostic accuracy. Conclusions: Results suggest early detection and recognition of critical image features by experienced pathologists, with relatively directed and efficient search behavior. The results also suggest that the immediate distribution of eye movements over medical images warrants further exploration as a potential metric for the objective monitoring and evaluation of progress during medical training.