A 'snapshot' of the visual search behaviours of medical sonographers

Introduction: Visual search is a task that humans perform in everyday life. Whether it involves looking for a pen on a desk or a mass in a mammogram, the cognitive and perceptual processes that underpin these tasks are identical. Radiologists are experts in visual search of medical images and studies on their visual search behaviours have revealed some interesting findings with regard to diagnostic errors. In Australia, within the modality of ultrasound, sonographers perform the diagnostic scan, select images and present to the radiologist for reporting. Therefore the visual task and potential for errors is similar to a radiologist. Our aim was to explore and understand the detection, localisation and eye-gaze behaviours of a group of qualified sonographers. Method: We measured clinical performance and analysed diagnostic errors by presenting fifty sonographic breast images that varied on cancer present and degree of difficulty to a group of sonographers in their clinical workplace. For a sub-set of sonographers we obtained eye-tracking metrics such as time-to-first fixation, total visit duration and cumulative dwell time heat maps. Results: The results indicate that the sonographers' clinical performance was high and the eye-tracking metrics showed diagnostic error types similar to those found in studies on radiologist visual search. Conclusion: This study informs us about sonographer visual search patterns and highlights possible ways to improve diagnostic performance via targeted education.