Implementation and initial experience with an interactive eye-tracking system for measuring radiologists' visual search in diagnostic tasks using volumetric CT images

Hao Gong, Scott S. Hsieh, David Holmes, David Cook, Akitoshi Inoue, David Bartlett, Francis Baffour, Hiroaki Takahashi, Shuai Leng, Lifeng Yu, Joel Fletcher, Cynthia McCollough

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Eye-tracking techniques can be used to understand the visual search process in diagnostic radiology. Nonetheless, most prior eye-tracking studies in CT only involved single cross-sectional images or video playback of the reconstructed volume and meanwhile applied strong constraints to reader-image interactivity, yielding a disconnection between the corresponding experimental setup and clinical reality. To overcome this limitation, we developed an eye-tracking system that integrates eye-tracking hardware with in-house-built image viewing software. This system enabled recording of radiologists' real-time eye-movement and interactivity with the displayed images in clinically relevant tasks. In this work, the system implementation was demonstrated, and the spatial accuracy of eye-tracking data was evaluated using digital phantom images and patient CT angiography exam. The measured offset between targets and gaze points was comparable to that of many prior eye-tracking systems (The median offset: phantom - visual angle 0.8°; patient CTA - visual angle 0.7 - 1.3°). Further, the eye-tracking system was used to record radiologists' visual search in a liver lesion detection task with contrast-enhanced abdominal CT. From the measured data, several variables were found to correlate with radiologists' sensitivity, e.g., mean sensitivity of readers with longer interpretation time was higher than that of the others (88 ± 3% vs 78 ± 10%; p < 0.001). In summary, the proposed eye-tracking system has the potential of providing high-quality data to characterize radiologists' visual-search process in clinical CT tasks.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2022
Subtitle of host publicationPhysics of Medical Imaging
EditorsWei Zhao, Lifeng Yu
ISBN (Electronic)9781510649378
StatePublished - 2022
EventMedical Imaging 2022: Physics of Medical Imaging - Virtual, Online
Duration: Mar 21 2022Mar 27 2022

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceMedical Imaging 2022: Physics of Medical Imaging
CityVirtual, Online


  • Eye tracking
  • diagnostic performance
  • visual search
  • x-ray computed tomography

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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