Unobtrusive evaluation of mammographer's eye movements during diagnosis of mammograms.

The authors sought to evaluate the visual search patterns of mammographers to better understand the process by which a diagnosis is reached when mammographic images are viewed. An unobtrusive gaze tracking system was applied to track gaze direction and pupil size. Data were collected at 60 Hz and analyzed to evaluate how visual search patterns (location and duration of gaze dwells and pupil size changes) altered when mammograms were repeatedly displayed. Two tests were performed. In the first test, a mammographer was shown the same mammogram on two occasions, separated by a 1-year interval. The second test evaluated the visual search patterns of four mammographers during a 30-minute display period, in which four mammograms were shown a variable number of times. Analysis of the gaze dwell data demonstrated that, although general recognition of a mammogram can occur within 1 second, even though 1 year separated the two occasions when the image was shown, repeated display of a mammogram may result in changes in (a) the time taken to reach a diagnosis, (b) the length of gaze dwell, (c) the total number of correct and incorrect diagnoses, and (d) pupillary constriction. Results from these tests may yield important information about how mammographers view images and how this process can affect diagnostic accuracy.

Unobtrusively tracking eye gaze direction and pupil diameter of mammographers.

RATIONALE AND OBJECTIVES: The visual process that radiologists use for diagnosis is incompletely understood. This study developed techniques to unobtrusively track direction and pupil diameter of radiologists reading a wide variety of films. We evaluated the eye gaze patterns of mammographic experts to gain knowledge that might improve the rate of early detection of breast cancer. METHODS: A video camera with a near-infrared light filter is pointed at the mammographic expert who is reading mammograms. The video images are analyzed in real time on a personal computer to detect eye gaze direction and pupil diameter. Two separate trials were used: 1) to demonstrate the system's speed and ability to work with mammograms (a brief test with one mammographer was used) and 2) four mammographic experts evaluated 14 mammograms. RESULTS: In the first trial, the system successfully tracked the eye gaze of a mammographer who quickly recognized the patient case, with the pupil diameter briefly increasing 40%, and then the gaze direction dwelling in an area of microcalcifications. In the second trial, 66% of the false-positive results for films with masses were associated with long eye gaze dwells, whereas 33% of the prolonged dwells for films with microcalcifications were associated with true-positive diagnoses. CONCLUSIONS: This near-infrared light system successfully tracked the eye gaze direction and pupil diameter of mammographic experts evaluating films. The association of long eye gaze dwells with diagnostic accuracy varied with the type of object being viewed. In films with masses, false-positive diagnoses were associated with long dwells. In films with microcalcifications, true-positive diagnoses were associated with long dwells.

Utilization of screening mammography by primary care physicians.

Although mammography is the primary modality for the detection of early breast cancer, routine screening of asymptomatic women in the U.S. has not occurred. A survey of the referral practices for breast cancer screening of 513 Virginia primary care physicians was conducted. An average percentage of 39% of women age 35 to 40, 55% of women age 40 to 50, and 57% of women over age 50 were referred for screening mammography. Gynecologists referred the greatest number of women for screening. An increase of mammography referrals was repeated by 81% of physicians; 21% of physicians stated that they referred all women over 50 for screening. Half of the physicians believed that women in their community were unaware of the benefits of mammography screening. Major deterrents were the cost of mammography and the lack of third-party coverage.