Eye-position study of the effects of a verbal prompt and pictorial backgrounds on the search for lung nodules in chest radiographs

摘要

Abstract: Peripherally inconspicuous nodules on chest radiographs are frequently missed by competent readers. In order to find a peripherally inconspicuous nodule the reader must inspect the nodule site with the central vision and decide if the features at the site are sufficiently characteristic to report a nodule. The experiment reported here was carried out to examine the effect of a nodule prompt and distraction by unrelated native abnormalities on the location and recognition of inconspicuous lung nodules on chest x-ray images. On two occasions separated by 3 years, 4 radiologists had their eye- position recorded while viewing 24 chest radiographs, 12 with prominent native abnormalities and 12 with no abnormalities. An inconspicuous nodule was simulated in the lungs of half of the radiographs on the first viewing and in the other half on the second viewing. For the first viewing, the readers were instructed to report any abnormalities. For the second viewing the readers were told to report any abnormalities including nodules. A nodule prompt triggers a scanning strategy that sends the central vision to high probability nodule sites early in search and at the same time relaxes the criteria used to evaluate nodule features resulting in more true positives and false positives without a change in absolute detectability. Prominent native abnormalities, unrelated to nodules, do not affect the search strategy but competitively inhibit the nodule feature recognition mechanism. !14