Actual versus intended use of CAD systems in the clinical environment

Although computer-aided detection (CAD) systems were designed and approved for and are assumed to be used as a "second-reader", namely radiologists are expected to interpret mammograms and detect suspected abnormalities (i.e., micro-calcification clusters and masses) independently before viewing CAD results, it is not clear whether radiologists in a busy clinical environment follow the intended use. In this study, we observed ten experienced radiologists during the clinical reading of 635 mammography examinations and recorded their workflow pattern in terms of the use of CAD. The observations suggest that for detecting micro-calcification clusters only a few radiologists actually used a magnifying glass to carefully and systematically scan all images. Areas in which no CAD cues were identified for micro-calcifications were largely discarded. The majority of radiologists used CAD for identification micro-calcifications clusters almost as a "pre-screening" tool. In less than 15% of cases with CAD cues for microcalcifications cluster the radiologists actually scanned the complete set of images for possible additional clusters. The majority of more careful searches were performed by only three radiologists who voluntarily admitted they knew they were an exception in regards to their reading style and admitted they personally believed they were also "slower". CAD marks of possible masses were often discarded by the majority of the radiologists in particular when cues appeared only on one view. We found that there was a large difference between the use of CAD for detection of micro-calcifications clusters and masses. In addition, radiologists frequently use CAD in a manner that is substantially different than originally intended.