The introduction of computer-aided detection into this practice was not associated with statistically significant changes in recall and breast cancer detection rates, both for the entire group of radiologists and for the subset of radiologists who interpreted high volumes of mammograms.

The purpose of this study was to develop and test a method for selecting "visually similar" regions of interest depicting breast masses from a reference library to be used in an interactive computer-aided diagnosis (CAD) environment. A reference library including 1000 malignant mass regions and 2000 benign and CAD-generated false-positive regions was established. When a suspicious mass region is identified, the scheme segments the region and searches for similar regions from the reference library using a multifeature based k-nearest neighbor (KNN) algorithm. To improve selection of reference images, we added an interactive step. All actual masses in the reference library were subjectively rated on a scale from 1 to 9 as to their "visual margins speculations". When an observer identifies a suspected mass region during a case interpretation he/she first rates the margins and the computerized search is then limited only to regions rated as having similar levels of spiculation (within +/-1 scale difference). In an observer preference study including 85 test regions, two sets of the six "similar" reference regions selected by the KNN with and without the interactive step were displayed side by side with each test region. Four radiologists and five nonclinician observers selected the more appropriate ("similar") reference set in a two alternative forced choice preference experiment. All four radiologists and five nonclinician observers preferred the sets of regions selected by the interactive method with an average frequency of 76.8% and 74.6%, respectively. The overall preference for the interactive method was highly significant (p < 0.001). The study demonstrated that a simple interactive approach that includes subjectively perceived ratings of one feature alone namely, a rating of margin "spiculation," could substantially improve the selection of "visually similar" reference images.

Purpose To compare radiologists’ performance during interpretation of screening mammograms in the clinic to their performance when reading the same examinations in a retrospective laboratory study. Materials and Methods This study was conducted under an Institutional Review Board approved HIPAA compliant protocol where informed consent was waived. Nine experienced radiologists rated an enriched set of examinations that they personally had read in the clinic (“reader-specific”) mixed with an enriched “common” set of examinations that none of the participants had read in the clinic, using a screening BI-RADS rating scale. The original clinical recommendations to recall the women for a diagnostic workup, or not, for both reader-specific and common sets were compared with their recommendations during the retrospective experiment. The results are presented in terms of reader-specific and group averaged “sensitivity” and “specificity” levels and the dispersion (spread) of reader-specific performance estimates. Results On average radiologists performed significantly better in the clinic as compared with their performance in the laboratory (p=0.035). Inter reader dispersion of the computed performance levels was significantly lower during the clinical interpretations (p<0.01). Conclusion Retrospective laboratory experiments may not represent well either expected performance levels or inter- reader variability during clinical interpretations of the same set of examinations in the clinical environment.

Performance of CAD systems for mass detection at mammography varies significantly, depending on examination and system used. Actual performance of all systems in clinical environment can be improved.

CAD systems have the potential to significantly improve diagnostic performance in mammography. However, poorly performing schemes could adversely affect observer performance in both cued and noncued areas.