Association between time spent interpreting, level of confidence, and accuracy of screening mammography.

OBJECTIVE

The objective of this study was to examine the effect of time spent viewing images and level of confidence on a screening mammography test set on interpretive performance.

MATERIALS AND METHODS

Radiologists from six mammography registries participated in this study and were randomized to interpret one of four test sets and complete 12 survey questions. Each test set had 109 cases of digitized four-view screening screen-film mammograms with prior comparison screening views. Viewing time for each case was defined as the cumulative time spent viewing all mammographic images before recording which visible feature, if any, was the "most significant finding." Log-linear regression fit via the generalized estimating equation was used to test the effect of viewing time and level of confidence in the interpretation on test set sensitivity and false-positive rate.

RESULTS

One hundred nineteen radiologists completed a test set and contributed data on 11,484 interpretations. The radiologists spent more time viewing cases that had significant findings or cases for which they had less confidence in their interpretation. Each additional minute of viewing time increased the probability of a true-positive interpretation among cancer cases by 1.12 (95% CI, 1.06-1.19; p < 0.001) regardless of confidence in the assessment. Among the radiologists who were very confident in their assessment, each additional minute of viewing time increased the adjusted risk of a false-positive interpretation among noncancer cases by 1.42 (95% CI, 1.21-1.68), and this viewing-time effect diminished with decreasing confidence.

CONCLUSION

Longer interpretation times and higher levels of confidence in an interpretation are both associated with higher sensitivity and false-positive rates in mammography screening.