Accuracy of screening mammography using single versus independent double interpretation

OBJECTIVE. We conducted an analysis among 31 community radiologists to iden tify the average change in screening mammography interpretive accuracy affo rded by independent double interpretation. MATERIALS AND METHODS. We assessed interpretive accuracy using a stratified random sample of test mammograms that included 30 women with cancer and 83 without. Radiologists were unaware of clinical information and of each oth er's assessments. We describe accuracy for individual radiologists and for double interpretation, including average sensitivity, specificity, diagnost ic likelihood ratios positive and negative, and area under the receiver ope rating characteristic (ROC) curve. We also assessed weighted and nonweighte d kappa statistics among all 465 pairs of radiologists and 31,465 pairs of unique pairs. The assessment for double interpretations used the "highest" (i.e., most abnormal) assessment of the two radiologists. We calculated the difference between each radiologist's individual accuracy and the average accuracy across that radiologist's 30 double interpretations. RESULTS. We found the following average accuracy statistics for individual radiologists: sensitivity, 79%; specificity, 81%; diagnostic likelihood rat io positive, 5.53; diagnostic likelihood ratio negative, 0.26; and area und er the ROC curve, 0.85. The mean kappa statistic among radiologists for can cer cases increased with double interpretation from 0.59 to 0.70, and for n oncancer cases from 0.30 to 0.34. Double interpretation resulted in an aver age increase in sensitivity of 7%, an average decrease in specificity of 11 %, a decrease in diagnostic likelihood ratio positive of 2.35, a decrease i n diagnostic likelihood ratio negative of 0.06, and an increase in area und er the ROC curve of 0.02. CONCLUSION. Independent double interpretation does not increase accuracy as measured by the area under the ROC curve.