Patient and Radiologist Characteristics Associated With Accuracy of Two Types of Diagnostic Mammograms

Abstract

Objective: Earlier studies of diagnostic mammography found wide unexplained variability in accuracy among radiologists. We assessed patient and radiologist characteristics associated with the interpretive performance of two types of diagnostic mammography.

Materials and methods: Radiologists interpreting mammograms in seven regions of the United States were invited to participate in a survey that collected information on their demographics, practice setting, breast imaging experience, and self-reported interpretive volume. Survey data from 244 radiologists were linked to data on 274,401 diagnostic mammograms performed for additional evaluation of a recent abnormal screening mammogram or to evaluate a breast problem, between 1998 and 2008. These data were also linked to patients' risk factors and follow-up data on breast cancer. We measured interpretive performance by false-positive rate, sensitivity, and AUC. Using logistic regression, we evaluated patient and radiologist characteristics associated with false-positive rate and sensitivity for each diagnostic mammogram type.

Results: Mammograms performed for additional evaluation of a recent mammogram had an overall false-positive rate of 11.9%, sensitivity of 90.2%, and AUC of 0.894; examinations done to evaluate a breast problem had an overall false-positive rate of 7.6%, sensitivity of 83.9%, and AUC of 0.871. Multiple patient characteristics were associated with measures of interpretive performance, and radiologist academic affiliation was associated with higher sensitivity for both indications for diagnostic mammograms.

Conclusion: These results indicate the potential for improved radiologist training, using evaluation of their own performance relative to best practices, and for improved clinical outcomes with health care system changes to maximize access to diagnostic mammography interpretation in academic settings.

Keywords: accuracy; characteristics; diagnostic mammography; patient; radiologist.

Fig. 1

Observed (unadjusted) radiologist-specific sensitivity versus false-positive rate and corresponding ROC within observed range of false-positive rates for interpretation of diagnostic mammograms. A and B, Graphs show data for additional evaluation of recent mammogram (A) and evaluation of breast problem (B). Area of each circle is proportional to number of mammograms from patients with diagnosis of breast cancer that were interpreted by that radiologist. One radiologist with false-positive rate of 60% (based on six diagnostic mammograms, five without cancer during follow-up) was excluded from these figures, but data were included in all other analyses.

Fig. 2

Association between patient and radiologist characteristics and false-positive and true-positive (sensitivity) diagnostic mammogram performed for additional evaluation of recent mammogram. Asterisk denotes radiologist self-reported average number of screening or diagnostic mammograms per year over past 5 years. Each model includes all variables listed (within specific column) and also adjusts for mammography registry and correlation within radiologist. OR = odds ratio.

Fig. 3

Association between patient and radiologist characteristics and false-positive and true-positive (sensitivity) diagnostic mammogram performed for evaluation of breast problem. Asterisk denotes patient self-reported breast symptoms and radiologist self-reported average number of screening or diagnostic mammograms per year over past 5 years. Each model includes all variables listed (within specific column) and also adjusts for mammography registry and correlation within radiologist. OR = odds ratio.