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Aim: To investigate patterns of false-positive decisions in mammography. The relationship between frequently falsely recalled mammograms, breast density, assigned confidence score of malignancy and presenting mammographic features of the case were explored. Method: There were 2 phases to this experiment. In Phase 1, 200 cases (180 normal, 20 cancer containing) were read by 5 Australian radiologists under three recall conditions: free recall, 15% recall rate and 10% recall rate. The readers assigned any suspicious cases a confidence score of malignancy. The most frequently recalled normal cases were identified via pattern analysis and assess for chance finding. These cases underwent case feature analysis including mammographic breast density and assigned confidence score of malignancy. In Phase 2: Seven expert breast radiologists were asked to review the cases knowing they were normal and rate rating each case for displaying “normal” and/or “benign” mammographic features and give a difficulty rating. Results: 18 normal cases were identified as repeatedly recalled across all recall rates. There was no correlation between mammographic breast density and FP frequency. Under the 10% recall rate condition, normal cases in the extremely difficult category were associated with significantly high confidence scores of malignancy (X2(2) =6.701, p=0.035). There was moderate correlation between the cohorts on case difficulty and the survey results indicated that benign disease was often marked as malignant. Conclusion: There was a clear pattern of normal mammograms persistently recalled. FP cases were not associated with higher mammographic breast density but did receive high confidence scores of malignancy. Radiologists agreed that highly difficult cases did not fit with their knowledge of normal variants. The phenomenon of repetitive occurrences of FP experience for screened women warrants further research on the analysis of the textural characteristics of normal mammographic cases.
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