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AJR Am J Roentgenol. 2000 Jun;174(6):1769-77.

Breast Imaging Reporting and Data System: inter- and intraobserver variability in feature analysis and final assessment.

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Department of Radiology, The Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore 21201, USA.



We sought to evaluate the use of the Breast Imaging Reporting and Data System (BI-RADS) standardized mammography lexicon among and within observers and to distinguish variability in feature analysis from variability in lesion management.


Five experienced mammographers, not specifically trained in BI-RADS, used the lexicon to describe and assess 103 screening mammograms, including 30 (29%) showing cancer, and a subset of 86 mammograms with diagnostic evaluation, including 23 (27%) showing cancer. A subset of 13 screening mammograms (two with malignant findings, 11 with diagnostic evaluation) were rereviewed by each observer 2 months later. Kappa statistics were calculated as measures of agreement beyond chance.


After diagnostic evaluation, the interobserver kappa values for describing features were as follows: breast density, 0.43; lesion type, 0.75; mass borders, 0.40; special cases, 0.56; mass density, 0.40; mass shape, 0.28; microcalcification morphology, 0.36; and microcalcification distribution, 0.47. Lesion management was highly variable, with a kappa value for final assessment of 0.37. When we grouped assessments recommending immediate additional evaluation and biopsy (BI-RADS categories 0, 4, and 5 combined) versus follow-up (categories 1, 2, and 3 combined), five observers agreed on management for only 47 (55%) of 86 lesions. Intraobserver agreement on management (additional evaluation or biopsy versus follow-up) was seen in 47 (85%) of 55 interpretations, with a kappa value of 0.35-1.0 (mean, 0.60) for final assessment.


Inter- and intraobserver variability in mammographic interpretation is substantial for both feature analysis and management. Continued development of methods to improve standardization in mammographic interpretation is needed.

[Indexed for MEDLINE]

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