Table 2.

Potential Misclassification of BI-RADS Density Categorization by Density Categories

Study	Repeat exam readers	% of women receiving a different breast density classification at 2nd exam (4 categories)	% of women receiving an opposite breast density classification at 2nd exam (2 categories)	% of dense exams reclassified as non-dense* (c or d) to (a or b)	% of dense exams reclassified as non-dense † (c) to (a or b)	% of dense exams reclassified as non-dense ‡ (c) to (b)	% of non-dense exams reclassified as dense § (a or b) to (c or d)	% of non-dense exams reclassified as dense ‖ (b) to (c or d)	% of non-dense exams reclassified as dense ¶ (b) to (c)
Harvey, 2013 (20)	Different community radiologists (n=703)	32	18.7	22	21	20	16	16	15
Spayne, 2012 (22)	Same community radiologists (n=34)	23	12.6	19	19	18	10	10	10
Gard, 2015 (24)	Same community radiologists (n=19)	29	16.9	10	10	10	23	23	23

^*Categorized as “heterogeneously dense” or “extremely dense” at first exam and “almost entirely fat” or “scattered fibroglandular densities” at second exam

^†Categorized as “heterogeneously dense” at first exam and “almost entirely fat” or “scattered fibroglandular densities” at second exam

^‡Categorized as “heterogeneously dense” at first exam and “scattered fibroglandular densities” at second exam

^§Categorized as “almost entirely fat” or “scattered fibroglandular densities” at first exam and “heterogeneously dense” or “extremely dense” at second exam

^‖Categorized as “scattered fibroglandular densities” at first exam and “heterogeneously dense” or “extremely dense” at second exam

^¶Categorized as “scattered fibroglandular densities” at first exam and “heterogeneously dense” at second exam

Abbreviations: BI-RADS=Breast Imaging-Reporting and Data System