Misclassification of breast imaging reporting and data system (BI-RADS) mammographic density and implications for breast density reporting legislation

TY - JOUR

T1 - Misclassification of breast imaging reporting and data system (BI-RADS) mammographic density and implications for breast density reporting legislation

AU - Gard, Charlotte C.

AU - Aiello Bowles, Erin J.

AU - Miglioretti, Diana L

AU - Taplin, Stephen H.

AU - Rutter, Carolyn M.

PY - 2015/9/1

Y1 - 2015/9/1

N2 - USA states have begun legislating mammographic breast density reporting to women, requiring that women undergoing screening mammography who have dense breast tissue (Breast Imaging Reporting and Data System [BI-RADS] density c or d) receive written notification of their breast density; however, the impact that misclassification of breast density will have on this reporting remains unclear. The aim of this study was to assess reproducibility of the four-category BI-RADS density measure and examine its relationship with a continuous measure of percent density. We enrolled 19 radiologists, experienced in breast imaging, from a single integrated health care system. Radiologists interpreted 341 screening mammograms at two points in time 6 months apart. We assessed intra- and interobserver agreement in radiologists'; interpretations of BI-RADS density and explored whether agreement depended upon radiologist characteristics. We examined the relationship between BI-RADS density and percent density in a subset of 282 examinations. Intraradiologist agreement was moderate to substantial, with kappa varying across radiologists from 0.50 to 0.81 (mean = 0.69, 95% CI [0.63, 0.73]). Intraradiologist agreement was higher for radiologists with ≥10 years experience interpreting mammograms (difference in mean kappa = 0.10, 95% CI [0.01, 0.24]). Interradiologist agreement varied widely across radiologist pairs from slight to substantial, with kappa ranging from 0.02 to 0.72 (mean = 0.46, 95% CI [0.36, 0.55]). Of 145 examinations interpreted as nondense (BI-RADS density a or b) by the majority of radiologists, 82.8% were interpreted as dense (BI-RADS density c or d) by at least one radiologist. Of 187 examinations interpreted as dense by the majority of radiologists, 47.1% were interpreted as nondense by at least one radiologist. While the examinations of almost half of the women in our study were interpreted clinically as having BI-RADS density c or d, only about 10% of examinations had percent density >50%. Our results suggest that breast density reporting based on a single BI-RADS density interpretation may be misleading due to high interradiologist variability and a lack of correspondence between BI-RADS density and percent density.

AB - USA states have begun legislating mammographic breast density reporting to women, requiring that women undergoing screening mammography who have dense breast tissue (Breast Imaging Reporting and Data System [BI-RADS] density c or d) receive written notification of their breast density; however, the impact that misclassification of breast density will have on this reporting remains unclear. The aim of this study was to assess reproducibility of the four-category BI-RADS density measure and examine its relationship with a continuous measure of percent density. We enrolled 19 radiologists, experienced in breast imaging, from a single integrated health care system. Radiologists interpreted 341 screening mammograms at two points in time 6 months apart. We assessed intra- and interobserver agreement in radiologists'; interpretations of BI-RADS density and explored whether agreement depended upon radiologist characteristics. We examined the relationship between BI-RADS density and percent density in a subset of 282 examinations. Intraradiologist agreement was moderate to substantial, with kappa varying across radiologists from 0.50 to 0.81 (mean = 0.69, 95% CI [0.63, 0.73]). Intraradiologist agreement was higher for radiologists with ≥10 years experience interpreting mammograms (difference in mean kappa = 0.10, 95% CI [0.01, 0.24]). Interradiologist agreement varied widely across radiologist pairs from slight to substantial, with kappa ranging from 0.02 to 0.72 (mean = 0.46, 95% CI [0.36, 0.55]). Of 145 examinations interpreted as nondense (BI-RADS density a or b) by the majority of radiologists, 82.8% were interpreted as dense (BI-RADS density c or d) by at least one radiologist. Of 187 examinations interpreted as dense by the majority of radiologists, 47.1% were interpreted as nondense by at least one radiologist. While the examinations of almost half of the women in our study were interpreted clinically as having BI-RADS density c or d, only about 10% of examinations had percent density >50%. Our results suggest that breast density reporting based on a single BI-RADS density interpretation may be misleading due to high interradiologist variability and a lack of correspondence between BI-RADS density and percent density.

KW - BI-RADS density

KW - breast density reporting legislation

KW - intra- and interradiologist agreement

KW - misclassification

KW - percent density

UR - http://www.scopus.com/inward/record.url?scp=84940725139&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84940725139&partnerID=8YFLogxK

U2 - 10.1111/tbj.12443

DO - 10.1111/tbj.12443

M3 - Article

C2 - 26133090

AN - SCOPUS:84940725139

VL - 21

SP - 481

EP - 489

JO - Breast Journal

JF - Breast Journal

SN - 1075-122X

IS - 5

ER -