Comparison between software volumetric breast density estimates in breast tomosynthesis and digital mammography images in a large public screening cohort

Daniel Förnvik ,Hannie Förnvik ,Andreas Fieselmann,Kristina Lång ,Hanna Sartor

doi:10.1007/s00330-018-5582-0

Daniel Förnvik , Hannie Förnvik + Show 3 more

Open Access

https://doi.org/10.1007/s00330-018-5582-0

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Abstract

ObjectivesTo compare software estimates of volumetric breast density (VBD) based on breast tomosynthesis (BT) projections to those based on digital mammography (DM) images in a large screening cohort, the Malmö Breast Tomosynthesis Screening Trial (MBTST).MethodsDM and BT images of 9909 women (enrolled 2010–2015) were retrospectively analysed with prototype software to estimate VBD. Software calculation is based on a physics model of the image acquisition process and incorporates the effect of masking in DM based on accumulated dense tissue areas. VBD (continuously and categorically) was compared between BT [central projection (mediolateral oblique view (MLO)] and two-view DM, and with radiologists’ BI-RADS density 4th ed. scores. Agreement and correlation were investigated with weighted kappa (κ), Spearman’s correlation coefficient (r), and Bland–Altman analysis.ResultsThere was a high correlation (r = 0.83) between VBD in DM and BT and substantial agreement between the software breast density categories [observed agreement, 61.3% and 84.8%; κ = 0.61 and ĸ = 0.69 for four (a/b/c/d) and two (fat involuted vs. dense) density categories, respectively]. There was moderate agreement between radiologists’ BI-RADS scores and software density categories in DM (ĸ = 0.55) and BT (ĸ = 0.47).ConclusionsIn a large public screening setting, we report a substantial agreement between VBD in DM and BT using software with special focus on masking effect. This automated and objective mode of measuring VBD may be of value to radiologists and women when BT is used as the primary breast cancer screening modality.Key Points• There was a high correlation between continuous volumetric breast density in DM and BT.• There was substantial agreement between software breast density categories (four groups) in DM and BT; with clinically warranted binary software breast density categories, the agreement increased markedly.• There was moderate agreement between radiologists’ BI-RADS scores and software breast density categories in DM and BT.

Highlights

Modern breast cancer diagnostics are reliant on early cancer detection, which has led to an implementation of public breastEur Radiol (2019) 29:330–336 cancer-screening programmes with mammography in many developed countries
Breast cancer screening is going through major changes and recent technical developments have produced imaging methods that are more sensitive than digital mammography (DM), of which digital breast tomosynthesis (BT), a pseudo 3D mammographic technique, is the most promising in a screening setting, being fast, accessible and accurate [1,2,3,4,5]
We report a high correlation (r = 0.83) for continuous volumetric breast density (VBD) and a substantial agreement between four-category breast density in DM and BT using software with special focus on masking effect

Summary

Introduction

Modern breast cancer diagnostics are reliant on early cancer detection, which has led to an implementation of public breastEur Radiol (2019) 29:330–336 cancer-screening programmes with mammography in many developed countries. Breast cancer screening is going through major changes and recent technical developments have produced imaging methods that are more sensitive than digital mammography (DM), of which digital breast tomosynthesis (BT), a pseudo 3D mammographic technique, is the most promising in a screening setting, being fast, accessible and accurate [1,2,3,4,5]. Further developments have included automated quantitative measurements of the anatomically more relevant volumetric breast density (VBD), showing high correlation with MRI which is often considered the Bgold standard^ of measuring breast density [8, 9]. Quantitative density methods produced strongest relations with breast cancer risk [10]. Automated volumetric measurements may be preferable because they can provide fast and objective breast density estimates

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