Breast MRI to Screen Women With Extremely Dense Breasts

Abstract

Women with extremely dense breasts are at a higher risk of breast cancer, and the sensitivity of mammography in this group is reduced due to the masking effect of overlapping tissue. This review examines supplemental screening methods to improve detection in this population, with a focus on MRI. Morphologic techniques offer limited benefits, digital breast tomosynthesis (DBT) shows inconsistent results, and ultrasound (US), while improving cancer detection rates (CDR), results in a higher rate of false positives. Functional imaging techniques show better performance, molecular breast imaging increases CDR but is limited in availability, and contrast-enhanced mammography is promising, with good results and as an accessible technique, but requires further validation. MRI, with sensitivity ranging from 81% to 100%, is the most supported modality. Despite strong evidence for MRI in this population, high costs, use of contrast, and longer scan times hinder widespread use. Abbreviated MRI protocols aim to overcome these barriers by reducing costs and scan duration. As personalized screening becomes a future focus, MRI remains the most effective option for women with extremely dense breasts. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 5.

Keywords: breast density; breast neoplasms; early detection cancer; magnetic resonance imaging.

FIGURE 1

BI‐RADS 5th Edition Mammographic Composition Categories/Densities: (a) almost entirely fatty; (b) scattered areas of fibroglandular density; (c) heterogeneously dense; (d) extremely dense.

FIGURE 2

Incremental cancer detection rates (CDR) per 1000 examinations of different imaging modalities in women with dense/extremely dense breasts. DBT = digital breast tomosynthesis, , ; US = ultrasound, ; MBI = molecular breast imaging, , ; CEM = contrast‐enhanced mammography, , , , ; MRI = magnetic resonance imaging., , , ^aExtremely dense breasts. ^b,cDense breasts (c and d). ^dExtremely dense breasts (CDR = 8.7) and dense breasts (CDR = 15.5). ^eExtremely dense breasts (CDR = 15.5) and dense breasts (CDR = 33.5).

FIGURE 3

BI‐RADS 5th Edition MRI composition categories: (a) almost entirely fatty; (b) scattered fibroglandular tissue; (c) heterogeneously fibroglandular tissue; (d) extremely fibroglandular tissue. Axial T2‐weighted MR images.

FIGURE 4

Background parenchymal enhancement (BPE) in extremely dense breasts. (a) minimal; (b) mild; (c) moderate; (d) marked. Top: Axial T1w fat‐suppressed first postcontrast images. Bottom: subtraction MIP (maximum intensity projection) images.

FIGURE 5

A 51‐year‐old woman with extremely dense breasts, screened for density. MRI detected 14‐mm invasive ductal carcinoma (IDC) retroareolar in the left breast (white circle).

FIGURE 6

Schematic drawing of abbreviated protocols: short protocols, abridged protocols, and unenhanced protocols. UF = ultrafast; DWI = diffusion weighted imaging; C = contrast.