Relationship Between Patient Age, Mammographic Density and Background Parenchymal Enhancement on Contrast-Enhanced Mammography.

Background: Breast magnetic resonance imaging (MRI) and contrast-enhanced mammography (CEM) have higher sensitivity than digital mammography, especially in women with high mammographic density (MD). However, high background parenchymal enhancement (BPE) can mask small lesions. Through the addition of kinetics, MRI performs better than CEM when BPE is high. This study assessed the extent to which patient age and MD are indicators of BPE on CEM, to support decision-making about selecting CEM or MRI.

Method: Retrospective analysis of 532 CEM exams performed between July 1, 2019 and June 30, 2020 at a single institution in eligible patients. Patient age, MD and BPE were recorded and the relationship between these factors was analyzed using Spearman's rank-order correlation and Fisher's exact test.

Results: There is a clear correlation between age, MD and BPE on CEM. Across all age groups, high BPE levels (moderate or marked) were more common in women with dense breasts (BI-RADS C/D MD) than nondense breasts (BI-RADS A/B MD) (51% versus 4%). High BPE was common in women younger than 60 with dense breasts (58%). The incidence of high BPE was low (7%) amongst all women 60 and over.

Conclusions: Women under 60 with dense breasts are likely to have high BPE on CEM and therefore may benefit more from MRI than CEM if they require a contrast-based investigation. Women 60 years and over, or women with nondense breasts at any age, are more likely to have low BPE and may be suitable for CEM.