Quantitative calculation of breast density with proton density fat fraction enables distinction between latest subjective BI-RADS categories

Breast density is a well-established risk factor for breast cancer but conventional visual assessment using mammography has high operator variability. Proton density fat fraction (PDFF) derived from chemical shift encoded (CSE)-MRI has recently been proposed as a quantitative, non-ionising, operator-independent tool for the calculation of breast density. This study demonstrates that breast density derived from PDFF maps which account for a breast-specific fat spectrum can distinguish between the latest density categorisations used in clinical practise and thereby may have use in cancer risk assessment and as a determinant of clinical pathways.