Multiparametric MRI Markers Associated with Breast Cancer Risk in Women with Dense Breasts

<b>Background/Objectives</b>: This study explored the associations of normal breast tissue characteristics on multiparametric MRI with clinical assessments of breast cancer risk in women with dense breasts. <b>Methods</b>: Women with dense breasts who underwent multiparametric MRI were included. Breast cancer risk was determined based on Tyrer-Cuzick (TC) lifetime risk scores, categorized as high (TC ≥ 20%) or low risk. Qualitative background parenchymal enhancement (BPE) assessment was obtained from imaging reports. Quantitative imaging markers were calculated, including median BPE, median apparent diffusion coefficient, and volume measures of the whole breast, fibroglandular tissue (FGT), blood vessels, and BPE regions. The associations between imaging markers and TC risk groups were evaluated using age-adjusted logistic regression and summarized by area under the receiver operating characteristic curve (AUC). <b>Results</b>: Seventy-seven women were evaluated; a total of 20 (26%) were low risk, and 57 (74%) were high risk. After adjusting for age and multiple testing, BPE:breast ratio (adj. <i>p</i> = 0.037), FGT:breast ratio (adj. <i>p</i> = 0.046), and BPE:vessel ratio (adj. <i>p</i> = 0.037) were positively associated with risk, while qualitative BPE was not (adj. <i>p</i> = 0.11). Overall, risk categorizations based on imaging markers were concordant with TC score in up to 70% of women. <b>Conclusions</b>: In women with dense breasts, quantitative measures from multiparametric MRI (BPE:breast, FGT:breast, and BPE:vessel ratios) moderately discriminated high- and low-risk groups, warranting further investigation of their value to supplement conventional breast cancer risk assessment tools.