Impact of Breast Density and Menopausal Status on Apparent Diffusion Coefficient Values of the Breast Tissues in Diffusion-Weighted MRI

Introduction: Breast density, a key factor linked to increased breast cancer risk, remains pivotal in clinical care. Yet, in implementing Diffusion Weighted Imaging (DWI), the impact of breast density on outcomes remains unclear. This study aims to elucidate the relationship between Apparent Diffusion Coefficient (ADC) values in benign, malignant, and fibroglandular tissues, alongside breast density and menopausal status, shedding light on breast cancer effects. Methods: One hundred and twenty-four subjects were enrolled for Magnetic Resonance Imaging (MRI), with 141 lesions. A bilateral MRI breast scan was conducted with T2-weighted Fat-Suppressed (T2 FS) sequences and Diffusion Weighted Imaging (DWI) sequences, and ADC values were calculated. Breast density was categorized according to the American College of Radiology Breast Imaging Reporting and Data System (ACR BI-RADS®). Results: A total of 124 patients with 141 breast lesions (62 benign, 79 malignant) were included, and ADC values were calculated for 124 fibroglandular tissue (FGT) regions. Breast density was classified according to ACR BI-RADS®: Category A (n = 25), B (n = 41), C (n = 35), and D (n = 23). Median ADC values differed significantly between benign and malignant lesions (p < 0.001), but not for fibroglandular tissue across density categories. Premenopausal women demonstrated higher ADC values than postmenopausal women, with a statistically significant difference observed only for benign lesions (p = 0.002). Quantile regression analysis confirmed that breast density and tissue type were significantly associated with ADC values (p < 0.001), while menopausal status was not statistically significant (p = 0.422). Conclusion: The diagnostic accuracy of the ADC value for breast lesions was significantly influenced by breast density and menopausal status. Hence, for differential diagnosis, breast density and menopausal status should be taken into consideration. Implication for Practice: By integrating breast density and menopausal status into the analysis of ADC values in DWI, radiologists and clinicians can improve the accuracy of breast cancer screening and diagnosis, leading to more effective, personalized management strategies. This approach emphasizes the importance of considering individual patient factors when interpreting advanced imaging modalities.