| The assessment of breast cancer risk is important in determination of personalized breast cancer prevention strategy and evaluation of the effectiveness of intervention drugs. In this thesis, two MR imaging biomarkers, parenchyma volume and parenchyma enhancement were proposed, quantified and tested their abilities to assess the breast cancer risk. This thesis is a sub-study of a pre-existing two-armed, double-blinded clinical trial in which patients were randomized into one treatment group receiving tamoxifen daily for one year and placebo group receiving no treatment and received repeated MRI scans every 6 months for 2 years. The quantification of these biomarkers involves developing a quantitative analyzing pipeline. The test of the association between the biomarker and breast cancer risk changes was performed by comparing the mean response of the biomarker over time between groups. The results showed that the parenchyma enhancement rate in the treatment group decreases significantly compared with placebo group; the parenchyma volume in treatment group decreases more quickly than that in placebo group but was not statistically significant at p-value level of 0.05. The conclusion of this thesis is these MR imaging biomarkers are correlated with breast cancer risk changes and have the potential to be surrogate endpoints for breast cancer preventive trials. |
