Abstract In this thesis we address various indications of breast MRI, with the emphasis on the value of MRI in screening of women with high genetic risk for breast cancer, and especially in BRCA1 mutation carriers. We showed that in the era of up-to-date MRI expertise and digital mammography the screening efficacy is improved. However, the additional value of mammography over MRI is little while at the same time BRCA carriers are more sensitive the risks of low dose radiation as in mammographic screening. Based on radiation risk estimations we advise to screen BRCA1 mutation carriers annually with MRI from age 25 onwards and to postpone mammographic screening until age 40. We demonstrated that addition of MRI to mammography for screen...