Primary Objective:~-To compare the diagnostic performance of Molecular Breast Imaging (MBI) to breast Magnetic Resonance Imaging (MRI) in women who are at high risk of developing breast cancer.~Secondary Objectives:~To evaluate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of MBI compared to breast MRI in women who are at high risk of developing breast cancer.~To assess patient preference for the two examinations by conducting a post examination survey and follow up questionnaire (see addendum).~To assess the relationship of tumor size, histologic subtype and location of lesion with lesion conspicuity (mild, moderate, marked uptake compared to background activity) according to MBI lexicon [1].
To evaluate the diagnostic performance of Tc99m sestamibi (MBI) compared to breast MRI in women who are at high risk for developing breast cancer.~To assess the relationship of tumor size, histologic subtype and location of lesion and how it affects lesion conspicuity and sensitivity in MBI detected cancers.