Molecular Breast Imaging: A Comprehensive Review

Molecular breast imaging (MBI), also called breast-specific gamma imaging (BSGI), has been an integral component of our breast imaging practice for over a decade. Unlike mammography and ultrasound that are based on anatomy, MBI is a physiologic approach to breast cancer detection. MBI detects additional foci of occult breast cancer in 9.0% of women with newly diagnosed breast cancer, has a high sensitivity for detecting high-risk lesions, and detects 98% of invasive breast cancer and 91.0% of ductal carcinoma in situ. Furthermore, in surveillance of high-risk women, BSGI/MBI detects occult cancer in up to 16.5 per 1000 women. This modality is increasingly being used to assess response to treatment in women undergoing neo-adjuvant chemotherapy and for adjunct screening in women with dense breasts. It has been shown to influence surgical management in nearly a quarter of women with newly diagnosed breast cancer. The Society of Nuclear Imaging has established clinical indications and The American College of Radiology has established appropriateness criteria as well as an accreditation program for MBI. A BIRADS-like lexicon for MBI has also been described. Initially, MBI utilized 10-20 mCi of 99 mTc sestamibi, however, recent studies have reported the use of 5-10 mCi with equal sensitivity to the higher dose of radiotracer. There are over 300 studies in the literature about MBI/BSGI with increasing integration of MBI into clinical practice. This chapter will describe the history, current literature and indications, clinical use, approach to biopsy and integration of MBI into clinical practice.