The Impact of Bilateral Salpingo-Oophorectomy on Breast MRI Background Parenchymal Enhancement and Fibroglandular Tissue

Objective The objective of this study was to evaluate the effect of bilateral salpingo-oophorectomy (BSO) on background parenchymal enhancement (BPE) and the amount of fibroglandular tissue (FGT) seen on breast MRI. Methods Retrospective review identified 21 BRCA mutation carriers who underwent breast MRI before and after elective BSO. After exclusion of patients placed on postoperative hormone replacement therapy, there were 18 eligible patients. Blinded to surgical status, three independent readers used categorical scales to rate BPE (minimal, mild, moderate, marked) and the amount of FGT (fatty, scattered, heterogeneously dense, dense) on pre- and post-BSO MRI examinations. The sign test was used to assess for changes in the categorical ratings of BPE and FGT. Results Significant proportions of women demonstrated decreases in BPE and in the amount of FGT following oophorectomy (P = 0.004 and 0.02, respectively.) BPE decreases were larger and seen earlier than FGT changes. There was no significant relationship between age/body mass index and changes in BPE and FGT. Conclusions BPE and the amount of FGT seen on breast MRI are significantly decreased by oophorectomy; BPE decreases to a greater extent and earlier than FGT. Key Points Background parenchymal enhancement significantly decreases at breast MRI following oophorectomy. Fibroglandular tissue significantly decreases on breast MRI following oophorectomy. Decrease in background parenchymal enhancement is greater than in fibroglandular tissue. Decrease in background parenchymal enhancement occurs earlier than in fibroglandular tissue.