Yajia Gu MD, Abstract Co-Author: Nothing to Disclose

Valencia King MD, Presenter: Nothing to Disclose

Jennifer Brisman Kaplan MD, Abstract Co-Author: Nothing to Disclose

Malcolm Pike, Abstract Co-Author: Nothing to Disclose

Elizabeth A. Morris MD, Abstract Co-Author: Nothing to Disclose

To evaluate the effect of pre- versus postmenopausal status on level of background parenchymal enhancement (BPE) and amount of fibroglandular tissue (FGT) on breast MRI.

A waiver of authorization was granted by the institutional review board. Retrospective review identified 1130 women who had screening breast MRI between July and November 2010. Of these, 330 had undergone 2 or more breast MRIs at our institution and had no current or prior history of breast cancer. Twenty-nine of these women underwent an MRI both at 1 time point while premenopausal and at 1 time point while postmenopausal and were not on hormonal or antihormonal therapy at either time. The first premenopausal and the last postmenopausal breast MRIs were used for this study (median interval between MRIs 48 months). Two independent readers, who were blind to menopausal status, rated level of BPE and amount of FGT using a categorical scale: BPE – Minimal, Mild, Moderate, Marked; FGT – Fatty, Scattered, Heterogeneously Dense, Dense (based on proposed BIRADS criteria for BPE and based on ACR criteria for FGT). A consensus was reached in cases of disagreement. The Wilcoxon signed-rank test was used to assess changes in the rating categories for BPE and FGT on pre versus postmenopausal breast MRI exams. Inter-reader agreement was calculated.

Compared with the premenopausal breast MRI, a significant proportion of women demonstrated visible decreases in both BPE and FGT after menopause (p=0.0001 and p=0.0009, respectively). BPE was stable in 41% (12/29) and decreased in 59% of women (17/29). FGT was stable in 62% (18/29) and decreased in 38% of women (11/29). Neither BPE nor FGT increased after menopause. Interobserver agreement was very good (kappa = 0.92 for BPE, and 0.93 for FGT).

After menopause, both level of BPE and amount FGT on breast MRI decrease visibly in a significant proportion of women; BPE decreases in a greater proportion of women than FGT.

This strongly supports the hypothesis that BPE and FGT are hormonally dependent and demonstrates menopausal status must be controlled for in any study regarding BPE or FGT and breast cancer risk.

Gu, Y, King, V, Kaplan, J, Pike, M, Morris, E, Impact of Menopausal Status on Background Parenchymal Enhancement and Fibroglandular Tissue on Breast MRI.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034375.html