Background parenchymal enhancement in the contralateral normal breast of patients undergoing neoadjuvant chemotherapy measured by DCE-MRI

Forty-five subjects were analyzed. Each patient had three MRIs, one baseline (B/L) and two follow-up (F/U) studies. The fibroglandular tissue in the contralateral normal breast was segmented using a computer-assisted algorithm. Based on the segmented fibroglandular tissue, BPE was calculated. BPE measured in baseline (B/L) and follow-up (F/U) MR studies were compared. The baseline BPE was also correlated with age and compared between pre/peri-menopausal (< 55 years old) and post-menopausal women (≥ 55 years old). The pre-treatment BPE measured in B/L MRI was significantly higher in women < 55 years old than in women ≥ 55 years old (20.1% ± 7.4% vs. 12.1% ± 5.1%, p ≤ 0.01). A trend of negative correlation between BPE and age was noted (r = − 0.29). In women < 55 years old, BPE at F/U-1 (18.8% ± 6.9%) was decreased compared to B/L, and was further decreased in F/U-2 (13.3% ± 5.7%) which was significant compared to B/L and F/U-1. In women ≥ 55 years old, no significant difference was noted in any paired comparison among B/L, F/U-1 and F/U-2 MRI. A higher baseline BPE was associated with a greater reduction of BPE in F/U-2 MRI (r = 0.73). Our study showed that younger women tended to have higher BPE than older women. BPE was significantly decreased in F/U-2 MRI after NAC in women < 55 years old. The reduction in BPE was most likely due to the ovarian ablation induced by chemotherapeutic agents.