Effect of Background Parenchymal Enhancement on Pre-Operative Breast Magnetic Resonance Imaging: How It Affects Interpretation and the Role of Second-Look Ultrasound in Patient Management.

Background parenchymal enhancement (BPE) on breast magnetic resonance imaging (MRI) may either obscure or mimic malignancy. We evaluated the impact of BPE on the diagnostic performance of pre-operative MRI in breast cancer patients, and how second-look ultrasound (US) can help in guiding patient management. Two hundred fifty-three breast cancer patients with pre-operative MRI were included. In moderate or marked BPE, abnormal interpretation rate (38.9% vs. 12.2%) and biopsy rate (27.8% vs. 8.3%) were higher, and specificity (64.7% vs. 89.8%) was lower, compared with minimal or mild BPE (all p < 0.001). Visibility of MRI-detected additional suspicious lesions on second-look US did not differ between the two groups (86.7% in minimal or mild BPE vs. 77.1% in moderate or marked BPE, p = 0.296). Increased BPE was related to increased abnormal interpretation rate, additional biopsy rate and decreased specificity. Second-look US was useful in visualization of MRI-detected additional suspicious lesions, regardless of BPE.