Contrast-enhanced MR imaging of the breast : association between asymmetric increased breast vascularity and ipsilateral cancer in a consecutive series of 197 patients

PURPOSE: This study was done to estimate the diagnostic performance of an asymmetric increase in breast vascularity (AIBV) for ipsilateral cancer. MATERIALS AND METHODS: A total of 197 patients without previous breast interventions underwent bilateral contrastenhanced (gadoterate meglumine, 0.1 mmol/kg) magnetic resonance (MR) imaging. Vessels >-2 mm in diameter and ≥3 cm in length were counted on maximum intensity projections: a difference ≥2 in number between the two breasts was considered AIBV. Pathology or ≥1 year follow-up served as a reference standard. The difference in sensitivity of AIBV between invasive and ductal carcinoma in situ (DCIS) as well as the association between AIBV and the diameter of invasive lesions or the histological grade were evaluated using χ(2) test. RESULTS: Pathology revealed 82 malignancies and 20 benign lesions: 70 invasive carcinomas (57 ductal, nine lobular, three mucinous, one papillary) and 12 DCIS: 10 fibroadenomas, two papillomas, two atypical ductal hyperplasias and six other benign lesions. The remaining 95 patients were negative at follow-up. Sensitivity of AIBV was 74% (61/82), specificity 94% (108/115), accuracy 86% (169/197), positive predictive value 90% (61/68) and negative predictive value 84% (108/129). Sensitivity for invasive cancers (80%; 56/70) was significantly higher than that for DCIS (42%; 5/12) (p<0.001). For invasive cancers, sensitivity was 40% (2/5) for lesions ≤9 mm in diameter, 69% (9/13) for those 10-14 mm, 79% (15/19) for those 15-19 mm and 91% (30/33) for those ≥20 mm (p<0.001). The G3 lesion rate was 49% (27/55) among true positives and only 7% (1/14) among false negatives (p=0.009). CONCLUSIONS: An association between AIBV and ipsilateral cancer exists, particularly for invasive cancers ≥20 mm or with high pathologic grade.