Association between enhancement patterns and parameters of contrast-enhanced ultrasound and microvessel distribution in breast cancer

The aim of the present study was to evaluate the association between enhancement patterns and parameters in contrast-enhanced ultrasonography (CEUS) and microvessel distribution and histological prognostic tumor characteristics of breast cancer. Between September 2011 and April 2013, 109 breast lesions were prospectively analyzed, which were classified into Breast Imaging Reporting and Data System class 4-5 by conventional ultrasound. Before core-needle biopsy, CEUS examination was performed. Different enhancement patterns (homogeneous, peripheral and regional enhancement) were evaluated. Following CEUS, biopsies were performed at the same body positions under guidance of ultrasound. Parameters (wash-in time, peak intensity, time to peak, area under the time-intensity curve, ascending slope) of CEUS at corresponding puncture sites were recorded. Microvessel density (MVD) and pathological prognostic factors, including histological grade, lymph node status, tumor-node-metastasis stage, estrogen and progesterone receptor status, Ki-67 proliferative index and human epidermal growth factor receptor 2 overexpression, were determined. Mann-Whitney U test, Spearman's rank-correlation test and independent-samples t-tests were used for evaluation. Core-needle biopsy or surgical resection specimens of 99 malignant breast lesions were included in the present study. Of the 99 malignant lesions, 44 lesions exhibited homogeneous enhancement, 43 exhibited peripheral enhancement and 12 exhibited regional enhancement. Lesions with peripheral enhancement exhibited a higher peripheral/central ratio of MVD compared with lesions with homogeneous enhancement (P<0.001). Peak intensity and ascending slope ratios of tumor periphery/center were correlated with the corresponding MVD ratios (P=0.017 and P=0.016, respectively). MVD ratio was positively correlated with histological grade (P=0.003). In conclusion, the enhancement patterns and parameters of CEUS may not only reflect the microvessel distribution but also indirectly indicate the histological grade of breast cancer.