reast MRI is an indispensable modality, along with mammography and US. Its main indications are staging of known cancer, screening for breast cancer in women at increased risk, and evaluation of response to neoadjuvant chemotherapy (1-3). As opposed to mammography and US, MRI is a functional technique. Heywang et al (4) and Kaiser and Zeitler (5) independently introduced this technique in the 1980s. Contrast material-enhanced MRI evaluates the permeability of blood vessels by using an intravenous contrast agent (gadolinium chelate) that shortens the local T1 time, leading to a higher signal on T1-weighted images (6). The underlying principle is that neoangiogenesis leads to formation of leaky vessels that allow for faster extravasation of contrast agents (7), thus leading to rapid local enhancement. Despite improvements in the technique of breast MRI, this principle is still the basis of all clinical MRI protocols. However, most MRI protocols nowadays are multiparametric (8,9). This review describes the current state of the art in breast MRI, with a focus on the major indications and the potential indication-based adaptations to the imaging protocol to maximize its value. Requirements for Breast MRI Breast MRI studies should be interpreted by radiologists with expertise in breast imaging, including mammographic and US studies, as these examinations are often complementary. Although empirical data on the learning curve for breast MRI are lacking, some studies showed improved performance of radiologists over time (10), and reporting breast MRI studies requires sufficient exposure to the technique. It is best practice to use a field strength of at least 1.5 T to acquire images at a sufficiently high spatial resolution (1-3). Utilization of a dedicated breast coil is mandatory to obtain images of diagnostic quality. Women lie in the prone position with the breasts hanging free in the recesses of the coil. This design allows the breast tissue to spread, which facilitates detection of abnormalities and prevents motion artifacts induced by respiration (11,12). A breast coil should have at least four channels, but modern designs

Shear wave elastography (SWE) is an emerging technique which can obtain quantitative elasticity values in breast disease. We therefore evaluated the diagnostic performance of SWE for the differentiation of breast masses compared with conventional ultrasound (US). Conventional US and SWE were performed by three experienced radiologists for 158 consecutive women who had been scheduled for US-guided core biopsy or surgical excision in 182 breast masses (89 malignancies and 93 benign; mean size, 1.76 cm). For each lesion, quantitative elasticity was measured in terms of the Young's modulus (in kilopascals, kPa) with SWE, and BI-RADS final categories were assessed with conventional US. The mean elasticity values were significantly higher in malignant masses (153.3 kPa ± 58.1) than in benign masses (46.1 kPa ± 42.9), (P < 0.0001). The average mean elasticity values of invasive ductal (157.5 ± 57.07) or invasive lobular (169.5 ± 61.06) carcinomas were higher than those of ductal carcinoma in situ (117.8 kPa ± 54.72). The average mean value was 49.58 ± 43.51 for fibroadenoma, 35.3 ± 31.2 for fibrocystic changes, 69.5 ± 63.2 for intraductal papilloma, and 149.5 ± 132.4 for adenosis or stromal fibrosis. The optimal cut-off value, yielding the maximal sum of sensitivity and specificity, was 80.17 kPa, and the sensitivity and specificity of SWE were 88.8% (79 of 89) and 84.9% (79 of 93). The area under the ROC curve (Az value) was 0.898 for conventional US, 0.932 for SWE, and 0.982 for combined data. In conclusion, there were significant differences in the elasticity values of benign and malignant masses as well as invasive and intraductal cancers with SWE. Our results suggest that SWE has the potential to aid in the differentiation of benign and malignant breast lesions.

Patients with breast cancer and a low pretreatment ADC tended to respond better to chemotherapy. Prediction of response to neoadjuvant chemotherapy with DW MR imaging might help physicians individualize treatments and avoid ineffective chemotherapy.

Purpose: To investigate whether a correlation exists between perfusion parameters obtained from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and prognostic factors or immunohistochemical subtypes of breast cancers. Materials and Methods:Quantitative parameters (K trans , k ep , and v e ) of 70 invasive ductal carcinomas were obtained using DCE-MRI as a postprocessing procedure. Correlations between parameters and prognostic factors, including tumor size, axillary nodal status, histologic grade, nuclear grade, expression of estrogen receptor (ER), progesterone receptor (PR), Ki-67, p53, bcl-2, and human epidermal growth factor receptor 2 (HER2) and subtypes categorized as luminal (ER or PR-positive), triple negative (ER or PR-negative, HER2-negative), and HER2 (ER and PR-negative, HER2 overexpression) were analyzed.Results: Mean K trans was higher in tumors with a high histologic grade than with a low histologic grade (P ¼ 0.007), with a high nuclear grade than with a low nuclear grade (P ¼ 0.002), and with ER negativity than ER positivity (P ¼ 0.056). Mean k ep was higher in tumors with a high histologic grade than with a low histologic grade (P ¼ 0.005), with a high nuclear grade than with a low nuclear grade (P ¼ 0.001), and with ER negativity than with ER positivity (P ¼ 0.043). Mean v e was lower in tumors with a high histologic grade than with a low histologic grade (P ¼ 0.038) and with ER negativity than with ER positivity (P ¼ 0.015). Triple-negative cancers showed a higher mean k ep than the luminal type (P ¼ 0.015).Conclusion: Breast cancers with higher K trans and k ep , or lower v e , had poor prognostic factors and were often of the triple-negative subtype. IN THE PAST DECADE, the role of dynamic contrastenhanced (DCE) breast magnetic resonance imaging (MRI) has expanded beyond the differentiation of benign from malignant masses, preoperative evaluation, and breast cancer screening to an early prediction of the response to neoadjuvant chemotherapy (1,2). There has been an emerging interest in the development of MRI-based biomarkers of the microvascular structure of breast cancers to predict the prognosis and therapeutic response to antiangiogenic treatment. Recently, peripheral rim enhancement on MRI was correlated with a high histologic grade, a negative expression of estrogen receptor, or a high expression of . However, controversy regarding the existence of a correlation between the kinetic parameters on DCE-MRI and prognostic factors remains. A small number of studies have reported no correlation between the enhancement ratio or time-signal intensity curve types and prognostic factors (7,8). Another study reported that the washout curve type was an independent predictor of positive Ki-67 expression (6). These studies have mainly reported the correlation between semiquantitative parameters including kinetic curve type and prognostic factors. They did not focus on the correlation between K trans (vascular permeability), k ep (the rate constant of contrast agent escape from the e...

Combined use of US elastography and color Doppler US increases both the accuracy in distinguishing benign from malignant masses and the specificity in decision-making for biopsy recommendation at B-mode US.

• Shear-wave elastography is increasingly used to measure the stiffness of breast tumours. • Triple-negative and HER2-positive tumours showed greater stiffness than ER-positive tumours. • All breast cancers classified as BI-RADS 3 on B-mode ultrasound were triple-negative subtype. • Tumour size, histological grade and subtype were independent factors influencing SWE stiffness.

IntroductionAnti-estrogen therapy has been shown to reduce mammographic breast density (MD). We hypothesized that a short-term change in breast density may be a surrogate biomarker predicting response to adjuvant endocrine therapy (ET) in breast cancer.MethodsWe analyzed data for 1,065 estrogen receptor (ER)-positive breast cancer patients who underwent surgery between 2003 and 2006 and received at least 2 years of ET, including tamoxifen and aromatase inhibitors. MD was measured using Cumulus software 4.0 and expressed as a percentage. MD reduction (MDR) was defined as the absolute difference in MD of mammograms taken preoperatively and 8-20 months after the start of ET.ResultsAt a median follow-up of 68.8 months, the overall breast cancer recurrence rate was 7.5% (80/1065). Mean MDR was 5.9% (range, -17.2% to 36.9%). Logistic regression analysis showed that age < 50 years, high preoperative MD, and long interval between start of ET to follow-up mammogram were significantly associated with larger MDR (p < 0.05). In a survival analysis, tumor size, lymph node positivity, high Ki-67 (≥ 10%), and low MDR were independent factors significantly associated with recurrence-free survival (p < 0.05). Compared with the group showing the greatest MDR (≥ 10%), the hazard ratios for MDRs of 5-10%, 0-5%, and < 0% were 1.33, 1.92, and 2.26, respectively.ConclusionsMD change during short-term use of adjuvant ET was a significant predictor of long-term recurrence in women with ER-positive breast cancer. Effective treatment strategies are urgently needed in patients with low MDR despite about 1 year of ET.

Objective. The purpose of this study was to evaluate the diagnostic potential of the sonoelastographic strain index for differentiation of nonpalpable breast masses. Methods. Ninety-nine nonpalpable breast masses (79 benign and 20 malignant) in 94 women (mean age, 45 years; range, 21-68 years) who had been scheduled for a sonographically guided core biopsy were examined with B-mode sonography and sonoelastography. Radiologists who had performed the biopsies analyzed the B-mode sonograms and provided American College of Radiology Breast Imaging Reporting and Data System categories. The strain index (fat to lesion strain ratio) was calculated by dividing the strain value of the subcutaneous fat by that of the mass. The histologic result from the sonographically guided core biopsy was used as a reference standard. The diagnostic performance of the strain index and that of B-mode sonography were compared by receiver operating characteristic (ROC) curve analysis. Results. The mean strain index values ± SD were 6.57 ± 6.62 (range, 1.29-28.69) in malignant masses and 2.63 ± 4.57 (range, 0.54-38.76) in benign masses (P = .019). The area under the ROC curve values were 0.835 (95% confidence interval [CI], 0.747-0.902) for B-mode sonography and 0.879 (95% CI, 0.798-0.936) for the strain index (P = .490). The sensitivity, specificity, positive predictive value, and negative predictive value were 95% (19 of 20), 75% (59 of 79), 48% (19 of 39), and 98% (59 of 60), respectively, when a best cutoff point of 2.24 was used. Conclusions. The strain index based on the fat to lesion strain ratio has diagnostic performance comparable with that of B-mode sonography for differentiation of benign and malignant breast masses.