1Breast Surgical Oncology, Showa University Koto Toyosu Hospital, 2Breast Surgical Oncology, Showa University Hospital
It has been pointed out that Shear-wave elastography （SWE） is possible to show a diagnostic imaging with high reproducibility regardless of the operator’s skill, because SWE can make an image without tissue compression. Tozaki et al. reported that the visual pattern classification could be classified into four categories: when they regarded lesions displayed （Pattern 1） and vertical stripe pattern artifacts （Pattern 2） as benign lesions, and a localized colored area at the margin of the lesion （Pattern 3） and heterogeneously colored areas in the interior of the lesion （Pattern 4） as malignant lesions. 【PURPOSE】 We performed a prospective study of SWE in three institutions to evaluate the diagnostic performance of SWE in differentiating malignant from benign breast lesions. 【MATERIAL AND METHODS】 Breast tumor was assessed by the quantitative elasticity value and the visual pattern classification, 416 lesions （175 benign, 241 malignant） were finally analyzed. 【RESULTS】 Elasticity value （kPa） of benign and malignant tumor were 59.0±54.4, 135.8±83.2 respectively. The cut-off value was 84.0, the area under the receiver operating characteristic curve of SWE was 0.78. All visual color map of SWE were assessed by two separate observer of different institution, the agreement for the Pattern classification was 313cases with κ of 0.63. There were 113 Pattern 1 lesions （83 benign, 30 malignant）, 42 Pattern 2 lesions （32 benign, 10 malignant）, 72 Pattern 3 lesions （6 benign, 66 malignant）, and 86 Pattern 4 lesions （17 benign, 69 malignant）. 【CONCLUSION】 The quantitative elasticity value and the visual pattern classification seems to be a useful method for differentiating breast lesions. Futher more, there are some report that breast cancer histological types have similar SWE characteristics. It is necessary to assess a therapeutic effect and prognosis on the basis of image data acquired by SWE before and after treatment.