Sonographic differentiation of invasive and intraductal carcinomas of the breast

The purpose of this study is to evaluate the diagnostic ability of ultrasound and define the sonographic features of symptomatic intraductal and invasive breast carcinoma. To achieve this the ultrasound features of 488 invasive carcinomas and 65 non-screening detected intraductal carcinomas were compared retrospectively. The features included size, AP/W (anteroposterior diameter/width) ratio, shape, margin, internal echogenicity, internal echotexture, posterior acoustic transmission, bilateral edge shadowing sign and calcifications. The sensitivity and specificity of the detection of calcifications by ultrasound in comparison with mammography were also studied. The accuracy of ultrasound diagnosis is 92.0% for invasive carcinoma of breast and 84.8% for intraductal carcinoma. Differentiation of ultrasound features of intraductal and invasive carcinoma can be based on the internal hypoechogenicity, loss of bilateral edge shadowing, posterior acoustic transmission, irregular shape and non-uniform internal echotexture with odds ratio of 0.3, 0.3, 0.4, 0.5 and 0.5, respectively. Internal echogenicity was the only significant differentiating factor on multiple logistic regression analysis. Non-comedo type ductal carcinoma in situ can be differentiated from comedo type by irregular shape with odds ratio of 0.3. The sensitivity, specificity and accuracy rate for the detection of calcifications in invasive carcinomas by ultrasound were 65.1%, 61.9% and 63.2%; in comedo type intraductal carcinoma 62.5%, 66.7% and 63.6%, and in non-comedo type intraductal carcinoma 30.0%, 86.7% and 64.0%, respectively. The ultrasound appearance of non-screening detected intraductal carcinoma is relatively isoechoic in comparison with invasive carcinoma. More than 60% of microcalcifications in comedo type intraductal carcinoma can be accurately demonstrated by ultrasound. However, the role of ultrasound in detecting symptomatic intraductal carcinoma warrants further study.