Differential Diagnosis of Breast Category 3 and 4 Nodules Through BI-RADS Classification in Conjunction with Shear Wave Elastography

Ultrasound (US) has become one of the important imaging methods for differentiating benign from malignant breast lesions. In 2013, the American College of Radiology published the fifth edition of the Breast Imaging-Reporting and Data System (BI-RADS). BI-RADS is a guide with recommendations for the standardization of breast imaging (US, mammography and magnetic resonance imaging) reports and for the auditing of centers employing such methods. Its objective is to standardize the nomenclature used in the reports. However, current US examinations are neither adequately sensitive nor sufficiently specific enough. The average Young's modulus was measured through shear wave elastography (SWE) to evaluate the diagnostic value of the BI-RADS classification in conjunction with SWE in differentiating BI-RADS 3 and 4 nodules. A total of 100 consecutive women with 126 breast lesions, including 65 benign and 61 malignant lesions, were included. The average Young's modulus of breast nodules and peri-nodule tissue (Emean1 and Emean2) was also determined through SWE. A receiver operating characteristic curve was drawn on the basis of pathologic results. The highest cut-off values were C1 and C2. At Emean1 > C1 or Emean2 > C2, BI-RADS 3 was increased to 4a and BI-RADS 4a was increased to 4b. At Emean1 ≤ C1 and Emean2 ≤ C2, BI-RADS 4b was decreased to 4a. Other BI-RADS classifications remained unchanged. BI-RADS 3 and 4a were considered benign. BI-RADS 4b and 4c were malignant. The area under the curve, sensitivity and specificity of the BI-RADS classification in conjunction with SWE were 0.952, 93.4% and 95.4%, respectively. The area under the curve, sensitivity and specificity of the original BI-RADS classification were 0.883, 82.0% and 87.7%, respectively. Differences were statistically significant (p = 0.028, Z-test). The diagnostic sensitivity and specificity were increased effectively. As a new method, BI-RADS classification in conjunction with SWE that combines the average Young's modulus yields a high value in terms of the differential diagnosis of breast nodules.