New elastographic classification of breast lesions during and after compression.

Abstract

PURPOSE: Proposal for the classification of breast masses through ultrasound elastography in order to differentiate benign and malignant lesions with histological correlation. MATERIALS AND METHODS: 188 patients enrolled for percutaneous biopsy of 228 breast lesions. Elastography was performed and interpreted according to criteria created by the authors, with scores varying from 1 to 4 based on elasticity of images obtained upon release of compression. These results were compared with the histological results; elasticity scores of 1 and 2 were considered benign, a score of 3 as probably benign, and 4 as suspicious for malignancy. Positive predictive value, specificity, and diagnostic accuracy have been calculated. The results were evaluated using Fisher's exact test and the analysis of the receiver operating characteristic (ROC) curve to determine the association with the histological results, and diagnostic accuracy of the proposed classification. RESULTS: The positive predictive value, specificity, and diagnostic accuracy of the scores were 76.5%, 95.9%, and 94.7%, respectively. Of 228 lesions tested, 26 tests yielded true positive results; 8 yielded false positive results; 190 true negative results; and 4 false negative results. There was association with the histological results by the Fisher method (P < 0.05) and an excellent area below the ROC curve of 0.954 (confidence range of 95%, 0.925-0.982). CONCLUSION: The classification by elastography proposed by the authors can be used as an important tool combined with ultrasonographic studies for differentiating benign and malignant lesions of the breast.