Role and clinical usefulness of elastography in small breast masses

Rationale and Objectives: The aim of this study was to evaluate and compare the diagnostic performance of elastography, B-mode ultrasound (US), and a combination of elastography and B-mode US for the differentiation of small breast masses. Materials and Methods: A total of 315 breast masses < 1 cm (267 benign, 48 malignant) in 278 patients were examined with B-mode US and elastography. Histopathologic results were used as a reference standard. Two radiologists retrospectively evaluated the B-mode images according to the American College of Radiology Breast Imaging Reporting and Data System and elastographic images according to the elasticity scoring classification system proposed by Itoh et al and the strain ratio. B-mode US and elastography were combined according to the cutoff value. The diagnostic performance of B-mode US, elastography, and the combination of the two modalities was compared using receiver-operating characteristic curve analysis. Results: The mean elasticity score for malignant masses (3.02 ± 1.33) was significantly higher than that for benign masses (1.72 ± 0.78) (P < .001). Areas under the receiver-operating characteristic curves were 0.616 for B-mode US, 0.784 for elasticity score, 0.668 for strain ratio, 0.727 for the combination of B-mode US and elasticity score, and 0.701 for the combination of B-mode US, elasticity score, and strain ratio. The sensitivity, specificity, positive predictive value, and negative predictive value were 93.8%, 51.7%, 25.9%, and 97.9%, respectively, when elasticity score and B-mode US were combined as follows: downgrade of B-mode US assessment category in cases with elasticity scores of 1, no change in cases with scores of 2 or 3, and upgrade in cases with scores of 4 or 5. Conclusion: Elasticity score alone showed the best diagnostic performance, but a combination of B-mode US and elasticity score may have predictive value for the differentiation of benign and malignant lesions <1 cm.