Diagnostic Performance of Superb Microvascular Imaging (SMI) Combined with Shear-Wave Elastography in Evaluating...

BACKGROUND This study explored the diagnostic value of a combined modality of Superb Microvascular Imaging (SMI) and shear-wave elastography in differentiating malignant and benign breast lesions. MATERIAL AND METHODS A total of 121 patients with 123 breast lesions enrolled underwent conventional ultrasound exam (US), Color Doppler Flow Imaging (CDFI), SMI examination, and Virtual Touch Tissue Quantification (VTQ) measurement between May 2016 and October 2017. Vessels were detected by both CDFI and SMI in a quantitative manner. The stiffness of all the breast tissues was evaluated by VTQ method. We further assessed the diagnostic performances of CDFI, SMI, VTQ, CDFI+VTQ, and SMI+VTQ. RESULTS Both CDFI and SMI exhibited significant differences between malignant and benign masses (p<0.001) in terms of Adler classification. The mean shear-wave velocity (SWV) of malignant neoplasms was 5.28 m/s, with interquartile range (IQR) 4.01-6.39 m/s (p<0.001). The mean SWV of benign lesions was 2.64 m/s, with IQR 2.30-5.01 m/s (p<0.001). No significant difference was found for the area under the receiver operating characteristic curve (AUC) for CDFI, SMI, and VTQ (c2=2.29, P=0.3715). The sensitivity was the highest on SMI+VTQ (85.42%) and the lowest on CDFI (58.33%). CDFI+VTQ (85.33%) had a slightly higher specificity than SMI+VTQ (84.00%). The accuracy rate of these 2 modalities remained the same (84.55%). CONCLUSIONS Superb Microvascular Imaging yields more detailed vascular information in the bloodstream in benign and malignant breast masses compared with conventional ultrasonography. VTQ provides standardized quantified results in assessing tissue stiffness. The combined modality of SMI+VTQ added to conventional ultrasonography presented a better diagnostic performance in differentiating malignant breast neoplasms.