Addition of shear-wave elastography during second-look MR imaging-directed breast US: effect on lesion detection and biopsy targeting.

Abstract

To determine if adding shear-wave elastography (SWE) to second-look ultrasonography (US) after breast dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging helps find or target lesions seen on DCE MR images for US-guided biopsy. This HIPAA-compliant prospective study was approved by the institutional review board, and written informed consent was obtained from patients. From May 2011 to July 2012, 73 women with 96 Breast Imaging Reporting and Data System (BI-RADS) category 4 or 5 lesions after DCE MR imaging prospectively consented to undergo SWE during second-look US. If a lesion was not confidently seen with B-mode US, SWE during real-time scanning was performed to determine if SWE helped find or target lesions for US biopsy. A qualitative SWE six-point color scale was used to record the maximum elasticity in and around lesions. All lesions underwent US or DCE MR imaging-guided core biopsy. Median participant age was 52 years (range, 21-81 years). In 72 patients who underwent DCE MR imaging, 96 BI-RADS category 4 or 5 lesions were detected in 81 breasts. There were 29 (30%) malignancies (one malignancy was of nonbreast origin), 14 (15%) high-risk lesions, and 53 (55%) benign lesions. US revealed 22 cancers, and seven cancers were detected only with MR imaging. Real-time SWE helped find one lesion and target four lesions that were incompletely assessed with gray-scale US. These five lesions that were localized or targeted for biopsy were invasive cancers, representing 23% of the 22 malignancies detected with US. Real-time SWE added to second-look US after DCE MR imaging increased the detection rate of cancers and helped target cancers for US-guided biopsy.