Second-look ultrasonography for MRI-detected suspicious breast lesions in patients with breast cancer

Abstract

Purpose: The purpose of this study is to evaluate the use of second-look ultrasonography (US) for investigating additional suspicious lesions detected on preoperative staging magnetic resonance imaging (MRI) for breast cancer.

Methods: Between September 2008 and August 2010, 1,970 breast MRIs were performed at our medical institution for the evaluation of breast cancer before surgery. Second-look US was recommended for 135 patients with 149 suspicious lesions, following the MRI interpretation, and 108 patients with 121 lesions were included in this study. The detection rate on second-look US, according to the lesion type, diameter, and histopathological outcome, was analyzed.

Results: Of the 121 lesions considered in this study, 97 (80.2%) were diagnosed on MRI as masses and 24 (19.8%) as non-mass-like lesions; 105 lesions (86.8%) were correlated and 16 (13.2%) were not correlated with the findings of second-look US. Of the 105 correlated lesions, 29 (27.6%) were proven to be malignant and 76 (72.4%) were benign. Although a greater number of large malignant lesions were correlated on second-look US than small benign lesions, there was no statistically significant difference according to lesion diameter or type, as seen on MRI or pathology.

Conclusion: We have concluded that second-look US is a useful diagnostic tool for lesions incidentally detected on breast MRI, as in this study, it could identify 86.8% of the MRI-detected breast lesions.

Keywords: Breast; Magnetic resonance imaging; Ultrasonography.

Fig. 1.. A 46-year-old woman with cancer in her left breast.

A. A dynamic contrast-enhanced and subtracted T1-weighted axial image shows the diagnosed cancer in her left breast. B, C. A dynamic contrast-enhanced and subtracted T1-weighted image shows incidental non-mass enhancement in the lower outer quadrant of her right breast in the axial (B) and sagittal (C) planes. D. Second-look ultrasonography (US) detects a corresponding ill-defined irregular hypoechoic lesion (arrows) in her right breast. US-guided core-needle biopsy confirmed invasive ductal carcinoma in her right breast.

Fig. 2.. A 52-year-old woman with cancer in her left breast.

A. A dynamic contrast-enhanced and subtracted T1-weighted axial image shows the diagnosed cancer in her left breast. B. A dynamic contrast-enhanced and subtracted T1-weighted axial image reveals another small enhancing mass (arrowhead) in her left breast. C. Second-look ultrasonography (US) detects a corresponding ovalshaped hypoechoic mass (arrow) in her left breast. US-guided needle localization and excision confirmed a fibroadenoma.

Fig. 3.. A 57-year-old woman with cancer in her left breast.

A. A dynamic contrast-enhanced and subtracted T1-weighted axial image shows a small enhancing mass in her right breast. There were no correlated lesions seen on second-look ultrasonography (US). B. On follow-up magnetic resonance imaging performed 30 months later, a 1.5-cm irregular, enhancing mass (arrow) is detected at the same location in her right breast. C. US shows an oval hypoechoic mass (arrow) with an indistinct margin and confirmed it as invasive ductal carcinoma.