Breast 3 T-MR imaging: indication for stereotactic vacuum-assisted breast biopsy

Abstract

Purpose: The purpose of this study was to assess indications for stereotactic vacuum-assisted breast biopsy (SVAB) evaluated by breast 3 T-magnetic resonance (3 T-MR) imaging in patients showing suspicious microcalcifications on mammography and negative ultrasound (US) findings.

Methods and materials: Fifty-five patients with 55 breast lesions showing suspicious microcalcifications on mammography and negative US findings underwent preoperative 3 T-MR examination including dynamic MR imaging. All patients underwent SVAB within 1 month of MR imaging. The pathological diagnosis of each breast lesion was made by examining tissues obtained by SVAB or radical/partial mastectomy. 3 T-MR imaging findings were evaluated by using the American College of Radiology Breast Imaging Reporting and Data System Atlas (BI-RADS-MRI) and then were correlated with the histopathological findings. When BI-RADS 4 and 5 MR imaging lesions were assumed to be malignant, the usefulness of 3 T-MR imaging was evaluated for diagnosis of impalpable breast lesions by SVAB among lesions with microcalcification detected by mammography and negative US findings.

Results: There were 21 malignant lesions, including 5 invasive ductal carcinomas, 16 lesions of ductal carcinoma in situ (DCIS). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 3 T-MR imaging for deciding the indications for SVAB was 90.5%, 97.1%, 95.0%, 94.3%, and 94.5%, respectively. The one-false negative case was a DCIS with small enhancing lesions (0.5 mm). The one false-positive case was ductal adenoma with a linear ductal pattern of enhancement.

Conclusions: 3 T-MR imaging may be useful for deciding the indications for SVAB in patients who have breast lesions with microcalcification that are impalpable and are detected by mammography and negative US findings. However, our findings should be considered preliminary and further prospective investigation is required.

Keywords: 3 T-MR imaging; Breast cancer; Mammography; Microcalcifications; Stereotactic vacuum-assisted breast biopsy.

Figure 1

Ductal carcinoma in situ (DCIS) with calcifications in the right breast of a 50-year-old woman. (a) Right craniocaudal mammogram with spot compression magnification demonstrates non mass-like segmental amorphous microcalcifications classified as BI-RADS category 4 (circle). (b) Axial contrast-enhanced T1-weighted fat-suppressed MR images of bilateral breasts is showing non mass-like segmental distribution and clustered ring enhancement in the area of microcalcifications (arrow). This finding was classified as BI-RADS category 5.

Figure 2

Secretory form calcifications in the left breast of a 62-year-old woman. (a) Left mediolateral mammogram with spot compression magnification demonstrates non mass-like clustered amorphous microcalcifications classified as BI-RADS category 4 (circle). (b) Axial contrast-enhanced T1-weighted fat-suppressed MR images of bilateral breasts is showing non mass-like focus enhancement in the area of microcalcifications (arrow). This finding was classified as BI-RADS category 3.