The value of MRI contrast enhancement in biopsy decision of suspicious mammographic microcalcifications: a prospective multicenter study.

OBJECTIVES

To investigate the inclusion of breast MRI in radiological assessment of suspicious, isolated microcalcifications detected with mammography.

METHODS

In this prospective, multicenter study, cases with isolated microcalcifications in screening mammography were examined with dynamic contrast-enhanced MRI (DCE-MRI) before biopsy, and contrast enhancement of the relevant calcification localization was accepted as a positive finding on MRI. Six experienced breast radiologists evaluated the images and performed the biopsies. Imaging findings and histopathological results were recorded. Sensitivity, specificity, NPV, and PPV of breast MRI were calculated and compared with histopathological findings.

RESULTS

Suspicious microcalcifications, which were detected by screening mammograms of 444 women, were evaluated. Of these, 276 (62.2%) were diagnosed as benign and 168 (37.8%) as malignant. Contrast enhancement was present in microcalcification localization in 325 (73.2%) of the cases. DCE-MRI was positive in all 102 invasive carcinomas and in 58 (87.9%) of 66 DCIS cases. MRI resulted in false negatives in eight DCIS cases; one was high grade and the other seven were low-to-medium grade. The false-negative rate of DCE-MRI was 4.76%. The sensitivity, specificity, PPV, and NPV for DCE-MRI for mammography-detected suspicious microcalcifications were 95.2%, 40.2%, 49.2%, and 93.3%, respectively.

CONCLUSIONS

In this study, all invasive cancers and all DCIS except eight cases (12.1%) were detected with DCE-MRI. DCE-MRI can be used in the decision-making algorithm to decrease the number of biopsies in mammography-detected suspicious calcifications, with a tradeoff for overlooking a small number of DCIS cases that are of low-to-medium grade.

KEY POINTS

• All invasive cancer cases and 87.8% of all in situ cancer cases were detected with MRI, showing a low false-negative rate of 4.7%. • Dynamic contrast-enhanced MRI can be used in the decision-making algorithm to decrease the number of biopsies in mammography-detected suspicious calcifications, with a tradeoff for overlooking a small number of DCIS cases that are predominantly low-to-medium grade. • If a decision for biopsy were made based on MRI findings in mammography-detected microcalcifications in this study, biopsy would not be performed to 119 cases (26.8%).