Breast MRI as a Problem-solving Study in the Evaluation of BI-RADS Categories 3 and 4 Microcalcifications: Is it Worth Performing?

RATIONALE AND OBJECTIVES

We aimed to investigate the utility of problem-solving breast magnetic resonance imaging (MRI) for mammographic Breast Imaging Reporting and Data System (BI-RADS) categories 3 and 4 microcalcifications.

MATERIALS AND METHODS

Between January 1, 2010 and December 31, 2011, 138 women with 146 areas of categories 3 and 4 microcalcifications without sonographic correlates underwent breast MRI and had a stereotactic core biopsy using an 11-gauge needle or follow-up at least for 24 months. Positive predictive value (PPV), negative predictive value, sensitivity, and specificity were calculated on the basis of BI-RADS category, with categories 1-3 being considered benign and categories 4 and 5 being considered malignant.

RESULTS

Twenty-four cases (16.4%) were malignant (18 ductal carcinoma in situ, 6 invasive). MRI increased PPV and specificity from 43% to 68% and from 80% to 93% (P = .054 and .005) compared to mammography. Within 102 category 3 microcalcifications, 5 carcinomas were assessed correctly as category 4 by MRI. Within 44 category 4 microcalcifications, a correct diagnosis was made by MRI in 77% (34 of 44) as opposed to 43% (19 of 44) by mammography, and 80% (20 of 25) of unnecessary biopsies could have been avoided. Within the 24 carcinomas, 5 were negative at MRI. MRI-negative carcinomas have a significantly higher possibility of being low grade (ductal carcinoma in situ or invasive) (P = .0362).

CONCLUSIONS

Breast MRI has the potential to improve the diagnosis of category 3 or 4 microcalcifications and could alter indications for biopsy. Breast MRI could help predict the presence or absence of higher-grade carcinoma for category 3 or 4 microcalcifications.