Background Parenchymal Enhancement on Baseline Screening Breast MRI: Impact on Biopsy Rate and Short-Interval Follow-Up

Background Parenchymal Enhancement on Baseline Screening Breast MRI: Impact on Biopsy Rate and Short-Interval Follow-Up
Niamh M. Hambly, Laura Liberman, D. David Dershaw, Sandra Brennan, and Elizabeth A. Morris
AJR 2011; 196:218-224

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Of the 250 MRI examinations, 24.8% showed minimal enhancement; 34%, mild; 24%, moderate; and 17.2%, marked enhancement. Women with minimal enhancement had a significantly higher number of BI-RADS categories 1 and 2 examinations (64.5%) than women with mild (38.8%), moderate (40%), or marked (25.6%) enhancement. The BI-RADS category 3 rate was 43.6% overall and was significantly lower for women with minimal enhancement (27.4% vs 47.1% for women with mild, 45.0% for women with moderate, and 58.1% for women with marked enhancement). At follow-up, 86.2% of the BI-RADS 3 lesions were converted to BI-RADS category 1 or 2 and 13.8% were converted to BI-RADS 4, with a malignancy rate of 0.9% for lesions undergoing short-interval follow-up. There was no significant difference in biopsy rate or cancer detection rate among enhancement categories.

Mild, moderate, and marked background parenchymal enhancement is associated with a significantly lower rate of BI-RADS categories 1 and 2 assessments and a significantly higher rate of BI-RADS category 3 assessments than minimal enhancement. There was no significant difference in biopsy rate or cancer detection rate among the enhancement categories.