Immediate Migration of Biopsy Clip Markers After Upright Digital Breast Tomosynthesis-Guided Vacuum-Assisted Core Biopsy

Rationale and Objectives: The goal of this retrospective study was to evaluate the rate of immediate post-biopsy clip migration on an upright digital tomosynthesis-guided vacuum-assisted core biopsy unit and determine if any factors were associated with immediate clip migration. Materials and Methods: We performed a retrospective review of patients who had undergone a biopsy performed at one facility from November 1, 2014 to September 30, 2016. Post-biopsy mammograms were reviewed to assess immediate clip position relative to the targeted lesion. The effects of age, lesion type, breast density, biopsy approach, number of samples, size of the biopsy chamber, and clip type on clip migration were examined using logistic regression analysis. Results: One hundred ninety-seven biopsies were performed on 188 patients for calcifications (n = 159), architectural distortions (n = 29), masses (n = 5), and asymmetries (n = 4). The clip migration rate was 38% as defined as greater than 0.5 cm from the site of the biopsied lesion. The only independently predictive variable of clip migration was breast density in a numeric covariate in the logistic regression model, as migration was more likely with decreased breast density. The estimated odds ratio for a single level increase in BI-RADS breast density was 0.60 (95% confidence interval: 0.40, 0.91) with p = 0.018. Conclusion: Immediate clip migration following biopsy was more likely with decreased breast density. Radiologists should be aware of immediate clip migration as correct clip location guides preoperative localization and allows the biopsy site to be monitored for changes on future mammograms.