Clip placement after an 11-gauge vacuum-assisted stereotactic breast biopsy: correlation between breast thickness and clip movement

Abstract

To retrospectively evaluate the accuracy of clip placement on the basis of measurements obtained on pre- and post-vacuum-assisted 11-gauge stereotactic biopsy mammograms and to analyze the factors that can predict which patients will experience a significant movement of the clip. The pre- and post-vacuum-assisted 11-guage stereotactic biopsy mammographic findings in 204 cases undergoing clip placement were reviewed. The clip-to-lesion distance was measured. The correlations between the clinical-mammographic findings and the likelihood of clip movement were evaluated. Target mammographic lesion types of the 204 cases were characterized as calcification in all but one case, which was a distortion lesion. The clip-to-lesion distance was within 5 mm on both the craniocaudal and mediolateral oblique projections in 119 (58%) cases, within 6-10 mm in 28 (14%), within 11-19 mm in 25 (12%), and was > 20 mm in 32 (16%). The variability of the clip-to-lesion distance was greatest in the plane orthogonal to the compression plane used for stereotactic biopsy. Breast thickness was the only factor that was predictive of a significant movement of the clip, and thin breasts tended to exhibit greater clip movement. Breast thickness may be a useful factor for predicting the degree of clip movement after 11-gauge vacuum-assisted stereotactic biopsy.