Marker clip placement following directional, vacuum-assisted breast biopsy.

The purpose of this study was to evaluate the accuracy of marker clip placement after 11-gauge directional, vacuum-assisted breast biopsies. During a 9-month period, 150 stereotactic breast biopsies were performed using a directional, vacuum-assisted device and an 11-gauge probe. In 114 cases, a marker clip was deployed at the biopsy site using the through-probe method. In 94 cases, stereotactic coordinates of the clip were obtained and were available for retrospective review. Comparing the coordinates of the lesion with those of the clip, placement errors were calculated. Overall, clip placement was within 5 mm of the lesion in 81 per cent of cases, within 5-10 mm of the lesion in 17 per cent of cases, and >10 mm from the lesion in 2 per cent of cases. Mean total placement error was 4.5 mm. The mean z axis error was 3.2 mm, compared with 0.88 and 2.0 mm for the x and y axes, respectively. Marker clip placement after vacuum-assisted biopsy is an accurate method of localizing the biopsy site should subsequent surgery be required.