Clip migration after stereotactic vacuum-assisted breast biopsy with the patient in the decubitus position.

OBJECTIVE

To investigate the factors contributing to clip migration in stereotactic vacuum-assisted biopsy (VAB) of the breast using an upright unit with the patient in the decubitus position.

METHODS

This retrospective study included 176 women with microcalcifications on mammograms undergoing stereotactic VAB with clip marking for analysis. The prebiopsy mammograms, stereotactic VAB images, immediate postbiopsy mammograms, and follow-up mammograms were reviewed. All VAB procedures were performed using an add-on upright unit with the patient in the decubitus position. The clip-to-lesion distance on the orthogonal view (craniocaudal view) on immediate postbiopsy mammography was estimated for each biopsy. Two cutoff points of clip-to-lesion distance of > 1 cm or > 2 cm were set for clip migration. The possible factors for clip migration based on clinical and imaging findings were then analyzed by Fisher's exact test.

RESULTS

When the cutoff for clip migration was set at > 1 cm, thin breast (p = 0.013) and more superficial lesion (lesion closer to the skin along the line perpendicular to the posterior nipple line, p = 0.004) were associated with clip migration. When the cutoff was set at > 2 cm, thin breast (p = 0.019), high specimen number (p = 0.030), and posterior depth (p = 0.021) were associated with clip migration.

CONCLUSIONS

Thin breasts, superficial lesion location, posterior lesion depth, and high specimen number were the factors associated with clip migration.

KEY POINTS

• We reported clip migration after ST VAB using an upright unit with the patient in the decubitus position. • The occurrence of clinically significant clip migration (> 2 cm) in our study was 8.5%, which was within the range of the other reports with the patient undergoing ST VAB in the prone position. • Thin breasts, high specimen number, and more posterior depth were the factors associated with significant clip migration.