Stereotactic core biopsy of breast microcalcifications: Comparison of filmversus digital mammography, both using an add-on unit

OBJECTIVE. The goal of this study was to assess the accuracy of an add-on s tereotactic unit for core biopsy of indeterminate breast microcalcification s and to compare digital with conventional stereotactic guidance. MATERIALS AND METHODS. We conducted a retrospective review of 232 lesions w ith indeterminate microcalcifications in 218 women who underwent stereotact ically guided breast biopsies. All biopsies were performed using a standard mammography machine with an add-on unit, 121 with conventional and 111 wit h digital stereotactic guidance. Successful sampling of the lesion was dete rmined by the detection of microcalcifications on specimen radiography or a t pathology. RESULTS. Using the add-on unit, 219 (94.4%) of the 232 targeted lesions wer e successfully sampled. The size, location, number of cores per lesion, and histology of the lesions were not different between the conventional and d igital stereotactic biopsy groups (p > 0.1). Indeterminate microcalcificati ons were missed on biopsy in nine (7.4%) of 121 cases using conventional ra diography and in only four (3.6%) of 111 cases using digital imaging. Digit al stereotactic guidance allowed sampling of lesions with fewer calcificati ons per square centimeter (p < 0.001). CONCLUSION. Sampling of indeterminate microcalcifications using a standard mammography machine and an add-on unit has a high accuracy, similar to rate s reported for dedicated prone biopsy tables. An add-on unit offers the adv antage of considerable cost and space savings. Relative to conventional rad iography, digital stereotactic guidance allows lesions with fewer calcifica tions to be sampled and achieves a greater biopsy success rate. Immediate d igital images in the biopsy room also permit rapid adjustment of alignment and minimize patient movement.