Mammography immediately after stereotaxic breast biopsy: is it necessary?

The purpose of this study was to determine whether mammography immediately after stereotaxic core breast biopsy should be performed routinely to diagnose hematoma, to confirm the sampling site, and to establish a new baseline for future mammograms.

Stereotaxic core biopsies of 113 mammographically indeterminate or suspicious lesions were performed by use of a dedicated stereotaxic table with digital imaging, a 14-gauge needle, and an automated gun. The indication for biopsy was a mass with or without calcifications in 59 cases (52%) and calcifications without a mass in 54 cases (48%). The number of core biopsies per case ranged from one to 16 (mean = six). Craniocaudal and mediolateral oblique mammograms of the sampled breast were obtained immediately after the biopsies and were compared with prebiopsy mammograms. In cases with microcalcifications, the mammograms also were compared with specimen radiographs.

Mammograms obtained immediately after the procedure showed changes related to the biopsy in 86 cases (76%). These findings included decreased lesion size in 11 (10%), air at the biopsy site in 47 (42%), and hematoma, manifested as poorly defined increased density at the biopsy site, in 58 (51%). One hematoma was clinically significant, but the remaining 57 were clinically occult. When core biopsies were performed for calcifications, the postprocedural mammograms showed a decrease in the number of calcifications in 26 (48%) of 54 cases, but specimen radiographs showed calcium in 50 (93%) of 54 cases. Four lesions (three masses and one cluster of microcalcifications) disappeared after biopsy. In three cases, hematomas obscured residual calcifications at the biopsy site.

Mammography immediately after core biopsy is not necessary for the diagnosis of procedure-related hematoma and is inferior to specimen radiography for verifying that calcifications have been sampled. Postprocedural mammograms also may be suboptimal for the establishment of a new baseline because of the frequent finding of hematoma.