Characterization of Breast Microcalcifications Using a New Ultrasound Image-Processing Technique

Objectives: To evaluate a new commercial image-processing technique (MicroPure; Toshiba America Medical Systems, Tustin, CA) for detection and characterization of breast microcalcifications in patients undergoing stereotactic or ultrasound-guided biopsies using mammography as the reference standard.

Methods: One hundred female patients, with a total of 104 lesions, scheduled for an image-guided biopsy of an area with breast microcalcifications (identified on a prior mammogram) underwent MicroPure examinations of the breast using an Aplio XG scanner (Toshiba America Medical Systems) with a broad-bandwidth linear array. MicroPure combines nonlinear imaging and speckle suppression to mark suspected calcifications as white spots in a blue overlay image. Four independent and blinded readers (2 radiologists and 2 physicists) analyzed 208 digital clips consisting of dual grayscale ultrasound and MicroPure imaging, counting the number of microcalcifications seen with MicroPure. The observers also assessed the level of suspicion on a qualitative, visual analog, 6-point scale from 0 (no findings) over 1 (benign) to 5 (malignant).

Results: The mean number of microcalcifications ± SD seen was 6.3 ± 3.5, whereas mammography saw 28.9 ± 24.6 (P = .66). When the MicroPure level of suspicion scores were compared with pathologic results using a receiver operating characteristic curve analysis, the areas under the curve ranged from 0.54 to 0.59. Nonetheless, malignant cases were seen to have significantly more microcalcifications than benign cases (mean number of microcalcifications, 6.9 ± 5.1 versus 5.3 ± 3.7; P = .02).

Conclusions: MicroPure can be used to identify areas with breast microcalcifications but cannot effectively characterize such areas. Instead, MicroPure may represent a new imaging method for guiding a biopsy to areas of microcalcifications.