Synthesized mammography could change breast screening

Synthesized mammography (SM) alone or with tomosynthesis may eliminate the need for full-field digital mammography (FFDM) in a routine clinical study, according to a study published online Jan. 21 by Radiology.

Currently, FFDM and digital breast tomosynthesis must be used in combination as per FDA requirement. However, concern about increased radiation exposure from using the pair has led to the advent of methods to decrease patient radiation exposure. “One such method to reduce dose is based on the fact that standard 2D mammograms can be reconstructed, or synthetically generated, from the information acquired during the tomosynthesis data acquisition. Radiation exposure to the patient could potentially be reduced by approximately 40%-50% if it can be demonstrated that radiologists’ interpretations are comparable by using 2D SM versus interpretations rendered from FFDM,” wrote the study’s lead author, Margarita L. Zuley, MD, of the University of Pittsburgh Medical Center, and colleagues.

The fully crossed, mode-balanced multicase, retrospective observer performance study assessed the interpretation performance and dose of 2D SM when used alone and in combination with digital breast tomosynthesis versus performance when standard FFDM was employed alone and in combination with tomosynthesis. The population was comprised of 36 cases of biopsy-proven cancer, 35 cases of biopsy-proven benign lesions, and 52 normal or benign cases with negative one year follow-up results.

Once the overall accuracy of the breast-based assessment of 246 breasts in 123 patients by eight radiologists with two sequential reading modes was completed, results revealed that the reader-averaged area under the curve (AUC) for SM was 0.894 and 0.889 for FFDM. The AUC for SM plus tomosynthesis was 0.916 and 0.939 for FFDM plus tomosynthesis.

Five readers performed better with SM alone than FFDM alone. All eight readers performed marginally better with FFDM plus tomosynthesis, yet the minimal differences did not produce any substantial differences in the mean AUCs. The researchers found similar findings by using a nonparametric analysis of forced Breast Imaging Reporting and Data System ratings.

“Both of the combined mammogram and tomosynthesis modalities used here had performance that was better than that using traditional FFDM alone, and the performance difference between the two corresponding 2D or combination imaging approaches is small, even with a stress test,” wrote Zuley and colleagues. “Hence, we believe that the FDA-approved synthetic 2D images should be considered acceptable and adequate for routine clinical practice. This approach will substantially reduce the radiation exposure to women undergoing imaging with this combined procedure. This is of particular importance in screening, where most women (>990 of 1000) do not have cancer in any one examination cycle.”