Improved microcalcification visualization using dual-energy digital mammography

Abstract

Background

Dual-energy digital mammography (DEDM), involving a combination of high-energy (HE) and low-energy (LE) images, has been investigated as offering a potential improvement in microcalcification detection obscured by overlapping tissue structures.

Purpose

To explore the possibility to improve detection of microcalcifications using the DEDM technique.

Material and Methods

Three DEDM protocols were performed by adjusting the effective tube current time product (mAs) of LE image at the same (100%), one half (50%), and one-quarter (25%) of that used in HE image acquisition, named DEDM_100%, DEDM_50%, and DEDM_25%, respectively. A single-energy digital mammography (SEDM) method was also used as a control. A total of 525 regions of interest (ROIs) were used to compare the performance of the DEDM to that of SEDM using free-response receiver-operating characteristic (FROC) and areas under the FROC curve (A_z).

Results

All DEDM protocols ranked significantly higher than the SEDM method (P < 0.001). The true-positive fraction was 0.90 for an average of 0.017–0.042 false-positive per image using the DEDM_100%, 0.017–0.114 using the DEDM_50%, 0.021–0.148 using the DEDM_25%, and 0.134–0.422 using the SEDM. The estimated A_z values were 0.915–0.940, 0.867–0.935, 0.824–0.930, and 0.567–0.673, respectively.

Conclusion

The DEDM_50% protocol provided a trade-off benefit between accurate microcalcification detectability and radiation dose for any tissue density. Therefore, the DEDM_50% has the potential to minimize excess radiation dose without a negative impact on image quality which could improve earlier diagnosis of breast cancer.