Small calcification depiction in ultrasonography using frequency domain interferometry

Mammography detects small calcifications that accompany breast cancer; however, it is not effective in young women with rich mammary glands. In contrast, the presence of mammary glands has little effect on the imaging performance of ultrasonography (US). In this study, we propose an imaging method based on frequency domain interferometry (FDI) to improve the performance of US in depicting small calcifications. The proposed FDI imaging method selectively depicts small calcifications, because it suppresses the contribution of undesired echoes when their waveforms differ from the waveform of a small calcification echo. To investigate the performance of the proposed method, we applied the method to the raw data obtained with a calcification phantom and a commercial US device (7.5 MHz linear array). The results show that the proposed FDI imaging method has the potential to depict small calcifications of 0.2 mm in diameter that are difficult to distinguish in the conventional B-mode images. Findings from this study indicate that the FDI imaging method has high potential in improving the performance of US in the depiction of small calcifications.