Contrast Enhancement for Ring-Echo Image using Temporal Dynamic Bandpass Filter

A Ring-Echo ultrasound imaging system is a commercial ultrasound computed tomography system specialized in female breast imaging. The conventional practice for processing the received raw ultrasound signal before reconstructing the B-mode echo image involves passing it through a bandpass filter with a fixed passband, usually aligned with the specific bandwidth of the transmitted pulse. However, we found that the contrast of the echo image is insufficient for breast cancer detection. In this paper, we propose a temporal dynamic bandpass filter that utilizes the frequency-down-shift phenomenon in ultrasound imaging to enhance the contrast of the echo image. We applied the proposed method to clinical data to evaluate its performance. Compared with images passed through a fixed bandpass filter, those reconstructed after going through a dynamic bandpass filter exhibit a higher contrast. Since contrast is a key factor in breast cancer detection from the echo image, the proposed method has the potential to make the Ring-Echo system more efficient.