A United Spatial-Angular Adaptive Scaling Wiener Postfilter based Beamformer for Improved Ultrafast Power Doppler Imaging

Ultrafast power Doppler imaging (uPDI) using high-frame-rate plane-wave transmission is a new microvascular imaging modality that offers high Doppler sensitivity. However, due to the unfocused transmission of plane waves, the echo signal is subject to interference from noise and clutter, resulting in a low signal-to-noise ratio and poor image quality. This study proposed an adaptive beamformer based on a united spatial-angular adaptive scaling Wiener postfilter to obtain high-quality microvessel images. The signal power and noise power of the Wiener postfilter are estimated by uniting spatial and angular signals, and a united generalized coherence factor is introduced to dynamically adjust the noise power estimation and enhance the robustness of the method. We used in vivo experimental datasets to evaluate the imaging performance of the proposed method. Results show that the proposed method significantly improves the imaging quality of uPDI compared to delay-and-sum (DAS) and coherence factor (CF) beamformers. Overall, the proposed method has the potential to become a reliable microvascular imaging technique.