Suppression of in vivo flow artifacts in power Doppler through spatial and angular coherence beamforming

Abstract

Power Doppler imaging is traditionally the flow imaging technique utilized clinically in the task of flow detection. Due to the relatively low pulse repetition frequencies used, power Doppler ensemble sizes are small to allow real-time imaging. The small ensemble size, however, makes power Doppler imaging subject to the so-called flash artifact due to limited stationary clutter filtering capabilities. In addition, with the increasing population of overweight and obese individuals, power Doppler imaging is subject to higher amounts of thermal noise and reverberation artifact that pass through the stationary clutter filters. We present coherence beamforming techniques, applied to in vivo human imaging, to demonstrate their ability to reduce flow artifacts and noise in power Doppler imaging. Using coherence beamforming techniques in Coherent Flow Power Doppler (CFPD), we show that artifacts due to reverberation and thermal noise are reduced, corresponding to an increase of 7.5 dB in signal-to-noise ratio, in liver imaging of overweight and obese individuals. Similarly, we demonstrate coherence beamforming techniques in CFPD to reduce flash artifacts in videos of the neonatal brain.