High Sensitivity Liver Vasculature Visualization Using a Real-Time Coherent Flow Power Doppler (CFPD) Imaging System: A Pilot Clinical Study

Abstract

Power Doppler (PD) imaging is a widely used technique for flow detection and vessel visualization in clinics. Despite its wide use, its capability is limited by multiple noise sources, including thermal noise, clutter, and tissue motion. These noise sources lead to deterioration of detection sensitivity to small vessels and slow flow, and a trade-off between acquisition time and PD image signal-to-noise ratio (SNR), particularly in deep body vessel detection among patients with high body-mass-indices (BMI). To improve the sensitivity of slow flow and small vessel detection, and alleviate the trade-off between acquisition time and image SNR, we have proposed the coherent flow power Doppler (CFPD) imaging technique, and shown its performance in flow phantom and porcine models. Here, we report on a pilot clinical study of CFPD on 15 healthy human volunteers to evaluate the clinical feasibility of CFPD in liver vasculature detection and visualization. For the study, we built a real-time CFPD (rtCFPD) imaging system based on a Verasonics Vantage 256 scanner. The real-time processing performed by a GPU-based software beamformer and Doppler processing software. Using the rtCFPD imaging system, the liver Doppler data of 15 healthy volunteers were acquired. PD and CFPD images were produced. The SNR of the images were measured to provide a quantitative comparison of image quality. CFPD images provide an improvement of 8.6 dB in SNR compared to PD produced with the same data. Examples are provided to show that the improvement in SNR leads to subjective improvement of liver vessel visualization.