Multiparametric hemodynamic analyses for carotid artery flow using ultrafast ultrasound flow imaging without a contrast agent*

Non-invasively obtaining hemodynamic information on the carotid artery is a significant challenge for medical imaging techniques due to their spatial and temporal limitation. The plane-wave imaging enabled high-precision characterization of complex blood flows obtained at a very high frame rate (>1000 fps). However, quantitative hemodynamic analyses in the carotid artery have not been shown yet. This study provides ultrafast and high-resolved ultrasound flow imaging for a human carotid artery without a contrast agent and quantitative hemodynamic analyses. The plane-wave imaging sequences of the carotid artery were obtained from healthy volunteers by a Vantage system and a customized linear ultrasonic probe at a 1 kHz frame rate. A spatio-temporal singular-value-decomposition filtered blood flow images were processed using the particle image velocimetry. The given flow velocity field estimated the hemodynamic indexes. During the peak systolic phase, reversed flow and vortices were observed in the carotid bulb due to its dilated vascular structure. The presence of a low WSS region mirrored that of the recirculating flow region. These results suggest that the proposed technique shows the good delineation of fast and complex carotid artery flow without a contrast agent.