Two-dimensional blood flow vector obtained with high frame rate acquisition of dual-angle Doppler signal

Quantitative measurement of flow in blood vessels is important to assess cardiovascular dynamics. The objective of the present study is to obtain two-dimensional (2D) blood flow vector in some carotid artery models and to validate the method in comparison with particle image velocimetry (PIV). Plane wave ultrasound with the repetition rate of 14 kHz was transmitted and received by a 7.5 MHz linear array transducer and a programmable ultrasound data acquisition system. Compound B-mode images and dual-angle Doppler data with the transmission angle of -10° and + 10° were obtained. 2D flow vector at arbitrary point was calculated by two velocity components along with each angle. Steady and pulsatile flow in normal and stenosed carotid artery models were simultaneously observed by the proposed method and PIV. 2D velocity vectors were successfully obtained in each flow states and the average error was approximately 5% in comparison with PIV in the carotid artery model. Steady flow in the distal stenosis model showed that the blood flow was influenced by vascular resistance while pulsatile flow seemed to push the blood to the high resistance portion. 2D blood flow obtained with dual-angle Doppler signal may provide important information in understanding cardiovascular dynamics.