Phantom study of flow speed measurement using ultrafast ultrasound plane wave imaging

Abstract

Color flow imaging is an ultrasound imaging technique widely used to image the blood movement through arteries and veins. Quantification of velocity is urgently demanding. The objective of this study is to use ultrafast plane wave imaging to measure the flow in speed in vitro. For the flow phantom, the diagonal vessel (2-mm inner diameter at 40° angle) was studied with injection of blood mimic fluid via syringe pump at various volume rates (15, 20, 25, and 30 ml/min). Verasonics Vantage system (Verasonics Inc., Kirkland, WA, USA) and a linear array transducer L11-4v (Verasonics Inc., Kirkland, WA, USA) were used for ultrasound acquisition, a 8-angle (−7° to 7°) plane wave compounding with effective pulse-repetition frequency (PRF) of 1000 Hz was used (central frequency = 6.42 MHz, number of transmit cycles = 4). A total of 600 ensembles were acquired. The frame rate was 1000/s.[XZ1] [BZ2] The ultrasound in-phase quadrature data size was 195 × 156 × 600 (axial x lateral x temporal) with data type of complex double. Singular value decomposition (SVD)-based ultrasound blood flow clutter filters was used for ultrafast plane wave imaging.[XZ3] [BZ4] Randomized SVD was utilized to filter noise and tissue motion. Power Doppler image was generated. The color flow images were generated by using the 2-D autocorrelation method. Results showed that color flow measurement can quantitatively evaluate the flow speed in the tube of the flow phantom.