Non-invasive Intravascular Pressure Gradient Estimation using Synthetic Aperture Ultrasound

This study presents a new method for noninvasive pressure gradient estimations. It combines a new method for estimating the spatio-temporal acceleration of the flowing blood with the Navier-Stokes equation. The method is based on a double cross-correlation approach, which is hypothesized to generate more precise pressure gradients than previous methods. The acceleration is determined by cross-correlating the correlation functions attained from the velocity estimation. Data are acquired using a 5.2 MHz linear transducer in combination with a Verasonics research scanner. A permuted, pulse inverted, interleaved sequence with four virtual sources evenly distributed on the aperture is used. The performance of the method is tested on experimental data, measured on a bifurcation phantom of the common carotid artery. The pressure drop across nine flow cycles varied from -20 Pa to 40 Pa, with a standard deviation of 15.7%.