Lateral blood velocity measurement in the carotid artery via speckle tracking
A method for measurement of lateral blood velocity in the carotid artery is presented. Conventional Doppler methods are not capable of measuring lateral velocities since they quantify only the axial component of blood flow. 2D Speckle Tracking methods measure both axial and lateral velocity components, and recent advances in Speckle Tracking enhance its ability to calculate lateral flow velocities in vivo. Specifically, adaptive wall filtering and the implementation of nine disparate transmit beams, each with 2 parallel receive beams, are presented with application to imaging with a Siemens Elegra scanner. Phantom measurements verify the calibration and performance of the data acquisition system and flow tracking algorithm. The methods are demonstrated for flow in the common carotid arteries of five volunteers; velocity magnitude and angle profiles from the nine transmit locations are shown. Velocities computed with Speckle Tracking are highest in the center of the artery and diminish to low velocities near the vessel walls, with velocity magnitudes consistent with physiological expectations. These results demonstrate that it is possible to measure both axial and lateral flow clinically. Comparison is made to Doppler measurements utilizing the same raw radio-frequency data.
