Journal article · Ahead of Print article
Fast Plane Wave 2-D Vector Flow Imaging Using Transverse Oscillation and Directional Beamforming
Department of Micro- and Nanotechnology, Technical University of Denmark1
MEMS-AppliedSensors, Department of Micro- and Nanotechnology, Technical University of Denmark2
Department of Electrical Engineering, Technical University of Denmark3
Biomedical Engineering, Department of Electrical Engineering, Technical University of Denmark4
Copenhagen University Hospital Herlev and Gentofte5
Department of Information Technology, Technical University of Denmark6
Center for Fast Ultrasound Imaging, Centers, Technical University of Denmark7
Several techniques can estimate the 2-D velocity vector in ultrasound. Directional beamforming (DB) estimates blood flow velocities with a higher precision and accuracy than transverse oscillation (TO), but at the cost of a high beamforming load when estimating the flow angle. In this paper, it is proposed to use TO to estimate an initial flow angle, which is then refined in a DB step.
Velocity magnitude is estimated along the flow direction using cross-correlation. It is shown that the suggested TO-DB method can improve the performance of velocity estimates compared to TO, and with a beamforming load, which is 4.6 times larger than for TO and seven times smaller than for conventional DB.
Steered plane wave transmissions are employed for high frame rate imaging, and parabolic flow with a peak velocity of 0.5 m/s is simulated in straight vessels at beamto- flow angles from 45 to 90. The TO-DB method estimates the angle with a bias and standard deviation (SD) less than 2, and the SD of the velocity magnitude is less than 2%.
When using only TO, the SD of the angle ranges from 2 to 17 and for the velocity magnitude up to 7%. Bias of the velocity magnitude is within 2% for TO and slightly larger but within 4% for TO-DB. The same trends are observed in measurements although with a slightly larger bias. Simulations of realistic flow in a carotid bifurcation model provide visualization of complex flow, and the spread of velocity magnitude estimates is 7.1 cm/s for TO-DB, while it is 11.8 cm/s using only TO.
However, velocities for TO-DB are underestimated at peak systole as indicated by a regression value of 0.97 for TO and 0.85 for TO-DB. An in vivo scanning of the carotid bifurcation is used for vector velocity estimations using TO and TO-DB. The SD of the velocity profile over a cardiac cycle is 4.2% for TO and 3.2% for TO-DB.
Language: | English |
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Publisher: | IEEE |
Year: | 2017 |
Pages: | 1050-1062 |
ISSN: | 15258955 and 08853010 |
Types: | Journal article and Ahead of Print article |
DOI: | 10.1109/TUFFC.2017.2693403 |
ORCIDs: | 0000-0002-9380-1688 , Jensen, Jonas , Jensen, Jørgen Arendt , Villagómez Hoyos, Carlos Armando and Stuart, Matthias Bo |
2D velocity vector Adult Array signal processing Blood Blood Flow Velocity Carotid Arteries Computer Simulation Correlation Estimation Fourier Analysis Humans Image Processing, Computer-Assisted Imaging Male Models, Cardiovascular Oscillators Phantoms, Imaging TO-DB method Ultrasonic imaging Ultrasonography bifurcation blood flow velocities carotid bifurcation confined flow directional beamforming fast plane wave 2D vector flow imaging flow simulation fluid oscillations haemodynamics magnitude medical ultrasound parabolic flow plane wave imaging transverse oscillation vector flow imaging velocity magnitude