TY - GEN

T1 - Blood vector velocity estimation using an autocorrelation approach

T2 - 2005 IEEE Ultrasonics Symposium

AU - Udesen, Jesper

AU - Nielsen, Michael Bachmann

AU - Nielsen, Kristina Rue

AU - Jerisen, Jørgen Arendt

PY - 2005

Y1 - 2005

N2 - In conventional techniques for blood velocity estimation, only the axial component of the velocity vector is found. We have previously shown that it is possible to estimate the 2-D blood velocity vector both in simulations and in flow phantom experiments using a fast and inexpensive method (the transverse oscillation (TO) method) based on an autocorrelation approach. The TO method makes use of a double oscillating pulse-echo field which is created by manipulating the receive apodization function. Two receive beams are beamformed, where the lateral distance between the two beams corresponds to a 90° phase shift in the lateral direction. The TO method works at angles where conventional methods fails to estimate any blood movement, i.e. when the angle between the ultrasound beam and the velocity vector is approximately 90°. In this paper the first in-vivo color flow map (CFM) images are presented using the TO method. A 128 element 5 MHz linear array transducer was used together with the experimental ultrasound scanner RASMUS operating at a sampling frequency of 40 MHz with a pulse repetition frequency of 24 kHz. After sampling the received channel data were beamformed off-line, and a transverse oscillation period of 1 mm was created in the lateral pulse-echo field by manipulating the receive apodization function. Echo-canceling was performed by subtracting a line from the sampled data, where the line was a linear fit to the sampled data. Three different scan areas were selected: 1) The common carotid artery, 2) the common carotid artery and the jugular vein, 3) the bifurcation of the common carotid artery. In all three cases the angle between the ultrasound beams and the blood velocity vector is larger than 60° i.e. the conventional Doppler velocity estimator degrades significantly in terms of standard deviation and bias. The velocity direction and magnitude could be estimated for all cases and it was found that the blood flow is within the values given by the literature.

AB - In conventional techniques for blood velocity estimation, only the axial component of the velocity vector is found. We have previously shown that it is possible to estimate the 2-D blood velocity vector both in simulations and in flow phantom experiments using a fast and inexpensive method (the transverse oscillation (TO) method) based on an autocorrelation approach. The TO method makes use of a double oscillating pulse-echo field which is created by manipulating the receive apodization function. Two receive beams are beamformed, where the lateral distance between the two beams corresponds to a 90° phase shift in the lateral direction. The TO method works at angles where conventional methods fails to estimate any blood movement, i.e. when the angle between the ultrasound beam and the velocity vector is approximately 90°. In this paper the first in-vivo color flow map (CFM) images are presented using the TO method. A 128 element 5 MHz linear array transducer was used together with the experimental ultrasound scanner RASMUS operating at a sampling frequency of 40 MHz with a pulse repetition frequency of 24 kHz. After sampling the received channel data were beamformed off-line, and a transverse oscillation period of 1 mm was created in the lateral pulse-echo field by manipulating the receive apodization function. Echo-canceling was performed by subtracting a line from the sampled data, where the line was a linear fit to the sampled data. Three different scan areas were selected: 1) The common carotid artery, 2) the common carotid artery and the jugular vein, 3) the bifurcation of the common carotid artery. In all three cases the angle between the ultrasound beams and the blood velocity vector is larger than 60° i.e. the conventional Doppler velocity estimator degrades significantly in terms of standard deviation and bias. The velocity direction and magnitude could be estimated for all cases and it was found that the blood flow is within the values given by the literature.

UR - http://www.scopus.com/inward/record.url?scp=33847094978&partnerID=8YFLogxK

U2 - 10.1109/ULTSYM.2005.1602821

DO - 10.1109/ULTSYM.2005.1602821

M3 - Article in proceedings

AN - SCOPUS:33847094978

SN - 0780393821

SN - 9780780393820

T3 - Proceedings - IEEE Ultrasonics Symposium

SP - 162

EP - 165

BT - 2005 IEEE Ultrasonics Symposium

Y2 - 18 September 2005 through 21 September 2005

ER -