Examples of in vivo blood vector velocity estimation.

In this paper, a case study of in-vivo blood vector velocity images of the carotid artery are presented. The transverse oscillation (TO) method for blood vector velocity estimation has been used to estimate the vector velocities. The carotid arteries of three healthy volunteers are scanned in-vivo at three different positions by experienced sonographers. The scanning regions are: 1) the common carotid artery at 88 degrees beam to flow angle, 2) the common carotid artery and the jugular vein at approximately 90 degrees beam to flow angle and 3) the bifurcation of the carotid artery. The resulting velocity estimates are displayed as vector velocity images, where the velocity vector is superimposed on a B-mode image showing the tissue structures. The volume flow is found for case 1) and when compared with MRI from the literature, a bias of approximately approximately 20% is found. The maximum flow velocity within the carotid artery is found to be 0.8 m/s, which is normal for a healthy person. In case 3), the estimated vector velocities are compared with numerical simulations. Qualitatively similar flow pattern can be seen in both simulations and in the vector velocity images. Furthermore, a vortex is identified in the carotid sinus at the deceleration phase after the peak systole. This vortex is seen in all of the three acquired cardiac cycles.

[1]  J. Jensen,et al.  Estimation of blood velocity vectors using transverse ultrasound beam focusing and cross-correlation , 1999, 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027).

[2]  Jørgen Arendt Jensen,et al.  Experimental ultrasound system for real-time synthetic imaging , 1999, 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027).

[3]  J. Jensen,et al.  Determination of velocity vector angles using the directional cross-correlation method , 2005, IEEE Ultrasonics Symposium, 2005..

[4]  M. E. Anderson,et al.  Spatial quadrature: a novel technique for multi-dimensional velocity estimation , 1997, 1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118).

[5]  D. Evans.  Doppler Ultrasound: Physics Instrumentation and Clinical Applications , 1989 .

[6]  J. A. Jensen,et al.  Transverse flow imaging using synthetic aperture directional beamforming , 2002, 2002 IEEE Ultrasonics Symposium, 2002. Proceedings..

[7]  M. Fox.  Multiple crossed-beam ultrasound Doppler velocimetry , 1978 .

[8]  J. Jensen,et al.  Directional velocity estimation using focusing along the flow direction. I: theory and simulation , 2003, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[9]  J. Jensen,et al.  A new estimator for vector velocity estimation [medical ultrasonics] , 2001, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[10]  J.A. Jensen,et al.  Ultrasound research scanner for real-time synthetic aperture data acquisition , 2005, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[11]  J. Jensen,et al.  Directional velocity estimation using focusing along the flow direction. II: experimental investigation , 2003, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[12]  Jørgen Arendt Jensen,et al.  An in vitro investigation of transverse flow estimation , 2004, SPIE Medical Imaging.

[13]  I. Marshall,et al.  MRI and CFD studies of pulsatile flow in healthy and stenosed carotid bifurcation models. , 2004, Journal of biomechanics.

[14]  K. Beach,et al.  Cross-beam vector Doppler ultrasound for angle-independent velocity measurements. , 2000, Ultrasound in medicine & biology.

[15]  K. Beach,et al.  Vector Doppler: accurate measurement of blood velocity in two dimensions. , 1992, Ultrasound in medicine & biology.

[16]  J. Jensen.  Estimation of Blood Velocities Using Ultrasound: A Signal Processing Approach , 1996 .

[17]  V. Newhouse,et al.  Ultrasound Doppler Probing of Flows Transverse with Respect to Beam Axis , 1987, IEEE Transactions on Biomedical Engineering.

[18]  René M. Botnar,et al.  Hemodynamics in the carotid artery bifurcation: a comparison between numerical simulations and in vitro MRI measurements. , 2000, Journal of biomechanics.

[19]  J. Jensen,et al.  Calculation of pressure fields from arbitrarily shaped, apodized, and excited ultrasound transducers , 1992, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[20]  G. Trahey,et al.  Angle Independent Ultrasonic Detection of Blood Flow , 1987, IEEE Transactions on Biomedical Engineering.

[21]  M. E. Anderson,et al.  A heterodyning demodulation technique for spatial quadrature , 2000, 2000 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.00CH37121).

[22]  J. Goodman.  Introduction to Fourier optics , 1969 .

[23]  K. Boone,et al.  Effect of skin impedance on image quality and variability in electrical impedance tomography: a model study , 1996, Medical and Biological Engineering and Computing.

[24]  J. Arendt,et al.  Experimental investigation of transverse flow estimation using transverse oscillation , 2003, IEEE Symposium on Ultrasonics, 2003.

[25]  M.E. Aderson,et al.  Multi-dimensional velocity estimation with ultrasound using spatial quadrature , 1998, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[26]  J. Jensen,et al.  A new method for estimation of velocity vectors , 1998, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[27]  J. Jensen,et al.  Investigation of transverse oscillation method , 2006, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[28]  Ian Marshall,et al.  Carotid flow rates and flow division at the bifurcation in healthy volunteers. , 2004, Physiological measurement.