2015, Number 1
<< Back Next >>
Rev Mex Ing Biomed 2015; 36 (1)
Detection of the blood flow direction using heterodyne demodulation for a Doppler ultrasound system and its validation by simulation
García F, Solano J, Fuentes M, Rubio E
Language: Spanish
References: 12
Page: 23-31
PDF size: 1129. Kb.
ABSTRACT
Doppler ultrasound blood flow measurement techniques have been widely used for the diagnosis of vascular
diseases. In particular, some Doppler systems which may be able to determine the blood flow direction use signals
produced by the homodyne quadrature demodulation technique. This approach has a major disadvantage, since it has
to process two channels (phase and quadrature), to equalize them (in amplitude) and to maintain these characteristics
throughout the complete signal bandwidth.
The work presented here, proposes an alternative method to determine the blood flow direction using heterodyne
demodulation. The technique involves shifting the complete band of frequencies (where information of interest lies),
at least a frequency equal to the bandwidth of the Doppler signal. This method simplifies the analog stage for
the acquisition of the Doppler signal since it only needs to process one channel. Results of simulations show the
effectiveness of the approach by determining the blood flow direction efficiently, in the frequency domain. It also
reduces the generation of artifacts, in the band of interest, caused by differences in the phase and quadrature channels.
REFERENCES
D.H. Evans, W.M. McDicken, Doppler Ultrasound Physics, Instrumentation and Signal Processing. Second Edition, John Wiley and Sons Ltd., 2000.
T.R. Nelson, D.H. Pretorius, “The Doppler signal: Where does it come from and what does it mean?,” Am. J. Roent., vol. 151, pp. 439-447, 1988. DOI: 10.2214/ajr.151.3.439.
N. Aydin, “Time varying filtering approach for simulation of ultrasonic Doppler signals,” J. Comp. Sim. & Mod. Med., vol. 1, no. 1, pp. 67-76, 2000.
N. Aydin, Computerized Graft Monitoring. Thesis submitted to the University of Leicester for the degree of Doctor of Philosophy. 1994.
N. Aydin, D.H. Evans, “Quadrature to directional format conversion of Doppler signals using digital methods,” Phys. Meas., vol. 15, pp. 181-199, 1994. DOI: 10.1088/0967-3334/15/2/007.
R. Lyons, “Quadrature signals: Complex, but not complicated,” 2008, www.ieee.li/pdf/essay/quadrature _signals.pdf
United States Bureau of Naval Personnel, Basic Electronics. Dover Publications, 1973.
J.V.L. Hogan, “The heterodyne receiver,” Elec. J., vol. 18, no. 4, pp. 166-119, 1921.
Y. Wang, P.J. Fish, “Arterial Doppler signal simulation by time domain processing,” Eur. J. Ultrasound, vol. 3, no. 1, pp. 71-81, 1996. DOI: 10.1109/IEMBS.1995.579414
J. Solano, M. Vázquez, E. Rubio, I. Sánchez, M. Fuentes, F. García, “Doppler ultrasound signal spectral response in the measurement of the blood flow turbulence caused by stenosis,” Phys. Proc., vol. 3, pp. 605-613, 2010. DOI: 10.1016/j.phpro.2010.01.077.
P. Atkinson, “A fundamental interpretation of ultrasonic Doppler velocimeter,” Ultrasound Med. Biol., vol. 2, no. 2, pp. 107-111, 1976. DOI: http://dx.doi.org/10.1016/0301- 5629(76)90018-1
F. García-Nocetti, J. Solano-González, M. Fuentes-Cruz, E. Moreno- Hernández, A. Villar-Inclán, J. Prohias- Martínez, “Doppler ultrasound blood flow measurement system,” 19th International Congress on Acoustics, Madrid, España, 2-7 de septiembre 2007, ISBN:84-87985-12-2 ULT-15- 003.PDF.