Evaluation of Post Wall Filter for Doppler Ultrasound Systems

Part of the Acoustical Imaging book series (ACIM, volume 29)


Recent advances in digital devices permit high-performance signal processing to be performed with ease. In conventional Doppler ultrasound examinations, the weak blood flow signals are separated from clutter signals, such as those from the cardiac valves and walls, using a time domain pre wall filter in order to avoid saturation of the subsequent frequency analyzer. At this time, due to the expanded dynamic range in signal processing, we have conducted investigations to determine whether it is possible to eliminate the pre wall filter and replace it with a post wall filter after the frequency analyzer. The results of these investigations showed that it is possible to obtain frequency characteristics equivalent to those obtained with a pre wall filter by compensating for the sampling function in frequency analysis processing and simplifying Doppler signal processing. Moreover, it was found that both blood inflow signals and mitral valve motion in the left ventricle can be observed without saturation, confirming the feasibility of real-time simultaneous display using a post wall filter.

Key words

Doppler ultrasound FFT Sampling function Wall filter Post filter Mitral valve Left ventricle 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Jorgen Arendet Jensen, 1996, Estimation of blood velocities using ultrasound: A signal processing approach, Cambridge University Press, New York, pp. 111–114.Google Scholar
  2. 2.
    Steinar Bajarum, Hans Torp and Kjell Kristoffersen, Clutter filter design for ultrasound color flow imaging, IEEE UFFC, 49(2), 204–216 (2002).Google Scholar
  3. 3.
    T. Baba, Investigation of auto gain control tecqunique in Doppler ultrasound system, Proc. J. Acoust. Soc. Jpn., p. 54 (2006)Google Scholar
  4. 4.
    R. N. Bracewell, 2000, The Fourier Transform and Its Applications, McGraw-Hill Companies Inc., Boston, pp. 385–398.Google Scholar
  5. 5.
    V. Cappellini, A. G. Constantinides and P. Emiliani, 1978, Didital Filters and Their Applications, Academic Press Inc., London, pp. 161–185.Google Scholar
  6. 6.
    T. Baba, Investigation of time scale optimization for Doppler measurement, Proc. J. Med Ultrasound Soc. Jpn., 2005(4), pp. 29–34 (2005)Google Scholar
  7. 7.
    T. Araki, 1985, The Communication System Theory and Reality, Kogaku Tosho Co., Inc., Tokyo, pp. 78–83.Google Scholar
  8. 8.
    K. Maeda, A. Sano, H. Takaie and S. Hara, 2001, Wavelet Transform and Its Application, Asakura Publishing Co., Ltd., Tokyo, pp. 67–81.Google Scholar
  9. 9.
    T. Baba, The investigation of the direction split technique of the Doppler ultrasound: Comparison of six kinds of Doppler audio processing, J. Soc. Signal Processing Applications and Technology of Japan, 8(2), 14–20 (2005).Google Scholar
  10. 10.
    T. Baba, Investigation of the audio direction separation in Doppler ultrasound system: Signal processing of Doppler audio for aliasing, J. Acoust. Soc. of Jpn., 62(3), 153–160 (2006).Google Scholar
  11. 11.
    Hiroshi Kanai and Yoshiro Koiwa, Myocardial Rapid Velocity Distribution, Ultrasound in Med. & Biol., 27(4), 481–498 (2001).CrossRefGoogle Scholar
  12. 12.
    Cecilia Wallentin Guron, MD, Marianne Hartford, MD, PhD, Anita Persson, MSC, Johan Herlitz, MD, PhD, Dag Thelle, MD, PhD, and Kenneth Caidahl, MD, PhD, Timing of Regional Left Ventricular Lengthening by Pulsed Tissue Doppler, J. Am. Soc. Echocardiography, 17(4), 307–312 (2004)CrossRefGoogle Scholar
  13. 13.
    Jennifer Lisauskas, Jasvindar Singh, Michael Courtois and Sandor J. Kovacs, The Relation of the peak Doppler E-wave to peak mitral annulus velocity ratio to diastolic function, Ultrasound in Med. & Biol., 27(4), 499–507 (2001)CrossRefGoogle Scholar
  14. 14.
    Christian Bruch, MD, Rainer Gradaus, MD, Stefan Gunia, MD, Gunter Breithardt, MD, FACC, and Thomas Wichter, MD, Doppler Tissue Analysis of Mitral Annular Velocities, J. Am. Soc. Echocardiography, 16(10), 1031–1036 (2003)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • T. Baba
    • 1
  1. 1.Toshiba Medical Systems CorporationOtawara-ShiJapan

Personalised recommendations