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Combined Two-Dimensional Tissue/Flow Imaging

  • E. Aaron Howard
  • Marco Brandestini
  • Jeff Powers
  • Saeed Taheri
  • Mark E. Eyer
  • David J. Phillips
  • Edward B. Weiler
Part of the Acoustical Imaging book series (ACIM, volume 9)

Abstract

A functional sectorscan system has been built which provides two-dimensional (2D) images based on a coherent echo/Doppler processor.

The phase and magnitude of the demodulated signal (complex video) are analyzed by means of a fast digital processor. An image field of 256 X 256 pixels is stored in memory. A digital scan convertor and color coding scheme formats the image for standard raster display. The tissue and flow features are distinguished by contrasting color or grey scale assignments. A microprocessor-based operating system provides flexible control of sector format, pulse repetition frequency, sample clock, encoding scheme, etc.

The significant features of the echo/Doppler processor are: The output of the receiver is log compressed and demodulated by a quadrature pair of double-balanced mixers to preserve the phase and magnitude information within a 1 MHz bandwidth. A flash 8 bit A/D convertor is multiplexed between the “real” and “imaginary” components at a 7 MHz rate. A linear approximation (hypotenuse function) is used to calculate the magnitude term. The phase is computed by means of a look-up table. To obtain the Doppler shift for any given point, the derivative dΘ/dt is substituted by the change of phase (ΔΘ/Δt) between consecutive transmit/receive cycles.

Initial in vivo trials show that the system is capable of producing a longitudinal view of the carotid artery. Both tissue and flow features are clearly distinguishable.

Keywords

Digital Controller Demodulate Signal Doppler Angle Quadrature Pair Complex Video 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Baker, D. W. (1970), Pulsed ultrasonic Doppler blood-flow sensing. IEEE Trans. Sonics Ultrasonics 17, 170–185.CrossRefGoogle Scholar
  2. Barber, F. E., Baker, D. W., Nation, A. W. C., Strandness, D. E., Jr., and Reid, J. M. (1974), Ultrasonic duplex echo-Doppler scanner. IEEE Trans. Biomed. Engr. 21, 109–113.CrossRefGoogle Scholar
  3. Brandestini, M. A., Forster, F. K. (1978), Blood flow imaging using a discrete-time frequency meter. Ultrasonics Symposium Proc. IEEE Cat.# 78 CH1344-1SU.Google Scholar
  4. Brandestini, M. A., Eyer, M. K., and Stevenson, J. G. (1979), M/Q-mode echocardiography — the synthesis of conventional echo with digital multigate Doppler. Echocardiology, Third Symposium on Echocardiology, Rotterdam, Netherlands, June 1979.Google Scholar
  5. Curry, G. R. and White, D. N. (1978), Color coded ultrasonic differential velocity arterial scanner (Echoflow). Ultrasound in Medicine and Biology 4, 27–35.CrossRefGoogle Scholar
  6. Eyer, M. K. (1978), A microprocessor based digital scan converter and color display system for ultrasonic image presentation. Masters thesis, Electrical Engineering, University of Washington, Seattle, Washington.Google Scholar
  7. Eyer, M. K., Brandestini, M. A., Phillips, D. J., and Baker, D. W. (1979), Color digital echo/Doppler image presentation. Article submitted to Ultrasound in Medicine and Biology.Google Scholar
  8. Hokanson, D. E., Mozersky, D. J., Sumner, D. S., McLeod, F. D., Jr. and Strandness, D. E., Jr. (1972), Ultrasonic arteriography: A non-invasive method of arterial visualization. Radiology 102, 435–436.Google Scholar
  9. Howard, E. A., Brandestini, M. A., Eyer, M. K., and Weiler, E. B. (1979), Color-coded digital echo/Doppler imaging, storage, and display. Proc. 4th International Symposium on Ultrasound Imaging and Tissue Characterization, pp. 25–28.Google Scholar
  10. Phillips, D. J., Blackshear, W. M., Baker, D. W. and Strandness, D. E., Jr. (1978), Ultrasound Duplex scanning in peripheral vascular disease. Radiology/Nuclear Medicine 8, 6–10.Google Scholar
  11. Phillips, D. J., Powers, J. E., Eyer, M. K., Blackshear, Jr., W. M., Bodily, K. C., Strandness, Jr., D. E., Baker, D. W. (1979), Detection of peripheral vascular disease using the Duplex scanner III. Article submitted to Ultrasound in Medicine and Biology.Google Scholar
  12. Stevenson, J. G., Brandestini, M. A., Weiler, E. B., Howard, E. A. and Eyer, M. K. (1979), Digital multigate Doppler with color echo and Doppler display — diagnosis of atrial and ventricular septal defects. Proc. 52 Meeting of the American Heart Association, Part II, Vol. 60, #4.Google Scholar

Copyright information

© Plenum Press, New York 1980

Authors and Affiliations

  • E. Aaron Howard
    • 1
  • Marco Brandestini
    • 2
  • Jeff Powers
    • 1
  • Saeed Taheri
    • 1
  • Mark E. Eyer
    • 1
  • David J. Phillips
    • 1
  • Edward B. Weiler
    • 2
  1. 1.Center for BioengineeringUniversity of WashingtonSeattleUSA
  2. 2.Advanced Technology Laboratories, Inc.BellevueUSA

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