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Investigation of a pulse compression technique for medical ultrasound: a simulation study

  • N. A. H. K. Rao
Medical Physics and Imaging

Abstract

Pulse compression techniques that are capable of producing a large signal-to-noise (SNR) enhancement, have been used successfully in many different fields. For medical applications, frequency-dependent attenuation in soft tissue can limit the usefulness of this method. In the paper, this issue is examined through model-simulation studies. Frequency-modulation (FM) chirp, considered in the study, is just one form of pulse coding technique. Pulse propagation effects in soft tissue are modelled as a linear zero phase filter. A method to perform simulations and estimate the effective time-bandwidth product K is outlined. K describes the SNR enhancement attainable under limitations imposed by the soft-tissue medium. An effective time-bandwidth product is evaluated as a function of soft-tissue linear attenuation coefficient αo, scatterer depth z and the bandwidth of the interrogating FM pulse, under realistic conditions. Results indicate that, under certain conditions, K can be significantly lower than its expected value in a non-attenuating medium. It is argued that although limitations exist, pulse compression techniques can still be used to improve resolution or increase penetrational depth. The real advantage over conventional short-pulse imaging comes from the possibility that these improvements can be accomplished without increasing the peak intensity of the interrogating pulse above any threshold levels set by possible bio-effect considerations.

Keywords

Pulse compression Signal-to-noise Ultrasonic imaging 

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References

  1. Apfel, R. E. (1982): ‘Acoustic cavitation: A possible consequence of biomedical uses of ultrasound’,Br. J. Cancer,45, pp. 140–146Google Scholar
  2. Apfel, R. E., andHolland, C. K. (1991): ‘Gauging the likelihood of cavitation from short-pulse, low-duty cycle diagnostic ultrasound’,Ultra. Med. Biol.,17, pp. 179–185CrossRefGoogle Scholar
  3. CDRH (Center for Devices and Radiological Health), Food and Drug Administration (1987): ‘510 (k) guide for measuring and reporting acoustic output of diagnostic ultrasound medical devices’. CDRH, Washington, DC, USAGoogle Scholar
  4. Chapelon, J. Y. (1988): ‘Pseudo-random correlation imaging and system characterization,’in Newhouse, V. L. (Ed.): ‘Progress in medical imaging’ (Springer-Verlag, Chap. 6Google Scholar
  5. Duck, F. A., Starritt, H. D., Aindow, J. D., Perkins, M. A., andHawkins, A. J. (1985): ‘The output of pulse-echo ultrasound equipment: A survey of powers, pressures, and intensities’,Br. J. Radiol.,58, pp. 989–1001CrossRefGoogle Scholar
  6. Gross, S. A., Johnston, R. D., andDunn, F. (1980): ‘Compilation of empirical ultrasonic properties of mammalian tissue II’,J. Acoust. Soc. Am.,68, pp. 93–108CrossRefGoogle Scholar
  7. Gurumurthy, K. V., andArthur, R. M. (1981): ‘A dispersive model for the propagation of ultrasound in soft tissue’,Ultrason. Imag.,4, pp. 355–377CrossRefGoogle Scholar
  8. Harris, R. A., Follett, D. H., Halliwell, M., andWells, D. N. T. (1991). ‘Ultimate limits in ultrasonic imaging resolution’,Ultra, Med. Biol.,17, pp. 547–558CrossRefGoogle Scholar
  9. Hill, C. R., Bamber, J. C., Crawford, D. C., Lowe, H. J., andWebb, S. (1991), ’What might echography learn from image science’,Ibid.,17, pp. 559–575CrossRefGoogle Scholar
  10. Kak, A. C., andDines, K. A. (1978): ‘Signal processing of broadband pulsed ultrasound’,IEEE Trans.,BME-25, pp. 321–344Google Scholar
  11. Klauder, J. R., Price, A. C., Darlington, S., andAlbersheim, W. J. (1960): ‘The theory and design of chirp Radars’,Bell Syst. Tech. J.,39, pp. 745–809Google Scholar
  12. Lewis, G. K. (1987): ‘Chird PVDF transducers for medical ultrasound imaging’,IEEE 1987 Ultrasonic Symp., pp. 879–881Google Scholar
  13. O’Donnell, M. (1992): ‘Coded excitation system for improving the penetration of real-time phased-array imaging system’,IEEE Trans.,UFFC-39, pp. 341–350Google Scholar
  14. Rao N., andAubry, M. (1993): ‘Evaluation of a pulse compression technique for ultrasound speckle reduction’,Electron. Lett.,29, (8), pp. 649–651.Google Scholar
  15. Rao, N. A. H. K., Ritenour, E. R., andHendrick, R. E. (1988): ‘Frequency modulated pulse for ultrasonic imaging’,Proc. SPIE Med. Imag.-II,914, pp. 67–74Google Scholar
  16. Rao, N. andMehra, S. (1991): ‘Experimental point spread function of FM pulse imaging scheme’,IEEE 1991 Ultrasonic Symp.,2, pp. 1249–1254Google Scholar
  17. Rao, N., andZhu, H. (1991): ‘Modeling ultrasound speckle formation and its dependence on imaging systems response’,Proc. SPIE Med. Imag. V: Image Physics,1443, pp. 81–95Google Scholar
  18. Starritt, H. C., Perkins, M. A., Duck, F. A., andHumphrey, V. F. (1985): ‘Evidence for ultrasonic finite amplitude distortion in muscle using medical equipment’,J. Acoust. Soc. Am.,77, pp. 302–306CrossRefGoogle Scholar
  19. Takeuchi, Y. (1979): ‘An investigation of a spread energy method for medical ultrasound systems’,Ultrasonics, pp. 175–182Google Scholar

Copyright information

© IFMBE 1994

Authors and Affiliations

  • N. A. H. K. Rao
    • 1
  1. 1.Center for Imaging ScienceRochester Institute of TechnologyRochesterUSA

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