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Speckle in the Doppler signal - correlation of CW-Doppler signals from blood for varying transmit frequency

In English

Författare

Summary, in English

Speckle is an unwanted noise in ultrasound images, and appears as returning echoes are coherently summed over the transducer surface. In Doppler applications, the total power of the received spectrum varies in a manner similar to speckle. This paper investigates the correlation of continuous-wave (CW) Doppler signals obtained from simultaneously transmitted carrier frequencies, when a slowly flowing blood stream is insonated. The covariance function of received Doppler power versus transmitted frequency is shown to agree well to a theoretical modelled function, as well as experiments made on static, independent scatterers, even though the present measurements have a larger variability. The speckle to noise ratio of the Doppler signal amplitude was found to be 1.87 (S.E. 0.04), compared to the theoretical number 1.91 valid for pulse-echo imaging. It was also found that average of spectral estimates from independent channels reduce the variability of such estimates

Publiceringsår

2002

Språk

Engelska

Sidor

1499-1502

Publikation/Tidskrift/Serie

2002 IEEE Ultrasonics Symposium. Proceedings (Cat. No.02CH37388)

Dokumenttyp

Konferensbidrag

Förlag

IEEE - Institute of Electrical and Electronics Engineers Inc.

Ämne

  • Medical Engineering

Nyckelord

  • static independent scatterers
  • received Doppler power
  • covariance function
  • slowly flowing blood stream
  • simultaneously transmitted carrier frequencies
  • continuous-wave Doppler signal correlation
  • received spectrum total power
  • transducer surface
  • returning echoes
  • ultrasound images
  • unwanted noise
  • varying transmit frequency
  • blood
  • Doppler signal speckle
  • CW-Doppler signals
  • speckle to noise ratio
  • variability
  • Doppler signal amplitude
  • pulse-echo imaging
  • spectral estimates
  • independent channels
  • blood perfsion measurements

Conference name

IEEE Ultrasonics Symposium, 2002

Conference date

2002-10-08 - 2002-10-11

Conference place

Munich, Germany

Status

Published

ISBN/ISSN/Övrigt

  • ISBN: 0-7803-7582-3