DocumentCode :
1251722
Title :
Spectrum of Doppler ultrasound signals from nonstationary blood flow
Author :
Bastos, Carlos A C ; Fish, Peter J. ; Vaz, Francisco
Author_Institution :
Dept. de Electron. e Telecoms, Aveiro Univ., Portugal
Volume :
46
Issue :
5
fYear :
1999
Firstpage :
1201
Lastpage :
1217
Abstract :
A new formulation for the Doppler signal generation process in pulsatile flow has been developed enabling easier identification and quantification of the mechanisms involved in spectral broadening and the development of a simple estimation formula for the measured rms spectral width. The accuracy of the estimation formula was tested by comparing it with the spectral widths found by using conventional spectral estimation on simulated Doppler signals from pulsatile flow. The influence of acceleration, sample volume size, and time window duration on the Doppler spectral width was investigated for flow with blunt and parabolic velocity profiles passing through Gaussian-shaped sample volumes. Our results show that, for short duration windows, the spectral width is dominated by window broadening and that acceleration has a small effect on the spectral width. For long duration windows, the effect of acceleration must be taken into account. The size of the sample volume affects the spectral width of the Doppler signal in two ways: by intrinsic broadening and by the range of velocities passing through it. These effects act in opposite directions. The simple spectral width estimation formula was shown to have excellent agreement with widths calculated using the model and indicates the potential for correcting not only for window and nonstationarity broadening but also for intrinsic broadening.
Keywords :
Doppler measurement; biomedical ultrasonics; blood flow measurement; Doppler ultrasound signals; Gaussian-shaped sample volumes; acceleration; blunt velocity profiles; estimation formula; intrinsic broadening; nonstationarity broadening; nonstationary blood flow; parabolic velocity profiles; pulsatile flow; rms spectral width; sample volume size; signal generation process; spectral broadening; time window duration; window broadening; Acceleration; Blood flow; Fluid flow measurement; Frequency estimation; Marine animals; Scattering; Signal generators; Signal processing; Testing; Ultrasonic imaging;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/58.796126
Filename :
796126
Link To Document :
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