Selection of a spectral analysis method for the assessment of velocity distribution based on the spectral distribution of ultrasonic Doppler signals

Abstract

The direct Fourier transform method, autoregressive modelling, the maximum likelihood method and the Wigner-Ville distribution were applied to the Doppler signal obtained from a fully insonated laminar model flow. The appreciation of the spectral method was based on the properties of the ratio variance/(fmean)2 (INT) of the spectrum. The basic criterion was the sensitivity of INT to the analysis parameters, especially the data window. The results of spectral analysis, as well as the properties of INT, were strongly affected by the method applied. The maximum likelihood method appeared best suited for the purpose of assessment of velocity distribution and is expected to give the best results in the case of in vivo blood flow. The performances of other discussed methods were inferior, due to their stronger incompatibility with the signal properties.

Time Frequency Analysis of Femoral Doppler Ultrasound Signals by AR Modelling

“…There are also a certain number of original approaches introduced by "Forsberg" and "Strong" et. al, who use decomposition in singular values to evaluate the Doppler frequency [2][3][4][5]. In order to value the parametric signal time-frequency plan, we rewrite the equation under the following matrix form:…”

“…Vaitkus et al [10] found that AR modelling yields estimates with variances considerably less than of the periodogram. Kaluzynski [4] reported the better statistical stability of AR spectra in comparison with the periodogram. These studies confirmed the usefulness of AR modeling for Doppler blood flow signal.…”

Pseudo-Wigner distribution for analysis of pulsed Doppler ultrasound

“…Moreover, no single TFR is optimal for all signal processing problems, and the choice of the TFR must depend on the specific application. Several authors have demonstrated the limitations of the spectrogram as a tool for analyzing blood velocity patterns [ 3 ] , [4]. Kitney and Talhami [3] showed that a spectrogram-based typical protocol employed in current Duplex scanners is unable to resolve deceleration phase oscillations.…”