A New Time Domain Technique for Velocity Measurements Using Doppler Ultrasound
TL;DR: The algorithm can be shown to give rigorously accurate values for instantaneous frequency and outperform the Fourier transform approach in poor signal-to-noise environments.
Abstract: A new technique for determining the Doppler frequency shift in a phase-coherent pulsed Doppler system is presented. In the new approach, the Doppler frequency shift is given directly in the time domain in terms of the measured I and Q components of the measured Doppler signal. The algorithm is based on an expression for the instantaneous rate of change of phase which separates rapidly varying from slowly varying terms. It permits noise smoothing in each term separately. Since the technique relies solely on signal processing in the time domain, it is significantly simpler to implement than the classic Fourier transform approach. In addition, the algorithm can be shown to give rigorously accurate values for instantaneous frequency and outperform the Fourier transform approach in poor signal-to-noise environments. Experimental results are presented which confirm the superiority of the new domain technique.
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TL;DR: A new formulation is presented which describes the pulse-Doppler effect on the successive echoes from a cloud of moving targets as a progressive translation in time due to the displacement of the scatterers between two excitations.
406 citations
TL;DR: In this paper, a constraint least-square approach is proposed to track the movement of the heart wall based on both the phase and magnitude of the demodulated signal to determine the instantaneous position of the object so that the vibration velocity of the moving object can be accurately estimated.
Abstract: For the noninvasive diagnosis of heart disease based on the acoustic and elastic characteristics of the heart muscle, it is necessary to transcutaneously measure small vibration signals, including components with an amplitude of less than 100 /spl mu/m, from various parts of the heart wall continuously for periods of more than several heartbeats in a wide frequency range up to 1 kHz. Such measurement, however, has not been realized by any ultrasonic diagnostic methods or systems to date. By introducing the constraint least-square approach, this paper proposes a new method for accurately tracking the movement of the heart wall based on both the phase and magnitude of the demodulated signal to determine the instantaneous position of the object so that the vibration velocity of the moving object can be accurately estimated. By this method, small vibrations of the heart wall with small amplitudes less than 100 /spl mu/m on the motion resulting from a heartbeat with large amplitude of 10 mm can be successfully detected with sufficient reproducibility in the frequency range up to several hundred Hertz continuously for periods of about 10 heartbeats. The resultant small vibration is analyzed not only in the time domain, but also in the frequency domain. As confirmed by the preliminary experiments herein reported, the new method offers potential for research in acoustical diagnosis of heart disease.
256 citations
TL;DR: In this paper, the authors proposed a new method for accurately tracking the movement of the heart wall based on the acoustic characteristics of the myocardial muscle and applied it to multiple points preset in the left ventricular (LV) wall along the ultrasonic beam so that the spatial distribution of the velocity at these points are simultaneously obtained.
Abstract: For the noninvasive diagnosis of heart disease based on the acoustic characteristics of the heart muscle, we have developed a new method for accurately tracking the movement of the heart wall. By this method, a velocity signal of the heart wall with a small amplitude of less than 10 /spl mu/m on the motion resulting from a heartbeat with large amplitude of 10 mm can be successfully detected with sufficient reproducibility in the frequency range up to several hundred Hertz continuously for periods of about 10 heartbeats. In this paper, the method is applied to multiple points preset in the left ventricular (LV) wall along the ultrasonic beam so that the spatial (depth) distributions of the velocity at these points are simultaneously obtained. The motion of the heart wall is divided into the following two components: parallel global motion of the heart wall and the change in myocardial layer thickening at each depth across the LV wall during myocardial contraction/relaxation. The latter component is superimposed on the M (motion) mode image using a color code to map contraction as red and expansion as blue. By preliminary human studies, the principle of the method proposed in this paper is verified and the frequency band of the components generated by thickening and/or thinning in the myocardium is identified. This new approach offers potential for research on noninvasive acoustical diagnosis of myocardial local motility, that is, the myocardial layer function at each depth in the ventricular wall.
190 citations
TL;DR: Correlation interpolation is introduced as a method to determine the displacement of moving biological tissue on the basis of a sequence of ultrasonic echo signals, while the ratio of the number of samples in depth and time is irrelevant.
149 citations
TL;DR: Software based on the MATLAB (R) graphical user interface (GUI) has been developed and provides a powerful and rapid tool for visualizing and processing the data acquired, giving theological information in real-time and in excellent agreement with conventional methods.
109 citations
References
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01 Jan 1969
TL;DR: This online pronouncement an introduction to statistical communication theory can be one of the options to accompany you as soon as having extra time.
Abstract: Getting the books an introduction to statistical communication theory now is not type of challenging means. You could not solitary going in imitation of book collection or library or borrowing from your connections to approach them. This is an enormously easy means to specifically get lead by on-line. This online pronouncement an introduction to statistical communication theory can be one of the options to accompany you as soon as having extra time.
504 citations
"A New Time Domain Technique for Vel..." refers methods in this paper
...One method of computing these statistics is to use the power spectrum as an approximation to the probability density function of frequency [9], that is, SQ....
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409 citations
TL;DR: The Doppler shift of ultrasound, scattered from moving elements within a stream of blood, is related to the velocity of blood flow and a flowmeter based on this principle was used to record blood flow through intact vessels in dogs.
Abstract: The Doppler shift of ultrasound, scattered from moving elements within a stream of blood, is related to the velocity of blood flow. A flowmeter based on this principle has been constructed and was used to record blood flow through intact vessels in dogs.
342 citations
"A New Time Domain Technique for Vel..." refers background in this paper
...Numerous experimental techniques exist for deriving particle velocity information from this expression [2] [4] ....
[...]
TL;DR: In this article, formulae for numerical differentiation, using the same data, are collected for numerical integration of a function in terms of its values at a set of arguments at equal intervals.
Abstract: In a recent paper (1) formulae were given for the numerical integration of a function in terms of its values at a set of arguments at equal intervals. In this companion paper, formulae for numerical differentiation, using the same data, are collected. Their utility in enabling derivatives of a function given numerically at such a set of arguments to be computed is obvious, the need arises in several approximate methods which are coming more and more into use (2), (3). The formulae avoid the labour of preliminary differencing, and are indeed more convenient than the finite difference formulae when the derivative is required at all the points of subdivision of a limited range.
114 citations
TL;DR: A pulsed Doppler volume flowmeter has been developed which measures flow normal to a thin uniformly illuminated sample volume, and implications for clinical use are discussed.
77 citations