Processing method and processing system of ultrasonic Doppler blood imaging

Abstract

The invention provides a processing method and a processing system of ultrasonic Doppler blood imaging. The method comprises steps of acquiring echo FR signals and carrying out Hilbert transform thereon to form orthogonal IQ complex signals; in slow time directions, carrying out filtering processing on the orthogonal IQ complex signals to acquire corresponding filtering transformation signal; in quick time directions, carrying out short-time Fourier transformation on the acquired filtering transformation signals so as to allow results to form frequency domain matrixes; acquiring a frequency component in each quick time direction in the current frequency domain matrixes; according to the one-dimensional related algorithm, estimating the average speed and the energy of corresponding frequency component of each line of data in the current frequency domain matrixes; and carrying out linear fitting on the average speed and the energy of corresponding frequency component in the current frequency domain matrixes and acquiring final energy and final speed used for final frequency spectrum displaying. According to the invention, by considering effects on ultrasonic signals imposed by organization attenuation, based on broadband emission, quite high resolution is provided and quality of ultrasonic images is further improved.

Description

technical field [0001] The invention belongs to the technical field of medical ultrasound, and mainly relates to a processing method and a processing system of ultrasonic Doppler blood flow imaging. Background technique [0002] With its unique real-time dynamic characteristics, the color blood flow imaging of color ultrasonic diagnostic equipment (B-ultrasound machine) has become one of the indispensable means of auxiliary diagnosis in modern medicine, and has become a criterion for judging certain diseases in clinical diagnosis. [0003] Currently, autocorrelation technology is commonly used in color blood flow imaging; according to the Doppler effect, the frequency shift caused by the movement of scatterers is proportional to the product of the frequency of the transmitted signal and the velocity of the scatterers. [0004] The traditional one-dimensional autocorrelation technology uses the autocorrelation in the slow time direction of the echo signal to estimate the phas...

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Problems solved by technology

[0004] The traditional one-dimensional autocorrelation technology uses the autocorrelation in the slow time direction of the echo signal to estimate the phase difference caused by the scatterers at the frequency of the transmitted signal, thereby estimating the velocity of the scatterers; the estimation algorithm is based on a narrowband On the basis of the signal model, the transmitted waveform is required to be longer to ensure compliance with the narrow-band model, and its velocity estimation performance, especially for fast-moving scatterers, deteriorates significantly with the increase in the bandwidth of the transmitted signal; at the same time, The imaging resolution of blood flow scatterers decreases when the emission waveform is longer

[0005] In addition, due to the non-linear frequency attenuation when ultrasound propagates in the tissue, the frequency components attenuate differently as the propagation distance of the sound velocity in the tissue increases. The traditional one-dimensional autocorrelation blood flow imaging technology is based on a fixed transmission signal. The center frequency and fixed bandwidth are calculated, so the performance of estimating the speed also decreases with the increase of propagation distance

[0006] As mentioned above, for the traditional one-dimensional autocorrelation blood flow imaging technology, because the theoretical basis of the technology is based on the narrow-band signal model, this requires a longer pulse width of the transmitted signal, which affects the resolution of the image

In addition, ultrasound has a nonlinear frequency attenuation phenomenon in the tissue. With the increase of ultrasound propagation distance, the frequency bandwidth and center frequency of the signal will shift. The traditional autocorrelation technology can only be based on a fixed transmission signal center. The frequency estimates the velocity, so as the depth increases, the estimated velocity error will also increase

[0007] Correspondingly, the currently disclosed cross-correlation blood flow imaging technology and butterfly search imaging technology are based on a broadband signal model, which solves the contradiction between the above-mentioned one-dimensional autocorrelation technology and resolution, but also has high computational complexity, which is difficult to implement in real time, and It cannot effectively solve the problem of speed deviation caused by frequency attenuation

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