CN205683094U - Ultrasonic imaging system - Google Patents

Abstract

The utility model discloses a kind of ultrasonic imaging system, belong to ultrasonic imaging system field, design for solving the problems such as existing apparatus Detection results difference.This utility model ultrasonic imaging system includes front end displacement transducer, signal-processing board and host computer, and between front end displacement transducer and signal-processing board, two-way signaling connects, two-way signaling connection between signal-processing board and host computer.This utility model ultrasonic imaging system good stability, testing result is more accurate.

Description

Ultrasonic imaging system

Technical Field

The utility model relates to an ultrasonic imaging system field.

Background

The principle of ultrasonic elastography is that an external excitation is applied to a detected object (detected tissue), the detected tissue generates a response (for example, the distribution of displacement, strain and speed generates difference) under the action of physical laws such as elastomechanics, biomechanics and the like, and the displacement change and the strain change of the detected tissue are calculated through digital signal processing and digital image processing technologies.

The existing one-dimensional elastography system does not consider the influence of transverse fluctuation and different differences of fat attenuation degrees, so that the accuracy and stability of displacement and strain values of elasticity calculation are not high.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an ultrasonic imaging system that detected signal stability is good.

To achieve the purpose, the utility model adopts the following technical proposal:

an ultrasonic imaging system comprises a front-end displacement sensor, a signal processing board and an upper computer, wherein the front-end displacement sensor is in bidirectional signal communication with the signal processing board, and the signal processing board is in bidirectional signal communication with the upper computer; the front-end displacement sensor is used for sending a shear wave signal, and the shear wave is used for reflecting the physical characteristic change of the detected object according to the speed change and the Young modulus of the shear wave in the detected object; the signal processing board is used for generating ultrasonic waves and receiving control port information sent by the upper computer; the upper computer is used for sending control port information to the signal processing board, processing ultrasonic echo signals and calculating the speed change and Young modulus of the shear waves in the detected object so as to obtain the physical property change of the detected object.

Particularly, the signal processing board comprises an FPGA chip for generating ultrasonic waves and a high-speed communication protocol chip for receiving control port information sent by the upper computer, and the FPGA chip is in two-way signal communication with the high-speed communication protocol chip.

Particularly, the high-speed communication protocol chip comprises a high-speed communication protocol serial port.

The utility model discloses ultrasonic imaging system includes front end displacement sensor, signal processing board and host computer, and ultrasonic imaging method based on this imaging system calculates the speed change and the young modulus of shear wave in being detected the object through handling ultrasonic echo signal and changes in order to reflect the physical characteristics who is detected the object, and system stability is good, and the testing result is more accurate.

Drawings

Fig. 1 is a schematic diagram of an ultrasonic imaging system according to a preferred embodiment of the present invention;

fig. 2 is a schematic diagram of a one-dimensional displacement scanning method according to a second preferred embodiment of the present invention.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.

The first preferred embodiment:

the preferred embodiment discloses an ultrasound imaging system. As shown in fig. 1, the ultrasonic imaging system mainly comprises a front-end displacement sensor, a signal processing board and an upper computer. By utilizing the non-invasive characteristic of ultrasonic waves, a shear wave signal is sent through a displacement sensor, an ultrasonic echo signal is used as a carrier of a shear wave echo, and the speed change and Young modulus of the shear wave in the detected object are calculated by processing the ultrasonic echo signal so as to reflect the physical characteristic change of the detected object.

The front-end displacement sensor converts a single-carrier signal transmitted by the signal processing board into a vector signal, and the driving motor transmits a shear wave signal and simultaneously transmits and receives an ultrasonic signal; the signal processing board mainly comprises an FPGA chip and a high-speed communication protocol chip, wherein the FPGA chip mainly completes interaction with related peripheral equipment, and the high-speed communication protocol mainly completes transmission of protocol data and sends instructions to the FPGA chip through an asynchronous serial port; the upper computer mainly completes the processing of the elastography algorithm and the display and control of the interface.

The signal processing flow of the FPGA module in the signal processing board is as follows:

1. initializing a link, namely after the upper computer finishes downloading the firmware and reads the information state description of the firmware, sending a handshake instruction to the upper computer through a serial port by power-on reset or manual reset;

2. ultrasonic wave emission and sampling data reception, starting equipment after receiving a starting instruction sent by an upper computer through a serial port, sending an ultrasonic square wave signal, and starting RF data acquisition after waiting for a period of time;

3. shear wave sending, namely starting to send shear waves after certain scanning lines are acquired, sending low-frequency single carriers to a displacement sensor, and then, sampling data contain shear wave information;

4. the information of the control path is used for transmitting control port information sent by an upper computer through a serial port of a high-speed communication protocol, wherein the control port information comprises read and write instructions of a data path (only data of the data path needs to be read through a block, and data is not written into the data path through the block); transmitting the state information instruction of the lower computer to the upper computer through a serial port of a high-speed communication protocol;

5. and storing the data in the storage medium through the read-write command of the upper computer by the information of the data path, wherein the default sending mode is that the read command reads the acquired data all the time.

Upper computer part processing flow:

1. initializing software, namely initializing firmware, sending a write command control word by an upper computer through a control endpoint, and starting a monitoring working thread cycle; the main content is that a control endpoint sends a read command control word, and serial port information is read back by the control endpoint to verify whether a device link starts handshake successfully;

2. starting a trigger thread cycle, sending a write start command through a control endpoint, and starting a block port read cycle thread;

3. reading data, namely reading the data to an upper computer by using a response block reading method in a block port reading circulation thread;

4. and the data processing comprises two independent parts, wherein one part generates M-mode image information by using the raw data, and the other part generates shear wave speed change information and Young modulus information by using the raw data.

The ultrasonic imaging method based on the ultrasonic imaging system uses an ultrasonic echo signal as a carrier of a shear wave echo, and the speed change and Young modulus of the shear wave in the detected object are calculated by processing the ultrasonic echo signal so as to obtain the physical characteristic change of the detected object.

Specifically, the M-mode ultrasound image can be rendered and the instantaneous elastic parameters can be calculated separately by processing the RF data. In the process of drawing the M-mode ultrasonic image, RF data collected by a lower computer are read and arranged into a data matrix, then the RF data are subjected to matched filtering to improve the signal-to-noise ratio of signals, the envelope of the signals is extracted after hibert filtering, and finally the M-mode ultrasonic image is drawn. In the transient elastic algorithm, reading original RF data, arranging the original RF data into a data matrix form, wherein each column represents a scanning line; performing band-pass filtering on original data to improve the signal-to-noise ratio of the data, performing cross-correlation operation on data blocks of adjacent scanning lines, calculating tissue displacement caused by shear wave propagation, performing smooth filtering and matched filtering on the tissue displacement, replacing singular values, calculating tissue strain according to the corrected tissue displacement, and finally calculating the shear wave speed and the Young modulus according to the tissue strain.

The second preferred embodiment:

the preferred embodiment discloses a one-dimensional displacement scanning method. As shown in fig. 2, the acquired echo scan line data is divided into data blocks of a specific size, each scan line is composed of certain sampling data, and the corresponding depth is the detection region of the detected object (detected tissue). In the conventional one-dimensional displacement calculation, only the longitudinal change of the tissue is generally considered, and the cross-correlation function of the data blocks at the corresponding positions on the adjacent scanning lines is calculated, but the transverse change of the tissue is not considered, so that the stability of the displacement calculation result is not high. In this embodiment, in addition to the cross-correlation function of the data blocks at the corresponding positions on the adjacent scanning lines, the cross-correlation function of the data blocks at the corresponding positions on the sub-adjacent scanning lines is also calculated, and the influence of the lateral variation is fully considered. In consideration of real-time imaging, in this embodiment, cross-correlation functions of the i-1 th scan line, the i-th scan line and the i +1 th scan line which are adjacent to each other are calculated, and the calculation results are weighted and averaged to be used as displacement offset values of corresponding data blocks on the i-th scan line.

The third preferred embodiment:

the preferred embodiment discloses a fat content detection method, and the application range comprises but is not limited to fat content detection at liver parts.

The fat content is estimated by the attenuation coefficient of the ultrasonic echo, and the detection method is based on the attenuation model of the ultrasonic in the heterogeneous tissues:the attenuation coefficients of ultrasound in different adipose tissues were estimated. ω is the digital frequency of the signal, d is the propagation depth of the signal, and S (ω, d) represents the echo spectrum of the signal. c (d) is the direct current component of the signal representing the diffraction coefficient, G (ω) represents the Gaussian distribution spectrum at the center frequency of the probe, β is the frequency dependent attenuation coefficient,is the phase feedback of the attenuation propagation equation, and R (ω, d) represents the diffuse reflection equation of the tissue.

In order to improve the sampling density of the estimated spectrum, the RF signal of each frame is windowed and divided into a plurality of overlapped parts, the spectrum S (ω, d) of each overlapped part is taken, and the spectrum S (ω, d) is logarithmically transformed to obtain the following:

$\log S(\mathrm{\ω},d)=\log c\left(d\right)+\log G\left(\mathrm{\ω}\right)-2\stackrel{\‾}{\mathrm{\β}}d\left|\frac{\mathrm{\ω}}{2\mathrm{\π}}\right|+\log R(\mathrm{\ω},d)$

each part of the spectrum is subtracted within the logarithmic threshold by the direct current component logc (d) and the corresponding gaussian distribution spectrum logG (ω) in the probe, where logc (d) is estimated by dividing the zero frequency component of the part of the spectrum, which can be written as:ω₀is the digital center frequency of the probe, σ represents the bandwidth of the signal, σ, which is also estimated from the RF signal. The ultrasonic pulse signal is considered to conform to Gaussian distribution to a certain extent, the central frequency of the Gaussian frequency spectrum of the ultrasonic pulse wave can change along with the change of the detection depth, and the bandwidth is fixed. By calculating the average spectrum of multiple adjacent arrays, the spectral width of the peak with amplitude 0.6 times is considered as an estimate of the signal bandwidth.

The residual spectrum of the gaussian spectrum minus the direct current component of the signal and the ultrasonic pulse is expressed at the logarithmic threshold as: ${\mathrm{logS}}_l(\mathrm{\ω},d)=-2\stackrel{\‾}{\mathrm{\β}}d\left|\frac{\mathrm{\ω}}{2\mathrm{\π}}\right|+\log R(\mathrm{\ω},d),$ representing the estimate of the ultrasound attenuation coefficient as a function of frequency and depth of emission, R (ω, d) is a diffuse reflection equation inside the tissue, a parameter that varies randomly with frequency, versus the spectrum logS_l(omega, d) linear fitting is carried out to obtain the slope K, and the attenuation coefficient of the ultrasound can be calculated through K/(-2d)

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (3)

1. An ultrasonic imaging system is characterized by comprising a front-end displacement sensor, a signal processing board and an upper computer, wherein the front-end displacement sensor is in bidirectional signal communication with the signal processing board, and the signal processing board is in bidirectional signal communication with the upper computer; wherein,

the front-end displacement sensor is used for sending shear wave signals;

the signal processing board is used for generating ultrasonic waves and receiving control port information sent by the upper computer;

and the upper computer is used for sending control port information to the signal processing board.

2. The ultrasonic imaging system of claim 1, wherein the signal processing board comprises an FPGA chip for generating ultrasonic waves and a high-speed communication protocol chip for receiving control port information sent by the upper computer, and the FPGA chip and the high-speed communication protocol chip are in bidirectional signal communication.

3. The ultrasonic imaging system of claim 2, wherein the high-speed communication protocol chip comprises a high-speed communication protocol serial port.