The utility model content
The technical problem that this utility model solves is: make up a kind of measuring probe, system that is used to measure ofelasticity of viscoelastic medium, overcoming needs high-precision position sensor to cause the cost height in the prior art, computational methods complicated technology problem.
The technical solution of the utility model is: make up a kind of measuring probe that is used to measure ofelasticity of viscoelastic medium, comprise that at least one produces the vibrator of mechanical vibration, the contact of at least one band ultrasonic transducer, described vibrator is fixed on the described ultrasonic transducer, described viscoelastic medium returns ultrasonic signal when passing through ultrasonic irradiation, described vibrator sends the instantaneous low frequency impact that frequency is 1Hz to 500Hz to described viscoelastic medium.
Further technical scheme of the present utility model is: the outer face of described contact is rounded.
Further technical scheme of the present utility model is: described vibrator is the power-actuated electromagnetic vibrator of electromagnetism.
Further technical scheme of the present utility model is: described electromagnetic vibrator comprises reciprocating axle, the axle of described electromagnetic vibrator moves back and forth under electromagnetic force drives, described axle is connected with described contact, and described reciprocating axle drives described contact and produces vibration.
Further technical scheme of the present utility model is: described viscoelastic medium is a liver.
The technical solution of the utility model is: make up a kind of measuring system that is used to measure ofelasticity of viscoelastic medium, comprise the measuring probe to viscoelastic medium emission ultrasonic signal and generation low-frequency vibration, the control unit that the described viscoelastic medium of collection returns the collecting unit of ultrasonic signal, the computing unit that calculates measurement result, control survey system, the output unit of output measurement result.
Further technical scheme of the present utility model is: also comprise the image generation unit that generates image according to the ultrasonic signal of gathering.
Technique effect of the present utility model is: make up a kind of measuring probe, system and method that is used to measure ofelasticity of viscoelastic medium, the described vibrator of measuring probe is fixed on the described ultrasonic transducer, described viscoelastic medium returns ultrasonic signal when passing through ultrasonic irradiation, described vibrator sends the instantaneous low frequency impact that frequency is 1Hz to 500Hz to described viscoelastic medium.This utility model only adopts simple measuring probe promptly to finish the measurement of ofelasticity of viscoelastic medium, measures the elasticity of viscoelastic medium by Displacement Estimation, and is simple in structure, cost is low, computational methods are easy.
The specific embodiment
Below in conjunction with specific embodiment, technical solutions of the utility model are further specified.
As shown in Figure 1, the specific embodiment of the present utility model is as follows: a kind of measuring probe that is used to measure ofelasticity of viscoelastic medium of this utility model, comprise that at least one produces the vibrator 3 of mechanical vibration, the contact of at least one band ultrasonic transducer 1, described vibrator 3 is fixed on the described ultrasonic transducer 1, contact is by lead 4 connection control system, described viscoelastic medium returns ultrasonic signal when passing through ultrasonic irradiation, described vibrator 3 sends the instantaneous low frequency impact that frequency is 1Hz to 500Hz to described viscoelastic medium 5.
As shown in Figure 2, specific implementation process of the present utility model is as follows: the contact of measuring probe vertically is pressed on the surface of tested viscoelastic medium 5 or biological tissue 5, fixes vibrator 3 during measurement.Vibrator 3 sends the vibration between one or more 1-500Hz then, and in this utility model, described vibration is adopted as the sinusoidal vibration signal.Ultrasonic transducer is launched ultrasound wave and is received echo-signal to viscoelastic medium 5 or biological tissue 5 simultaneously.The ultrasonic echo signal is transferred in the data processor by line.By the elasticity computational methods ultrasonic echo signal is carried out the elastic modelling quantity that this tested viscoelastic medium or biological tissue are obtained in analytical calculation then.In the specific implementation process, the outer face of described contact is rounded.In this utility model, described viscoelastic medium 5 is livers of human or animal's organ, particularly people.
As shown in Figure 1, preferred implementation of the present utility model is: described vibrator 3 is the power-actuated electromagnetic vibrator of electromagnetism, described electromagnetic vibrator comprises reciprocating axle 2, the axle 2 of described electromagnetic vibrator moves back and forth under electromagnetic force drives, described axle 2 is connected with described contact, and described reciprocating axle drives described contact generation and vibrates.
As shown in Figure 3, the specific embodiment of the present utility model is: make up a kind of measuring system that is used to measure ofelasticity of viscoelastic medium, comprise the measuring probe 61 to viscoelastic medium emission ultrasonic signal and generation low-frequency vibration, the control unit 65 that the described viscoelastic medium of collection returns the collecting unit 62 of ultrasonic signal, the computing unit 63 that calculates measurement result, control survey system, the output unit 64 of output measurement result.
Specific implementation process is as follows: the contact of measuring probe 61 vertically is pressed on the surface of tested viscoelastic medium 5 or biological tissue 5, fixes vibrator 3 during measurement.Sinusoidal signal between the one or more 1-500Hz of vibrator 3 input then.Ultrasonic transducer is launched ultrasound wave and is received echo-signal to viscoelastic medium 5 or biological tissue 5 simultaneously.The ultrasonic echo signal is transferred in the data processor by line.Collecting unit 62 collects the ultrasonic signal that returns after computing unit 63 carries out the elastic modelling quantity that this tested viscoelastic medium or biological tissue are obtained in analytical calculation by the elasticity computational methods to the ultrasonic echo signal, then result of calculation is exported through output unit 64, the control of whole measuring system is controlled by control unit 65.In the preferred implementation of the present utility model, measuring system also comprises the image generation unit 66 that generates image according to the ultrasonic signal of gathering, image generation unit 66 generates image according to the calculating data of output unit 64 outputs, and described image comprises two dimensional image and 3-D view.
As shown in Figure 4, the specific embodiment of the present utility model is: comprise to viscoelastic medium emission ultrasonic signal and produce the measuring probe of low-frequency vibration that the measuring method that is used to measure ofelasticity of viscoelastic medium comprises the steps:
Step 100: obtain ultrasonic signal, that is: measuring probe produces the low-frequency pulse impact to described viscoelastic medium, and described viscoelastic medium carried out ultrasonic irradiation, described viscoelastic medium returns ultrasonic signal behind ultrasonic irradiation, obtain the ultrasonic signal data that described viscoelastic medium returns.Specific implementation process is as follows: measuring probe impacts the low-frequency pulse that described viscoelastic medium produces one or more 1-500Hz, measuring probe carries out ultrasonic irradiation to described viscoelastic medium simultaneously, described viscoelastic medium returns ultrasonic signal behind ultrasonic irradiation, measuring system is obtained the ultrasonic signal data that described viscoelastic medium returns.
Step 200: Displacement Estimation, that is: viscoelastic medium is estimated because of the displacement that vibration produces.
Specific implementation process is as follows: after obtaining the ultrasonic signal data that described viscoelastic medium returns, as shown in Figure 5, utilize data disaply moudle to obtain a frame M-mode(promptly by viscoelastic medium or biological tissue in the echo-signal of different time to different depth, " Motion mode ", M type ultrasonoscopy), demonstrate viscoelastic medium or the biological tissue motion conditions under low-frequency vibration of different depth.Displacement Estimation adopts classical cross correlation algorithm, and introduces quick cross correlation algorithm on this basis.To be the ultrasonic signal data that will collect be divided into the segment x (s) of 0.05mm along depth direction to concrete grammar, and Duplication is 50%~90%.X wherein
1(s), x
2(s) be adjacent signal segment, then cross-correlation function R(n) will have a very outstanding peak value appearance.If with x
1(s), x
2(s) in regular length, carry out convolution.Work as n=n
0The time, x
1(s), x
2(s) signal section in overlaps, and R(n) maximum is arranged, and at this moment, passes through x
1(s) move apart from n
0Be viscoelastic medium or biological tissue displacement.
For the ultrasonic signal that collects, the expression formula of cross-correlation function is:
Wherein, R(n) be cross correlation value; N is the data sum of integrating range; N is the value sequence of displacement, and the value of n is identical with the ultrasonic signal depth direction sampling interval at interval.
Step 300: strain is estimated, that is: viscoelastic medium is estimated because of the elastic strain that vibration produces.
Specific implementation process is as follows: strain estimate to utilize is derivative relation between strain and the displacement, therefore strain only need to be estimated on the basis of Displacement Estimation displacement differentiated along depth direction and can be obtained strain, some other strain method of estimation substantially all is based on this, intends adopting the least square strain estimation technique.As shown in Figure 5, the strain size is used gray scale representation, just can form the two dimensional image that a frame strain changed with the degree of depth and time.
Step 400: obtain the elastic shear wave velocity, that is: obtain the elastic shear wave velocity according to strain and time relation.
Specific implementation process is as follows: after obtaining strain pattern, the slope of the wave pattern of area-of-interest in the image (ROI-region of interest) is exactly the The mean propagation velocity of this shearing wave in the human liver tissue.As shown in Figure 6, the degree of depth between 25~45mm is exactly the part in the solid line boxes among the interesting areas 6(figure), wherein strain facies with the line (the oblique dotted line among the figure in the solid line boxes) that is linked to be of point be exactly the The mean propagation velocity of shearing wave in the human liver tissue with respect to the slope of abscissa (time).The principle of its dependence is: strain facies point is together represented the same phase place of shearing wave, and shearing wave has a Phase delay between the tissue of different depth, suppose that a certain depth d 2 is t2-t1 with respect to the Phase delay of d1, and its spread speed can be expressed as so:
In fact just among the figure dotted line with respect to the slope of time.
Step 500: the calculating elastic modulus that is: calculates the elastic modelling quantity of viscoelastic medium.
If approximate as non-sticky, isotropic line elastomer tissues such as livers, its elastic modelling quantity can be expressed as so:
Wherein: represent the density (being approximately 1000kg/) of hepatic tissue, V
sBe exactly the The mean propagation velocity of shearing wave in hepatic tissue.Can calculate the average elasticity modulus E of hepatic tissue thus, represent with kPa.Data disaply moudle finally can be the M-mode ultrasonoscopy, and strain pattern and the shearing wave The mean propagation velocity of calculating thus and average elastic modulus E are shown on the display.In the specific embodiment, with the elastic modelling quantity result calculated with organize strain imaging figure to be built up image.Generate two dimensional image or 3-D view according to the result who obtains the tissue elasticity modulus, judge intuitively by image.
This utility model makes up a kind of measuring probe, system and method that is used to measure ofelasticity of viscoelastic medium, the described vibrator of measuring probe is fixed on the described ultrasonic transducer, described viscoelastic medium returns ultrasonic signal when passing through ultrasonic irradiation, described vibrator sends the instantaneous low frequency impact that frequency is 1Hz to 1000Hz to described viscoelastic medium.This utility model only adopts simple measuring probe promptly to finish the measurement of ofelasticity of viscoelastic medium, measures the elasticity of viscoelastic medium by Displacement Estimation, and is simple in structure, cost is low, computational methods are easy.
Above content be in conjunction with concrete preferred implementation to further describing that this utility model is done, can not assert that concrete enforcement of the present utility model is confined to these explanations.For this utility model person of an ordinary skill in the technical field, under the prerequisite that does not break away from this utility model design, can also make some simple deduction or replace, all should be considered as belonging to protection domain of the present utility model.