Summary of the invention
A kind of shearing wave imaging method and system is provided, detection signal-to-noise ratio is promoted, reduces the detection number of redundancy, accelerates inspectionSurvey process.
A kind of shearing wave imaging method, includes the following steps,
Shearing wave is generated in organization internal；
The shearing wave is estimated in the position of different moments, the corresponding shearing wave sends multiple in the position of different momentsTracking pulse and the echo information for receiving the tracking pulse；
Shearing wave parameter is carried out according to the echo information of the tracking pulse to calculate；
The result that the imaging display shearing wave parameter calculates.
Further, when estimating shearing wave, the corresponding shearing wave sends repeatedly tracking pulse in the position of different momentsAnd when receiving the echo information of the tracking pulse, further comprise the steps,
Shearing wave is estimated in the spread speed in destination organization；
Shearing wave is estimated at various moments in the target group in the spread speed in destination organization according to the shearing waveShearing wave in knitting estimates position；
Position is estimated to corresponding shearing wave respectively at each moment and sends tracking pulse, and receives each tracking arteries and veinsThe echo information of punching.
Further, when obtaining the shearing wave of the shearing wave at various moments and estimating position, the shearing wave away fromThe positional distance of wave sourceMeet:
Wherein, the tkAny moment after being generated for shearing wave, the t0It is originated for the shearing wave and propagates the moment,It is shearing wave in the average speed propagated in the destination organization.
Further, the moving distance of shearing wave detection position is less than or equal to c Δ t between adjacent detection moment twice,And the detection width of shearing wave is greater than or equal to Δ t (c when detecting every timeh-cl), wherein the change of the shear wave velocity estimatedChange range is clTo ch, Δ t is the time interval of adjacent detection moment twice.
Further, when carrying out shearing wave parameter calculating according to the echo information of the tracking pulse, to the shearing wavePropagation distance, the spread speed of shearing wave, at least one of the Young's modulus of destination organization calculated.
Further, according to it is described tracking pulse echo information carry out shearing wave parameter calculate when, further comprise withLower step:
Set reference information；
By the echo information reference corresponding with the position of the tracking pulse of the different moments of position each in target areaInformation is done cross-correlation and is compared, and the particle displacement data of different moments at the position are obtained.
Further, when setting reference information, select the echo information of tracking pulse at a certain moment as reference informationOr reference pulse is sent before shearing wave is propagated, and using the echo information of the reference pulse as Control echo information.
Further, when carrying out shearing wave parameter calculating according to the echo information of the tracking pulse, the shearing waveSpread speed meets following formula:
In formula, c indicates spread speed, uzLength travel data can be considered as, longitudinal velocity data can also be used and countedIt calculates, x represents lateral coordinates, and z represents longitudinal coordinate.
Further, when the result that the imaging display shearing wave parameter calculates, spread speed distribution map, Young mould are formedMeasure Parameter Map, modulus of shearing Parameter Map, the propagation distance Parameter Map in certain time, the average speed value parameter in target areaAt least one of figure.
A kind of shearing wave imaging system, including ultrasonic probe, control module, signal processing module, computing module and displaySystem, the ultrasonic probe are equipped with transceiver module, and the transceiver module of the ultrasonic probe, computing module, is shown signal processing moduleShow that system is sequentially connected, the control module is connected to the transceiver module,
The transceiver module is used to estimate position transmitting tracking pulse according to shearing wave, and receives the tracking pulse and instituteState the echo information of reference pulse；
The control module is for controlling the transceiver module transmitting tracking pulse；
The signal processing module is used to carry out Signal Pretreatment to echo information；
The computing module estimates position for estimating shearing wave of the shearing wave in different moments, and to signal processing moduleThe signal of output carries out processing calculating；
The display system is for performing image display the shearing wave parameter calculated result that the computing module generates.
Further, the computing module includes,
Unit is estimated, for the propagation duration and shearing wave according to shearing wave in the average speed propagated in the destination organizationDegree estimates the shearing wave of the shearing wave at various moments and estimates position.
Data Computation Unit, for calculating the propagation parameter of shearing wave.
Shearing wave imaging method and system provided by the invention pre-estimates the detection position of shearing wave, so that shearing waveDetection can accurately be carried out with small range so that detection energy Relatively centralized, promoted detection signal-to-noise ratio.It also reduces simultaneouslyThe detection number of redundancy accelerates detection process, mitigates data processing load.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, completeSite preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based onEmbodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every otherEmbodiment shall fall within the protection scope of the present invention.
Referring to Fig. 1, better embodiment of the present invention provides a kind of shearing wave imaging method, the inspection of shearing wave is estimated in advanceLocation is set, so that the detection of shearing wave can accurately be carried out with small range, so that detection energy Relatively centralized, promotes detectionSignal-to-noise ratio.The detection number of redundancy is also reduced simultaneously, accelerates detection process, mitigates data processing load.
Shearing wave imaging method of the invention the following steps are included:
Step S101 generates shearing wave in organization internal.In this step, various methods can be used to generate in organization internalShearing wave can also be by organization internal transmitting sound as generated shearing wave in organization internal by the external force vibration outside tissueThe modes such as radiation force pulses (ARFI, acoustic radiation force impulse) generate shearing wave in organization internal.Wherein, the acoustic radiation force pulse can focus, can also be without focusing.
It is understood that since shearing wave itself amplitude that transmitting acoustic radiation force pulse generates is smaller, and due to shearingWave can decay rapidly with propagating, therefore the intensity of shearing wave can be improved by emitting a series of acoustic radiation force pulses, orThe spread scope of shearing wave is widened, or changes shearing wave wave character and has improved detection sensitivity etc., to avoid due to cuttingCut the influence of fading imaging of wave.
As shown in Fig. 2, can continuously emit multi-focusing pulse to the same position, to improve the strong of produced shearing waveDegree.As shown in Figure 3,4, can to change the longitudinal direction (direction for referring to focus emission) of focusing pulse that continuously emit and laterally (refer toThe vertical direction of focus emission) position, to widen the spread scope of shearing wave, and shearing wave is passed along certain specific directionIt broadcasts.As shown in figure 5, pulse can be emitted in different lateral positions simultaneously, so that two shearing wave waves that successively different time reachesShape stacks up, and facilitates detection.
Step S102 estimates the shearing wave in the position of different moments, and the corresponding shearing wave is in the position of different momentsSet the echo information for sending repeatedly tracking pulse and receiving the tracking pulse.
The step S102 is further included steps of
Step S1021 estimates shearing wave in the spread speed in destination organization.
After shearing wave generates, start to propagate in the tissue, with the difference of tissue elasticity characteristic, it is different for propagating speed's.Shearing wave is pursued and attacked in order to estimate, needs to estimate an average speed according to destination organizationAnd estimate possible velocity variationsRange clTo ch, this average speed and range can refer to existing academic measurement data or measurement experience etc., by systemAccording to circumstances preassign.For example assume that the mean propagation velocity of shearing wave in destination organization is about 2m/s, possible variation modelIt encloses for 1~4m/s etc., or assumes that its mean propagation velocity is 1m/s, possible variation range is 0.5~2m/s etc..
Step S1022, according to the shearing wave in the spread speed in destination organization estimate shearing wave at various moments inPosition in the destination organization obtains the shearing wave of the shearing wave at various moments and estimates position.
Different moments t after shearing wave generationk, it is assumed that shearing wave starting propagates the moment as t0, then it can be estimated away from waveThe positional distance in sourceMeet following formula relationship:
Assuming that the time interval of adjacent detection moment twice is Δ t, that is, meet: Δ t=tk-tk-1, then can estimate twiceThe spread scope Δ d of shearing wave between detection momentl~Δ dh, meet:
Δdl=clΔt
Δdh=chΔt
Then, the moving distance of shearing wave detection position is less than or equal to Δ d between adjacent detection moment twicel, avoidShearing wave estimates positioning in advance when propagating too slow, while the detection width of shearing wave is greater than or equal to Δ d when each detectionh-Δdl=Δ t (ch-cl), to guarantee that estimating positioning every time can include all possible positions of moment shearing wave.
Step S1021 estimates position to corresponding shearing wave respectively at each moment and sends tracking pulse, and receivesThe echo information of each tracking pulse.
As shown in fig. 6, system sends tracking pulse with lasting detection, often with interval of delta t since shearing wave propagates startingSecondary detection keeps certain detection lateral beam width, i.e., withdraws the echo information of one fixed width simultaneously, and echo information includesThe interval of the information of each lateral position in above-mentioned one fixed width, lateral position cannot guarantee greatly very much certain lateral resolutionPower.Meanwhile beam center remains less than Δ d between adjacent detectionlMoving distance, or if Δ t is smaller to lead to Δ dlTooIt is small, then it is also equivalent to and remains less than n Δ d every beam center distance between n detection momentlMoving distance.Certainly, systemIt can detect since any time or be detected since apart from shearing wave wave source certain distance, only be needed first according to average propagationUnder velocity estimation under current position or current time shearing wave possible position, need equal shearing waves to pass to the positionJust start to change the center detected every time after setting and leaving.
Due to detecting the lateral beam width that must keep certain every time, and x wire spacing cannot be too greatly to guarantee centainlyTransverse resolution, then may require system and have a ultra-wide wave beam synthesis capability, i.e., withdraw the echo of multiple lateral positions simultaneouslyThe ability of information, as shown in Figures 7 and 8.Wave beam number such as 1~1024, system is adjusted as needed, such as 4 wave beams, 16 wavesBeam, 32 wave beams, 64 wave beams, 96 wave beams, 128 wave beams etc..Wave beam is wider, then means that the focusing for emitting sound field is weaker, sound field energyThe cross direction profiles the uniform does not concentrate for amount, this can also bring the reduction of the signal-to-noise ratio of each detection position in wave beam simultaneously.In order toImprove detection quality, to the same center, can continuously emit repeatedly, the angle of each launching beam is different, then willThe echo-signal of different angle is synthesized to increase signal-to-noise ratio.Angle number and the size of deflection angle are all by system according to realityBorder needs to adjust, for example uses 3 angles, -5 °, 0 °, 5 ° of deflection etc..
Step S103 carries out shearing wave parameter according to the echo information of the tracking pulse and calculates.According to the tracking arteries and veinsThe echo information of punching can calculate many kinds of parameters, such as propagation distance, spread speed, Young's modulus etc..
In this step, it can be integrated by the echo information of the tracking pulse to each moment, to obtain shearingEcho information at each position of wave destination organization in communication process in a bit of time, and shearing wave is just a bit of at thisPass through the corresponding position in time.
The step S103 is further included steps of
Step S1031 obtains reference information；It is understood that the reference information can be selected voluntarily as needed.Such asSelect the echo information of tracking pulse at corresponding position a certain moment as reference information.Ginseng can also be sent before shearing wave is propagatedPulse is examined, and using the echo information of the reference pulse as Control echo information.The reference is needed for cutting with to describedIt cuts the tracking pulse that wave is pursued and attacked and does cross-correlation and compare.
Step S1032, by the echo information of the tracking pulse of the different moments of position each in target area and the positionCorresponding reference information does cross-correlation and compares, and obtains the particle displacement data of different moments at the position.Further, it can be formedDisplacement-time curve at the position, during this period of time, shearing wave can undergo full mistake that is close, reaching and leave the positionThere is wave crest in journey, homologous thread.As shown in figure 5, pursuing and attacking detection due to estimating, it is small that each lateral position can obtain corresponding oneSection displacement-time curve, it is different at the time of only curve corresponds to, it might have a part of overlapping at the time of adjacent position corresponds to.Displacement-time curve upward peak position is at the time of corresponding to shearing wave to reach the position.
There are many calculation methods can be used for the spread speed of shearing wave, for example, to two in same depth different lateral positionsCorresponding displacement-time curve carries out cross-correlation comparison, corresponding time difference between available two lateral position, this whenBetween difference correspond to shearing wave propagation time between the two lateral positions.The ratio between distance and propagation time between lateral position are i.e.Spread speed between the two row positions.
For example, taking out shearing wave to some position and reaching corresponding each cross of neighbouring two moment at position momentTo the displacement data of position, the displacement-lateral position curve at two moment is formed, carrying out cross-correlation to two curves can relatively obtainLateral position difference between two moment, the alternate position spike have corresponded to the propagation distance of the shearing wave between the two moment.The ratio between propagation distance and twice differences are the spread speed near the position.
For example directly it can derive that approximate formula is as follows using the propagation equation of wave:
In formula, c indicates spread speed, uzLength travel data can be considered as, longitudinal velocity data can also be used and countedIt calculates, x represents lateral coordinates, and z represents longitudinal coordinate.Above-mentioned formula frequency domain can also be transformed to calculate.
Under certain condition, the spread speed with tissue hardness of shearing wave have approximate fixed relationship:
E=3 ρ c2
In formula, ρ indicates tissue density, and E indicates the Young's modulus value of tissue.Under certain condition, Young's modulus is bigger, meaningTissue hardness it is bigger.
In addition, the spread speed value of the shearing wave from each position, can also further calculate to obtain modulus of shearing, certain section solidThe mean propagation velocity etc. in propagation distance, target area in fixing time.
Step S104, the result that the imaging display shearing wave parameter calculates.
It is each on figure it will be shown in can form spread speed distribution map on image after obtaining final spread speed dataSpread speed difference between position directly reflects its nonhomogeneous hardness.It is of course also possible to show other parameters figure, such as Young mouldMeasure Parameter Map, modulus of shearing Parameter Map, the propagation distance Parameter Map in certain time, the average speed value parameter in target areaFigure etc..To above-mentioned parameter, film figure, plane or spatial distribution map, parameter value, curve graph can be become by certain processing displayDeng grayscale or coloud coding can also be used, display together after can also being overlapped or merge with other ideographs such as internal anatomy.
As shown in figure 9, the present invention also provides a kind of shearing wave imaging system, including ultrasonic probe 11, control module 12, letterNumber processing module 13, computing module 15 and display system 17, the ultrasonic probe 11 are equipped with transceiver module 110, and the ultrasound is visitedFirst 11 transceiver module 110, signal processing module 13, computing module 15, display system 17 are sequentially connected, the control module 12It is connected to the transceiver module 110.
Wherein:
The transceiver module 110 is used to emit tracking pulse, and receives the tracking pulse and time of the reference pulseWave number evidence.
The control module 12 is for controlling the transmitting of the transceiver module 110 tracking pulse.In actual use, the controlModule 12 emits the specific ultrasonic sequence that tracking pulse is constituted according to prefixed time interval, consequently facilitating pursuing and attacking shearing wave and supplyingThe transceiver module 110 of the ultrasonic probe 11 receives corresponding echo data.
The signal processing module 13 is used to carry out Signal Pretreatment to echo data, consequently facilitating computing module 15 carries outSubsequent calculating, the Signal Pretreatment may include Beam synthesis processing, may also include such as signal amplification, analog-to-digital conversion, orthogonal pointSolution etc..
Computing module 15 is for estimating shearing wave in the position of different moments, and for for exporting to Beam synthesisSignal carries out processing calculating.
In the present embodiment, the computing module 15 includes:
Unit 151 is estimated, for flat in what is propagated in the destination organization according to the propagation duration and shearing wave of shearing waveEqual speed estimates the shearing wave of the shearing wave at various moments and estimates position.
Data Computation Unit 153, for calculating the propagation parameter of shearing wave.
Display system 17 is for performing image display the shearing wave parameter calculated result that the computing module 15 generates.
It is understood that the ultrasonic probe 11, control module 12, signal processing module 13, computing module 15 and aobviousShow that the physics setting position of system 17 can voluntarily adjust as needed, it such as can be by ultrasonic probe 11, control module 12, signal processingModule 13, computing module 15 and display system 17 are uniformly set in same housing, to realize integrated setting；It can also be usedSplit settings, and be connected by wired or wireless mode to carry out data communication.
Shearing wave imaging method and system provided by the invention generates shearing wave in organization internal, and whithin a period of timeThe communication process for estimating and pursuing and attacking shearing wave pursues and attacks position as the progress of propagation constantly changes, therefore each moment only needs fastlyFast small range obtains it and propagates location information, then integrates gained information, calculates shearing wave wavefront in target areaThe related parameter with elasticity such as film figure, propagation distance, spread speed, is ultimately imaged to reflect the poor flexibility between different tissuesIt is different.The detection position of shearing wave imaging method of the invention due to having estimated shearing wave in advance, so that the detection of shearing wave can be withSmall range accurately carries out, so that detection energy Relatively centralized, promotes detection signal-to-noise ratio.The inspection of redundancy is also reduced simultaneouslyNumber is surveyed, detection process is accelerated, alleviates the data processing load of system.
Above disclosed is only a preferred embodiment of the present invention, cannot limit the power of the present invention with this certainlySharp range, those skilled in the art can understand all or part of the processes for realizing the above embodiment, and weighs according to the present inventionBenefit requires made equivalent variations, still belongs to the scope covered by the invention.