WO2020113381A1 - Ultrasonic imaging method and apparatus - Google Patents

Abstract

Disclosed are an ultrasonic imaging method and apparatus. A particular position is selected in the internal space of an annular array probe as a virtual sound source for simulating an ultrasonic emission source. By simulating the simulation duration for ultrasonic waves emitted by the virtual sound source reaching each array element in the annular array probe, simulation time points at which respective array element emit ultrasonic waves can be determined separately. For each array element to emit the ultrasonic wave according to the corresponding simulation time point is, in fact, similar to emitting a spherical ultrasonic wave from the virtual sound source. On this basis, since there are ultrasonic echo signals at various positions of a tissue area scanned by the ultrasonic waves, an ultrasonic image can be formed on the basis of received ultrasonic echo signals. On the basis of the solution of the present application, a radio frequency signal image for generating an ultrasonic image can be obtained only by controlling to each array element to transmit an ultrasonic wave once, so that fast imaging by an ultrasonic endoscope system having an annular array probe is implemented.

Description

Ultrasound imaging method and device Technical field

The invention belongs to the field of medical ultrasound imaging, and particularly relates to an ultrasound imaging method and device.

Background technique

Ultrasound endoscopy is a widely used ultrasound diagnostic technology. It generally refers to the digestive tract examination technology that combines an optical endoscope and an ultrasound probe. A miniature high-frequency ultrasound probe is placed on the top of the endoscope, which can be directly observed through the endoscope The morphology of the tract cavity can also be real-time ultrasound scanning to obtain the histological characteristics of the layered structure of the digestive tract and ultrasound images of the surrounding organs.

At present, in an ultrasound endoscope system with a ring array probe, ultrasound imaging is performed according to a focused scanning line imaging method, multiple scanning lines are obtained through multiple emission focusing, and an ultrasound image is formed by the multiple scanning lines.

In this way, each array element needs to be transmitted multiple times, and it takes a long time to significantly reduce the imaging frame rate. The reduction in imaging frame rate makes ultrasound imaging slow, which limits the application of ultrasound endoscopy systems in applications that require high frame rates, such as blood flow imaging.

Summary of the invention

In view of this, the object of the present invention is to provide an ultrasound imaging method and device, so that an ultrasound endoscopic system with a ring array ultrasound probe can quickly image.

To achieve the above objective, on the one hand, the present application provides an ultrasound imaging method, which is applied to an ultrasound endoscope system, the ultrasound endoscope system having a ring array probe, including:

From the internal space of the ring array probe, determine a location point for simulating an ultrasonic emission source;

For each array element on the ring array probe, determine the simulation duration required to propagate the ultrasound emitted by the position point to the array element;

According to the simulation time corresponding to each array element on the ring array probe, determine the simulation time at which the ultrasonic waves simulated at the position point are respectively emitted through each array element, wherein the estimated time based on the simulation time of each array element is The starting moments of the simulated simulated ultrasonic waves at the location points are the same;

For each array element, when the simulation time corresponding to the array element is reached, the array element is controlled to emit ultrasonic waves;

Based on the ultrasound echo signals received by each array element, a radio frequency signal image for generating an ultrasound image is generated.

Preferably, after generating a radio frequency signal image for generating an ultrasound image, the method further includes:

An ultrasound image is generated based on the radio frequency signal image.

Preferably, after generating the radio frequency signal image used for generating the ultrasound image, the method further includes:

Detecting whether the number of position points for simulating the ultrasonic emission source determined from the internal space of the ring array probe reaches a preset number;

If no, from the internal space of the ring array probe, a point not selected as the position point is selected as the position point for simulating the ultrasonic emission source, and based on the currently determined position point, return to execute the For each array element on the ring array probe, determine the simulation time required for the ultrasound emitted by the position point to propagate to the array element, and obtain the RF signal image generated at the currently determined position point;

If so, according to the radio frequency signal images respectively generated with the preset number of position points, pixel point amplitudes are superimposed to obtain a superimposed radio frequency signal image;

Based on the superimposed radio frequency signal image, an ultrasound image is generated.

Preferably, the determining, according to the simulation time corresponding to each array element on the ring array probe, the simulation time at which the ultrasonic waves simulated by the position point are emitted through each array element respectively includes:

From the ring array probe, determine the corresponding reference array element with the shortest simulation duration, and set the simulation time at which the ultrasonic waves simulated at the position point are emitted through the reference array element;

Determining the relative simulation time difference between each array element and the reference array element;

Based on the relative simulation time difference between each array element and the reference, and the simulation time corresponding to the reference array element, the simulation time at which the ultrasonic waves simulated at the position point are emitted through each array element is determined.

Preferably, the generating an RF signal image for generating an ultrasound image based on the ultrasound echo signals received by each array element includes:

From the biological tissue detected by ultrasound, determine the tissue location point corresponding to each pixel point in the radio frequency signal image to be generated;

For each pixel point corresponding to the tissue position point, from the ultrasound echo signals received by the respective array elements, the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position point is determined;

The radio frequency signal image is generated based on the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position corresponding to each pixel.

Preferably, the ultrasonic echo signals received from each array element determine the signal intensity amplitude of the ultrasonic echo signal scattered by the tissue location point, including:

For each array element, determine the length of time that the emitted ultrasonic wave returns to the array element position through the tissue position point;

Determining the sampling interval duration of the channel corresponding to the array element for sampling the ultrasonic echo signal;

For each sampling point obtained by sampling the ultrasonic echo signal from the channel corresponding to the array element, determining the sampling time of the sampling point relative to the starting time of the location point at which the simulated ultrasound is emitted;

Judging whether the absolute value of the difference between the sampling duration of the sampling point and the duration of the emitted ultrasonic wave returning to the array element via the tissue position point is less than or equal to the sampling interval duration;

If yes, determine that the sampling point can reflect the ultrasound echo information scattered from the tissue position point;

The amplitudes of the sampling points that can reflect the ultrasonic echo information scattered from the tissue position point in the channels corresponding to the respective array elements are superimposed to obtain the signal intensity amplitude of the ultrasonic echo signal scattered from the tissue position point.

Preferably, the length of time that the determined emitted ultrasonic wave returns to the position of the array element through the tissue position point includes:

Construct a coordinate system on the plane of the ring formed by the array elements arranged in the ring array probe,

Determine the coordinates of the position point in the coordinate system;

Determine the coordinates of the array element in the coordinate system;

Determine the coordinates of the pixel point corresponding to the tissue position point in the coordinate system;

Determine the forward transmission duration of the ultrasonic wave based on the coordinates of the pixel point corresponding to the tissue position point, the coordinates of the position point and the propagation speed of the ultrasonic wave;

Determine the duration of reverse transmission of the ultrasonic wave based on the coordinates of the pixel point corresponding to the tissue position point, the coordinates of the array element and the propagation speed of the ultrasonic wave;

Adding the forward transmission duration and the reverse transmission duration to obtain the duration of the emitted ultrasonic wave returning to the array element location through the pixel corresponding to the tissue location point.

Preferably, the generating an ultrasound image according to the radio frequency signal image includes:

The radio frequency signal image is subjected to signal envelope, logarithmic compression, dynamic range adjustment, and digital scan transformation to generate an ultrasound image.

On the other hand, the present application provides an ultrasound imaging device, which is applied to an ultrasound endoscopic system, the ultrasound endoscopic system having a ring array probe, including:

A position point determination unit, used to determine a position point for simulating an ultrasonic emission source from the internal space of the ring array probe;

The simulation time determining unit is used to determine, for each array element on the ring array probe, the simulation time required for the ultrasound emitted by the location point determined by the location point determining unit to propagate to the array element;

A simulation time determination unit, configured to determine the simulated ultrasound emitted by the position point determined by the position point determination unit according to the simulation time period corresponding to each array element on the ring array probe determined by the simulation time determination unit The simulation time shot through each array element respectively, wherein the starting time for simulating the emission of ultrasonic waves at the position point calculated based on the simulation time of each array element is the same;

A control transmitting unit, for each array element, when the simulation time corresponding to the array element determined by the simulation time determination unit is reached, the array element is controlled to transmit ultrasonic waves;

The image generating unit is used to generate a radio frequency signal image for generating an ultrasound image based on the ultrasound echo signals received by the respective array elements.

Preferably, the ultrasound imaging device further includes:

A detection unit, configured to detect whether the number of position points for simulating the ultrasonic emission source determined from the internal space of the ring array probe reaches a preset number; if not, trigger the first processing unit to execute; if yes, trigger The second processing unit executes;

The first processing unit is used to select a point that is not selected as the position point from the internal space of the ring array probe as the position point for simulating the ultrasonic emission source, and based on the currently determined position point , Triggering the simulation duration determination unit to execute, to obtain a radio frequency signal image generated at the currently determined position point;

The second processing unit is configured to superimpose pixel amplitudes based on the radio frequency signal images respectively generated with the preset number of position points to obtain a superimposed radio frequency signal image; and based on the superimposed RF signal image to generate ultrasound image.

As can be seen from the above solution, in the embodiment of the present application, a certain point in the internal space of the ring array probe is selected as the virtual sound source for simulating the ultrasonic emission source. By simulating the simulation time of the ultrasonic wave emitted by the virtual sound source reaching each element in the ring array probe, the simulation time for each element to emit ultrasound can be determined separately, and each element emits ultrasound according to the corresponding simulation time. Spherical ultrasonic waves are similarly emitted from the virtual sound source. On this basis, because ultrasonic waves are emitted at various positions in the tissue area to which the ultrasonic waves are scanned, an ultrasonic image can be formed based on the received ultrasonic echo signals. It can be seen that based on the solution of the present application, it is only necessary to control each array element to emit ultrasonic waves once to obtain the radio frequency signal image used to generate the ultrasonic image, so that it is possible to base on the obtained radio frequency without controlling each multiple ultrasonic waves Signal images generate ultrasound graphics. Compared with the existing focused scanning line imaging method, the imaging speed is greatly improved, and the rapid imaging of the ultrasonic endoscope system with the ring array probe is realized.

BRIEF DESCRIPTION

FIG. 1 is a schematic diagram of the composition architecture of an ultrasound endoscope system applicable to the ultrasound imaging method according to the embodiment of the present application;

2 is a schematic flowchart of an ultrasound imaging method according to an embodiment of the present application;

3 is a schematic flowchart of generating an RF signal image according to an embodiment of the present application;

4 is another schematic flowchart of an ultrasound imaging method according to an embodiment of the present application;

5 is a simulation experiment result of the ultrasound imaging method of the embodiment of the present application;

6 is a schematic diagram of a composition of an ultrasound imaging apparatus according to an embodiment of the present application.

detailed description

In order to facilitate understanding of the scheme of this application, first introduce some technical terms, abbreviations or abbreviations involved in the scheme of this application:

Frame rate: the number of imaging frames per second.

Focused scanning line imaging: Exciting multiple array elements, which may be all the array elements of the probe, or may be several adjacent array elements, so that the ultrasonic waves emitted by these array elements are focused to a certain position, and then these array elements The signals received by the element returning from this point are accumulated together, so that one transmission and one reception form a scan line. Repeat the above process to focus and receive at different positions, obtain multiple scan lines, and convert the multiple scan lines into an ultrasound image.

An ultrasound imaging method and device according to an embodiment of the present application are suitable for increasing the frame rate of an ultrasound endoscope system with a ring array ultrasound probe, so that the ultrasound endoscope system with a ring array ultrasound probe can quickly image.

The technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

In order to facilitate understanding, the ultrasound endoscope system applicable to the solution of the present application will be introduced first. For example, referring to FIG. 1, it shows a schematic diagram of the composition architecture of an ultrasound endoscope system applicable to the ultrasound imaging method of the present application.

The ultrasound endoscope system 100 shown in FIG. 1 includes an ultrasound probe 10, an ultrasound transmitting module 20, an ultrasound receiving module 30, a processing module 40, and a display module 50.

Among them, the ultrasonic probe 10, also called an ultrasonic transducer, is an acoustic-electric reversible conversion device, which can convert high-frequency electrical energy into ultrasonic mechanical energy to radiate outward, and receive ultrasonic echoes to convert acoustic energy into electrical energy.

The ultrasound probe 10 may include multiple array elements. Considering factors such as hardware cost, the number of array elements is between 128-256. In this application, these array elements are arranged in a ring shape, which may be called a ring array probe. Among them, each array element can be excited to emit ultrasonic waves in different chronological order. The ultrasonic waves emitted by each array element are coherently superimposed to form an ultrasonic wave propagating outwards with different forms of wave arrays. At a certain point, it can also be a plane wave or a spherical wave; in this application, all the array elements are excited in a specific time sequence, and the emitted ultrasonic wave propagates outward in the form of a spherical wave.

The ultrasound transmitting module 20 is connected to the ultrasound probe 10 and is used to send out voltage pulse signals to excite each array element of the ultrasound probe 10 to send out ultrasound waves.

The ultrasound receiving module 30 is connected to the ultrasound probe 10, and is used to receive ultrasound echo signals received by the various array elements of the ultrasound probe 10, wherein the ultrasound echo signals may be voltage signals.

The processing module 40 is connected to the ultrasound transmitting module 20 and the ultrasound receiving module 30, and is used to control the ultrasound transmitting module 20 to excite each element of the ultrasound probe 10, and can also be used to obtain the ultrasound echo signal received by the ultrasound receiving module. And use ultrasound echo signals to generate ultrasound images.

The display module 50 is connected to the processing module 40 and is used to display the generated ultrasound image for the user to view the ultrasound image.

The ultrasound imaging method in the embodiments of the present application will be described below in conjunction with a flowchart. For example, referring to FIG. 2, which shows a schematic flowchart of an embodiment of the ultrasound imaging method of the present application. The method of this embodiment is applied to an ultrasound endoscope system having a ring array probe. The ultrasound endoscope system 100 mentioned above may be used. The processing module 40 in executes, the method may include:

S201: Determine a position point for simulating an ultrasonic emission source from the internal space of the ring array probe.

The internal space of the ring array probe refers to the ring area formed by the array elements in the probe. The position point can be any point in the ring area, which can be set according to actual needs. This application does not limit this, such as ring The center of the area.

It should be noted that, because the purpose of selecting the location point is to control the timing of transmitting ultrasonic waves by each array element, so that each of the transmitted ultrasonic waves can form a spherical ultrasonic wave similar to that emitted from the location point, therefore, the selected location point In fact, the virtual sound source used to simulate the spherical ultrasonic wave is selected.

S202: For each array element on the ring array probe, determine the simulation duration required for the ultrasonic wave simulated by the position point to propagate to the array element.

It can be understood that, because the location point is only a virtual sound source and does not have the ability to emit ultrasonic waves, this step actually simulates the location point assuming that the location point can emit ultrasonic waves. The time required for the emitted ultrasonic wave to propagate to each array element. Among them, in order to facilitate the distinction, the time required for simulating the ultrasonic wave emitted at this position to propagate to the array element is called the simulation time.

Wherein, the simulation time required to simulate the ultrasonic wave emitted by the position point to propagate to the array element can be calculated based on the distance between the position point and the position of the array element and the propagation speed of the ultrasonic wave.

In specific implementation, the center point of the ring is taken as the center of the circle, and any two vertical directions on the plane where the ring is located are the x direction and the z direction to establish a coordinate system. Select a certain point in the ring as the virtual sound source i, the coordinates are (x _i , z _i ).

Suppose that the virtual sound source i emits ultrasonic waves and propagates outward in the form of spherical waves. Using formula one, the simulation duration t _i (j) required by the virtual sound source i to simulate the ultrasonic wave propagating to the array element j can be calculated.

Where c is the propagation speed of ultrasound in tissue, generally defined as 1540 m/s. j represents an array element of the ring array probe, (x _j , z _j ) is the position coordinate of array element j.

S203, according to the simulation duration corresponding to each array element on the ring array probe, determine the simulation time at which the ultrasonic waves simulated by the position point are respectively emitted through each array element.

Similar to the previous simulation duration, since the location point does not emit ultrasonic waves, in step 203, it is actually simulated that the location point emits ultrasonic waves at a certain time point, and the ultrasonic waves emitted from the location point at this time point pass through the array The moment when the element is emitted is called the simulation moment.

It can be understood that the basis for determining the simulation time of each array element is to ensure that the ultrasound emitted by each array element can form a spherical ultrasonic wave similar to the position point. Therefore, the simulation based on the simulation time of each array element is used to simulate The starting moments of the ultrasonic waves are all the same.

It can be understood that there are many different implementations for determining the simulation time of each array element. In a possible implementation, a ring array probe may be used to determine the corresponding reference array element with the shortest simulation duration, and set the simulation time at which the simulated ultrasound emitted at the selected position point is emitted through the reference array element to determine each array element The relative simulation time difference with the reference array element, based on the relative simulation time difference between each array element and the reference array element and the simulation time corresponding to the reference array element, determine the simulation of the ultrasonic waves emitted from the position point through each array element time.

In a specific implementation, based on the above calculated t _i (j), the relative simulation time difference Δt _i (j) between each array element and the reference array element can be obtained by using formula two.

□t _i (j)=t _i (j)-min(t _i (j)) (Formula 2);

Among them, min(t _i (j)) is the shortest simulation time. Take the array element corresponding to min(t _i (j)) as the reference array element, set the simulation time of the ultrasonic wave emitted from the selected position point through the reference array element to be t ₀ , on the basis of t ₀ , delay The time obtained by Δt _i (j) is the simulation time when the ultrasonic waves simulated at the position point are respectively emitted through the respective array elements.

It can be understood that if the number of array elements of the ring array probe is J, J analog time difference Δt _i (j) can be obtained.

For example, the ring array probe includes 5 array elements A, B, C, D, and E, and the simulation duration corresponding to each array element is 5 microseconds, 10 microseconds, 7 microseconds, 12 microseconds, and 8 microseconds, respectively. Taking the array element A with a simulation time of 5 microseconds as the reference array element, the relative simulation time difference between each array element and the reference array element is 0 microseconds, 5 microseconds, 2 microseconds, 7 microseconds, and 3 microseconds. The simulation time of element B is the simulation time of element A plus 5 microseconds, the simulation time of element C is the simulation time of element A plus 2 microseconds, and the simulation time of element D is the simulation time of element A plus 7 In microseconds, the simulation time of array element E is the simulation time of array element A plus 3 microseconds.

In another possible implementation, you can first determine the starting time to simulate the emission of ultrasonic waves at the location point, and based on the simulation time corresponding to each array element, determine the simulation of the ultrasonic waves emitted at the location point through each array element. time.

In the above example, the simulation time of element A is the start time minus 5 microseconds, the simulation time of element B is the start time minus 10 microseconds, and the simulation time of element C is the start time minus 7 In microseconds, the simulation time of array element D is the starting time minus 12 microseconds, and the simulation time of array element E is the starting time minus 8 microseconds.

S204: For each array element, when the simulation time corresponding to the array element is reached, the array element is controlled to emit ultrasonic waves.

Among them, each array element emits ultrasonic waves according to the corresponding simulation time, which is actually similar to the spherical ultrasonic wave emitted from the virtual sound source. .

S205: Generate a radio frequency signal image for generating an ultrasound image based on the ultrasound echo signals received by each array element.

It can be understood that, after the radio frequency signal image is obtained, the radio frequency signal image can be used to generate an ultrasound image for diagnosis.

Among them, in a possible implementation, generating an ultrasound image based on the radio frequency signal image includes: taking the signal envelope of the radio frequency signal image, logarithmic compression, adjusting the dynamic range, and digital scanning transformation to generate an ultrasound image. In this application, the ultrasound image may be a B-grayscale image.

In the embodiment of the present application, in the embodiment of the present application, a certain point in the internal space of the ring array probe is selected as the virtual sound source for simulating the ultrasonic emission source. By simulating the simulation duration of the ultrasound emitted by the virtual sound source to each element in the ring array probe, the simulation time for each element to emit ultrasound can be determined separately, and each element can emit ultrasound according to the corresponding simulation time. Spherical ultrasonic waves are similarly emitted from the virtual sound source. On this basis, because ultrasonic waves are emitted at various positions in the tissue area to which the ultrasonic waves are scanned, an ultrasonic image can be formed based on the received ultrasonic echo signals. It can be seen that, based on the solution of the present application, it is only necessary to control each array element to emit ultrasound once to obtain the radio frequency signal image used to generate the ultrasound image, so that it is possible to base on the obtained radio frequency without controlling each multiple transmission of ultrasound. Signal images generate ultrasound graphics. Compared with the existing focused scanning line imaging method, the imaging speed is greatly improved, and the rapid imaging of the ultrasonic endoscope system with the ring array probe is realized.

In the embodiments of the present application, a method of simulating the transmission of ultrasonic waves with a virtual sound source is adopted. The actually formed ultrasonic wave front is a regular shape, which can realize the accurate calculation of the forward propagation time during the ultrasonic wave transmission, so as to accurately determine the image pixel points The signal intensity amplitude of the ultrasonic echo signal scattered by the corresponding tissue position point is to obtain an image with high image quality. At the same time, the method of simulating the transmission of ultrasonic waves with a virtual sound source can reduce the interference of the ultrasonic waves emitted by each array element and form a wavefront with high signal strength. Accordingly, the signal strength of the ultrasonic echo signal is also high, which will Improve the signal-to-noise ratio, thereby improving the image quality of the generated image.

For ease of understanding, the manner of generating the radio frequency signal image in the above embodiment is specifically described below. Refer to FIG. 3, which shows a schematic diagram of a process for generating a radio frequency signal image for generating an ultrasound image in the present application, including:

S301: Determine, from the biological tissue detected by ultrasound, the tissue position point corresponding to each pixel point in the radio frequency signal image to be generated.

S302: Determine the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position point from the ultrasound echo signals received from various array elements for the tissue position point corresponding to each pixel point.

Among them, the ultrasonic echo signals received by each array element may include ultrasonic echo signals scattered from multiple tissue locations, and may also include noise signals, so it is necessary to screen the received ultrasonic echo signals from each array. Among the ultrasonic echo signals received by the cell, the ultrasonic echo signals scattered from the same tissue location point are screened out. In a possible implementation, screening the ultrasonic echo signals received by each array element includes:

S3011: For each array element, determine the length of time that the emitted ultrasonic wave returns to the location of the array element through the tissue position point.

Among them, the duration of the transmitted ultrasonic wave back to the position of the array element through the tissue position point includes the forward transmission time and the reverse transmission time of the ultrasonic wave, where the forward transmission time refers to the length of time that the ultrasonic wave reaches the tissue position point from the transmission position. Calculated based on the distance between the location point and the tissue location point and the propagation speed of ultrasonic waves. Reverse transmission duration refers to the length of time that the ultrasonic echo reaches the array element receiving the ultrasonic echo from the tissue position point, and can be calculated based on the distance between the tissue position point and the array element position and the propagation speed of the ultrasonic wave.

In specific implementation, the imaging plane and the plane of the ring formed by the array elements in the ring array probe are the same plane, with the center point of the ring as the center, and any two vertical directions on the plane of the ring are the x direction and the z direction. Under the established coordinate system, set the number of pixels of the ultrasound image to be generated as N = N _x × N _z , where N _x and N _z are the number of rows and columns of image pixels in the x and z directions, respectively The coordinates of n are expressed as (x _n , z _n ), n is 1, 2,... N.

Each pixel point corresponds to a certain tissue position point, and accordingly, the distance between the position point and a tissue position point can be calculated by (x _i , z _i ) and (x _n , z _n ) The distance between two points is obtained.

Formula 3 can be used to obtain the duration of the ultrasonic wave from the virtual sound source i to the tissue position corresponding to the pixel n.

Equation 4 can be used to obtain the duration of the ultrasonic wave returning from the tissue position corresponding to the pixel n to the array element j.

The total duration is:

t _total (n, j) = t _{i_forward} (n) + t _backward (n, j) (Formula 5);

Among them, t _{i_forward} (n) is the forward transmission duration, t _backward (n, j) is the reverse transmission duration, and t _total (n, j) is the emitted ultrasonic wave back to the matrix through the tissue position corresponding to the pixel The duration of the location of element j.

It is understandable that if the number of array elements of the ring array probe is J, N×J time delay data t _total (n, j) can be obtained.

S3012: Determine the sampling interval duration of the channel corresponding to the array element for sampling the ultrasonic echo signal.

Among them, the channel corresponding to each array element starts sampling the ultrasonic echo signal from the starting point of the simulated emission of ultrasonic waves at the location point, and the starting point of the simulated emission of ultrasonic waves from the location point is the sampling time of the first sampling point.

The sampling interval duration for sampling the ultrasonic echo signal by the channel corresponding to each array element, that is, the interval duration between two sampling points, can be obtained by the sampling frequency.

S3013: For each sampling point obtained by sampling the ultrasonic echo signal from the channel corresponding to the array element, determine the sampling time of the sampling point relative to the sampling point of the starting time at which the position point simulates the start of ultrasonic wave emission.

Among them, in a possible implementation, the sampling time of the sampling point relative to the sampling time of the starting point at which the simulated ultrasonic wave is emitted at the location point can be obtained by: obtaining the sampling frequency of the ultrasonic echo signal from the channel corresponding to the array element For each channel corresponding to each array element, obtain the sampling number of each sampling point; based on the sampling frequency and sampling number, determine the sampling time of each sampling point relative to the location point to simulate the time of the ultrasound emission.

During specific implementation, the sampling time of the d-th sampling point of the channel corresponding to the j-th array element receiving the ultrasonic echo RF signal relative to the sampling time t _j (d) of the ultrasonic transmission time is:

t _j (d) = (d-1)/f _s (Formula 6);

Among them, f _s is the sampling frequency.

It can be understood that the number of sampling points of each array element is D, and D×J sampling durations can be obtained.

S3014: Determine whether the absolute value of the difference between the sampling duration of the sampling point and the duration of the emitted ultrasonic wave returning to the array element through the tissue position point is less than or equal to the sampling interval duration;

S3015. If yes, determine that the sampling point can reflect the ultrasound echo information scattered from the tissue position point.

In specific implementation, for t _j (d) corresponding to the d-th sampling point in the channel corresponding to the j-th array element, search in all t _total (n, j) which also corresponds to the channel j, if丨t _j (d)－t _total (n,j)丨≤1/f _s , it is considered that the d-th sampling point in the j-th channel reflects the ultrasonic echo information scattered from the tissue position point n.

S3016, superimposing the amplitudes of the sampling points in the channel corresponding to each array element that can reflect the ultrasonic echo information scattered from the tissue position point to obtain the signal intensity amplitude of the ultrasonic echo signal scattered from the tissue position point.

In specific implementation, the amplitudes d _j of the sampling points that can reflect the ultrasonic echo information scattered from the tissue position point in the channels corresponding to all array elements are summed to obtain the amplitude P _n of the scattered signal intensity at the tissue position point _n .

It can be understood that the stronger the scattering coefficient, the greater the amplitude of the signal strength.

S303. Generate a radio frequency signal image based on the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position corresponding to each pixel.

It is understandable that the signal intensity amplitudes of the ultrasonic echo signals scattered by the tissue positions corresponding to all pixels are plotted as a two-dimensional image, which reflects the distribution of tissues with different ultrasonic scattering coefficients in the tissue, that is, the obtained An RF signal image.

In the first embodiment described above, since actually formed ultrasonic waves propagating outward in the form of spherical waves are not focused, the imaging quality is not high. Moreover, the angle between adjacent array elements is large, and the sound wave energy is rapidly dispersed during transmission. Only a few array elements can receive the echo signal in a certain direction during reception, and the signal-to-noise ratio is low, which also leads to poor imaging quality. In order to improve the imaging quality, for example, refer to FIG. 4, which shows a schematic flowchart of another embodiment of the ultrasonic imaging method of the present application. The method includes:

S401: Determine a position point for simulating an ultrasonic emission source from the internal space of the ring array probe.

S402. For each array element on the ring array probe, determine the simulation duration required for the ultrasonic wave emitted by the position point to be propagated to the array element.

S403: According to the simulation duration corresponding to each element on the ring array probe, determine the simulation time at which the ultrasound emitted by the position point is emitted through each element.

Among them, the starting time of the simulated emission of ultrasonic waves at the position point calculated according to the simulation time of each array element is the same.

S404: For each array element, when the simulation time corresponding to the array element is reached, the array element is controlled to emit ultrasonic waves.

S405: Generate a radio frequency signal image for generating an ultrasound image based on the ultrasound echo signals received by each array element.

For steps S401-S405, reference may be made to the introduction of the above embodiments, and details are not repeated here.

S406: Detect whether the number of position points for simulating the ultrasonic emission source determined from the internal space of the ring array probe reaches a preset number; if not, perform step S407, and if yes, perform step S408.

S407, select a point not selected as a position point from the internal space of the ring array probe as the position point for simulating the ultrasonic emission source, and based on the currently determined position point, return to execute steps S402 to S405 to obtain the current The radio frequency signal image generated at the determined position.

S408: Perform superposition of pixel point amplitudes according to the radio frequency signal images respectively generated with the preset number of position points to obtain a superimposed radio frequency signal image.

S409: Generate an ultrasound image based on the superimposed radio frequency signal image.

It is understandable that the number of position points can reflect the number of times of ultrasonic transmission required to generate an ultrasound image. The more the number of position points, the more times of ultrasonic transmission required to generate an ultrasound image. The longer the time required for the ultrasound image, the lower the frame rate. In order to avoid a reduction in the frame rate, the number of position points cannot be too large. Preferably, the preset number may be 10-100.

Among them, in a possible implementation, generating an ultrasound image based on the superimposed radio frequency signal image includes: taking the signal envelope of the radio frequency signal image, logarithmic compression, adjusting the dynamic range, and digital scan transformation to generate an ultrasound image.

In the embodiment of the present application, a plurality of different position points are selected in the internal space of the ring array probe as a virtual sound source for simulating an ultrasonic emission source, and the process of generating an RF signal image based on the determined position points is repeated multiple times to generate multiple RF The signal image, and the generated multiple RF signal images are superimposed on the pixel amplitude to obtain a new high-quality RF signal image. This process can be called time-domain superimposed simulation of spatial coherent recombination. In this way, superimposing the radio frequency signal images obtained by each transmission is equivalent to the spatial coherent superposition effect formed in the biological tissue when multiple different sound sources are transmitted at the same time, also known as " "Focus" effect. Therefore, in this way, only a few times of ultrasonic emission can be achieved, and emission focus is formed at all positions (pixel points) in the imaging plane, and the image quality is greatly improved while maintaining a high frame rate.

Referring to FIG. 5, it shows the simulation experiment results of the ultrasound imaging method of the embodiment of the present application. The upper row is a schematic diagram of the position of the ring array probe, point scatterer and virtual sound source. The black circle is the ring array probe, the point outside the ring is the point scatterer, and the point inside the ring is the virtual sound source. From left to right, set to 1, 5, 11 virtual sound sources. The next row is the B-grayscale image results obtained by simulation calculation. It can be seen that as the number of virtual sound sources increases, the artifacts in the image are well suppressed and the image quality is greatly improved.

Corresponding to an ultrasound imaging method of the present application, the present application also provides an ultrasound imaging device.

For example, referring to FIG. 6, which shows a schematic structural diagram of an embodiment of an ultrasound imaging device of the present application, the device can be applied to an ultrasound endoscope system having a ring array probe. The device may include:

The position point determination unit 601 is used to determine a position point for simulating an ultrasonic emission source from the internal space of the ring array probe;

The simulation duration determining unit 602 is used to determine, for each array element on the ring array probe, the simulation duration required to propagate the ultrasonic waves simulated by the location point determined by the location point determining unit 601 to the array element ;

The simulation time determination unit 603 is configured to determine the position point simulation determined by the position point determination unit 601 according to the simulation time period corresponding to each array element on the ring array probe determined by the simulation time determination unit 602 The simulated times of the emitted ultrasonic waves are emitted through the respective array elements, wherein the starting moments of the simulated emission of the ultrasonic waves at the position points calculated according to the simulated times of the respective array elements are the same;

Controlling the transmitting unit 604, for each array element, when the simulation time corresponding to the array element determined by the simulation time determining unit 603 is reached, the array element is controlled to transmit ultrasonic waves;

The image generating unit 605 is configured to generate a radio frequency signal image for generating an ultrasound image based on the ultrasound echo signals received by the respective array elements.

In a possible implementation manner, the device further includes:

The ultrasound image generating unit is used for generating an ultrasound image according to the radio frequency signal image after the image generating unit 605 generates the radio frequency signal image for generating the ultrasound image.

In a possible implementation manner, the device further includes:

A detection unit, configured to detect whether the number of position points for simulating the ultrasonic emission source determined from the internal space of the ring array probe reaches a preset number; if not, trigger the first processing unit to execute; if yes, trigger The second processing unit executes;

The first processing unit is used to select a point not selected as the position point from the internal space of the ring array probe as the position point for simulating the ultrasonic emission source, and based on the currently determined position point , Triggering the simulation duration determination unit to execute, to obtain a radio frequency signal image generated at the currently determined position point;

The second processing unit is configured to superimpose pixel amplitudes based on the radio frequency signal images respectively generated with the preset number of position points to obtain a superimposed radio frequency signal image; and based on the superimposed RF signal image to generate ultrasound image.

In a possible implementation manner, the simulation time determining unit 603 is specifically configured to:

From the ring array probe, determine the corresponding reference array element with the shortest simulation duration, and set the simulation time at which the ultrasonic waves simulated at the position point are emitted through the reference array element;

Determining the relative simulation time difference between each array element and the reference array element;

Based on the relative simulation time difference between each array element and the reference, and the simulation time corresponding to the reference array element, the simulation time at which the ultrasonic waves simulated at the position point are emitted through each array element is determined.

In a possible implementation, the image generating unit 605 includes:

The first determining subunit is used to determine the tissue position point corresponding to each pixel point in the radio frequency signal image to be generated from the biological tissue detected by ultrasound;

The second determining subunit is used to determine the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position point from the ultrasound echo signals received by the respective array elements for each pixel point corresponding to the tissue position point ;

The image generating subunit is configured to generate the radio frequency signal image based on the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position corresponding to each pixel.

In a possible implementation manner, the second determining subunit includes:

The first time length determining subunit is used to determine, for each array element, the length of time that the emitted ultrasonic wave returns to the position of the array element via the tissue position point;

A second duration determining subunit, used to determine the sampling interval duration of the channel corresponding to the array element for sampling the ultrasonic echo signal;

The third duration determining subunit is used for each sampling point obtained by sampling the ultrasonic echo signal from the channel corresponding to the array element, and determining the sampling time of the sampling point relative to the position point to simulate the start of the ultrasonic wave The sampling time at the beginning;

The echo information determination subunit is used to determine whether the absolute value of the difference between the sampling duration of the sampling point and the duration of the emitted ultrasound wave returning to the array element via the tissue position point is less than or equal to the sampling interval duration ; If yes, determine that the sampling point can reflect the ultrasound echo information scattered from the tissue location point;

A superposition subunit, used to superimpose the amplitude of the sampling points in the channels corresponding to each array element that can reflect the ultrasonic echo information scattered from the tissue position point to obtain the ultrasonic echo signal scattered from the tissue position point Amplitude of the signal strength.

Optionally, the length of time that the determined emitted ultrasonic wave returns to the array element position through the tissue position point includes:

Determine the distance between the position point and the pixel point corresponding to the tissue position point;

Based on the distance between the position point and the pixel point corresponding to the tissue position point and the propagation speed of the ultrasonic wave, determining the forward transmission time of the ultrasonic wave;

Determining the distance between the pixel corresponding to the tissue position and the position of the array element;

Based on the distance between the pixel point corresponding to the tissue position point and the position of the array element and the propagation speed of the ultrasonic wave, determining the duration of reverse transmission of the ultrasonic wave;

Adding the forward transmission duration and the reverse transmission duration to obtain the duration of the emitted ultrasonic wave returning to the array element location through the pixel corresponding to the tissue location point.

In a possible implementation manner, the ultrasound image generating unit is specifically configured to:

The radio frequency signal image is subjected to signal envelope, logarithmic compression, dynamic range adjustment, and digital scan transformation to generate an ultrasound image.

For the ultrasound imaging apparatus according to the embodiment of the present invention, since it corresponds to the ultrasound imaging method in the above embodiment, the description is relatively simple. For related similarities, please refer to the description of the ultrasound imaging method in the above embodiment. , No more details here.

It should be noted that the embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments refer to each other. can.

For the convenience of description, when describing the above system or device, the functions are divided into various modules or units and described separately. Of course, when implementing this application, the functions of each unit may be implemented in one or more software and/or hardware.

It can be known from the description of the above embodiments that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product in essence or part that contributes to the existing technology, and the computer software product can be stored in a storage medium, such as ROM/RAM, magnetic disk , CD-ROM, etc., including several instructions to enable a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in the embodiments or some parts of the embodiments of the present application.

Finally, it should also be noted that in this article, relational terms such as first, second, third, and fourth are used only to distinguish one entity or operation from another entity or operation, not It must be required or implied that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also those not explicitly listed Or other elements that are inherent to this process, method, article, or equipment. Without more restrictions, the element defined by the sentence "include one..." does not exclude that there are other identical elements in the process, method, article or equipment that includes the element.

The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of the present invention, several improvements and retouches can be made. These improvements and retouches also It should be regarded as the protection scope of the present invention.

Claims (10)

An ultrasound imaging method is applied to an ultrasound endoscope system. The ultrasound endoscope system has a ring array probe, including: From the internal space of the ring array probe, determine a location point for simulating an ultrasonic emission source; For each array element on the ring array probe, determine the simulation duration required to propagate the ultrasound emitted by the position point to the array element; According to the simulation time corresponding to each array element on the ring array probe, determine the simulation time at which the ultrasonic waves simulated at the position point are respectively emitted through each array element, wherein the estimated time based on the simulation time of each array element is The starting moments of the simulated simulated ultrasonic waves at the location points are the same; For each array element, when the simulation time corresponding to the array element is reached, the array element is controlled to emit ultrasonic waves; Based on the ultrasound echo signals received by each array element, a radio frequency signal image for generating an ultrasound image is generated. The method of claim 1, wherein after generating the radio frequency signal image for generating the ultrasound image, further comprising: An ultrasound image is generated based on the radio frequency signal image. The method according to claim 1, wherein after the generating the radio frequency signal image for generating the ultrasound image, further comprising: Detecting whether the number of position points for simulating the ultrasonic emission source determined from the internal space of the ring array probe reaches a preset number; If no, from the internal space of the ring array probe, a point not selected as the position point is selected as the position point for simulating the ultrasonic emission source, and based on the currently determined position point, return to execute the For each array element on the ring array probe, determine the simulation time required for the ultrasound emitted by the position point to propagate to the array element, and obtain the RF signal image generated at the currently determined position point; If so, according to the radio frequency signal images respectively generated with the preset number of position points, pixel point amplitudes are superimposed to obtain a superimposed radio frequency signal image; Based on the superimposed radio frequency signal image, an ultrasound image is generated. The method according to claim 1 or 3, wherein, according to the simulation duration corresponding to each array element on the ring array probe, the simulation time at which the ultrasonic waves simulated by the position point are emitted through each array element is determined, include: From the ring array probe, determine the corresponding reference array element with the shortest simulation duration, and set the simulation time at which the ultrasonic waves simulated at the position point are emitted through the reference array element; Determining the relative simulation time difference between each array element and the reference array element; Based on the relative simulation time difference between each array element and the reference, and the simulation time corresponding to the reference array element, the simulation time at which the ultrasonic waves simulated at the position point are emitted through each array element is determined. The method according to claim 1 or 3, wherein the generating of an RF signal image for generating an ultrasound image based on the ultrasound echo signals received by each array element includes: From the biological tissue detected by ultrasound, determine the tissue location point corresponding to each pixel point in the radio frequency signal image to be generated; For each pixel point corresponding to the tissue position point, from the ultrasound echo signals received by the respective array elements, the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position point is determined; The radio frequency signal image is generated based on the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position corresponding to each pixel. The method according to claim 5, wherein the determination of the signal intensity amplitude of the ultrasound echo signal scattered by the tissue position point in the ultrasound echo signals received from each array element includes: For each array element, determine the length of time that the emitted ultrasonic wave returns to the array element position through the tissue position point; Determining the sampling interval duration of the channel corresponding to the array element for sampling the ultrasonic echo signal; For each sampling point obtained by sampling the ultrasonic echo signal from the channel corresponding to the array element, determining the sampling time of the sampling point relative to the starting time of the location point at which the simulated ultrasound is emitted; Judging whether the absolute value of the difference between the sampling duration of the sampling point and the duration of the emitted ultrasonic wave returning to the array element via the tissue position point is less than or equal to the sampling interval duration; If yes, determine that the sampling point can reflect the ultrasound echo information scattered from the tissue position point; The amplitudes of the sampling points that can reflect the ultrasonic echo information scattered from the tissue position point in the channels corresponding to the respective array elements are superimposed to obtain the signal intensity amplitude of the ultrasonic echo signal scattered from the tissue position point. The method according to claim 6, wherein the length of time that the determined emitted ultrasonic wave returns to the position of the array element via the tissue position point includes: Construct a coordinate system on the plane of the ring formed by the array elements arranged in the ring array probe, Determine the coordinates of the position point in the coordinate system; Determine the coordinates of the array element in the coordinate system; Determine the coordinates of the pixel point corresponding to the tissue position point in the coordinate system; Determine the forward transmission duration of the ultrasonic wave based on the coordinates of the pixel point corresponding to the tissue position point, the coordinates of the position point and the propagation speed of the ultrasonic wave; Determine the duration of reverse transmission of the ultrasonic wave based on the coordinates of the pixel point corresponding to the tissue position point, the coordinates of the array element and the propagation speed of the ultrasonic wave; Adding the forward transmission duration and the reverse transmission duration to obtain the duration of the emitted ultrasonic wave returning to the array element location through the pixel corresponding to the tissue location point. The method of claim 2, wherein the generating an ultrasound image based on the radio frequency signal image includes: The radio frequency signal image is subjected to signal envelope, logarithmic compression, dynamic range adjustment, and digital scan transformation to generate an ultrasound image. An ultrasound imaging device is applied to an ultrasound endoscopic system. The ultrasound endoscopic system has a ring array probe, including: A position point determination unit, used to determine a position point for simulating an ultrasonic emission source from the internal space of the ring array probe; The simulation time determining unit is used to determine, for each array element on the ring array probe, the simulation time required for the ultrasound emitted by the location point determined by the location point determining unit to propagate to the array element; A simulation time determination unit, configured to determine the simulated ultrasound emitted by the position point determined by the position point determination unit according to the simulation time period corresponding to each array element on the ring array probe determined by the simulation time determination unit The simulation time shot through each array element respectively, wherein the starting time for simulating the emission of ultrasonic waves at the position point calculated based on the simulation time of each array element is the same; A control transmitting unit, for each array element, when the simulation time corresponding to the array element determined by the simulation time determination unit is reached, the array element is controlled to transmit ultrasonic waves; The image generating unit is used to generate a radio frequency signal image for generating an ultrasound image based on the ultrasound echo signals received by the respective array elements. The method of claim 9, further comprising: A detection unit, configured to detect whether the number of position points for simulating the ultrasonic emission source determined from the internal space of the ring array probe reaches a preset number; if not, trigger the first processing unit to execute; if yes, trigger The second processing unit executes; The first processing unit is used to select a point that is not selected as the position point from the internal space of the ring array probe as the position point for simulating the ultrasonic emission source, and based on the currently determined position point , Triggering the simulation duration determination unit to execute, to obtain a radio frequency signal image generated at the currently determined position point; The second processing unit is configured to superimpose pixel amplitudes based on the radio frequency signal images respectively generated with the preset number of position points to obtain a superimposed radio frequency signal image; and based on the superimposed RF signal image to generate ultrasound image.

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