Viscoelasticity measurement method and ultrasonic measurement system

Abstract

A viscoelasticity measurement method (100, 700) and an ultrasonic measurement system (1000), the viscoelasticity measurement method (100, 700) comprising: emitting an acoustic radiation force pulse to a subject to be measured to generate a shear wave in a region of interest of the subject to be measured (S110); emitting a first ultrasonic wave to track the shear wave to the region of interest and receiving a first ultrasonic echo of the region of interest to obtain first ultrasonic echo data (S120); obtaining a shear wave signal of the region of interest from the first ultrasonic echo data (S130); extracting shear wave components of at least two different frequencies from the shear wave signal (S140); determining phase velocities of the shear wave respectively according to the shear wave components of the at least two different frequencies (S150); determining viscosity information reflecting viscosity of the region of interest according to the at least two phase velocities (S160); and outputting the viscosity information (S170). The viscosity information of the region of interest can be determined by one viscoelasticity measurement.

Description

[0001] This application is a divisional application of the invention patent application with application number 202080053473.1, application date of April 24, 2020, entitled "Viscoelasticity Measurement Method and Ultrasonic Measurement System". Technical Field

[0002] This application relates to the field of ultrasonic measurement technology, and more specifically to a viscoelasticity measurement method and ultrasonic measurement system. Background Technology

[0003] Ultrasound elastography, which extracts information related to tissue stiffness for imaging, is relevant to the non-invasive auxiliary diagnosis of major diseases such as breast cancer and cirrhosis, and has been a research hotspot in the field of ultrasound imaging for the past two decades. After years of development, ultrasound elastography has matured and has recently been more widely applied in clinical research and auxiliary diagnosis of various parts of the human body, including the liver, breast, thyroid, muscles and bones, blood vessels, prostate, and cervix. Ultrasound elastography can qualitatively reflect the difference in hardness of a lesion relative to surrounding tissues, or quantitatively reflect the stiffness-related physical parameters of the target tissue, such as Young's modulus and shear modulus, making it widely popular among physicians.

[0004] Commonly used ultrasound elastography techniques include strain elastography, shear wave elastography, and transient elastography. Among these, shear wave elastography generates shear waves by emitting special pulses into the tissue to create acoustic radiation force. The propagation process of these shear waves is then detected and recorded using ultrasound, and the propagation velocity is calculated to obtain the elastic modulus parameter, which reflects the tissue's stiffness, thus achieving quantitative elastography. This technology has greatly expanded the clinical applications of elastography and has attracted significant research interest.

[0005] In most current elasticity-related studies, tissues are treated as purely elastic bodies, and elastography techniques are primarily based on this assumption. Quantitative elastography, in particular, typically only calculates the elastic modulus for visualization. However, a growing body of research indicates that human tissues possess not only elasticity but also viscosity, and both elasticity and viscosity influence the propagation speed of shear waves within the tissue. While clinical studies on the correlation between tissue viscosity and disease are currently scarce, existing research suggests that tissue viscosity may be associated with the progression of diseases such as hepatitis. Therefore, extracting viscosity-related information simultaneously during elastography would have significant clinical potential value. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] The first aspect of this application provides a viscoelasticity measurement method, including:

[0008] A sound radiation force pulse is emitted toward the object under test to generate a shear wave in the region of interest of the object under test;

[0009] A first ultrasonic wave that tracks the shear wave is emitted toward the region of interest, and a first ultrasonic echo is received from the region of interest to obtain first ultrasonic echo data.

[0010] The shear wave signal of the region of interest is obtained based on the first ultrasonic echo data;

[0011] Extract at least two shear wave components of different frequencies from the shear wave signal;

[0012] The phase velocity of the shear wave is determined based on the at least two different frequency shear wave components, respectively.

[0013] Viscous information reflecting the viscosity of the region of interest is determined based on at least two of the phase velocities;

[0014] Output the viscosity information.

[0015] A second aspect of this application provides a viscoelasticity measurement method, comprising:

[0016] Acquire the shear wave signal of the region of interest of the object under test;

[0017] Extract at least two shear wave components of different frequencies from the shear wave signal;

[0018] The phase velocity of the shear wave is determined based on the at least two different frequency shear wave components, respectively.

[0019] Viscous information reflecting the viscosity of the region of interest is determined based on at least two of the phase velocities.

[0020] A third aspect of this application provides an elasticity measurement method, the method comprising:

[0021] A sound radiation force pulse is emitted toward the object under test to generate a broadband shear wave in the region of interest of the object under test;

[0022] A first ultrasonic wave that tracks the shear wave is emitted toward the region of interest, and a first ultrasonic echo is received from the region of interest to obtain first ultrasonic echo data.

[0023] The shear wave signal of the region of interest is obtained based on the first ultrasonic echo data;

[0024] Extract at least one frequency shear wave component from the shear wave signal;

[0025] The phase velocity of the shear wave is determined based on the shear wave component of at least one frequency.

[0026] A fourth aspect of this application provides an elasticity measurement method, the method comprising:

[0027] Acquire the shear wave signal of the region of interest of the object under test;

[0028] Extract at least one frequency shear wave component from the shear wave signal;

[0029] The phase velocity of the shear wave is determined based on the shear wave component of at least one frequency.

[0030] A fifth aspect of this application provides an ultrasonic measurement system, comprising:

[0031] Ultrasonic probe;

[0032] A transmitting / receiving circuit is used to excite the ultrasonic probe to emit acoustic radiation force pulses toward the object under test to generate shear waves in the region of interest of the object under test; and to excite the ultrasonic probe to emit a first ultrasonic wave that tracks the shear waves toward the region of interest, and to receive a first ultrasonic echo from the region of interest to obtain first ultrasonic echo data.

[0033] Processor, used for:

[0034] The shear wave signal of the region of interest is obtained based on the first ultrasonic echo data;

[0035] Extract at least two shear wave components of different frequencies from the shear wave signal;

[0036] The phase velocity of the shear wave is determined based on the at least two different frequency shear wave components, respectively.

[0037] Viscous information reflecting the viscosity of the region of interest is determined based on at least two of the phase velocities;

[0038] An output device for outputting the viscosity information.

[0039] A sixth aspect of this application provides an ultrasonic measurement system, which includes a memory and a processor. The memory stores a computer program executed by the processor. When the computer program is run by the processor, it performs the following steps:

[0040] Acquire the shear wave signal of the region of interest of the object under test;

[0041] Extract at least two shear wave components of different frequencies from the shear wave signal;

[0042] The phase velocity of the shear wave is determined based on the at least two different frequency shear wave components, respectively.

[0043] Viscous information reflecting the viscosity of the region of interest is determined based on at least two of the phase velocities.

[0044] A seventh aspect of this application provides an ultrasonic measurement system, the ultrasonic measurement system comprising:

[0045] Ultrasonic probe;

[0046] A transmitting / receiving circuit is used to excite the ultrasonic probe to emit acoustic radiation force pulses toward the object under test to generate shear waves in the region of interest of the object under test; and to excite the ultrasonic probe to emit a first ultrasonic wave that tracks the shear waves toward the region of interest, and to receive a first ultrasonic echo from the region of interest to obtain first ultrasonic echo data.

[0047] Processor, used for:

[0048] The shear wave signal of the region of interest is obtained based on the first ultrasonic echo data;

[0049] Extract at least one frequency shear wave component from the shear wave signal;

[0050] The phase velocity of the shear wave is determined based on the shear wave component of at least one frequency.

[0051] An eighth aspect of this application provides an ultrasonic measurement system, which includes a memory and a processor. The memory stores a computer program executed by the processor. When the computer program is run by the processor, it performs the following steps:

[0052] Acquire the shear wave signal of the region of interest of the object under test;

[0053] Extract at least one frequency shear wave component from the shear wave signal;

[0054] The phase velocity of the shear wave is determined based on the shear wave component of at least one frequency.

[0055] A ninth aspect of this application provides a computer storage medium storing a computer program thereon, wherein the computer program, when executed by a computer or processor, implements the steps of the viscoelasticity measurement method or elasticity measurement method provided in this application.

[0056] The viscoelasticity measurement method and ultrasonic measurement system according to embodiments of this application extract shear wave components of different frequencies from shear wave signals and obtain the phase velocity of each shear wave component, thus obtaining information reflecting tissue viscosity with only one measurement. The elasticity measurement method according to embodiments of this application extracts shear wave components from shear wave signals and calculates their corresponding phase velocities, which can reflect the elasticity information of the tissue. Attached Figure Description

[0057] Figure 1 A schematic flowchart of a viscoelasticity measurement method according to an embodiment of this application is shown;

[0058] Figure 2 A spectrum diagram of a shear wave signal according to an embodiment of this application;

[0059] Figure 3 From Figure 2 The spectrum diagram of the shear wave component separated from the shear wave signal is shown.

[0060] Figure 4A The vibration waveform of a shear wave signal according to an embodiment of this application is shown;

[0061] Figure 4B , Figure 4C Showing from Figure 4A The vibration waveforms of shear wave components of different frequencies extracted from the shear wave signal are shown.

[0062] Figure 5A A baseline ultrasound image and a region of interest defined in the baseline ultrasound image are shown according to one embodiment of this application.

[0063] Figure 5B This invention illustrates an overlay display of a basic ultrasound image and an elasticity image according to an embodiment of this application;

[0064] Figure 5C This invention illustrates an overlay display of a base ultrasound image and a viscous image according to an embodiment of the present application;

[0065] Figure 6 The basic ultrasound image and elastic modulus and viscosity coefficient are shown according to one embodiment of this application;

[0066] Figure 7 A schematic flowchart of a viscoelasticity measurement method according to another embodiment of this application is shown;

[0067] Figure 8 A schematic flowchart of an elasticity measurement method according to an embodiment of this application is shown;

[0068] Figure 9 A schematic flowchart of an elasticity measurement method according to another embodiment of this application is shown;

[0069] Figure 10 A schematic block diagram of an ultrasonic measurement system according to an embodiment of this application is shown;

[0070] Figure 11 A schematic block diagram of an ultrasonic measurement system according to another embodiment of this application is shown. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this application more apparent, exemplary embodiments according to this application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein. Based on the embodiments of this application described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of this application.

[0072] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0073] It should be understood that this application can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art.

[0074] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0075] To fully understand this application, detailed steps and structures will be presented in the following description to illustrate the technical solutions proposed in this application. Preferred embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0076] To fully understand this application, a detailed structure will be presented in the following description to illustrate the technical solution proposed in this application. Optional embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0077] This application's embodiments are mainly used to reuse ultrasonic echo data obtained during shear wave elasticity measurement, separating shear wave components of different frequencies from the shear wave signal and calculating the corresponding shear wave velocities to obtain viscous information. Below, reference will be made to... Figure 1 A viscoelasticity measurement method according to an embodiment of this application is described. Figure 1 This is a schematic flowchart of a viscoelasticity measurement method 100 according to an embodiment of this application.

[0078] like Figure 1 As shown, a viscoelasticity measurement method 100 according to an embodiment of this application includes the following steps:

[0079] In step S110, an acoustic radiation force pulse (ARFI) is emitted toward the object under test to generate a shear wave in the region of interest of the object under test.

[0080] In step S120, a first ultrasonic wave that tracks the shear wave is emitted toward the region of interest, and a first ultrasonic echo is received from the region of interest to obtain first ultrasonic echo data.

[0081] In step S130, the shear wave signal of the region of interest is obtained based on the first ultrasonic echo data;

[0082] In step S140, at least two shear wave components of different frequencies are extracted from the shear wave signal;

[0083] In step S150, the phase velocity of the shear wave is determined based on the at least two different frequency shear wave components.

[0084] In step S160, viscosity information reflecting the viscosity of the region of interest is determined based on at least two phase velocities;

[0085] In step S170, the viscosity information is output.

[0086] The viscoelasticity measurement method 100 of this application, based on conventional shear wave elasticity measurement, adds a step of extracting shear wave components of different frequencies from the shear wave signal, and calculates the shear wave propagation velocity corresponding to each shear wave component of different frequencies, thereby obtaining viscous information reflecting tissue viscosity. According to the viscoelasticity measurement method 100 of this application, both viscous and elastic information of the tissue can be obtained simultaneously based on a single viscoelasticity measurement.

[0087] Generally, before performing step S110, the location of the region of interest is first determined based on the conventional ultrasound images of the object being tested.

[0088] Specifically, a second ultrasound wave can be emitted towards the object being measured using an ultrasound probe, and the echo of the second ultrasound wave can be received to obtain second ultrasound echo data. Then, a beamforming circuit can perform beamforming processing on the second ultrasound echo data, and the beamformed second ultrasound echo data is sent to a processor for relevant image processing to obtain a basic ultrasound image. Depending on the imaging mode required by the user, the processor can perform different processing on the second ultrasound echo signal to obtain ultrasound image data of different modes. Then, through logarithmic compression, dynamic range adjustment, digital scan transformation, and other processing, basic ultrasound images of different modes are formed, such as two-dimensional ultrasound images including B-images and C-images. Conventional ultrasound images can provide information such as lesion morphology and blood flow distribution.

[0089] Then, the location of the region of interest can be determined based on the baseline ultrasound image. In one example, determining the location of the region of interest based on a conventional ultrasound image specifically includes: outputting the conventional ultrasound image and marking the location of the region of interest on the conventional ultrasound image. For example, the baseline ultrasound image can be displayed on a monitor, allowing the user to manually select the region of interest on the baseline ultrasound image, and the location of the region of interest can be determined based on detected user input commands.

[0090] In another example, the location of the region of interest (ROI) on the baseline ultrasound image can be automatically determined based on relevant machine recognition algorithms. In other examples, the ROI can also be obtained through semi-automatic detection; for instance, the location of the ROI on the baseline ultrasound image can first be automatically detected based on machine recognition algorithms, and then further modified or corrected by the user to obtain a more accurate location of the ROI.

[0091] Next, in steps S110 to S130, acoustic radiation force focusing impact can be performed according to a pre-set pulse sequence based on the region of interest selected in the above manner. Specifically, the ultrasonic probe emits special ultrasonic driving pulses towards the tissue of the region of interest of the object being tested, so as to generate shear wave propagation in the tissue based on acoustic radiation force. The length of the ultrasonic driving pulse is generally greater than 100 μs. Since the shear wave generated by the acoustic radiation force pulse itself has a small amplitude and the shear wave attenuates rapidly with propagation, multiple ultrasonic driving pulses are often emitted continuously in order to enhance the intensity and range of the generated shear wave.

[0092] Next, a series of first ultrasound waves tracking the shear wave are continuously emitted into the tissue region of interest by an ultrasound probe for a period of time (typically tens of milliseconds), and the ultrasound echoes are received to obtain first ultrasound echo data. Based on this data, a shear wave signal is obtained, which characterizes the vibration state of the tissue as the shear wave propagates within it. The shear wave signal obtained in this manner is a broadband signal, including multiple shear wave components within the range of 0–1000 Hz. Each shear wave component can be considered as a signal characterizing the tissue vibration state caused by a shear wave of a certain frequency.

[0093] Specifically, the processor of the ultrasonic measurement system can calculate the vibration state of the tissue when the shear wave propagates within it, based on the aforementioned first ultrasonic echo data. The shear wave signal characterizes the vibration state of the tissue over a period of time. According to wave characteristics, when a shear wave passes through a certain location within the tissue, the tissue at that location will vibrate; when the shear wave propagates away from that location, the tissue at that location will return to its original state. Therefore, by comparing the ultrasonic echoes obtained at different times, the motion information of the tissue over a period of time can be obtained. This motion information can be the tissue's displacement relative to a reference time, the tissue's velocity, the tissue's acceleration, the tissue's strain, etc., or data further processed by filtering, differentiation, integration, etc., based on the aforementioned variables.

[0094] The correlation comparison can be a comparison between ultrasound echo signals obtained at adjacent different times, or a comparison between ultrasound echoes at different times and echo signals at the same reference time. The correlation comparison algorithm can include general algorithms for conventional tissue displacement detection, such as block-matching-based cross-correlation comparison algorithms, Doppler frequency shift-based calculation methods, and phase shift-based detection methods. This application does not limit the specific algorithm used to detect tissue motion information.

[0095] Then, by summarizing the tissue motion information caused by the shear wave at different times, the vibration waveform of the shear wave signal can be observed. Figure 4A The diagram shows the tissue velocity-time curve at a specific location within the tissue over a given period. Alternatively, the vibration waveform of the shear wave signal can be observed by summarizing other tissue motion information mentioned above over a period of time, such as by plotting a tissue displacement-time curve.

[0096] In step S140, at least two shear wave components of different frequencies are extracted from the shear wave signal. These shear wave components of different frequencies can be considered as tissue vibration information caused by shear waves of different frequencies. By extracting shear wave components of different frequencies from the shear wave signal, only one acoustic radiation force pulse transmission and one first ultrasonic wave transmission and one first ultrasonic echo reception are required to obtain the tissue vibration information caused by shear waves of different frequencies for subsequent calculation of viscosity parameters, without the need for multiple transmissions and receptions.

[0097] In one embodiment, at least two different frequency shear wave components can be extracted from the shear wave signal by filtering. It should be noted that the filtering method can be performed in the time domain, frequency domain, or using various algorithms, such as convolution operations. Furthermore, the filtering process may include a series of pre- or post-filtering processing steps, which are not specifically limited here.

[0098] See Figure 2 and Figure 3 , Figure 2 The spectrum of the wideband shear wave signal obtained in step S130 is shown. The shear wave signal includes multiple shear wave components in the range of 0 to 1000 Hz, so the spectrum has a high amplitude in a wide frequency band. Figure 3 The spectrum of the shear wave component with a center frequency of 300Hz extracted from this shear wave signal is shown. Figure 3 As can be seen, the spectrum of this shear wave component only has a high amplitude around 300 Hz.

[0099] Reference Figures 4A-4C As mentioned above, Figure 4A The waveform of the broadband shear wave signal is shown. Figure 4B From Figure 4A The waveform of the shear wave component with a center frequency of 300Hz extracted from the broadband shear wave signal is shown. Figure 4C From Figure 4A The waveform of the shear wave component with a center frequency of 600Hz extracted from the broadband shear wave signal is shown. Figure 4B , Figure 4C It can be seen that the vibration waveforms of shear wave components of different frequencies are different, which means that the vibration state of the tissue caused by the propagation of shear waves of different frequencies in the tissue in step S110 is different.

[0100] As mentioned above, the shear wave signal can be a time-domain signal that describes the change of tissue motion information in the region of interest over time. Filtering of the shear wave signal can be performed in the time domain, that is, time-domain filtering of the shear wave signal.

[0101] As another implementation, the shear wave signal can be transformed into a frequency domain signal, and then frequency domain filtering can be performed on the frequency domain signal. For example, the amplitudes of all frequency bands outside the desired frequency band in the frequency domain signal can be set to zero, and then the frequency domain filtered signal can be inversely transformed into a time domain signal. Exemplarily, the transformation of the shear wave signal from the time domain to the frequency domain can be achieved by Fourier transform, and the transformation of the shear wave signal from the frequency domain to the time domain can be achieved by inverse Fourier transform.

[0102] In one embodiment, the shear wave component in the shear wave signal can be extracted based on various suitable filters. The filters used can be software filters or hardware filters additionally set in the ultrasonic measurement system.

[0103] For example, as a more accurate filtering method, at least two bandpass filters of different frequencies can be used to filter the signal with different center frequencies, thereby extracting the shear wave components at the corresponding frequencies. For instance, bandpass filters of 300Hz and 600Hz can be used to extract shear wave components with center frequencies of 300Hz and 600Hz from a wide-band shear wave signal ranging from 0 to 1000Hz. It is understood that when using bandpass filters, two or more bandpass filters can be used to extract shear wave components at multiple frequencies from the shear wave signal.

[0104] Furthermore, as a relatively simplified filtering method, low-pass and high-pass filters can be used separately to filter the shear wave signal, thereby extracting the low-frequency and high-frequency components from the shear wave signal. For example, a 500Hz high-pass filter and a low-pass filter can be used to extract the low-frequency component of 0-500Hz and the high-frequency component of 500-1000Hz from a wide-band shear wave signal of 0-1000Hz.

[0105] Furthermore, from Figure 3 and Figure 4B , Figure 4C As can be seen, the shear wave component separated at each frequency does not necessarily include only the single center frequency, but also includes a frequency band with a preset bandwidth centered at a preset frequency point.

[0106] Taking a center frequency of 300Hz as an example, the frequency distribution of the extracted shear wave component can be a frequency range dominated by 300Hz, such as 250–350Hz, or 200–400Hz, etc. Figure 3 As shown, the center frequency of this shear wave component is 300Hz, and it also contains a shear wave component with a certain bandwidth. The bandwidth of the extracted shear wave component can be changed by adjusting the filter parameters used for filtering. The more concentrated the extracted shear wave component, the more accurately the tissue motion information at the current frequency can be obtained; however, correspondingly, because more shear wave components are filtered out, the signal-to-noise ratio of the obtained signal will decrease. Therefore, the desired balance between the accuracy of tissue motion information and the signal-to-noise ratio can be achieved by adjusting the filter parameters.

[0107] In step S150, the phase velocity of the shear wave is determined based on at least two different frequency shear wave components.

[0108] Specifically, the propagation speed of the shear wave can be calculated based on the original shear wave signal obtained in step S130, or based on the shear wave components of different frequencies extracted through frequency separation. Since the shear wave source possesses a wide frequency band, the propagation speed of the shear wave calculated from the original shear wave signal is the combined propagation speed of shear waves at multiple frequencies, referred to as the shear wave group speed. The propagation speed of the shear wave calculated using the separated shear wave components is the propagation speed of the shear wave at that specific frequency, and is therefore called the phase velocity of the shear wave.

[0109] For example, the phase velocity of a shear wave can be calculated using various methods for determining the propagation velocity of a shear wave, as used in conventional shear wave elastic measurements. For instance, the propagation velocity can be calculated by determining the arrival times of the shear wave at two different locations within the tissue at a certain distance. Specifically, the displacement-time curves corresponding to the two different locations in the tissue can be cross-correlated and compared to obtain the time difference between them. This time difference corresponds to the propagation time of the shear wave between these two locations, and the ratio of the distance between the two locations to the propagation time is the propagation velocity of the shear wave. Alternatively, the propagation velocity of the shear wave can be calculated through the inversion of the wave equation, etc. This application does not limit the method for calculating the shear wave propagation velocity.

[0110] In step S160, viscosity information reflecting the viscosity of the region of interest is determined based on at least two phase velocities.

[0111] For a purely elastic body, the shear wave propagation velocity is primarily influenced by the elastic parameters. For a viscoelastic body, the shear wave velocity is affected by both elasticity and viscosity. Due to the influence of viscosity, the shear wave propagation velocity in tissue exhibits a dispersion effect, meaning that shear waves of different frequencies propagate at different velocities. Therefore, the viscosity parameters of the region of interest can be determined based on the relationship between the viscosity parameters and the phase velocity determined in step S150 and the corresponding shear wave frequency, serving as viscosity information reflecting the viscosity of the tissue in the region of interest. According to embodiments of this application, the viscosity parameters, or both viscosity and elastic parameters, can be determined based on ultrasonic measurement data obtained from a single transmission and reception process, without the need for repeated acoustic radiation force impacts and echo acquisition processes.

[0112] Specifically, viscosity parameters can be determined based on various theoretical models. For example, according to the Voigt model, the phase velocity c of the shear wave... φ The following relationship exists between the viscosity parameter and the viscosity parameter:

[0113]

[0114] Wherein, ρ is the tissue density, μ1 is the tissue elasticity parameter, μ2 is the tissue viscosity parameter, and ω is the angular frequency of the shear wave. The angular frequency of the shear wave can be determined based on the center frequency of the shear wave component. Specifically, the angular frequency is 2π times the center frequency.

[0115] Based on the above formula, the tissue viscosity parameters can be calculated by calculating the propagation velocities of at least two shear wave components at different frequencies. Of course, in some embodiments, to more accurately calculate the tissue viscosity parameters, the propagation velocities of multiple shear wave components at different frequencies can be calculated, and then fitted using the above formula to obtain the best estimate of the viscosity parameters. These multiple shear wave components at different frequencies can be extracted from shear wave signals obtained from a single acoustic radiation force impact and echo acquisition process, or they can be extracted from shear wave signals obtained from multiple acoustic radiation force impact and echo acquisition processes.

[0116] Of course, more simply, since the shear wave propagation speed is related to tissue viscosity, the difference in phase velocity of the shear wave components of different frequencies can be directly used to reflect the viscosity of the tissue. That is, the phase velocities determined according to the shear wave components of different frequencies are compared to obtain a comparison result, and the comparison result is used as the viscosity information reflecting the viscosity of the region of interest.

[0117] For example, parameters such as the difference in phase velocities of shear wave components at different frequencies, the ratio of phase velocities, and the slope of the phase velocity change with shear wave frequency can be calculated to reflect viscosity. For instance, a linear fit can be performed based on multiple shear wave frequencies and their corresponding phase velocities to obtain a phase velocity-frequency line, and the slope of this line can be determined. This slope reflects the relationship between the phase velocity and the shear wave frequency as the shear wave passes through the same tissue location, and can qualitatively reflect the viscous characteristics of the tissue. That is, the larger the slope, the greater the tissue viscosity; conversely, the smaller the slope, the smaller the tissue viscosity.

[0118] Furthermore, according to the Voigt model described above, in addition to the viscosity parameter μ2, a ​​first elastic parameter (i.e., elastic parameter μ1) of the region of interest can be calculated based on the relationship between phase velocity and the viscosity parameter μ2, the elastic parameter μ1, and the shear wave frequency. This first elastic parameter is different from the elastic modulus calculated based on the shear wave group velocity (i.e., the second elastic parameter described below), but it can also reflect the elastic characteristics of the tissue. Therefore, in one embodiment, this elastic parameter μ1 can also be output as an elastic measurement result reflecting the tissue elasticity.

[0119] In addition, the viscoelasticity measurement method 100 of this application embodiment can also reuse the same set of first ultrasonic echo data to obtain conventional elasticity measurement results.

[0120] Specifically, the group velocity of the shear wave can be determined based on the first ultrasound echo data, and a second elastic parameter of the region of interest can be obtained based on the group velocity. The second elastic parameter can be the elastic modulus of the tissue, such as Young's modulus or shear modulus. Under certain conditions, a larger elastic modulus indicates greater tissue stiffness. For example, the elastic modulus of the tissue can be calculated based on the following formula: Shear modulus G = ρc s 2 Young's modulus E = 3ρc s 2 Where ρ is tissue density, c s This represents the shear group velocity.

[0121] Furthermore, in some embodiments, the elastic modulus of the tissue can be calculated based on the phase velocity of at least one shear wave component obtained from the separation. Specifically, the corresponding shear modulus or Young's modulus can be calculated based on the phase velocity of the shear wave, for example, by replacing the shear wave group velocity c with the shear wave phase velocity. s The shear modulus G or Young's modulus E mentioned above can be calculated. Since the elastic modulus calculated using the shear wave phase velocity corresponds to a fixed shear wave frequency, the stability of elasticity measurements can be improved.

[0122] In step S170, the viscosity information is output.

[0123] The output viscosity information may include numerical values ​​and / or images of the output viscosity parameters.

[0124] In one embodiment, for the output viscosity parameter values, the viscosity parameters can be obtained separately for multiple locations within the region of interest, and the distribution of viscosity parameters within the region of interest can be displayed. For example, after determining the viscosity parameters at multiple locations within the region of interest, they can be displayed at the corresponding locations on a conventional ultrasound image to form a viscosity parameter distribution map, thereby visually displaying differences in tissue viscosity.

[0125] In another embodiment, the output viscosity parameter value can be a statistical result of the viscosity parameter, used as an estimate of the overall viscosity of the region of interest. Specifically, statistical results of the viscosity information of the region of interest can be obtained based on viscosity information at one or more locations within the region of interest, and the numerical value of the statistical results can be output. The statistical results of the viscosity information can include at least one of the following: the mean, median, standard deviation, quartiles, maximum, or minimum value of multiple viscosity information values.

[0126] Furthermore, the statistical results of the viscosity information are not limited to the statistical results of viscosity information at multiple locations obtained from a single viscoelastic measurement, but may also include the statistical results of viscosity information obtained from multiple viscoelastic measurements. For example, the statistical results of viscosity information obtained from multiple viscoelastic measurements may also include the average, median, standard deviation, quartiles, maximum or minimum values, etc., of the viscosity information obtained from multiple viscoelastic measurements.

[0127] Specifically, for images that output viscosity information, viscosity information at multiple locations within a region of interest can be acquired to generate a viscosity image of that region of interest, which is then displayed on a display interface. For example, viscosity parameters can be processed using grayscale or color encoding to generate a viscosity image, which can then be overlaid or fused with a conventional ultrasound image for display.

[0128] In addition to outputting viscous information, elasticity information of the region of interest can also be output. The elasticity information can be displayed synchronously with the viscous information, for example, on the same display interface; alternatively, the elasticity information can be displayed separately from the viscous information. The elasticity information may include the aforementioned first elastic parameter, second elastic parameter, or elastic modulus calculated using phase velocity. Outputting the elasticity information may include outputting the values ​​and / or images of the first elastic parameter, second elastic parameter, and / or elastic modulus calculated using phase velocity.

[0129] Furthermore, in one embodiment, relevant information about shear wave velocity can also be output. This information includes shear wave group velocity information and shear wave phase velocity information, specifically including numerical values ​​and / or images of the shear wave group velocity and / or numerical values ​​and / or images of the shear wave phase velocity. When outputting numerical values ​​of the shear wave group velocity or the shear wave phase velocity, the output may also include the distribution of shear wave group velocity or phase velocity values ​​at multiple locations, or the output of statistical results of the numerical values ​​of the shear wave group velocity or phase velocity at multiple locations.

[0130] Furthermore, conventional ultrasound images can be displayed simultaneously with the display of viscous and / or elastic information of the region of interest. These conventional ultrasound images can be generated based on first ultrasound echo data or second ultrasound echo data. The conventional ultrasound images can be images acquired in real-time during the viscoelastic measurement, images acquired at regular time intervals during the viscoelastic measurement, or non-real-time images acquired before each viscoelastic measurement and not updated afterward.

[0131] For example, when displaying viscosity and elasticity values, these values ​​can be displayed at appropriate locations on a standard ultrasound image, such as... Figure 6 As shown, it can be displayed in the lower right corner of a conventional ultrasound image, or it can be displayed within the region of interest. When displaying images containing viscous and elastic information, the viscous and elastic images can be overlaid on the conventional ultrasound image, for example, overlaid within the region of interest of the conventional ultrasound image. (See reference...) Figures 5A-5C ,in, Figure 5A The region of interest selected in a standard ultrasound image is shown. Figure 5B This shows an elastic image superimposed on the region of interest of a conventional ultrasound image. Figure 5C A viscous image is shown superimposed on the region of interest of a conventional ultrasound image.

[0132] The above exemplarily illustrates a viscoelasticity measurement method 100 according to an embodiment of this application. Based on the above description, the viscoelasticity measurement method 100 according to the embodiment of this application can obtain viscous information reflecting tissue viscosity by extracting shear wave components of different frequencies from the shear wave signal and calculating the phase velocity of the shear wave components of different frequencies in a single measurement.

[0133] The following is a reference to the appendix. Figure 7 A viscoelasticity measurement method according to another embodiment of this application is described. Figure 7 A schematic flowchart of a viscoelasticity measurement method 700 according to another embodiment of this application is shown. (Refer to...) Figure 7The described viscoelasticity measurement method 700 is generally similar to the viscoelasticity measurement method 100 described above, but some identical details have been omitted. For example... Figure 7 As shown, the viscoelasticity measurement method 700 includes the following steps:

[0134] Step S710: Obtain the shear wave signal of the region of interest of the object under test;

[0135] Step S720: Extract at least two shear wave components of different frequencies from the shear wave signal;

[0136] Step S730: Determine the phase velocity of the shear wave based on the at least two different frequency shear wave components respectively;

[0137] Step S740: Determine viscosity information reflecting the viscosity of the region of interest based on at least two phase velocities.

[0138] Reference Figure 7 In the described embodiment, shear wave components of different frequencies are extracted from the shear wave signal, and viscous information reflecting the viscosity of the region of interest is determined based on the phase velocity determined from at least two shear wave components. Unlike the viscoelasticity measurement method 100 described above, the viscoelasticity measurement method 700 does not limit the method of acquiring the shear wave signal: for example, the shear wave signal can be acquired in real time or extracted from a storage medium; the shear wave can be generated by acoustic radiation force pulse impact as described above, by applying external mechanical vibration, or by any other suitable method.

[0139] According to the viscoelasticity measurement method 700 of this application embodiment, by extracting shear wave components of different frequencies from the shear wave signal and calculating the phase velocity of the shear wave components of different frequencies, viscoelastic information reflecting tissue viscosity can be obtained by performing a single measurement.

[0140] The following is a reference to the appendix. Figure 8 A method for measuring elasticity according to an embodiment of this application is described. Figure 8 A schematic flowchart of an elasticity measurement method 800 according to one embodiment of this application is shown. Figure 8 As shown, the elasticity measurement method 800 may include the following steps:

[0141] In step S810, an acoustic radiation force pulse is emitted toward the object under test to generate a broadband shear wave in the region of interest of the object under test;

[0142] In step S820, a first ultrasonic wave that tracks the shear wave is emitted toward the region of interest, and a first ultrasonic echo is received from the region of interest to obtain first ultrasonic echo data.

[0143] In step S830, the shear wave signal of the region of interest is obtained based on the first ultrasonic echo data;

[0144] In step S840, at least one frequency of shear wave component is extracted from the shear wave signal;

[0145] In step S850, the phase velocity of the shear wave is determined based on the shear wave component of the at least one frequency.

[0146] The viscoelasticity measurement method 800 of this application embodiment adds a step of extracting shear wave components of different frequencies from the shear wave signal based on conventional shear wave elasticity measurement, and calculates the phase velocity of the shear wave based on the separated shear wave components. The phase velocity can be used to determine the elasticity or viscosity information of the tissue.

[0147] Generally, before performing step S810, the location of the region of interest is first determined based on the conventional ultrasound images of the object being tested.

[0148] Specifically, a second ultrasonic wave can be emitted towards the object under test using an ultrasonic probe, and the ultrasonic echo of the second ultrasonic wave can be received to obtain second ultrasonic echo data. Then, a beamforming circuit can perform beamforming processing on the second ultrasonic echo data, and the beamformed second ultrasonic echo data is then sent to a processor for relevant image processing to obtain a base ultrasound image. Subsequently, the location of the region of interest can be determined based on this base ultrasound image. In one example, determining the location of the region of interest based on a conventional ultrasound image specifically includes: outputting the conventional ultrasound image and marking the location of the region of interest on the conventional ultrasound image.

[0149] Next, in steps S810 to S830, acoustic radiation force focusing impact can be performed according to a pre-set pulse sequence based on the region of interest selected in the above manner. Specifically, the ultrasonic probe emits special ultrasonic driving pulses towards the tissue of the region of interest of the object being tested, so as to generate shear wave propagation in the tissue based on acoustic radiation force. The length of the ultrasonic driving pulse is generally greater than 100 μs, and in order to enhance the intensity and range of the generated shear wave, multiple ultrasonic driving pulses are often emitted continuously.

[0150] Next, a series of first ultrasound waves tracking shear waves are continuously emitted into the tissue of the region of interest by an ultrasound probe for a period of time, and the ultrasound echoes are received to obtain first ultrasound echo data. A shear wave signal is then obtained based on the first ultrasound echo data. This shear wave signal characterizes the vibration state of the tissue as the shear wave propagates within it. The shear wave signal obtained in this manner is a broadband signal, including multiple shear wave components within the range of 0–1000 Hz. Each shear wave component of the shear wave signal corresponds to the tissue vibration state caused by a shear wave of a specific frequency.

[0151] In step S840, the shear wave signal is filtered to extract at least one shear wave component of a specific frequency. Shear wave components of different frequencies can be considered as tissue vibration information caused by shear waves of different frequencies. The shear wave signal can be a time-domain signal describing the change of tissue motion information over time within a region of interest. Filtering of the shear wave signal can be performed in the time domain, i.e., time-domain filtering of the shear wave signal. Alternatively, the shear wave signal can be transformed into a frequency-domain signal, and frequency-domain filtering can be performed on the frequency-domain signal. Then, the frequency-domain filtered signal is inversely transformed back into a time-domain signal.

[0152] For example, filtering can be performed based on a bandpass filter with a selected frequency as the center frequency to extract the shear wave component at the corresponding frequency. Alternatively, low-pass and / or high-pass filters can be used to filter the shear wave signal separately.

[0153] Furthermore, each separated shear wave component does not necessarily include only a single center frequency, but rather a frequency band with a preset bandwidth centered at a preset frequency point. The bandwidth of the extracted shear wave component can be changed by adjusting the filter parameters used for filtering. The more concentrated the separated shear wave components, the more accurately the tissue motion information at the current frequency can be obtained; however, correspondingly, because more shear wave components are filtered out, the signal-to-noise ratio of the obtained signal will decrease. Therefore, by adjusting the filter parameters, the desired balance between the accuracy of tissue motion information and the signal-to-noise ratio of the signal can be achieved.

[0154] In step S850, the phase velocity of the shear wave is determined based on the shear wave components. Exemplarily, the phase velocity of the shear wave can be calculated using various methods for determining the propagation velocity of shear waves commonly used in shear wave elasticity measurements, such as calculating the arrival times of shear waves at two different locations spaced a certain distance apart in the tissue. Alternatively, the propagation velocity of the shear wave can be calculated through inversion of the wave equation, etc. This application embodiment does not limit the method for calculating the shear wave propagation velocity.

[0155] Then, the phase velocity of the shear wave can be directly output. The output phase velocity can include numerical values ​​and / or images. The numerical values ​​of the output phase velocity can include the phase velocity values ​​at various locations within the region of interest, or statistical results of the phase velocity values ​​at multiple locations. The image of the output phase velocity can include a statistical graph of the output phase velocity, or a phase velocity image formed by grayscale or color encoding based on the phase velocity values ​​superimposed on a conventional ultrasound image, or it can also include a curve showing the change of phase velocity with the shear wave frequency, etc.

[0156] In one embodiment, a third elastic parameter of the region of interest can be determined based on the phase velocity of the shear wave, and the value and / or image of the third elastic parameter can be output. The third elastic parameter may include the elastic modulus calculated using the phase velocity, or it may include the elastic parameter calculated based on the Voigt model.

[0157] For example, the output value of the third elasticity parameter can be a statistical result of the third elasticity parameter, used as an estimate of the overall elasticity of the region of interest. The statistical result of the third elasticity parameter may include at least one of the following: the average, median, standard deviation, quartiles, maximum, or minimum value of multiple elasticity information values.

[0158] Furthermore, the statistical results of the third elastic parameter are not limited to the statistical results of the third elastic parameter at multiple locations obtained from a single elastic measurement, but may also include the statistical results of the third elastic parameter obtained from multiple elastic measurements. For example, the statistical results of the third elastic parameter obtained from multiple elastic measurements may also include the average, median, standard deviation, quartiles, maximum or minimum values ​​of the third elastic parameter obtained from multiple elastic measurements.

[0159] Specifically, for the image outputting the third elastic parameter, the third elastic parameter at multiple locations within the region of interest can be acquired to generate an elastic image of the region of interest, which is then displayed on the display interface. For example, the third elastic parameter can be processed by grayscale or color encoding to generate an elastic image, which is then overlaid or fused with a conventional ultrasound image for display.

[0160] In one embodiment, the group velocity of the shear wave can be determined based on the shear wave signal, and a fourth elastic parameter of the region of interest can be obtained based on the group velocity. Then, the value and / or image of the fourth elastic parameter can be output. The fourth elastic parameter may include the shear modulus or Young's modulus calculated using the group velocity of the shear wave. The output method of the fourth elastic parameter can be found in the output method of the third elastic parameter described above.

[0161] The above exemplarily illustrates an elasticity measurement method 800 according to an embodiment of this application. Based on the above description, the elasticity measurement method 800 according to an embodiment of this application extracts the shear wave component from the shear wave signal and calculates the phase velocity of the shear wave component, which can reflect information such as the elasticity or viscosity of the tissue in the region of interest.

[0162] The following is a reference to the appendix. Figure 9 A method for measuring elasticity according to another embodiment of this application is described. Figure 9 A schematic flowchart of an elasticity measurement method 900 according to another embodiment of this application is shown. (Refer to...) Figure 9 The described elasticity measurement method 900 is generally similar to the elasticity measurement method 800 described above, but some identical details are omitted. For example... Figure 9 As shown, the elasticity measurement method 900 includes the following steps:

[0163] Step S910: Obtain the shear wave signal of the region of interest of the object under test;

[0164] Step S920: Extract at least one frequency shear wave component from the shear wave signal;

[0165] Step S930: Determine the phase velocity of the shear wave based on the shear wave component of the at least one frequency.

[0166] refer to Figure 9 The described elasticity measurement method 900 and reference Figure 8 The elasticity measurement method 8008 is similar, both determining the phase velocity of the shear wave based on the shear wave component extracted from the shear wave signal. The difference lies in that, in the elasticity measurement method 900, the method of acquiring the shear wave signal is not limited; the region of interest of the target object can be acquired in any suitable manner to perform the aforementioned elasticity measurement. For example, the shear wave signal can be acquired in real time or extracted from a storage medium; the shear wave can be generated by acoustic radiation force pulse impact as described above, by applying external mechanical vibration, or by any other suitable method.

[0167] According to the embodiment of this application, the elasticity measurement method 900 extracts the shear wave component from the shear wave signal and calculates the phase velocity of the shear wave component, which can reflect information such as the elasticity or viscosity of the tissue in the region of interest.

[0168] The above exemplarily illustrates an elasticity measurement method according to an embodiment of this application. The following, in conjunction with... Figure 10 The ultrasonic measurement system according to embodiments of this application is described, which can be used to implement the viscoelasticity measurement method or elasticity measurement method described above according to embodiments of this application. Figure 10A schematic structural block diagram of an ultrasonic measurement system 1000 according to an embodiment of this application is shown.

[0169] like Figure 10 As shown, the ultrasonic measurement system 1000 includes an ultrasonic probe 1010, a transmit / receive circuit 1020, a processor 1030, and an output device 1040. Further, the ultrasonic measurement system may also include a beamforming circuit and a transmit / receive selection switch, and the transmit / receive circuit 1020 can be connected to the ultrasonic probe 1010 via the transmit / receive selection switch.

[0170] In the shear wave elasticity measurement, the ultrasonic probe 1010, under the control of the processor 1030, emits acoustic radiation force pulses towards the object under test to generate shear waves in the region of interest of the object. The ultrasonic probe 1010 is equipped with multiple transducers for emitting ultrasonic waves based on electrical signals or converting received ultrasonic echoes into electrical signals. The multiple transducers can be arranged in a row to form a linear array, or arranged in a two-dimensional matrix to form a surface array. The multiple transducers can also form a convex array, a phased array, etc. This embodiment does not limit the arrangement of the multiple transducer array elements.

[0171] Transducers can emit ultrasonic waves based on excitation electrical signals, or convert received ultrasonic waves into electrical signals. Therefore, each transducer can be used to emit ultrasonic waves into tissue in a target area, or to receive ultrasonic echoes returning from the tissue. During ultrasonic measurements, the transmitter / receiver circuit 1020 can control which transducers emit ultrasonic waves, which transducers receive ultrasonic waves, or control the transducers to be used in time-slotted manner for emitting ultrasonic waves or receiving ultrasonic echoes. All transducers involved in ultrasonic wave emission can be simultaneously excited by electrical signals, thus emitting ultrasonic waves simultaneously; or transducers involved in ultrasonic wave emission can be excited by several electrical signals with certain time intervals, thus continuously emitting ultrasonic waves with certain time intervals.

[0172] The region of interest (ROI) can be selected by the user. For example, when a conventional ultrasound image is displayed on the screen, the user can select the ROI on the conventional ultrasound image, and the ultrasound measurement system 1000 can calculate the transmission and reception sequences based on the selected ROI. In some embodiments, the ultrasound measurement system 1000 defaults to the subepidermal area of ​​the tissue contacted by the ultrasound probe 1010 as the ROI.

[0173] Optionally, the ultrasound probe 1010 may also include a pressure sensor to provide feedback on the force applied when the ultrasound probe 1010 contacts the human body, allowing the user to control the pressure and ensuring that the shear waves generated by the ultrasound probe 1010 are effectively transmitted to the tissue.

[0174] The transmitting / receiving circuit 1020 is used to excite the ultrasonic probe 1010 to emit ultrasonic waves that track the shear wave toward the target area, and to receive the ultrasonic echo corresponding to the ultrasonic waves returning from the target area, thereby obtaining ultrasonic echo data. Then, the transmitting / receiving circuit 1020 sends the electrical signal of the ultrasonic echo to a beamforming circuit, which performs focusing delay, weighting, and channel summation on the ultrasonic echo data, and then sends it to the processor 1030.

[0175] Optionally, the processor 1030 can be implemented using software, hardware, firmware, or any combination thereof. It can use circuits, one or more application-specific integrated circuits (ASICs), one or more general-purpose integrated circuits, one or more microprocessors, one or more programmable logic devices, or any combination of the aforementioned circuits and / or devices, or other suitable circuits or devices. Furthermore, the processor 1030 can control other components in the ultrasonic measurement system 1000 to perform desired functions.

[0176] The processor 1030 performs viscoelastic processing on the received ultrasound echo data to obtain viscous and elastic information of the region of interest, and can store the obtained viscous and elastic information in a memory. As an example, the processor can also perform different processing on the ultrasound echo data acquired by the transmitting / receiving circuit 1020 according to the imaging mode required by the user to obtain ultrasound tissue images of different modes. In one embodiment, the processor can simultaneously obtain viscous information, elastic information, and ultrasound tissue images by processing the same ultrasound echo; in another embodiment, the ultrasound probe 1010 can emit a first ultrasound wave and a second ultrasound wave sequentially or intermittently, and the processor 1030 can obtain viscous and elastic information by processing the first ultrasound echo of the first ultrasound wave, and generate ultrasound tissue images of different modes by processing the second ultrasound echo of the second ultrasound wave.

[0177] Output device 1040 is connected to processor 1030 and is used to output viscosity information and elasticity information. In one embodiment, output device 1040 may be a display for displaying viscosity information and elasticity information on a display interface. As an example, the display may be a touch screen, liquid crystal display, etc., or it may be a standalone display device such as a liquid crystal display or a television; alternatively, the display may be the screen of an electronic device such as a smartphone or tablet, etc. The number of displays may be one or more.

[0178] In addition to displaying ultrasound images, the monitor can also provide a graphical user interface (GUI) for human-computer interaction. One or more controlled objects can be set on the GUI, allowing the user to input operating commands via the GUI to control these objects and execute corresponding control operations. For example, the GUI may display icons that can be manipulated using the GUI to perform specific functions.

[0179] In addition, output device 1040 may also include speakers, printers, etc. Output device 1040 may also be any other suitable information output device.

[0180] Optionally, the ultrasonic measurement system 1000 may also include other human-machine interface devices connected to the processor 1030. For example, the processor 1030 may be connected to the human-machine interface device via an external input / output port, which may be a wireless communication module, a wired communication module, or a combination of both. The external input / output port may also be implemented based on USB, bus protocols such as CAN, and / or wired network protocols.

[0181] For example, a human-computer interaction device may include an input device for detecting user input information, which may be, for example, a selection instruction for a region of interest, or may include other instruction types. The input device may include one or a combination of a keyboard, mouse, scroll wheel, trackball, mobile input device (such as a mobile device with a touchscreen, a mobile phone, etc.), a multi-function knob, etc.

[0182] The ultrasonic measurement system 1000 may also include a memory for storing instructions executed by the processor, viscous and elastic information, ultrasonic images, etc. The memory can be a flash memory card, solid-state memory, hard disk, etc. It can be volatile and / or non-volatile memory, removable and / or non-removable memory, etc.

[0183] It should be understood that Figure 10 The components included in the ultrasonic measurement system 1000 shown are merely illustrative and may include more or fewer components, which is not limited in this application.

[0184] In one embodiment, the ultrasonic measurement system 1000 is used to implement the viscoelasticity measurement method 100 of this application embodiment. The transmitting / receiving circuit 1020 is used to excite the ultrasonic probe 1010 to emit acoustic radiation force pulses towards the object under test to generate shear waves in the region of interest of the object under test, and to excite the ultrasonic probe 1010 to emit first ultrasonic waves that track the shear waves towards the region of interest, and to receive first ultrasonic echoes from the region of interest to obtain first ultrasonic echo data. The processor 1030 is used to: obtain the shear wave signal of the region of interest based on the first ultrasonic echo data; extract at least two shear wave components of different frequencies from the shear wave signal; determine the phase velocity of the shear wave based on the at least two different frequency shear wave components respectively; determine viscous information reflecting the viscosity of the region of interest based on at least two phase velocities; and the output device 1040 is used to output the viscous information.

[0185] In one embodiment, the ultrasonic measurement system 1000 is used to implement the elasticity measurement method 800 of this application embodiment. The transmitting / receiving circuit 1020 is used to excite the ultrasonic probe 1010 to emit acoustic radiation force pulses towards the object under test to generate shear waves in the region of interest of the object under test; and to excite the ultrasonic probe 1010 to emit a first ultrasonic wave that tracks the shear wave towards the region of interest, and to receive a first ultrasonic echo from the region of interest to obtain first ultrasonic echo data. The processor 1030 is used to: obtain the shear wave signal of the region of interest based on the first ultrasonic echo data; extract at least one frequency shear wave component from the shear wave signal; determine the phase velocity of the shear wave based on the at least one frequency shear wave component; and the output device 1040 is used to output the phase velocity of the shear wave.

[0186] The above exemplarily illustrates an ultrasonic measurement system 1000 according to an embodiment of this application. Based on the above description, the ultrasonic measurement system 1000 according to an embodiment of this application can, on the one hand, be used to extract shear wave components of different frequencies from a shear wave signal to determine the viscosity information of a tissue, and on the other hand, can be used to extract at least one shear wave component of a frequency from a shear wave signal to determine the phase velocity of a tissue.

[0187] Reference Figure 11 This application also provides an ultrasonic measurement system 1100 for implementing the above-described viscoelasticity measurement method 70 or elasticity measurement method 900. The ultrasonic measurement system 1100 includes a memory 1110 and a processor 1120, wherein the memory 1110 stores a computer program executed by the processor 1120.

[0188] The processor 1120 can be implemented by software, hardware, firmware or any combination thereof, and can be a circuit, a single or multiple application-specific integrated circuits, a single or multiple general-purpose integrated circuits, a single or multiple microprocessors, a single or multiple programmable logic devices, or any combination of the aforementioned circuits and / or devices, or other suitable circuits or devices. The processor 1120 can control other components in the ultrasonic measurement system 1100 to perform the desired functions.

[0189] The memory 1110 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory and / or cache memory. The non-volatile memory may include, for example, read-only memory, hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 520 may execute the program instructions to implement the ultrasound imaging or ultrasound image processing functions (implemented by the processor) in the embodiments of the present invention described below (implemented by the processor) and / or other various desired functions. Various application programs and various data may also be stored in the computer-readable storage medium, such as various data used and / or generated by the application programs.

[0190] In one embodiment, a computer program stored in memory 1110 performs the following steps when run by processor 1120: acquiring a shear wave signal of a region of interest of the object under test; extracting at least two shear wave components of different frequencies from the shear wave signal; determining the phase velocity of the shear wave based on the at least two shear wave components of different frequencies; and determining viscosity information reflecting the viscosity of the region of interest based on at least two of the phase velocities.

[0191] In another embodiment, the computer program stored on memory 1110 performs the following steps when run by processor 1120: acquiring a shear wave signal of the region of interest of the object under test; extracting a shear wave component of at least one frequency from the shear wave signal; and determining the phase velocity of the shear wave based on the shear wave component of at least one frequency.

[0192] Other specific details of the functions implemented by the ultrasonic measurement system 1100 can be found in the relevant description in the Methods section above, and will not be repeated here.

[0193] Furthermore, according to embodiments of this application, a storage medium is also provided, on which program instructions are stored. When executed by a computer or processor, these program instructions are used to perform corresponding steps of the viscoelasticity measurement method 200, viscoelasticity measurement method 700, elasticity measurement method 800, or elasticity measurement method 900 of this application. The storage medium may, for example, include a memory card of a smartphone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disc read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0194] Furthermore, according to embodiments of this application, a computer program is also provided, which can be stored on a cloud or local storage medium. When this computer program is run by a computer or processor, it is used to perform the corresponding steps of the viscoelasticity measurement method or elasticity measurement method of the embodiments of this application.

[0195] Based on the above description, the viscoelasticity measurement method and ultrasonic measurement system according to embodiments of this application extract shear wave components of different frequencies from the shear wave signal and obtain the phase velocity of each shear wave component, thus obtaining information reflecting tissue viscosity with only one measurement. The elasticity measurement method according to embodiments of this application extracts shear wave components from the shear wave signal and calculates their corresponding phase velocities, which can reflect the elasticity information of the tissue.

[0196] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0197] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0198] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed.

[0199] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0200] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0201] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0202] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0203] The various component embodiments of this application can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some modules according to the embodiments of this application. This application can also be implemented as an apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0204] It should be noted that the above embodiments are illustrative of this application and not limiting of it, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0205] The above description is merely a specific embodiment or illustration of the embodiments of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A method for measuring viscoelasticity, characterized in that, The method includes: Acquire conventional ultrasound images of the subject; The region of interest is determined based on the conventional ultrasound images; Acquire the shear wave signal of the region of interest, wherein the shear wave signal is used to characterize the vibration state of the tissue when the shear wave propagates in the tissue corresponding to the region of interest, and the shear wave signal is a broadband signal; By filtering the shear wave signal, at least two shear wave components of different frequencies are extracted from the shear wave signal. Viscous information reflecting the viscosity of the region of interest is determined based on at least two shear wave components of different frequencies; Output the viscosity information.

2. The viscoelasticity measurement method according to claim 1, characterized in that, The shear wave component of each frequency includes a frequency band with a preset bandwidth centered at a preset frequency point.

3. The viscoelasticity measurement method according to claim 1, characterized in that, The step of filtering the shear wave signal to extract at least two different frequency shear wave components from the shear wave signal includes: performing bandpass filtering on the shear wave signal based on at least two different frequency bandpass filters to extract the corresponding frequency shear wave components respectively.

4. The viscoelasticity measurement method according to claim 1, characterized in that, The step of filtering the shear wave signal to extract at least two different frequency shear wave components from the shear wave signal includes: filtering the shear wave signal based on a high-pass filter and a low-pass filter respectively to extract the high-frequency component and the low-frequency component in the shear wave signal.

5. The viscoelasticity measurement method according to claim 1, characterized in that, The shear wave signal includes a time-domain signal describing the change of tissue motion information over time within the region of interest. The step of filtering the shear wave signal to extract at least two shear wave components of different frequencies includes: Perform time-domain filtering on the shear wave signal, or The shear wave signal is transformed into a frequency domain signal, the frequency domain signal is filtered in the frequency domain, and the frequency domain signal after filtering is inversely transformed into a time domain signal.

6. The viscoelasticity measurement method according to any one of claims 1 to 5, characterized in that, The viscosity information includes viscosity parameters, and the determination of viscosity information reflecting the viscosity of the region of interest based on at least two shear wave components of different frequencies includes: The phase velocity of the shear wave is determined based on at least two shear wave components of different frequencies. The viscosity parameters of the region of interest are determined based on the relationship between the phase velocity, viscosity parameters, and shear wave frequency, wherein the shear wave frequency is determined based on the center frequency of the shear wave component.

7. The viscoelasticity measurement method according to claim 6, characterized in that, The determination of the viscosity parameters of the region of interest based on the relationship between the shear wave phase velocity, viscosity parameters, and shear wave frequency includes: The viscosity parameters are obtained by fitting multiple shear wave frequencies and their corresponding phase velocities.

8. The viscoelasticity measurement method according to claim 6, characterized in that, Also includes: The first elastic parameter of the region of interest is calculated based on the relationship between the phase velocity and the viscosity parameter, the first elastic parameter, and the shear wave frequency. Output the numerical value and / or image of the first elastic parameter.

9. The viscoelasticity measurement method according to any one of claims 1 to 5, characterized in that, The step of determining the viscosity information reflecting the viscosity of the region of interest based on at least two shear wave components of different frequencies includes: The phase velocity of the shear wave is determined based on at least two shear wave components of different frequencies. The phase velocities determined based on shear wave components of different frequencies are compared to obtain a comparison result, and the comparison result is used as the viscosity information reflecting the viscosity of the region of interest.

10. The viscoelasticity measurement method according to claim 9, characterized in that, The comparison results include at least one of the following: the difference between different phase velocities, the ratio of different phase velocities, or the slope of the phase velocity as a function of the shear wave frequency.

11. The viscoelasticity measurement method according to claim 1, characterized in that, Also includes: The viscosity information at multiple locations within the region of interest is acquired to generate a viscosity image of the region of interest; The output of the viscosity information includes displaying the viscosity image.

12. The viscoelasticity measurement method according to any one of claims 1 to 5, characterized in that, Also includes: Statistical results of the viscosity information of the region of interest are obtained based on the viscosity information at one or more locations within the region of interest; The output of the viscosity information includes displaying the numerical values ​​of the statistical results.

13. The viscoelasticity measurement method according to claim 12, characterized in that, The statistical results of the viscosity information include at least one of the following: the mean, median, standard deviation, quartiles, maximum or minimum value of the multiple viscosity information.

14. The viscoelasticity measurement method according to claim 12 or 13, characterized in that, The statistical results of the viscosity information include the statistical results of the viscosity information obtained from multiple viscoelastic measurements.

15. The viscoelasticity measurement method according to claim 1 or 8, characterized in that, The acquisition of conventional ultrasound images of the subject includes: A second ultrasonic wave is emitted toward the object under test, and the ultrasonic echo of the second ultrasonic wave is received to obtain second ultrasonic echo data. A conventional ultrasound image of the object under test is obtained based on the second ultrasound echo data.

16. The viscoelasticity measurement method according to claim 15, characterized in that, Also includes: Output the conventional ultrasound image and mark the location of the region of interest on the conventional ultrasound image.

17. The viscoelasticity measurement method according to claim 1 or 16, characterized in that, Also includes: The group velocity of the shear wave is determined based on the shear wave signal, and the second elastic parameter of the region of interest is obtained based on the group velocity.

18. The viscoelasticity measurement method according to claim 17, characterized in that, Also includes: Output at least one of the following: The value of the second elastic parameter, the image of the second elastic parameter, the value of the group velocity, and the image of the group velocity.

19. The viscoelasticity measurement method according to any one of claims 1 to 18, characterized in that, The acquisition of the shear wave signal of the region of interest of the object under test includes: An acoustic radiation force pulse is emitted toward the object under test to generate a shear wave in the region of interest of the object under test; A first ultrasonic wave that tracks the shear wave is emitted toward the region of interest, and a first ultrasonic echo is received from the region of interest to obtain first ultrasonic echo data. The shear wave signal of the region of interest is obtained based on the first ultrasonic echo data.

20. The method according to claim 19, characterized in that, The step of obtaining the shear wave signal of the region of interest based on the first ultrasonic echo data includes: Tissue motion information is determined based on the first ultrasound echo data corresponding to different times, and the tissue motion information is used as the shear wave signal; wherein, the tissue motion information includes at least one of tissue displacement, tissue velocity, tissue acceleration, and tissue strain.

21. The method according to claim 20, characterized in that, Also includes: The vibration waveform of the shear wave signal is determined based on tissue motion information at different times, wherein the vibration waveform includes a tissue motion velocity-time curve or a tissue motion displacement-time curve.

22. A method for measuring viscoelasticity, characterized in that, The method includes: Acquire the shear wave signal of the region of interest of the test object, wherein the shear wave signal is used to characterize the vibration state of the tissue when the shear wave propagates in the tissue corresponding to the region of interest, and the shear wave signal is a broadband signal; By filtering the shear wave signal, at least two shear wave components of different frequencies are extracted from the shear wave signal. Viscous information reflecting the viscosity of the region of interest is determined based on at least two shear wave components of different frequencies; Output the viscosity information.

23. The viscoelasticity measurement method according to claim 22, characterized in that, The method further includes: The group velocity of the shear wave is determined based on the shear wave signal, and the second elastic parameter of the region of interest is obtained based on the group velocity. Output at least one of the following: the value of the second elastic parameter, the image of the second elastic parameter, the value of the group velocity, and the image of the group velocity.

24. The viscoelasticity measurement method according to claim 22, characterized in that, The viscosity information includes viscosity parameters, and the determination of viscosity information reflecting the viscosity of the region of interest based on at least two shear wave components of different frequencies includes: The phase velocity of the shear wave is determined based on at least two shear wave components of different frequencies. The viscosity parameters of the region of interest are determined based on the relationship between the phase velocity, viscosity parameters, and shear wave frequency, wherein the shear wave frequency is determined based on the center frequency of the shear wave component.

25. The viscoelasticity measurement method according to claim 24, characterized in that, Also includes: The first elastic parameter of the region of interest is calculated based on the relationship between the phase velocity and the viscosity parameter, the first elastic parameter, and the shear wave frequency. Output the numerical value and / or image of the first elastic parameter.

26. The viscoelasticity measurement method according to claim 22, characterized in that, Also includes: The viscosity information at multiple locations within the region of interest is acquired to generate a viscosity image of the region of interest; The output of the viscosity information includes displaying the viscosity image.

27. The viscoelasticity measurement method according to claim 22, characterized in that, The acquisition of the shear wave signal of the region of interest of the object under test includes: A first ultrasonic wave that tracks the shear wave is emitted toward the region of interest, and a first ultrasonic echo is received from the region of interest to obtain first ultrasonic echo data. Tissue motion information is determined based on the first ultrasound echo data corresponding to different times, and the tissue motion information is used as the shear wave signal; wherein, the tissue motion information includes at least one of tissue displacement, tissue velocity, tissue acceleration, and tissue strain.

28. The viscoelasticity measurement method according to claim 27, characterized in that, Also includes: The vibration waveform of the shear wave signal is determined based on tissue motion information at different times, wherein the vibration waveform includes a tissue motion velocity-time curve or a tissue motion displacement-time curve.

29. The viscoelasticity measurement method according to any one of claims 22 to 28, characterized in that, Also includes: Statistical results of the viscosity information of the region of interest are obtained based on the viscosity information at one or more locations within the region of interest; The output of the viscosity information includes displaying the numerical values ​​of the statistical results.

30. The viscoelasticity measurement method according to claim 29, characterized in that, The statistical results of the viscosity information include at least one of the following: the mean, median, standard deviation, quartiles, maximum or minimum value of the multiple viscosity information.

31. The viscoelasticity measurement method according to claim 22, characterized in that, The step of filtering the shear wave signal to extract at least two different frequency shear wave components from the shear wave signal includes: performing bandpass filtering on the shear wave signal based on at least two different frequency bandpass filters to extract the corresponding frequency shear wave components respectively.

32. A method for measuring elasticity, characterized in that, The method includes: Acquire the shear wave signal of the region of interest of the test object, wherein the shear wave signal is used to characterize the vibration state of the tissue when the shear wave propagates in the tissue corresponding to the region of interest, and the shear wave signal is a broadband signal; By filtering the shear wave signal, at least one frequency shear wave component is extracted from the shear wave signal. The shear wave velocity is determined based on the shear wave components of at least one frequency.

33. The elasticity measurement method according to claim 32, characterized in that, The step of filtering the shear wave signal to extract at least one frequency shear wave component from the shear wave signal includes: performing bandpass filtering on the shear wave signal based on a bandpass filter to extract the shear wave components of the corresponding frequencies respectively.

34. The elasticity measurement method according to claim 32, characterized in that, The shear wave signal includes a time-domain signal describing the change of tissue motion information over time within the region of interest. The step of filtering the shear wave signal to extract at least two shear wave components of different frequencies includes: Perform time-domain filtering on the shear wave signal, or The shear wave signal is transformed into a frequency domain signal, the frequency domain signal is filtered in the frequency domain, and the frequency domain signal after filtering is inversely transformed into a time domain signal.

35. The elasticity measurement method according to claim 32, characterized in that, The acquisition of the shear wave signal of the region of interest of the object under test includes: A first ultrasonic wave that tracks the shear wave is emitted toward the region of interest, and a first ultrasonic echo is received from the region of interest to obtain first ultrasonic echo data. Tissue motion information is determined based on the first ultrasound echo data corresponding to different times, and the tissue motion information is used as the shear wave signal; wherein, the tissue motion information includes at least one of tissue displacement, tissue velocity, tissue acceleration, and tissue strain.

36. The elasticity measurement method according to claim 35, characterized in that, Also includes: The vibration waveform of the shear wave signal is determined based on tissue motion information at different times, wherein the vibration waveform includes a tissue motion velocity-time curve or a tissue motion displacement-time curve.

37. The elasticity measurement method according to claim 34 or 35, characterized in that, Determining the shear wave velocity based on the shear wave components of at least one frequency includes: The shear wave velocity is determined based on the tissue motion information corresponding to the arrival time of the shear wave at different locations under at least one frequency of shear wave component.

38. An ultrasonic measurement system, characterized in that, include: Ultrasonic probe; A transmitting / receiving circuit is used to excite the ultrasonic probe to emit ultrasonic waves toward the object under test and to receive ultrasonic echoes. A processor for performing the method according to any one of claims 1 to 37; An output device for outputting the results executed by the processor.

39. A computer storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a computer or processor, it implements the steps of the method according to any one of claims 1 to 37.

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