Method and system for performing diagnostic ultrasound imaging

Abstract

Methods, systems and methods for performing diagnostic ultrasound imaging can collect ultrasound information of an object region. The ultrasound information can be based on one or more exponentially scanned ultrasound chirped pulses emitted toward the object region and backscattering of the one or more exponentially scanned ultrasound chirped pulses by the object region. One or more corresponding harmonic responses and corresponding fundamental responses to each of the one or more exponentially scanned ultrasound chirped pulses can be separated from the ultrasound information. In addition, one or more nonlinear properties of the object region can be identified based on one or both of the one or more corresponding harmonic responses and corresponding fundamental responses to each of the one or more exponentially scanned ultrasound chirped pulses.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 832,388, filed on April 11, 2019, and entitled “Ultrasonic Tissue Characterization of B / A Coefficients,” whose inventors are Glen W. McLaughlin et al., the entire contents of which are hereby incorporated by reference. Technical Field

[0003] This article relates to diagnostic ultrasound imaging and, more particularly, to identifying nonlinear properties of tissue by exponentially scanning ultrasound chirp pulses. Background Art

[0004] Ultrasound imaging is widely used to examine a variety of materials and objects in a variety of different applications. Ultrasound imaging provides a quick and easy tool to analyze materials and objects in a non-invasive manner. As a result, ultrasound imaging is particularly prevalent in medical practice as a disease diagnosis, treatment, and prevention tool. Specifically, due to its relatively non-invasive nature, low cost, and fast response time, ultrasound imaging is widely used throughout the medical industry to diagnose and prevent disease. Moreover, because ultrasound imaging is based on non-ionizing radiation, it does not carry the same risks as other diagnostic imaging tools (such as X-ray imaging or other imaging systems that use ionizing radiation).

[0005] Characterizing tissue properties using ultrasound, especially in vivo, has been a long-standing area of ​​research over the past few decades. In particular, much effort has been made to efficiently collect and interpret ultrasound measurements to characterize both global and local tissue properties of tissues. However, extracting meaningful and consistent ultrasound measurements and interpreting these ultrasound measurements to identify tissue properties has been challenging for a number of reasons. Summary of the invention

[0006] According to various embodiments, a method for performing diagnostic ultrasound imaging includes acquiring ultrasound information of an object region. The ultrasound information may be based on one or more exponentially scanned ultrasound chirp pulses emitted toward the object region and backscattering of the object region to the one or more exponentially scanned ultrasound chirp pulses. The method may also include separating one or more corresponding harmonic responses and corresponding fundamental responses for each of the one or more exponentially scanned ultrasound chirp pulses from the ultrasound information. In addition, the method may include identifying one or more nonlinear properties of the object region based on one or both of the one or more corresponding harmonic responses and corresponding fundamental responses for each of the one or more exponentially scanned ultrasound chirp pulses.

[0007] In some embodiments, a system for performing diagnostic ultrasound imaging includes an ultrasound transducer and a main processing console. The ultrasound transducer can collect ultrasound information of an object area. The ultrasound information can be based on one or more exponentially scanned ultrasound chirp pulses emitted toward the object area and the backscattering of the object area to the one or more exponentially scanned ultrasound chirp pulses. The main processing console can separate one or more corresponding harmonic responses and corresponding fundamental responses from the ultrasound information to each of the one or more exponentially scanned ultrasound chirp pulses. The main processing console can also identify one or more nonlinear properties of the object area based on one or both of the one or more corresponding harmonic responses and corresponding fundamental responses to each of the one or more exponentially scanned ultrasound chirp pulses.

[0008] In various embodiments, a system for performing diagnostic ultrasound imaging includes one or more processors and a computer-readable medium. The computer-readable medium provides instructions accessible to the one or more processors to enable the one or more processors to collect ultrasound information of an object area. The ultrasound information can be based on one or more exponentially scanned ultrasound chirp pulses emitted toward the object area and the backscattering of the object area to the one or more exponentially scanned ultrasound chirp pulses. The instructions can also enable the one or more processors to separate one or more corresponding harmonic responses and corresponding fundamental responses from the ultrasound information to each of the one or more exponentially scanned ultrasound chirp pulses. In addition, the instructions can enable the one or more processors to identify one or more nonlinear properties of the object area based on one or both of the one or more corresponding harmonic responses and corresponding fundamental responses to each of the one or more exponentially scanned ultrasound chirp pulses. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An example of an ultrasound system is shown.

[0010] Figure 2 is a graph of the intensity of the fundamental and harmonic responses to an exponentially swept ultrasonic chirp pulse as a function of time for linear and nonlinear object regions.

[0011] Figure 3 3A is a positive phase image of the object area generated by a Gaussian ultrasound emission profile, 3B is a negative phase image of the object area generated by a Gaussian ultrasound emission profile, 3C is a sum image of the images shown in 3A and 3B, and 3D is a difference image of the images shown in 3A and 3B.

[0012] Figure 4 4A is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 10 mm, 4B is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 20 mm, 4C is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 30 mm, 4D is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 40 mm, 4E is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 50 mm, and 4F is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 60 mm.

[0013] Figure 5 In the figure, 5A is a positive phase image of the object area generated by exponential scanning of ultrasonic chirp signals, 5B is a negative phase image of the object area generated by exponential scanning of ultrasonic chirp signals, 5C is the sum image of the images shown in 5A and 5B, and 5D is the difference image of the images shown in 5A and 5B.

[0014] Figure 6 Figure 6A is an intensity diagram of the fundamental and harmonic responses of an exponentially scanned ultrasonic chirp pulse centered at a depth of 10 mm, Figure 6B is an intensity diagram of the fundamental and harmonic responses of an exponentially scanned ultrasonic chirp pulse centered at a depth of 20 mm, Figure 6C is an intensity diagram of the fundamental and harmonic responses of an exponentially scanned ultrasonic chirp pulse centered at a depth of 30 mm, Figure 6D is an intensity diagram of the fundamental and harmonic responses of an exponentially scanned ultrasonic chirp pulse centered at a depth of 40 mm, Figure 6E is an intensity diagram of the fundamental and harmonic responses of an exponentially scanned ultrasonic chirp pulse centered at a depth of 50 mm, and Figure 6F is an intensity diagram of the fundamental and harmonic responses of an exponentially scanned ultrasonic chirp pulse centered at a depth of 60 mm.

[0015] Figure 7 7A is Figure 6 The sum and difference graphs of the fundamental and harmonic responses centered at a depth of 10 mm in 6A and 7B are Figure 6 6B is a graph of the sum and difference of the fundamental and harmonic responses centered at a depth of 20 mm, and 7C is Figure 6 The sum and difference graphs of the fundamental and harmonic responses at a depth of 30 mm centered in 6C and 7D are Figure 6 The sum and difference graphs of the fundamental and harmonic responses centered at a depth of 40 mm in 6D and 7E are Figure 6The sum and difference graphs of the fundamental and harmonic responses centered at a depth of 50 mm in 6E and 7F are Figure 6 A graph of the sum and difference of the fundamental and harmonic responses of the 6F centered at a depth of 60mm.

[0016] Figure 8 is a flow chart of an example method for identifying nonlinear properties of an object region by exponentially scanning ultrasonic chirp pulses.

[0017] Fig. 9 is a flow chart of an example method for estimating B / A parameters of an object region by exponentially scanning an ultrasonic chirp signal. DETAILED DESCRIPTION

[0018] Over the past few decades, the use of ultrasound to characterize tissue properties, especially in vivo tissue properties, has been a long-standing field of research. In particular, many efforts have been made to effectively collect and interpret ultrasound measurements to characterize the overall and local tissue properties of tissues. However, for a variety of reasons, extracting meaningful and consistent ultrasound measurements and interpreting these ultrasound measurements to identify tissue properties has always been a challenging task. First, basic ultrasound measurements are often operator-dependent, which makes it difficult to consistently and accurately identify tissue features from measurements collected by different operators. In addition, ultrasound measurements are sensitive to noise, which makes it difficult to accurately identify tissue features from measurements. In addition, ultrasound may have difficulty penetrating a region of interest at a large depth, making it difficult to collect measurements used to accurately identify tissue features in the region of interest. In addition, the correlation between different ultrasound system implementations is also a challenge, resulting in consistency and accuracy issues associated with characterizing tissues based on measurements collected by different system implementations.

[0019] With respect to in vivo tissue characterization, the motion of tissue creates problems in acquiring meaningful ultrasound measurements and accurately identifying tissue features from such measurements. As a result, measurements used to identify tissue features (e.g., non-linear tissue features) are typically obtained from excised tissue. However, the process of surgically excising patient tissue complicates the overall process of tissue characterization and presents a number of risks to the patient.

[0020] Systems, methods, and computer-readable media for addressing these issues / deficiencies are described below. Specifically, the present technology relates to systems, methods, and computer-readable media for identifying nonlinear properties of an object region by one or more exponentially scanned ultrasonic chirp pulses emitted toward the object region. More specifically, the present technology relates to systems, methods, and computer-readable media for identifying nonlinear properties of an object region based on one or both of one or more corresponding harmonic responses and corresponding fundamental responses for each of the one or more exponentially scanned ultrasonic chirp pulses.

[0021] Reference is now made to the accompanying drawings, in which like parts are represented by like reference numerals throughout this document. Some infrastructures that can be used with the embodiments disclosed herein are already available, such as general-purpose computers, computer programming tools and techniques, digital storage media, and communication networks. The computing device may include a processor, such as a microprocessor, a microcontroller, a logic circuit, and the like. The processor may include a special processing device, such as an ASIC, a PAL, a PLA, a PLD, an FPGA, or other custom or programmable device. The computing device may also include a computer-readable storage device, such as a non-volatile memory, a static RAM, a dynamic RAM, a ROM, a CD-ROM, a disk, a tape, a magnetic, an optical, a flash memory, or other non-temporary computer-readable storage medium.

[0022] Various aspects of some embodiments may be implemented using hardware, software, firmware, or a combination thereof. As used herein, a software module or component may include any type of computer instructions or computer executable code located within or on a computer-readable storage medium. A software module may, for example, include one or more physical or logical blocks of computer instructions, which may be organized into routines, programs, objects, components, data structures, etc., which perform one or more tasks or implement specific abstract data types.

[0023] In some embodiments, a particular software module may include different instructions stored in different locations of a computer-readable storage medium, which together implement the described functions of the module. In practice, a module may include a single instruction or multiple instructions, and may be distributed over multiple different code segments, between different programs, and across multiple computer-readable storage media. Some embodiments may be practiced in a distributed computing environment, where tasks are performed by remote processing devices linked through a communication network.

[0024] The embodiments of this invention will be best understood by reference to the accompanying drawings. As generally described and illustrated in the drawings of this invention, the components of the disclosed embodiments may be arranged and designed in a variety of different configurations. In addition, the features, structures, and operations associated with one embodiment may be applicable to or combined with the features, structures, or operations described in another embodiment. In other cases, well-known structures, materials, or operations are not shown or described in detail to avoid making various aspects of the present disclosure unclear.

[0025] Therefore, the following detailed description of the embodiments of the systems and methods herein is not intended to limit the scope of the claimed invention, but is merely representative of possible embodiments. In addition, the steps of the method do not necessarily have to be performed in any particular order, do not even have to be performed sequentially, and do not have to perform the steps only once.

[0026] Figure 1 1 is a schematic block diagram of an exemplary embodiment of a medical imaging device, such as an ultrasound imaging device 100. Those skilled in the art will recognize that the principles disclosed herein can be applied to a variety of medical imaging devices, including but not limited to X-ray imaging devices, computed tomography (CT) imaging devices, magnetic resonance imaging (MRI) devices, and positron emission tomography (PET) imaging devices. Thus, the components of each device can be combined with Figure 1 Different than shown.

[0027] In one embodiment, the ultrasound imaging device 100 may include an array focusing unit, referred to herein as a beamformer 102, by which image formation may be performed on a scan line by scan line basis. The device may be controlled by a main controller 104 implemented by a microprocessor or the like, which receives operator input through an operator interface and controls the various subsystems of the device 100.

[0028] For each scan line, the transmitter 106 generates a radio frequency (RF) excitation voltage pulse waveform and applies it to the transmit aperture (defined by a subarray of active elements in one embodiment) with appropriate timing to produce a focused acoustic beam along the scan line.

[0029] The RF echoes received by one or more receive apertures or receivers 108 are amplified, filtered, and then fed into the beamformer 102, which can perform dynamic receive focusing, i.e., rearrange the RF signals generated from the same location along each scan line. Collectively, the transmitter 106 and the receiver 108 can be components of the transducer 110. Various types of transducers 110 are known in the art of ultrasound imaging, such as linear probes, curved probes, and phased array probes.

[0030] The image processor 112 may perform processing tasks specific to the various active imaging modes, including 2D scan conversion, which converts image data from a grid of acoustic rays into an XY pixel image for display. For other modes, such as spectral Doppler mode, the image processor 112 may perform wall filtering followed by spectral analysis of the Doppler shifted signal samples, typically using a sliding FFT window. The image processor 112 may also generate stereo audio signal outputs corresponding to the forward and reverse flow signals. In cooperation with the main controller 104, the image processor 112 may also format images from two or more active imaging modes, including display annotations, graphic overlays, and playback of movies and recorded timeline data.

[0031] The cine memory 114 provides resident digital image storage to enable single or multiple image cycles and serves as a buffer for transferring images to a digital archival device such as a hard drive or optical storage device. In some systems, video images at the end of the data processing path may be stored in the cine memory. In state-of-the-art systems, beamformed data after amplitude detection may also be stored in the cine memory 114. For spectral Doppler mode, baseband Doppler I / Q data after wall filtering of a user-selected sampling gate may be stored in the cine memory 114. Subsequently, a display 116 such as a computer monitor may display the ultrasound image created by the image processor 112 and / or an image created using the data stored in the cine memory 114.

[0032] The beamformer 102, the main controller 104, the image processor 112, the cine memory 114, and the display 116 may be included as part of a main processing console 118 of the ultrasound imaging device 100, which may include more or fewer components or subsystems than those illustrated. The ultrasound transducer 110 may be incorporated into a device separate from the main processing console 118, such as into a separate device that is wired or wirelessly connected to the main processing console 118. This allows for easier manipulation of the ultrasound transducer 110 when performing a particular ultrasound procedure on a patient. In addition, the transducer 110 may be an array transducer that includes an array of transmit and receive elements for transmitting and receiving ultrasound waves.

[0033] Those skilled in the art will recognize that a wide variety of ultrasonic imaging devices are available on the market, and that additional details regarding how images are generated are not necessary for a thorough understanding of the principles disclosed herein. Specifically, the systems, methods, and computer-readable media described herein can be applied by applicable ultrasonic imaging devices in a wide variety of ultrasonic imaging devices available on the market.

[0034] Exponentially scanned ultrasound chirp pulses can be used to characterize the nonlinearity of an object region. Specifically, exponentially scanned ultrasound chirp pulses can be used to identify the nonlinear properties of tissue. More specifically, exponentially scanned ultrasound chirp pulses can be used to identify the nonlinear properties of in vivo tissue. Characterizing in vivo tissue is advantageous because it reduces the complexity associated with surgically removing tissue to ultimately characterize the tissue. In addition, characterizing in vivo tissue is advantageous because it eliminates patient risks associated with surgical procedures to remove tissue.

[0035] The nonlinear property of the object region may include an applicable nonlinear property of the object region that can be identified by ultrasound. Specifically, the nonlinear property of the object region may include an applicable acoustic nonlinear property of a tissue that can be identified by ultrasound. For example, the nonlinear property of the object region may include a value of an acoustic nonlinear parameter B / A of the tissue.

[0036] An exponentially swept chirp pulse can be expressed as Equations 1 and 2 shown below.

[0037] Equation 1

[0038] Equation 2θ(f) = A(flog(f)-f)-(Alogf1-T start )f

[0039] In equation 1, In equation 2, f1 is the starting frequency of the exponentially scanned chirp pulse, f2 is the ending frequency of the exponentially scanned chirp pulse. T is the pulse duration of the exponentially scanned chirp pulse, T start is the pulse start time.

[0040] The exponentially swept chirp signal has the following characteristics: the group delay between the fundamental response and the harmonic response to the chirp signal is a function of the Nth harmonic. More specifically, the group delay between the fundamental response and the harmonic response to the chirp signal is not a function of the frequency of the harmonic response (e.g., the instantaneous frequency of the chirp signal corresponding to the harmonic response). Therefore, the fundamental and Nth harmonic responses of the exponentially swept chirp signal are summed to form respective impulse responses that are offset by the difference in the corresponding group delay between the corresponding harmonic response and the corresponding fundamental response (which is otherwise referred to as the time delay between the corresponding harmonic response and the fundamental response).

[0041] These response characteristics of the exponentially swept chirp signal are further described by the following equations: Equation 3 is the instantaneous frequency of the exponentially swept chirp signal.

[0042] Equation 3

[0043] Equation 4 is the fundamental response τ of the exponentially scanned chirp signal. groupDelay (f) The time of generation.

[0044] Equation 4

[0045] As shown below, the fundamental response τ groupDelay (f), the generation time (as shown in Equation 5) can be expressed as a function of the starting frequency f1 and the ending frequency f2 of the exponentially scanned chirp pulse.

[0046] Equation 5

[0047] In addition, the Nth harmonic of the exponentially scanned chirp signal The generation time can be expressed as Equation 6.

[0048] Equation 6

[0049] Therefore, the time delay Δ between the corresponding Nth harmonic response and the fundamental response of the exponentially scanned chirp signal can be expressed by Equation 7: t .

[0050] Equation 7

[0051] As shown in Equation 7, Δ t is a function of N, but not of f, such as the instantaneous frequency of a chirp signal corresponding to a harmonic response. Thus, over the entire frequency range, all N harmonics have the same group delay and will therefore add to form a "harmonic" impulse response. Specifically, all frequencies due to a particular subharmonic may arrive at the same time, resulting in a frequency response that is offset by the time delay Δ relative to the corresponding fundamental impulse response. t The harmonic pulse response.

[0052] Since the harmonic responses to the Nth harmonic can be added to effectively form a single harmonic pulse response, an exponentially scanned ultrasonic chirp pulse can effectively produce two pulse responses, namely a fundamental response and a corresponding Nth harmonic response. Specifically, the backscatter from the object region generated in response to the exponentially scanned ultrasonic chirp pulse interacting with the object region may include a fundamental response and one or more harmonic responses (e.g., corresponding to each Nth harmonic). As shown in Equation 7, these responses are shifted in time by a time delay Δ t This time delay may be a known quantity, for example based on N and the start and end frequencies f1 and f2 of an exponentially scanned ultrasound chirp pulse.

[0053] This time delay between the harmonic response and the fundamental response to an exponentially scanned chirp pulse may depend on the presence of nonlinearity in the object region. Specifically, when the object region interacting with the exponentially scanned chirp pulse includes nonlinearity, this time delay between the fundamental response and the harmonic response may be generated. Conversely, when the object region lacks nonlinearity, the generated fundamental response and the harmonic response may not have this time shift. Then, the time delay generated in response to the nonlinearity in the object region may be used as a basis for identifying the nonlinear properties of the object region. Specifically, the time delay between the fundamental response and the harmonic response may form the basis for the superposition of two or more images generated by ultrasonic backscattering. Then, the displacement amount existing between the two or more superimposed images (which, for example, is at least partially based on the time delay between the fundamental response and the harmonic response) may be analyzed to identify the nonlinear properties of the object region.

[0054] Figure 2 The time offset between the fundamental and harmonic responses generated when the object area has nonlinearity is shown. Specifically, Figure 2 2 is a graph 200 of the intensity of the fundamental and harmonic responses to an exponentially swept ultrasonic chirp pulse as a function of time for both linear and nonlinear object regions. Figure 2 As shown, both the linear object region and the nonlinear object region have a fundamental pulse response at time 0.0uS (202). Figure 2 As shown, the nonlinear object region has a time-shifted harmonic response 204 at time -2.0 uS (206). However, the linear object region does not show a corresponding time-shifted harmonic response, for example due to a lack of nonlinearity in the linear object region.

[0055] Figure 33A in the figure is a positive phase image 300 of the object area generated by a Gaussian ultrasound emission profile, 3B is a negative phase image 302 of the object area generated by a Gaussian ultrasound emission profile, 3C is a sum image 304 of the images shown in 3A and 3B, and 3D is a difference image 306 of the images shown in 3A and 3B.

[0056] A Gaussian ultrasound emission profile is often used to form images by ultrasound. Specifically, phase reversals or positive and negative pulses of a Gaussian ultrasound emission profile are often used to generate two separate images by harmonic mode imaging. Then, when the two images are combined, the fundamental component can be cancelled, leaving only the harmonic component. Figure 3 The corresponding positive phase image 300 shown in FIG. 3A is generated by a positive narrowband Gaussian emission profile, while the corresponding negative phase image 302 is generated by a negative narrowband Gaussian emission profile.

[0057] As shown in the positive and negative phase images 300 and 302, the points in the imaging field are offset by 10 mm. For example, the positive phase image 300 has a point 308 at 60 mm, which is offset by approximately 10 mm from an adjacent point (e.g., a point at 50 mm). The same situation can be seen in the negative phase image 302, where a point (e.g., point 310 at 60 mm) is offset from an adjacent point by approximately 10 mm. In addition and as shown in the positive and negative phase images 300 and 302, the harmonic signals are not offset from the fundamental signal. Specifically, the corresponding harmonic signal and the fundamental signal form a single corresponding point (e.g., point 308), rather than two separate points, which will be shown in more detail later. This indicates that there is no separation caused by, for example, time delay, due to the application of a typical ultrasound emission profile (e.g., a Gaussian ultrasound emission profile).

[0058] This lack of separation between the corresponding harmonic signals and the fundamental signal is further illustrated in Figure 3 3C and 3D are shown in the sum image 304 and the difference image 306. The sum image 304 of the positive orientation pulse and the negative orientation pulse applied to produce the corresponding positive phase image 300 and the negative phase image 302 represents the fundamental signal. In addition, the difference image 306 of the positive orientation pulse and the negative orientation pulse applied to produce the corresponding positive phase image 300 and the negative phase image 302 represents the harmonic signal. As shown in the figure, in the sum image 304, the fundamental signal at 60 mm is a single point 312. Similarly, in the difference image 306, the harmonic signal is also a single point 314 at 60 mm. Points 312 and 314 are both at 60 mm and do not show depth separation corresponding to the lack of time delay between the fundamental signal and the harmonic signal.

[0059] Figure 4 4A is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 10 mm, 4B is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 20 mm, 4C is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 30 mm, 4D is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 40 mm, 4E is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 50 mm, and 4F is an intensity graph of the fundamental and harmonic responses of a narrow-band Gaussian emission profile centered at a depth of 60 mm.

[0060] As in Figure 4 As can be seen in FIG4C, the response from the fundamental signal 412 and the response from the harmonic component 414 are arranged in a space at a depth of about 30 mm. The same arrangement of the fundamental and harmonic signals can be seen in other intensity graphs. Figure 4 This further demonstrates that a narrowband Gaussian transmission profile (i.e., a typical transmission used in ultrasound systems) does not produce a range offset between the fundamental and harmonic components.

[0061] Figure 5 5A is a positive phase image 500 of the object area generated by exponential scanning of an ultrasonic chirp signal, 5B is a negative phase image 502 of the object area generated by exponential scanning of an ultrasonic chirp signal, and 5C is a sum image 504 of the images shown in 5A and 5B. Figure 5 The 5D is Figure 5 5A and Figure 4 The difference image 506 is the image shown in 4B.

[0062] Figure 55A-5D show the time delay generated between the fundamental response and the harmonic response to the exponentially scanned ultrasonic chirp signal. In the positive phase image 500, the fundamental signal is located at point 508 at 30 mm. In addition, the harmonic response in the positive phase image 500 is at point 510 before 30 mm, which is offset relative to point 508 of the fundamental response at 30 mm. This offset corresponds to the time delay between the fundamental response and the harmonic response generated by applying the exponentially scanned ultrasonic chirp signal. This spatial offset is also shown in the negative phase image 502, where the fundamental response is located at point 512 at 30 mm, and the harmonic response is located at point 512, which is offset relative to point 512 of the fundamental response at 512.

[0063] exist Figure 5 The sum image 504 and the difference image 506 shown in FIGS. 5C and 5D further illustrate the time separation between the corresponding harmonic signals and the fundamental signal. Figure 5 The sum image 504 of the positive exponential scanning ultrasonic chirp pulse and the negative exponential scanning ultrasonic chirp pulse corresponding to 5A and 5B represents the fundamental wave signal. In addition, Figure 5 The difference image 506 of the positive exponential scanning ultrasonic chirp pulse and the negative exponential scanning ultrasonic chirp pulse corresponding to 5A and 5B represents a harmonic signal. Figure 5 As shown in FIG5C , there is a fundamental response at point 516 at 30 mm. In addition, and as Figure 5 As shown in FIG5D , there is a harmonic response at point 518. The harmonic response at point 518 is offset relative to the fundamental response at point 516. Specifically, the fundamental response at point 516 is at 30 mm, while the harmonic response at point 518 is offset to closer to 26 mm. This spatial offset corresponds to the time offset between the fundamental response and the harmonic response to an exponentially scanned ultrasonic chirp pulse.

[0064] Figure 6 6A-6F are intensity diagrams of the fundamental and harmonic responses of the object region to an exponentially scanned ultrasonic chirp signal centered at different depths of the object region. Figure 6 6C, the fundamental response (e.g., at point 600) does not coexist with the harmonic response (e.g., at point 602) at a depth of 30 mm. The same non-coexistence relationship of the fundamental and harmonic signals is shown in the range of points located at other increments of 10 mm offset. Figure 6 This can also be seen in the other intensity graphs of 6A, 6B, 6D, 6E and 6F. Thus, the exponentially scanned ultrasonic chirp signal can separate the harmonic response and the fundamental response in time / distance.

[0065] Figure 7 7A-7F are at different depths of the object area Figure 6 6A-6F of FIG. 6A-6F. It can be seen from the target at 30 mm that the response from the fundamental signal at point 700 is within the expected range, while the response of the harmonic signal is closer to the 26 mm range at point 702. Similar shifts in time / range can be observed for points throughout the figure. This clearly shows that not only are the harmonic and fundamental responses separated in time / distance, but the signal response associated with the fundamental and the signal response associated with the harmonics can also be separated for analysis, especially for identifying nonlinear properties of the object area.

[0066] Figure 8 is a flow chart 800 of an example method for identifying nonlinear properties of an object region by exponentially scanning ultrasonic chirp pulses. Figure 8 The example methods shown in, as well as other methods and techniques for ultrasound imaging described herein, can be performed by an applicable ultrasound imaging system (such as Figure 1 For example, the techniques for ultrasound imaging described herein may be implemented using one or both of the ultrasound transducer 110 and the main processing console 118 (eg, the image processor 112) of the ultrasound system 100.

[0067] In step 802, ultrasonic information of the object area is collected. The ultrasonic information may include ultrasonic information of one or more exponentially scanned ultrasonic chirp pulses emitted toward the object area. For example, the ultrasonic information may include the emission profile of one or more exponentially scanned ultrasonic chirp pulses emitted toward the object area. In addition, the ultrasonic information may include backscattering information of fundamental response and harmonic response generated by the object area in response to one or more exponentially scanned ultrasonic chirp pulses emitted toward the object area.

[0068] When an exponentially scanned ultrasound chirp pulse generates time-shifted harmonic and fundamental responses, the backscatter information may include information related to the time-shifted harmonic and fundamental responses. For example, the ultrasound information may include harmonic and fundamental responses that are time-shifted relative to each other due to nonlinearities in the object region. The harmonic and fundamental responses may then be analyzed, such as based on the time shift, to identify the nonlinear nature of the object region.

[0069] The ultrasound information may include multiple ultrasound images of the object area based on the fundamental and harmonic signals, or other data for generating the multiple ultrasound images. The multiple ultrasound images of the object area can be superimposed relative to each other based on one or more spatial offsets. For example, a feature in the object area can be moved in the multiple ultrasound images by the amount of the spatial offset. The one or more spatial offsets may correspond to the fundamental signal and the harmonic signal. Specifically, the one or more spatial offsets may correspond to one or more time delays between the harmonic and fundamental signals. Furthermore, as will be discussed in more detail later, the spatial offsets in the superimposed ultrasound images can be used as a basis for identifying the nonlinear properties of the object area from the ultrasound information.

[0070] In step 804, one or more corresponding harmonic responses and a corresponding fundamental response may be separated from the ultrasound information for each of the one or more index-scanned ultrasound chirp pulses. The corresponding harmonic responses and the fundamental response may be separated from each other in the ultrasound information to identify one or more nonlinear properties of the object region. Specifically, the corresponding harmonic response and the fundamental response may be separated from each other to identify a time offset between the harmonic response and the fundamental response. More specifically, the corresponding harmonic response and the fundamental response may be separated from each other to identify a spatial offset between one or more ultrasound images generated by the harmonic response and the fundamental response.

[0071] Furthermore, one or more nonlinear properties of the object region may be identified based on one or both of the corresponding harmonic response and the fundamental response for each of the one or more exponentially scanned ultrasonic chirp pulses at step 806. Specifically, and as will be discussed in more detail later, the nonlinear properties of the object region may be identified based on the time offset and / or spatial offset corresponding to the harmonic response and the fundamental response of each of the applied exponentially scanned ultrasonic chirp pulses.

[0072] The fundamental response and the harmonic response can be filtered out from the ultrasonic information to separate the harmonic response and the fundamental response. Specifically, the fundamental response and the harmonic response can be filtered out from the ultrasonic information to separate the fundamental response and the harmonic response. For example, the fundamental response and the harmonic response can be filtered out from the ultrasonic information based on time, such as to separate the fundamental response and the harmonic response based on one or more time delays between the fundamental response and the harmonic response.

[0073] In addition, the fundamental response and the harmonic response can be separated by eliminating the fundamental response from the ultrasonic information. Specifically, the ultrasonic information can be processed to eliminate the fundamental response, thereby effectively isolating the harmonic response in the ultrasonic information. Subsequently, the nonlinear properties of the object area can be identified based on the remaining harmonic response and potentially combined with the fundamental response. The fundamental response can be eliminated from the ultrasonic information by applicable signal processing techniques. For example, pulse inversion can be applied to eliminate the fundamental response from the ultrasonic information.

[0074] The fundamental response and the harmonic response can be correlated with each other from the ultrasonic information to generate correlated harmonic and fundamental response information. Furthermore, the nonlinear properties of the object area can be identified based on the correlated harmonic and fundamental response information. The harmonic response and the fundamental response can be correlated with each other based on the time offset generated between the harmonic response and the fundamental response. As described above, when the object area includes nonlinear properties, the time offset can be generated by applying one or more exponentially scanned ultrasonic chirp pulses to the object area. Based on the characteristics of the one or more exponentially scanned ultrasonic chirp pulses, such as the start and stop frequencies of the pulses, this time offset can be known. Therefore, the nonlinear properties of the object area can be identified based on the known time offset.

[0075] When the nonlinear property of the object region is identified based on the fundamental and harmonic responses, one or more corresponding spatial offsets in the object region can be identified based on the relevant harmonic and fundamental response information. Furthermore, the nonlinear property of the object region can be identified based on the spatial offset in the object region. The spatial offset can correspond to the time delay between the fundamental response and the harmonic response. In addition, the spatial offset can be represented as a spatial offset in the result of processing the ultrasound information including the fundamental response and the harmonic response. Specifically, the spatial offset can correspond to the spatial offset in multiple ultrasound images generated based on the fundamental and harmonic responses, such as the spatial offset of the feature.

[0076] In addition, when identifying the nonlinear properties of the object area based on the fundamental and harmonic responses, the fundamental and harmonic responses can be averaged to generate average harmonic and fundamental response information. In turn, the nonlinear properties of the object area can be identified based on the average harmonic and fundamental response information. The fundamental and harmonic responses can be averaged by applying an applicable averaging technique to the ultrasonic information including the harmonic and fundamental responses. For example, coherent data averaging can be applied to the ultrasonic information to generate average harmonic and fundamental response information.

[0077] The nonlinear properties identified based on one or both of the fundamental and harmonic responses of each exponentially scanned ultrasonic chirp signal can be identified as part of the overall nonlinear property estimate of the object area. For example, the estimate of the identified nonlinear properties can be averaged over the entire object area to identify an overall nonlinear property estimate for a specific nonlinear property of the entire object area. In addition, nonlinear properties can be identified on a sub-region basis for different sub-regions of the object area. For example, the values ​​of nonlinear properties can be identified or estimated for different parts of the object area. As described below, a nonlinear property map of the object area can be generated. A nonlinear property map of the object area can be generated based on the nonlinear properties identified on a sub-region basis for the object area. For example, a map showing different values ​​of nonlinear properties on different sub-regions of the object area can be generated.

[0078] The object region may be a volume region. Specifically, the object region may be a certain volume of tissue, such as in vivo tissue. For example, the object region may include a certain volume of fatty liver tissue, cirrhotic liver tissue, thyroid cancer tissue, prostate cancer tissue, or breast cancer tissue. The nonlinear property may be a volume nonlinear property of the volume region. Specifically, the nonlinear property of the volume region may be an overall nonlinear property estimate of the volume region. Ultrasound information of the volume region may be acquired by an applicable ultrasound system for acquiring volume ultrasound information. For example, ultrasound information of the volume region may be acquired by an ultrasound system incorporating one or more volume-based ultrasound transducers.

[0079] Fig. 9 Flowchart 900 of an example method for estimating B / A parameters of an object region by exponentially scanning an ultrasonic chirp signal. In step 902, an exponentially scanning ultrasonic chirp signal is formed. In step 904, the signal is transmitted toward the object region. In step 906, backscatter from the transmitted signal is received and processed into one or more images. Then, in step 908, the desired harmonic signal (usually the second harmonic) is correlated with the fundamental signal to determine, for example, a spatial offset in the object region based on the image. In step 910, the B / A parameters of the object region are estimated based on the correlation between the fundamental signal and the harmonic signal.

[0080] The techniques described herein can be applied in applicable ultrasound imaging modes, such as B-mode, contrast-enhanced ultrasound (CEUS), CD mode, 2D / 3D / 4D, etc. Specifically, the techniques described herein are not limited to B-mode, but can also be applied to other modes where improved temporal resolution within the region of interest has substantial clinical benefits, such as CEUS.

[0081] The present invention has been described with reference to various exemplary embodiments including the best mode. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary embodiments without departing from the scope of the present invention. For example, depending on the specific application or considering any number of cost functions associated with the operation of the system, the various operating steps and components for performing these operating steps may be implemented in alternative ways, for example, one or more of these steps may be deleted, modified, or combined with other steps.

[0082] Although the principles of the present invention have been shown in various embodiments, many modifications of the structures, arrangements, proportions, elements, materials and assemblies that are particularly suitable for specific environments and operational requirements can be used without departing from the principles and scope of the present invention. These and other changes or modifications are intended to be included within the scope of the present invention.

[0083] It has been described above with reference to various embodiments. However, it will be appreciated by those skilled in the art that various modifications and changes may be made without departing from the scope of the present invention. Therefore, this article should be considered illustrative rather than restrictive, and all such modifications are intended to be included within its scope. Similarly, the benefits, other advantages and solutions to the problems have been described above with reference to various embodiments. However, the benefits, advantages, solutions to the problems and any elements that may cause any benefits, advantages or solutions to appear or become more obvious should not be interpreted as key, necessary or necessary features or elements. As used herein, the terms "include", "comprise" and any other variants thereof are intended to cover non-exclusive inclusions, so that the process, method, article or equipment including a series of elements not only include those listed elements, but also may include other elements that are not explicitly listed or inherent to such processes, methods, systems, articles or equipment. Moreover, as used herein, the terms "couple", "couple" and any other variants thereof are intended to cover physical connections, electrical connections, magnetic connections, optical connections, communication connections, functional connections and / or any other connections.

[0084] Those skilled in the art will appreciate that many changes may be made to the details of the above embodiments without departing from the basic principles of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

1. A method for performing diagnostic ultrasound imaging, characterized in that include: Ultrasonic information of the object region is acquired based on one or more exponentially scanned ultrasonic chirp pulses emitted toward the object region and backscattering of the one or more exponentially scanned chirp pulses by the object region; wherein the exponentially scanned ultrasonic chirp pulses are expressed as the following equations 1 and 2: Equation 1 Equation 2θ(f) = A(flog(f)-f)-(Alogf1-T start )f; in, f1 is the starting frequency of the exponentially scanned chirp pulse; f2 is the end frequency of the exponentially scanned chirp pulse; T is the pulse duration of the exponentially scanned chirp pulse; T start is the pulse start time; for each of the one or more exponentially scanned ultrasonic chirp pulses, separating one or more corresponding harmonic responses and a corresponding fundamental response from the ultrasonic information; and One or more nonlinear properties of the object region are identified based on one or both of the one or more corresponding harmonic responses and the corresponding fundamental response to each of the one or more exponentially swept ultrasound chirp pulses.

2. The method according to claim 1, characterized in that The target area includes in vivo tissue.

3. The method according to claim 1, characterized in that The one or more nonlinear properties of the object region include one or more B / A parameters of the object region.

4. The method according to claim 1, characterized in that: Also includes: The corresponding fundamental response and the one or more corresponding harmonic responses for each of the one or more exponentially scanned ultrasonic chirp pulses are respectively filtered out from the backscatter as a part of separating the one or more corresponding harmonic responses and the corresponding fundamental response from the ultrasonic information for each of the one or more exponentially scanned ultrasonic chirp pulses.

5. The method according to claim 1, characterized in that Also includes: The corresponding fundamental response of each of the one or more exponentially swept ultrasonic chirp pulses is eliminated from the backscatter to identify the one or more corresponding harmonic responses of each of the one or more exponentially swept ultrasonic chirp pulses from the backscatter as part of separating the one or more corresponding harmonic responses and the corresponding fundamental response from the ultrasonic information for each of the one or more exponentially swept ultrasonic chirp pulses.

6. The method according to claim 5, characterized in that Also includes: Pulse inversion is applied to eliminate the respective fundamental response of each of the one or more exponentially swept ultrasound chirp pulses from the backscatter.

7. The method according to claim 1, characterized in that Also includes: correlating the one or more corresponding harmonic responses of each of the one or more exponentially swept ultrasonic chirp pulses with the corresponding fundamental response to generate correlated harmonic and fundamental response information; and The one or more nonlinear properties of the object region are identified based on the correlated harmonic and fundamental response information.

8. The method according to claim 7, characterized in that The one or more corresponding harmonic responses of each of the one or more exponentially swept ultrasonic chirp pulses are correlated with the corresponding fundamental response based on the corresponding time offset between each of the one or more corresponding harmonic responses of each of the one or more exponentially swept ultrasonic chirp pulses and the corresponding fundamental response.

9. The method according to claim 8, characterized in that The respective time offset between each of the one or more respective harmonic responses and the respective fundamental response is based on a known time offset of a respective harmonic order of each of the one or more respective harmonic responses and is independent of one or more frequencies of the one or more respective harmonic responses in the respective harmonic orders.

10. The method according to claim 7, characterized in that The correlated harmonic and fundamental response information includes a plurality of ultrasound images of the object region, the plurality of ultrasound images being overlapped relative to each other by one or more corresponding spatial offsets, the method further comprising: determining the one or more corresponding spatial offsets based on the correlated harmonic and fundamental response information; and The one or more non-linear properties of the object region are identified based on the one or more corresponding spatial offsets.

11. The method according to claim 1, characterized in that: Also includes: applying coherent data averaging between the one or more corresponding harmonic responses and the corresponding fundamental response of each of the one or more exponentially swept ultrasonic chirp pulses to generate averaged harmonic and fundamental response information; and The one or more nonlinear properties of the object region are determined based on the averaged harmonic and fundamental response information.

12. The method according to claim 1, characterized in that The one or more non-linear properties of the object region are identified as part of an overall non-linear property estimate of the object region.

13. The method according to claim 1, characterized in that Also included is generating a map of the one or more nonlinear properties of the object region across the object region.

14. The method according to claim 1, characterized in that The object region is a volumetric region, and the method further comprises: identifying the one or more nonlinear properties throughout the volumetric region.

15. The method according to claim 14, characterized in that The ultrasound information is generated over the volumetric region by one or more volume-based ultrasound transducers.

16. The method according to claim 14, characterized in that The one or more non-linear properties of the object region are identified as part of an overall non-linear property estimate of the volumetric region.

17. The method according to claim 14, characterized in that The object region is a volume of tissue and the one or more nonlinear properties are characteristics of the volume of tissue.

18. The method according to claim 17, characterized in that The volume tissue includes at least one of fatty liver tissue, cirrhotic liver tissue, thyroid cancer tissue, prostate cancer tissue and breast cancer tissue.

19. A system for performing diagnostic ultrasound imaging, characterized in that include: An ultrasonic transducer, the ultrasonic transducer being configured to: Ultrasonic information of the object region is acquired based on one or more exponentially scanned ultrasonic chirp pulses emitted toward the object region and backscattering of the one or more exponentially scanned chirp pulses by the object region; wherein the exponentially scanned ultrasonic chirp pulses are expressed as the following equations 1 and 2: Equation 1 Equation 2θ(f) = A(flog(f)-f)-(Alogf1-T start )f; in, f1 is the starting frequency of the exponentially scanned chirp pulse; f2 is the end frequency of the exponentially scanned chirp pulse; T is the pulse duration of the exponentially scanned chirp pulse; T start is the pulse start time; A main processing console, the main processing console being configured to: for each of the one or more exponentially scanned ultrasonic chirp pulses, separating one or more corresponding harmonic responses and a corresponding fundamental response from the ultrasonic information; and One or more nonlinear properties of the object region are identified based on one or both of the one or more corresponding harmonic responses and the corresponding fundamental response to each of the one or more exponentially swept ultrasound chirp pulses.

20. A system for performing diagnostic ultrasound imaging, characterized in that include: one or more processors; and A computer-readable medium providing instructions accessible to the one or more processors to cause the one or more processors to perform operations comprising: Ultrasonic information of the object region is acquired based on one or more exponentially scanned ultrasonic chirp pulses emitted toward the object region and backscattering of the one or more exponentially scanned chirp pulses by the object region; wherein the exponentially scanned ultrasonic chirp pulses are expressed as the following equations 1 and 2: Equation 1 Equation 2θ(f) = A(flog(f)-f)-(Alogf1-T start )f; in, f1 is the starting frequency of the exponentially scanned chirp pulse; f2 is the end frequency of the exponentially scanned chirp pulse; T is the pulse duration of the exponentially scanned chirp pulse; T start is the pulse start time; for each of the one or more exponentially scanned ultrasonic chirp pulses, separating one or more corresponding harmonic responses and a corresponding fundamental response from the ultrasonic information; and One or more nonlinear properties of the object region are identified based on one or both of the one or more corresponding harmonic responses and the corresponding fundamental response to each of the one or more exponentially swept ultrasound chirp pulses.

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