Ultrasonic contrast imaging method and ultrasonic imaging system

Abstract

The invention discloses an ultrasonic contrast imaging method and an ultrasonic imaging system, and the method comprises the steps: controlling an ultrasonic probe to emit first ultrasonic waves to a target tissue containing a contrast agent, receiving echoes, and obtaining a first echo signal; all array elements, half array elements and the other half array elements in the transmitting aperture of the ultrasonic probe are controlled to transmit second ultrasonic waves, third ultrasonic waves and fourth ultrasonic waves to the target tissue respectively, and second echo signals, third echo signals and fourth echo signals corresponding to the multiple receiving channels are obtained; performing superposition cancellation on signals corresponding to the same receiving channel in the second echo signal, the third echo signal and the fourth echo signal to obtain contrast microbubble echo signals corresponding to the plurality of receiving channels; performing beam forming on the contrast microbubble echo signals corresponding to the plurality of receiving channels to obtain contrast image data; and performing beam forming on the first echo signal to obtain tissue image data. According to the invention, the imaging frame rate of contrast imaging can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic imaging, and more particularly to an ultrasonic contrast imaging method and an ultrasonic imaging system. Background Art

[0002] Ultrasonic medical imaging uses ultrasound as a detection method to display images of human organs by receiving scattered, reflected or projected sound waves from the inside and surface of human organs. If a medium (microbubbles) with a completely different acoustic impedance from blood is added to the blood, the scattering in the blood will be enhanced. This is the basic principle of ultrasound contrast imaging. It is based on this principle that ultrasound contrast agents, i.e. solutions containing microbubbles, are injected intravenously. The contrast agents enter organs and tissues with blood perfusion, making the organs and tissues visible or enhancing their appearance, thus providing an important basis for clinical diagnosis.

[0003] When performing contrast examination, the doctor first selects the appropriate probe to locate the lesion and the section according to the examination site, then enters the contrast imaging mode, and adjusts the appropriate imaging parameters according to the depth of the lesion, such as imaging frequency, gain, mechanical index, etc. Next, the timer is started while the ultrasound contrast agent is injected, and the entire process of contrast microbubbles entering and exiting the lesion is observed, and compared with the normal tissue around the lesion, so as to make a differential diagnosis of the benign or malignant nature of the lesion.

[0004] Since doctors need to continuously observe the entire process of dynamic perfusion of microbubbles during contrast imaging, in order to present the perfusion process of microbubbles more smoothly, it is necessary to provide a higher frame rate while ensuring the quality of contrast imaging. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] An embodiment of the present invention provides an ultrasound contrast imaging method, the method comprising:

[0007] Controlling the ultrasonic probe to transmit a first ultrasonic wave to a target tissue containing a contrast agent, and receiving an echo of the first ultrasonic wave to obtain first echo signals corresponding to a plurality of receiving channels before beamforming;

[0008] Controlling all array elements within the transmitting aperture of the ultrasonic probe to transmit a second ultrasonic wave to the target tissue containing the contrast agent, and receiving an echo of the second ultrasonic wave to obtain second echo signals corresponding to a plurality of receiving channels before beamforming;

[0009] Controlling half of the array elements within the transmitting aperture of the ultrasonic probe to transmit a third ultrasonic wave to the target tissue containing the contrast agent, and receiving an echo of the third ultrasonic wave to obtain third echo signals corresponding to a plurality of receiving channels before beamforming;

[0010] Controlling the other half of the array elements within the transmitting aperture of the ultrasonic probe to transmit a fourth ultrasonic wave to the target tissue containing the contrast agent, and receiving an echo of the fourth ultrasonic wave to obtain fourth echo signals corresponding to the multiple receiving channels before beamforming;

[0011] superimpose and cancel signals corresponding to the same receiving channel among the second echo signal, the third echo signal and the fourth echo signal to obtain contrast microbubble echo signals corresponding to multiple receiving channels before beamforming;

[0012] Performing beam synthesis on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data;

[0013] Performing beam synthesis on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data;

[0014] A contrast image is obtained based on the contrast image data, and a tissue image is obtained based on the tissue image data.

[0015] In one embodiment, the half array elements and the other half array elements respectively include a plurality of array element groups, and each array element group includes at least one array element;

[0016] The multiple array element groups of the half array elements and the multiple array element groups of the other half array elements are arranged alternately.

[0017] In one embodiment, the transmitting aperture includes all array elements of the ultrasound probe, and controlling the ultrasound probe to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave, and the fourth ultrasound wave includes: controlling the ultrasound probe to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave, and the fourth ultrasound wave respectively at multiple transmitting angles, so as to obtain the contrast image data and the tissue image data corresponding to each transmitting angle;

[0018] The step of obtaining a contrast image according to the contrast image data and obtaining a tissue image according to the tissue image data comprises:

[0019] spatially compounding the angiography image data corresponding to the multiple emission angles to obtain the angiography image;

[0020] And, spatially compounding the tissue image data corresponding to the multiple emission angles to obtain the tissue image.

[0021] In one embodiment, the transmitting aperture includes all array elements of the ultrasonic probe, and controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave includes: controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave respectively at multiple transmitting angles, so as to obtain the contrast microbubble signal and the first echo signal corresponding to each transmitting angle;

[0022] The performing beam synthesis on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data includes:

[0023] Performing spatial compounding on contrast microbubble echo signals corresponding to multiple emission angles under each receiving channel to obtain a composite contrast microbubble echo signal corresponding to each receiving channel, and performing beam synthesis on the composite contrast microbubble echo signals corresponding to multiple receiving channels to obtain contrast image data;

[0024] The performing beam synthesis on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data includes:

[0025] The first echo signals corresponding to multiple transmission angles under each receiving channel are spatially compounded to obtain a composite first echo signal corresponding to each receiving channel, and the composite first echo signals corresponding to multiple receiving channels are beamformed to obtain tissue image data.

[0026] In one embodiment, the angle difference between every two adjacent emission angles is greater than or equal to 1.5° and less than or equal to 2°, and the angle range of the multiple emission angles is greater than or equal to -15° and less than or equal to +15°.

[0027] In one embodiment, the ultrasound probe includes a plurality of transmitting apertures, each of the transmitting apertures includes adjacent partial array elements in the ultrasound probe, and controlling the ultrasound probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave includes: controlling the plurality of transmitting apertures to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave, respectively, so as to obtain the contrast image data and the tissue image data corresponding to each transmitting aperture;

[0028] The step of obtaining a contrast image according to the contrast image data and obtaining a tissue image according to the tissue image data comprises:

[0029] spatially compounding the contrast image data corresponding to the multiple transmit apertures to obtain the contrast image;

[0030] And, spatially compounding the tissue image data corresponding to the multiple transmission apertures to obtain the tissue image.

[0031] In one embodiment, the ultrasound probe includes a plurality of transmitting apertures, each of the transmitting apertures includes adjacent partial array elements in the ultrasound probe, and controlling the ultrasound probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave includes: controlling the plurality of transmitting apertures to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave, respectively, to obtain the contrast microbubble signal and the first echo signal corresponding to each transmitting aperture;

[0032] The performing beam synthesis on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data includes:

[0033] Performing spatial compounding on contrast microbubble echo signals corresponding to a plurality of transmit apertures under each receiving channel to obtain a compound contrast microbubble echo signal corresponding to each receiving channel, and performing beam synthesis on the compound contrast microbubble echo signals corresponding to a plurality of receiving channels to obtain contrast image data;

[0034] The performing beam synthesis on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data includes:

[0035] The first echo signals corresponding to multiple transmit apertures under each receiving channel are spatially compounded to obtain a composite first echo signal corresponding to each receiving channel, and the composite first echo signals corresponding to multiple receiving channels are beamformed to obtain tissue image data.

[0036] In one embodiment, the method further comprises:

[0037] The number of array elements included in each transmit aperture is determined according to a preset number of spatial recombination times and a preset number of transmit apertures, wherein the array elements included in every two adjacent transmit apertures partially overlap.

[0038] In one embodiment, the number of transmit apertures is no more than 75.

[0039] In one embodiment, controlling the ultrasound probe to transmit a first ultrasound wave to a target tissue containing a contrast agent and receiving an echo of the first ultrasound wave comprises:

[0040] All array elements within the transmitting aperture of the ultrasonic probe are controlled to transmit a first ultrasonic wave to the target tissue, and receive an echo of the first ultrasonic wave.

[0041] In one embodiment, the ultrasound probe is a convex array ultrasound probe, and the first ultrasound wave, the second ultrasound wave, the third ultrasound wave, and the fourth ultrasound wave are unfocused ultrasound waves.

[0042] Another aspect of an embodiment of the present invention provides an ultrasonic imaging system, the ultrasonic imaging system comprising:

[0043] An ultrasonic probe, wherein the ultrasonic probe comprises a plurality of array elements;

[0044] A transmitting circuit, used for stimulating the ultrasound probe to transmit ultrasound waves toward a target tissue containing a contrast agent;

[0045] A receiving circuit, used for controlling the ultrasonic probe to receive the ultrasonic echo signal;

[0046] A processor, configured to generate an ultrasonic image of the target tissue according to the echo signal, and the processor is further configured to execute the ultrasonic contrast imaging method as described above;

[0047] A display is used to display the ultrasound image generated by the processor.

[0048] The ultrasound contrast imaging method and ultrasound imaging system of the embodiments of the present invention perform two full-aperture transmissions and two half-aperture transmissions, and the echo signals obtained by one full-aperture transmission and the echo signals obtained by two half-aperture transmissions are first superimposed and canceled, and then beamformed, thereby reducing the number of beamformations and improving the imaging frame rate of contrast imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The above and other purposes, features and advantages of the present invention will become more apparent by describing the embodiments of the present invention in more detail in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0050] Figure 1 A structural block diagram of an ultrasound imaging system according to an embodiment of the present invention is shown;

[0051] Figure 2 A schematic flow chart showing an ultrasound contrast imaging method according to an embodiment of the present invention;

[0052] Figure 3 A flowchart of an ultrasound contrast imaging method according to an embodiment of the present invention is shown;

[0053] Figure 4 A flowchart of an existing ultrasound contrast imaging method is shown;

[0054] Figure 5 A schematic diagram showing half of the array elements transmitting ultrasonic waves according to an embodiment of the present invention;

[0055] Figure 6 A schematic diagram showing a transmit aperture including all array elements according to an embodiment of the present invention;

[0056] Figure 7 A schematic diagram showing a transmit aperture including a portion of array elements according to an embodiment of the present invention;

[0057] Figure 8 A schematic diagram showing how to determine the number of array elements included in each transmit aperture according to the number of spatial recombination times and the number of transmit apertures according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and advantages of the present invention more obvious, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described in the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the protection scope of the present invention.

[0059] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0060] It should be understood that the present invention can be implemented in different forms and should not be interpreted as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0061] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0062] In order to fully understand the present invention, a detailed structure will be proposed in the following description to illustrate the technical solution proposed by the present invention. The optional embodiments of the present invention are described in detail as follows, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0063] Next, first refer to Figure 1 An ultrasound imaging system according to an embodiment of the present invention is described. Figure 1 FIG. 1 is a schematic structural block diagram of an ultrasound imaging system 100 according to an embodiment of the present invention.

[0064] like Figure 1 As shown, the ultrasound imaging system 100 includes an ultrasound probe 110, a transmitting circuit 112, a receiving circuit 114, a processor 116, and a display 118. Further, the ultrasound imaging system may also include a transmit / receive selection switch 120 and a beamforming module 122, and the transmitting circuit 112 and the receiving circuit 114 may be connected to the ultrasound probe 110 through the transmit / receive selection switch 120.

[0065] The ultrasonic probe 110 includes a plurality of transducer array elements, which can be arranged in a row to form a linear array, or arranged in a two-dimensional matrix to form a surface array, or a plurality of transducer array elements can also form a convex array. The transducer array element is used to transmit ultrasonic waves according to the excitation electrical signal, or to convert the received ultrasonic waves into electrical signals, so each transducer array element can be used to realize the mutual conversion between the electrical pulse signal and the ultrasonic wave, so as to realize the transmission of ultrasonic waves to the tissue of the target area of ​​the object to be tested, and can also be used to receive the ultrasonic wave echo reflected by the tissue. When performing ultrasonic testing, which transducer array elements are used to transmit ultrasonic waves and which transducer array elements are used to receive ultrasonic waves can be controlled by the transmission sequence and the reception sequence, or the transducer array elements can be controlled to transmit ultrasonic waves or receive ultrasonic wave echoes in time slots. The transducer array elements participating in ultrasonic wave transmission can be excited by electrical signals at the same time, so as to transmit ultrasonic waves at the same time; or, the transducer array elements participating in ultrasonic wave beam transmission can also be excited by several electrical signals with a certain time interval, so as to continuously transmit ultrasonic waves with a certain time interval.

[0066] During the ultrasonic imaging process, the processor 116 controls the transmitting circuit 112 to send the delayed focused transmitting pulse to the ultrasonic probe 110 through the transmitting / receiving selection switch 120. The ultrasonic probe 110 is stimulated by the transmitting pulse to transmit an ultrasonic beam to the target tissue of the object under test, and receives the ultrasonic echo with tissue information reflected from the target tissue after a certain delay, and reconverts the ultrasonic echo into an electrical signal. The receiving circuit 114 receives the electrical signal converted and generated by the ultrasonic probe 110, obtains the ultrasonic echo signal, and sends these ultrasonic echo signals to the beamforming module 122, which performs focusing delay, weighting and channel summing on the ultrasonic echo data, and then sends them to the processor 116. The processor 116 performs signal detection, signal enhancement, data conversion, logarithmic compression and other processing on the ultrasonic echo signal to form an ultrasonic image. The ultrasonic image obtained by the processor 116 can be displayed on the display 118 or stored in the memory 124.

[0067] Optionally, the processor 116 may be implemented as software, hardware, firmware or any combination thereof, and may use a single or multiple application specific integrated circuits (ASICs), 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. Furthermore, the processor 116 may control other components in the ultrasound imaging system 100 to perform the corresponding steps of the methods in various embodiments of the present specification.

[0068] The display 118 is connected to the processor 116, and the display 118 may be a touch screen, a liquid crystal display, etc.; or, the display 118 may be an independent display such as a liquid crystal display, a television, etc., which is independent of the ultrasound imaging system 100; or, the display 118 may be a display screen of an electronic device such as a smart phone or a tablet computer, etc. The number of the display 118 may be one or more.

[0069] The display 118 can display the ultrasound image obtained by the processor 116. In addition, while displaying the ultrasound image, the display 118 can also provide the user with a graphical interface for human-computer interaction. One or more controlled objects are set on the graphical interface, and the user is provided with a human-computer interaction device to input operation instructions to control these controlled objects, thereby performing corresponding control operations. For example, an icon is displayed on the graphical interface, and the icon can be operated by the human-computer interaction device to perform a specific function, such as drawing a region of interest box on the ultrasound image.

[0070] Optionally, the ultrasound imaging system 100 may further include other human-machine interaction devices in addition to the display 118, which are connected to the processor 116. For example, the processor 116 may be connected to the human-machine interaction device via an external input / output port, and the external input / output port may be a wireless communication module, or a wired communication module, or a combination of the two. The external input / output port may also be implemented based on USB, bus protocols such as CAN, and / or wired network protocols.

[0071] The human-computer interaction device may include an input device for detecting user input information, which may be, for example, a control instruction for ultrasonic transmission / reception timing, an operation input instruction for drawing points, lines or frames on an ultrasonic image, or other instruction types. The input device may include a keyboard, a mouse, a scroll wheel, a trackball, a mobile input device (such as a mobile device with a touch screen, a mobile phone, etc.), a multi-function knob, etc., or a combination of multiple thereof. The human-computer interaction device may also include an output device such as a printer.

[0072] The ultrasound imaging system 100 may further include a memory 124 for storing instructions executed by the processor, storing received ultrasound echoes, storing ultrasound images, etc. The memory may be a flash memory card, a solid-state memory, a hard disk, etc. It may be a volatile memory and / or a non-volatile memory, a removable memory and / or a non-removable memory, etc.

[0073] It should be understood that Figure 1 The components included in the ultrasonic imaging system 100 are only exemplary, and the ultrasonic imaging system 100 may include more or fewer components, and the present invention is not limited thereto.

[0074] Next, we will refer to Figure 2 A method for ultrasound contrast imaging according to an embodiment of the present invention is described. Figure 2 2 is a schematic flow chart of an ultrasound contrast imaging method 200 according to an embodiment of the present invention.

[0075] like Figure 2 As shown, an ultrasound contrast imaging method 200 according to an embodiment of the present invention comprises the following steps:

[0076] In step S210, the ultrasonic probe is controlled to transmit a first ultrasonic wave to a target tissue containing a contrast agent, and an echo of the first ultrasonic wave is received to obtain first echo signals corresponding to a plurality of receiving channels before beamforming;

[0077] In step S220, all array elements within the transmitting aperture of the ultrasound probe are controlled to transmit a second ultrasound wave to the target tissue containing the contrast agent, and an echo of the second ultrasound wave is received to obtain second echo signals corresponding to a plurality of receiving channels before beamforming;

[0078] In step S230, half of the array elements within the transmitting aperture of the ultrasonic probe are controlled to transmit a third ultrasonic wave to the target tissue containing the contrast agent, and an echo of the third ultrasonic wave is received to obtain third echo signals corresponding to the multiple receiving channels before beamforming;

[0079] In step S240, the other half of the array elements within the transmit aperture of the ultrasound probe are controlled to transmit a fourth ultrasound wave to the target tissue containing the contrast agent, and an echo of the fourth ultrasound wave is received to obtain fourth echo signals corresponding to the multiple receiving channels before beamforming;

[0080] In step S250, signals corresponding to the same receiving channel among the second echo signal, the third echo signal and the fourth echo signal are superimposed and cancelled to obtain contrast microbubble echo signals corresponding to multiple receiving channels before beamforming;

[0081] In step S260, beam synthesis is performed on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data;

[0082] In step S270, beam synthesis is performed on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data;

[0083] In step S280, a contrast image is obtained according to the contrast image data, and a tissue image is obtained according to the tissue image data.

[0084] Exemplarily, the ultrasound probe used in the ultrasound contrast imaging method 200 is a convex array ultrasound probe, that is, multiple array elements in the ultrasound probe are arranged in a convex array; the first ultrasound wave, the second ultrasound wave, the third ultrasound wave, and the fourth ultrasound wave are unfocused ultrasound waves, and further are divergent waves emitted by the convex array. Optionally, the ultrasound probe may also be an ultrasound probe capable of unfocused ultrasound imaging, such as a linear array ultrasound probe or a phased array ultrasound probe.

[0085] Before contrast imaging of the target tissue, contrast agent needs to be injected into the target tissue. The contrast agent contains contrast microbubbles, which can enhance the intensity of reflected echoes and diffuse to various organs of the human body with the blood. Since the blood vessels in the lesion area such as tumors are active and the contrast microbubbles are richly perfused, the lesion area is clearly imaged in the contrast image.

[0086] The contrast image is usually displayed synchronously with the tissue image, for example, the contrast image is superimposed and displayed on the tissue image. Therefore, in the process of contrast imaging, it is necessary to obtain the contrast image and the tissue image at the same time. In order to obtain the tissue image, it is necessary to control the ultrasonic probe to transmit the first ultrasonic wave to the target tissue containing the contrast agent, and receive the echo of the first ultrasonic wave to obtain the first echo signal corresponding to the multiple receiving channels before beam synthesis. Then, the first echo signals corresponding to the multiple receiving channels are beam synthesized to obtain tissue image data, and the tissue image is obtained based on the tissue image data. Specifically, all the array elements within the transmitting aperture of the ultrasonic probe can be controlled to transmit the first ultrasonic wave to the target tissue, and receive the echo of the first ultrasonic wave, that is, the tissue image data is obtained in a non-focused manner to improve the frame rate of obtaining the tissue image data.

[0087] like Figure 3 As shown, in order to obtain contrast image data, the embodiment of the present invention performs one full-aperture transmission and two half-aperture transmissions. Among them, one full-aperture transmission is: controlling all array elements in the transmission aperture of the ultrasonic probe to transmit a second ultrasonic wave to the target tissue containing a contrast agent, receiving the echo of the second ultrasonic wave, and obtaining the second echo signal corresponding to the multiple receiving channels before beam synthesis. Two half-aperture transmissions are: controlling half of the array elements in the transmission aperture of the ultrasonic probe to transmit a third ultrasonic wave to the target tissue containing a contrast agent, receiving the echo of the third ultrasonic wave, and obtaining the third echo signal corresponding to the multiple receiving channels before beam synthesis; and controlling the other half of the array elements in the transmission aperture of the ultrasonic probe to transmit a fourth ultrasonic wave to the target tissue containing a contrast agent, receiving the echo of the fourth ultrasonic wave, and obtaining the fourth echo signal corresponding to the multiple receiving channels before beam synthesis.

[0088] After obtaining the second echo signal corresponding to the full aperture and the third echo signal and the fourth echo signal corresponding to the half aperture, the signals corresponding to the same receiving channel in the second echo signal, the third echo signal and the fourth echo signal are superimposed and cancelled to obtain the contrast microbubble echo signals corresponding to the multiple receiving channels. Finally, the contrast microbubble echo signals corresponding to the multiple receiving channels are beamformed to obtain the contrast image data.

[0089] Specifically, when ultrasound waves propagate in tissues, if they encounter a regular interface, the ultrasound waves will be reflected and refracted, i.e., linear propagation. If they encounter an irregular interface, the waveform will be distorted, the harmonic components will increase, and the acoustic attenuation coefficient will increase, i.e., nonlinear propagation. The nonlinear propagation of ultrasound waves in tissues distorts the waveform of ultrasound waves propagating to the tissue or the interface of contrast microbubbles, including both the emitted fundamental wave components and the harmonic components. The greater the energy of the ultrasound waves, the stronger the nonlinear propagation effect, and the more obvious the waveform distortion propagating to the interface, in which the fundamental wave is enhanced at a constant ratio, while the harmonic enhancement ratio is greater.

[0090] Regardless of how the energy of the ultrasound changes, the ratio of the scattering intensity of the tissue's scattering interface to the ultrasound intensity remains constant, and the scattering waveform does not undergo further distortion and is always the same as the transmitted waveform. In contrast, the scattering ability of the scattering interface of the contrast microbubble increases with the increase in ultrasound intensity: the greater the ultrasound intensity, the greater the ratio of the scattering intensity to the incident intensity, and the scattering waveform undergoes further distortion, and the degree of distortion increases with the increase in ultrasound intensity.

[0091] Based on the above principle, the embodiment of the present invention performs one full-aperture transmission and two half-aperture transmissions, the intensity of the second ultrasonic wave transmitted by the full aperture is twice the intensity of the third ultrasonic wave and the fourth ultrasonic wave transmitted by the half aperture, and the second echo signal obtained by the full-aperture transmission and the third echo signal and the fourth echo signal obtained by the half-aperture transmission are superimposed and cancelled, that is, the second echo signal minus the third echo signal and the fourth echo signal. For the echo signal generated by the tissue, the second echo signal minus the third echo signal and the fourth echo signal, the result is that the fundamental signal is completely cancelled, the harmonic signal is partially cancelled, and because the harmonic signal intensity generated by nonlinear propagation is very small, the echo signal generated by the tissue only has a harmonic signal with a low intensity.

[0092] As for the echo signal of contrast microbubbles, the result of subtracting the third echo signal and the fourth echo signal from the second echo signal is that the fundamental signal is partially canceled and there is still a lot of residue, and the harmonic signal is partially canceled. Due to the nonlinear scattering and strong scattering properties of contrast microbubbles, the intensity of the harmonic signal generated is greater than the intensity of the harmonic signal generated by the tissue. Therefore, the echo signal of the contrast microbubble includes a very high-intensity residual fundamental signal and a slightly higher-intensity harmonic signal remaining after subtraction.

[0093] It can be seen that after superposition and cancellation, the remaining fundamental wave signal only includes the fundamental wave signal generated by the contrast microbubbles, while the harmonic signal includes the harmonic signal generated by the tissue and the harmonic signal generated by the contrast microbubbles. Therefore, the fundamental wave signal after superposition and cancellation can be extracted as the contrast microbubble echo signal to improve the suppression effect on the tissue signal and improve the signal-to-noise ratio of the contrast microbubble echo signal.

[0094] The above-mentioned superposition and cancellation process of the embodiment of the present invention is carried out in the receiving channel, that is, the second echo signal, the third echo signal and the fourth echo signal of each receiving channel are superimposed and cancelled. Specifically, if the minimum processing area for receiving and reflecting ultrasound in the target tissue is called a position point in the tissue, then different reflections will be generated after the ultrasound reaches each position point in the target tissue, and the reflected echo signal is received by the receiving array element, and each receiving array element can receive echo signals of multiple position points. The echo signals of different position points received by each receiving array element form different channel signals, and the receiving channel corresponds to the receiving array element receiving the ultrasound wave one by one. After superimposing and canceling the signals corresponding to the same receiving channel in the second echo signal, the third echo signal and the fourth echo signal, the contrast microbubble echo signals corresponding to the multiple receiving channels can be obtained.

[0095] After obtaining the contrast microbubble echo signal corresponding to each receiving channel by superposition and cancellation, the contrast microbubble echo signals corresponding to multiple receiving channels are beamformed to obtain contrast image data for generating a frame of contrast image. Beamformation includes corresponding delay and weighted summation processing of contrast microbubble echo signals corresponding to different receiving channels. Since the distances from the same position point in the tissue to different receiving array elements are different, the channel data of the same position point output by different receiving array elements have delay differences. The role of delay processing is to align the phases of the signals of different receiving channels. After that, the data of different receiving channels at the same position point are weighted and summed to obtain the contrast image data after beamformation. After the contrast image data is processed by envelope detection, logarithmic compression, etc., the contrast image can be obtained.

[0096] Reference Figure 4 , which shows the existing contrast imaging scheme. The existing contrast imaging scheme performs one full-aperture transmission and two half-aperture transmissions, and after beamforming the echo signals obtained from the three transmissions respectively, the beamformed data are superimposed and cancelled to extract the nonlinear components therein for contrast imaging; at the same time, tissue imaging is performed on the echo signals obtained from the full-aperture transmission. The existing contrast imaging scheme requires three beamformations for one contrast imaging, while the embodiment of the present invention only requires two beamformations. Since the imaging frame rate of non-focused wave contrast imaging is mainly limited by the computing speed of the chip, the amount of computation in the embodiment of the present invention is reduced by 1 / 3, effectively improving the imaging frame rate in the contrast imaging mode.

[0097] In one embodiment, Figure 5 As shown, half of the array elements and the other half of the array elements in the transmitting aperture respectively include multiple array element groups, each array element group includes at least one array element; the multiple array element groups of half of the array elements and the multiple array element groups of the other half of the array elements are arranged alternately, so that the ultrasound waves cover the target tissue relatively evenly.

[0098] According to the number of transmit apertures, the embodiment of the present invention can adopt the following Figure 6 and Figure 7 Either of the two launch strategies shown.

[0099] like Figure 6 As shown, in the first transmission strategy, the transmission aperture includes all array elements of the ultrasound probe, and multiple deflection transmissions are performed, that is, the ultrasound probe is controlled to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave respectively at multiple transmission angles to obtain contrast image data and tissue image data corresponding to each transmission angle; the contrast image data corresponding to the multiple transmission angles are spatially compounded to obtain a contrast image, and the tissue image data corresponding to the multiple transmission angles are spatially compounded to obtain a tissue image.

[0100] Specifically, spatial compounding mainly includes spatial alignment of contrast image data or tissue image data obtained at different emission angles, and compounding of the spatially aligned data. Spatial compounding can reduce speckle noise, reduce the variance of speckle formation, increase the visibility of the edge of the scatterer or the boundary of the tissue, and improve image quality. Among them, speckle noise is the speckle generated by the coherent superposition of scattered echoes of uniform tissue. Its essence is not noise, but since uniform tissue should ideally be a smooth image, these spots become noise that affects the image effect. If the relative position of the ultrasound probe and the tissue is fixed, the position of the spot is fixed, but if the relative position of the ultrasound probe and the tissue is changed, the position of the spot image will also change. Spatial compounding technology is based on the above principle. The relative position of the ultrasound probe and the tissue remains unchanged, but the direction of the sound beam scanning has changed, which is equivalent to the change of the position of the ultrasound probe and the tissue, thereby obtaining a completely different speckle image; after spatial alignment, the speckle noise at different angles no longer corresponds to the same pixel point, so a smooth effect can be obtained after image superposition.

[0101] In addition, spatial compounding can also produce better display effects for strong reflective interfaces at different inclination angles. When ultrasound is incident on a strong reflective interface in the tissue, a strong reflection effect will be generated, so that the ultrasound echo signal can only return to the ultrasound probe when the incident direction is perpendicular to the reflective interface. Scanning at different deflection angles can detect interfaces in different directions; when the tissue interface is a curved surface, since different parts of the curved surface are imaged at different deflection angles, the continuity of the curved surface can be improved after spatial compounding.

[0102] Exemplarily, the embodiment of the present invention further improves the imaging frame rate by increasing the deflection angle step. In one embodiment of the present invention, the angle difference between each two adjacent emission angles is greater than or equal to 1.5° and less than or equal to 2°, and the angle range of multiple emission angles is greater than or equal to -15° and less than or equal to +15°. Taking the imaging depth of 17 cm as an example, the traditional imaging scheme usually deflects and transmits 75 times, the angle range of multiple emission angles is greater than or equal to -15° and less than or equal to +15°, and the deflection angle step θ of each time is 0.405°. At this time, the imaging frame rate is 10 frames per second. The embodiment of the present invention maintains the original angle range unchanged, and increases the angle difference between each two adjacent emission angles to between 1.5° and 2°. For example, when the angle difference is 1.875°, the number of deflection transmissions is reduced to 17 times, thereby increasing the theoretical frame rate to more than 40 frames per second.

[0103] like Figure 7 As shown, in the second transmission strategy, the ultrasound probe includes multiple transmission apertures, each of which includes adjacent partial array elements in the ultrasound probe. The multiple transmission apertures can slide to transmit ultrasound waves, thereby having better penetration. When performing sliding transmission of multiple transmission apertures, the sliding angle step θ can also be increased, or the number of array elements included in each transmission aperture can be increased, so that the number of transmissions required to form a frame of contrast image is reduced, thereby improving the frame rate.

[0104] When the transmission strategy of sliding transmission is adopted, the contrast microbubble echo signal and the first echo signal after superposition and cancellation in the receiving channel can be spatially compounded, and then the spatially compounded signal can be beam synthesized; or beam synthesis can be performed first, and then the contrast image data and tissue image data after beam synthesis can be spatially compounded. Specifically, when the contrast microbubble echo signal and the first echo signal after superposition and cancellation are spatially compounded, multiple transmission apertures are controlled to respectively transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave and the fourth ultrasonic wave to obtain the contrast microbubble signal and the first echo signal corresponding to each transmission aperture; the contrast microbubble echo signals corresponding to the multiple transmission apertures under each receiving channel are spatially compounded to obtain the composite contrast microbubble echo signal corresponding to each receiving channel, and the composite contrast microbubble echo signals corresponding to the multiple receiving channels are beam synthesized to obtain the contrast image data; the first echo signals corresponding to the multiple transmission apertures under each receiving channel are spatially compounded to obtain the composite first echo signal corresponding to each receiving channel, and the composite first echo signals corresponding to the multiple receiving channels are beam synthesized to obtain the tissue image data. Performing spatial recombination on the contrast microbubble echo signal and the first echo signal after superposition and cancellation in the receiving channel can reduce the number of spatial recombination times and the amount of calculation.

[0105] When the contrast image data and tissue image data after beam synthesis are spatially compounded, multiple transmit apertures are controlled to respectively transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave and the fourth ultrasonic wave, and the superposition, cancellation and beam synthesis described above are performed to obtain the contrast image data and tissue image data corresponding to each transmit aperture. Afterwards, the contrast image data corresponding to the multiple transmit apertures are spatially compounded to obtain a contrast image, and the tissue image data corresponding to the multiple transmit apertures are spatially compounded to obtain a tissue image. The method and principle of spatially compounding the contrast image data and the tissue image data can refer to the relevant description above.

[0106] like Figure 8 As shown, in one embodiment, the number of array elements included in each transmit aperture may be determined according to a preset number of spatial recombination times and a preset number of transmit apertures, wherein the array elements included in every two adjacent transmit apertures partially overlap. Figure 8 The preset number of spatial compounding times is two, that is, each receiving channel needs to obtain two sets of echo signals; the preset number of transmit apertures is seven. The second transmit aperture has some array elements overlapping with the first transmit aperture, and these array elements can obtain two sets of echo signals. Since another part of the array elements of the second transmit aperture does not overlap with the first transmit aperture, these array elements need to overlap with the third transmit aperture, thereby ensuring that each array element of the second transmit aperture can obtain two sets of echo signals, and so on.

[0107] In one embodiment, the number of transmit apertures is not greater than 75, and may be specifically 7 or 17. Limiting the number of transmit apertures means limiting the number of transmissions, thereby reducing the number of transmissions required to form a frame of contrast image or a frame of tissue image, and improving the frame rate of contrast imaging.

[0108] To summarize, the ultrasound contrast imaging method 200 of the embodiment of the present invention performs two full-aperture transmissions and two half-aperture transmissions, and the echo signals obtained by one full-aperture transmission and the echo signals obtained by two half-aperture transmissions are first superimposed and canceled, and then beamformed, thereby reducing the number of beamformations and improving the imaging frame rate of contrast imaging.

[0109] The embodiment of the present invention further provides an ultrasound imaging system for implementing the ultrasound contrast imaging method 200. Figure 1 , the ultrasound imaging system can be implemented as follows Figure 1The ultrasound imaging system 100 shown may include an ultrasound probe 110, a transmitting circuit 112, a receiving circuit 114, a processor 116 and a display 118. Optionally, the ultrasound imaging system 100 may also include a transmit / receive selection switch 120 and a beamforming module 122. The transmitting circuit 112 and the receiving circuit 114 may be connected to the ultrasound probe 110 via the transmit / receive selection switch 120. The relevant description of each component may refer to the relevant description above and will not be repeated here.

[0110] Among them, the transmitting circuit 112 is used to stimulate the ultrasonic probe 110 to transmit ultrasonic waves to the target tissue; the receiving circuit 114 is used to control the ultrasonic probe 110 to receive the echo of the ultrasonic wave to obtain an ultrasonic echo signal; the processor 116 is used to execute the steps of the above-mentioned ultrasonic contrast imaging method 200 to obtain a contrast image and a tissue image; the processor 118 is used to display the contrast image and the tissue image.

[0111] The above only describes the main functions of the components of the ultrasound imaging system. For more details, please refer to the related description of the ultrasound contrast imaging method 200. The ultrasound imaging system of the embodiment of the present invention can improve the imaging frame rate of contrast imaging.

[0112] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present invention thereto. Various changes and modifications may be made therein by one of ordinary skill in the art without departing from the scope and spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as required by the appended claims.

[0113] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0114] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0115] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0116] Similarly, it should be understood that in order to streamline the present invention and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present invention should not be interpreted as reflecting the following intention: the claimed invention requires more features than the features explicitly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present invention.

[0117] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0118] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0119] The various component embodiments of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functions of some modules according to embodiments of the present invention. The present invention can also be implemented as a device program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present invention can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0120] It should be noted that the above embodiments illustrate rather than limit the invention, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of means, several of these means may be embodied by the same hardware item. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

[0121] The above is only a specific embodiment of the present invention or an explanation of a specific embodiment. The protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An ultrasound contrast imaging method, characterized in that: The method comprises: Controlling the ultrasonic probe to transmit a first ultrasonic wave to a target tissue containing a contrast agent, and receiving an echo of the first ultrasonic wave to obtain first echo signals corresponding to a plurality of receiving channels before beamforming; Controlling all array elements within the transmitting aperture of the ultrasonic probe to transmit a second ultrasonic wave to the target tissue containing the contrast agent, and receiving an echo of the second ultrasonic wave to obtain second echo signals corresponding to a plurality of receiving channels before beamforming; Controlling half of the array elements within the transmitting aperture of the ultrasonic probe to transmit a third ultrasonic wave to the target tissue containing the contrast agent, and receiving an echo of the third ultrasonic wave to obtain third echo signals corresponding to a plurality of receiving channels before beamforming; Controlling the other half of the array elements within the transmitting aperture of the ultrasonic probe to transmit a fourth ultrasonic wave to the target tissue containing the contrast agent, and receiving an echo of the fourth ultrasonic wave to obtain fourth echo signals corresponding to the multiple receiving channels before beamforming; superimpose and cancel signals corresponding to the same receiving channel among the second echo signal, the third echo signal and the fourth echo signal to obtain contrast microbubble echo signals corresponding to multiple receiving channels before beamforming; Performing beam synthesis on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data; Performing beam synthesis on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data; A contrast image is obtained based on the contrast image data, and a tissue image is obtained based on the tissue image data.

2. The method according to claim 1, characterized in that The half array elements and the other half array elements respectively include a plurality of array element groups, each of the array element groups includes at least one array element; The multiple array element groups of the half array elements and the multiple array element groups of the other half array elements are arranged alternately.

3. The method according to claim 1, characterized in that The transmitting aperture includes all array elements of the ultrasonic probe, and controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave includes: controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave respectively at multiple transmitting angles, so as to obtain the contrast image data and the tissue image data corresponding to each transmitting angle; The step of obtaining a contrast image according to the contrast image data and obtaining a tissue image according to the tissue image data comprises: spatially compounding the angiography image data corresponding to the multiple emission angles to obtain the angiography image; And, spatially compounding the tissue image data corresponding to the multiple emission angles to obtain the tissue image.

4. The method according to claim 1, characterized in that The transmitting aperture includes all array elements of the ultrasonic probe, and controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave includes: controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave respectively at multiple transmitting angles, so as to obtain the contrast microbubble signal and the first echo signal corresponding to each transmitting angle; The performing beam synthesis on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data includes: Performing spatial compounding on contrast microbubble echo signals corresponding to multiple emission angles under each receiving channel to obtain a composite contrast microbubble echo signal corresponding to each receiving channel, and performing beam synthesis on the composite contrast microbubble echo signals corresponding to multiple receiving channels to obtain contrast image data; The performing beam synthesis on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data includes: The first echo signals corresponding to multiple transmission angles under each receiving channel are spatially compounded to obtain a composite first echo signal corresponding to each receiving channel, and the composite first echo signals corresponding to multiple receiving channels are beamformed to obtain tissue image data.

5. The method according to claim 3, characterized in that: The angular difference between each two adjacent emission angles is greater than or equal to 1.5° and less than or equal to 2°, and the angular range of the multiple emission angles is greater than or equal to -15° and less than or equal to +15°.

6. The method according to claim 1, characterized in that The ultrasonic probe comprises a plurality of transmitting apertures, each of the transmitting apertures comprises adjacent partial array elements in the ultrasonic probe, and controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave comprises: controlling the plurality of transmitting apertures to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave, respectively, so as to obtain the contrast image data and the tissue image data corresponding to each transmitting aperture; The step of obtaining a contrast image according to the contrast image data and obtaining a tissue image according to the tissue image data comprises: spatially compounding the contrast image data corresponding to the multiple transmit apertures to obtain the contrast image; And, spatially compounding the tissue image data corresponding to the multiple transmission apertures to obtain the tissue image.

7. The method according to claim 1, characterized in that The ultrasonic probe comprises a plurality of transmitting apertures, each of the transmitting apertures comprises adjacent partial array elements in the ultrasonic probe, and controlling the ultrasonic probe to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave comprises: controlling the plurality of transmitting apertures to transmit the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave, and the fourth ultrasonic wave respectively, so as to obtain the contrast microbubble signal and the first echo signal corresponding to each transmitting aperture; The performing beam synthesis on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data includes: Performing spatial compounding on contrast microbubble echo signals corresponding to a plurality of transmit apertures under each receiving channel to obtain a compound contrast microbubble echo signal corresponding to each receiving channel, and performing beam synthesis on the compound contrast microbubble echo signals corresponding to a plurality of receiving channels to obtain contrast image data; The performing beam synthesis on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data includes: The first echo signals corresponding to multiple transmit apertures under each receiving channel are spatially compounded to obtain a composite first echo signal corresponding to each receiving channel, and the composite first echo signals corresponding to multiple receiving channels are beamformed to obtain tissue image data.

8. The method according to claim 6 or 7, characterized in that: Also includes: The number of array elements included in each transmit aperture is determined according to a preset number of spatial recombination times and a preset number of transmit apertures, wherein the array elements included in every two adjacent transmit apertures partially overlap.

9. The method according to claim 8, characterized in that The number of the transmitting apertures is no more than 75.

10. The method according to claim 1, characterized in that The controlling the ultrasonic probe to transmit a first ultrasonic wave to a target tissue containing a contrast agent and receiving an echo of the first ultrasonic wave comprises: All array elements within the transmitting aperture of the ultrasonic probe are controlled to transmit a first ultrasonic wave to the target tissue, and receive an echo of the first ultrasonic wave.

11. The method according to claim 1, characterized in that: The ultrasonic probe is a convex array ultrasonic probe, and the first ultrasonic wave, the second ultrasonic wave, the third ultrasonic wave and the fourth ultrasonic wave are unfocused ultrasonic waves.

12. An ultrasonic imaging system, characterized in that: The ultrasonic imaging system comprises: An ultrasonic probe, wherein the ultrasonic probe comprises a plurality of array elements; A transmitting circuit, used for stimulating the ultrasound probe to transmit ultrasound waves toward a target tissue containing a contrast agent; A receiving circuit, used for controlling the ultrasonic probe to receive the ultrasonic echo signal; a processor, configured to generate an ultrasonic image of the target tissue according to the echo signal, wherein the processor is further configured to execute the ultrasonic contrast imaging method according to any one of claims 1 to 11; A display is used to display the ultrasound image generated by the processor.

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