Ultrasound contrast imaging method and ultrasound imaging system

Abstract

The application discloses an ultrasonic contrast imaging method and an ultrasonic imaging system, and the method comprises the following steps: controlling an ultrasonic probe to emit first ultrasonic waves to target tissue containing contrast agents and receiving echoes to obtain first echo signals; controlling the ultrasonic probe to emit second ultrasonic waves, third ultrasonic waves and fourth ultrasonic waves to the target tissue by all array elements, half array elements and the other half array elements in the emission aperture of the ultrasonic probe respectively, and obtaining second echo signals, third echo signals and fourth echo signals corresponding to multiple receiving channels; superimposing and canceling signals corresponding to the same receiving channel in the second echo signals, the third echo signals and the fourth echo signals to obtain contrast microbubble echo signals corresponding to the multiple receiving channels; performing beam synthesis on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data; and performing beam synthesis on the first echo signals to obtain tissue image data. The application can improve the imaging frame rate of contrast imaging.

Description

TECHNICAL FIELD

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

[0002] Ultrasonic medical imaging is a method of displaying the image of the internal organs of the human body by receiving the scattered, reflected or projected sound waves of the internal organs of the human body with ultrasonic waves as the detection means. If a medium (micro-bubbles) with a sound impedance that is completely different from that of blood is added to the blood, the scattering in the blood is enhanced, which is the basic principle of ultrasonic contrast imaging. It is just by using this principle that ultrasonic contrast agents, i.e. solutions containing micro-bubbles, are injected into veins, and the contrast agents are perfused into organs and tissues along with the blood flow, so that the organs and tissues are developed or developed more strongly, thereby providing an important basis for clinical diagnosis.

[0003] When a doctor performs a contrast examination, the doctor first selects a suitable probe according to the examination site, positions the probe to the position and section of the lesion, then enters the contrast imaging mode, adjusts suitable imaging parameters such as imaging frequency, gain, mechanical index, etc. according to the depth of the lesion. Next, the timer is started while the ultrasonic contrast agent is injected, and the whole process of the contrast micro-bubbles entering and exiting the lesion is observed, and compared with the normal tissue around the lesion, so as to make a differential diagnosis on the benign and malignant properties of the lesion.

[0004] Since the doctor needs to continuously observe the whole process of the micro-bubble dynamic perfusion when performing contrast imaging, in order to more smoothly present the perfusion process of the micro-bubbles, it is necessary to provide a higher frame rate while ensuring the quality of the contrast images. SUMMARY

[0005] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiments section. The summary section of the present application does not mean to attempt to limit the key features and necessary technical features of the claimed technical solutions, and even less to determine the protection scope of the claimed technical solutions.

[0006] The embodiment of the present application provides an ultrasonic contrast imaging method, and the method comprises the following steps:

[0007] controlling an ultrasonic probe to emit first ultrasonic waves to target tissue containing a contrast agent, and receiving echoes of the first ultrasonic waves to obtain first echo signals corresponding to a plurality of receiving channels before beam synthesis;

[0008] controlling all elements in a transmitting aperture of the ultrasonic probe to emit second ultrasonic waves to the target tissue containing the contrast agent, and receiving echoes of the second ultrasonic waves to obtain second echo signals corresponding to a plurality of receiving channels before beam synthesis;

[0009] controlling a half of the elements within a transmit aperture of the ultrasound probe to transmit third ultrasound waves to the target tissue containing the contrast agent and receive echoes of the third ultrasound waves to obtain third echo signals corresponding to the plurality of receiving channels before beamforming;

[0010] controlling the other half of the elements within the transmit aperture of the ultrasound probe to transmit fourth ultrasound waves to the target tissue containing the contrast agent and receive echoes of the fourth ultrasound waves to obtain fourth echo signals corresponding to the plurality of receiving channels before beamforming;

[0011] superimposing and canceling signals corresponding to the same receiving channel in the second echo signals, the third echo signals and the fourth echo signals to obtain contrast microbubble echo signals corresponding to the plurality of receiving channels before beamforming;

[0012] performing beamforming on the contrast microbubble echo signals corresponding to the plurality of receiving channels to obtain contrast image data;

[0013] performing beamforming on the first echo signals corresponding to the plurality of receiving channels to obtain tissue image data;

[0014] obtaining a contrast image according to the contrast image data and obtaining a tissue image according to the tissue image data.

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

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

[0017] In one embodiment, the transmit aperture includes all of the elements of the ultrasound probe, and the controlling the ultrasound probe to transmit the first ultrasound waves, the second ultrasound waves, the third ultrasound waves and the fourth ultrasound waves includes: controlling the ultrasound probe to transmit the first ultrasound waves, the second ultrasound waves, the third ultrasound waves and the fourth ultrasound waves respectively at a plurality of transmission angles to obtain the contrast image data and the tissue image data corresponding to each transmission angle.

[0018] The obtaining a contrast image according to the contrast image data and obtaining a tissue image according to the tissue image data includes:

[0019] spatially compositing the contrast image data corresponding to the plurality of transmission angles to obtain the contrast image;

[0020] and spatially compositing the tissue image data corresponding to the plurality of transmission angles to obtain the tissue image.

[0021] In an embodiment, the transmitting aperture comprises all elements of the ultrasound probe, and the controlling the ultrasound probe to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave comprises: 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 a plurality of transmitting angles, to obtain the contrast microbubble signal and the first echo signal corresponding to each transmitting angle.

[0022] The beamforming the contrast microbubble echo signals corresponding to the plurality of receiving channels to obtain contrast image data comprises:

[0023] The spatial compounding the contrast microbubble echo signals corresponding to the plurality of transmitting angles at each receiving channel to obtain the compound contrast microbubble echo signal corresponding to each receiving channel, and the beamforming the compound contrast microbubble echo signals corresponding to the plurality of receiving channels to obtain contrast image data.

[0024] The beamforming the first echo signals corresponding to the plurality of receiving channels to obtain tissue image data comprises:

[0025] The spatial compounding the first echo signals corresponding to the plurality of transmitting angles at each receiving channel to obtain the compound first echo signal corresponding to each receiving channel, and the beamforming the compound first echo signals corresponding to the plurality of receiving channels to obtain tissue image data.

[0026] In an embodiment, an angle difference between each two adjacent transmitting angles is greater than or equal to 1.5° and less than or equal to 2°, and an angle range of the plurality of transmitting angles is greater than or equal to -15° and less than or equal to +15°.

[0027] In an embodiment, the ultrasound probe comprises a plurality of transmitting apertures, each transmitting aperture comprising adjacent partial elements in the ultrasound probe, and the controlling the ultrasound probe to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave comprises: controlling the plurality of transmitting apertures to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave respectively, to obtain the contrast image data and the tissue image data corresponding to each transmitting aperture.

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

[0029] The spatial compounding the contrast image data corresponding to the plurality of transmitting apertures to obtain the contrast image.

[0030] and spatially compounding the tissue image data corresponding to the multiple transmit apertures to obtain the tissue image.

[0031] In one embodiment, the ultrasound probe comprises multiple transmit apertures, each of the transmit apertures comprising adjacent partial elements in the ultrasound probe, and the controlling the ultrasound probe to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave comprises: controlling the multiple transmit apertures to transmit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave respectively to obtain the contrast microbubble signal and the first echo signal corresponding to each transmit aperture.

[0032] The beamforming the first echo signal corresponding to the multiple receiving channels to obtain tissue image data comprises:

[0033] spatially compounding the contrast microbubble echo signal corresponding to the multiple transmit apertures under each receiving channel to obtain the compounded contrast microbubble echo signal corresponding to each receiving channel, and beamforming the compounded contrast microbubble echo signal corresponding to the multiple receiving channels to obtain the contrast image data.

[0034] The beamforming the first echo signal corresponding to the multiple receiving channels to obtain tissue image data comprises:

[0035] spatially compounding the first echo signal corresponding to the multiple transmit apertures under each receiving channel to obtain the compounded first echo signal corresponding to each receiving channel, and beamforming the compounded first echo signal corresponding to the multiple receiving channels to obtain the tissue image data.

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

[0037] determining the number of elements included in each transmit aperture according to a preset spatial compounding number and a preset transmit aperture number, wherein the elements included in each adjacent two transmit apertures partially overlap.

[0038] In one embodiment, the number of transmit apertures is not greater than 75.

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

[0040] controlling all elements in the transmit aperture of the ultrasound probe to transmit the first ultrasound wave to the target tissue and receive the echo of the first ultrasound wave.

[0041] In one embodiment, the ultrasonic probe is a convex array ultrasonic probe, and the first, second, third and fourth ultrasonic waves are non-focused ultrasonic waves.

[0042] In another aspect, the present application provides an ultrasonic imaging system, comprising:

[0043] an ultrasonic probe comprising a plurality of array elements;

[0044] a transmitting circuit configured to excite the ultrasonic probe to transmit ultrasonic waves to a target tissue containing contrast agent;

[0045] a receiving circuit configured to control the ultrasonic probe to receive echo signals of the ultrasonic waves;

[0046] a processor configured to generate an ultrasonic image of the target tissue according to the echo signals, and further configured to perform the ultrasonic contrast imaging method as described above;

[0047] a display configured to display the ultrasonic image generated by the processor.

[0048] The ultrasonic contrast imaging method and the ultrasonic imaging system of the present application perform two full-aperture transmissions and two half-aperture transmissions, and superpose and cancel the echo signals obtained from one of the full-aperture transmissions and the echo signals obtained from the two half-aperture transmissions, and then perform beamforming, thereby reducing the number of times of beamforming and improving the imaging frame rate of contrast imaging. BRIEF DESCRIPTION OF DRAWINGS

[0049] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which like reference characters designate like elements in the figures. The accompanying drawings are intended to provide a further understanding of the present application, and are incorporated and constitute a part of this specification, illustrate embodiments of the present application and serve to explain the present application, and are not intended to limit the present application in any manner. In the drawings:

[0050] Figure 1 a structural block diagram of an ultrasonic imaging system according to one embodiment of the present application is shown;

[0051] Figure 2 a schematic flow chart of an ultrasonic contrast imaging method according to one embodiment of the present application is shown;

[0052] Figure 3 a flow block diagram of an ultrasonic contrast imaging method according to one embodiment of the present application is shown;

[0053] Figure 4 a flow block diagram of an ultrasonic contrast imaging method according to an existing method is shown;

[0054] Figure 5 Fig. 6 shows a schematic diagram of transmitting ultrasound waves by half array elements according to one embodiment of the present application;

[0055] Figure 6 Fig. 7 shows a schematic diagram of transmitting aperture including all array elements according to one embodiment of the present application;

[0056] Figure 7 Fig. 8 shows a schematic diagram of transmitting aperture including part array elements according to one embodiment of the present application;

[0057] Figure 8 Fig. 9 shows a schematic diagram of determining the number of array elements included in each transmitting aperture according to the number of spatial compounding times and the number of transmitting apertures according to one embodiment of the present application. DETAILED DESCRIPTION

[0058] In order to make the objects, technical solutions and advantages of the present application more clear, the following will describe the example embodiments of the present application in detail with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present application.

[0059] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present application. However, it should be apparent to those skilled in the art that the present application can be practiced without one or more of these details. In other instances, well-known features have not been described in detail in order to avoid obscuring the present application.

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

[0061] The terms used herein are only for the purpose of describing specific embodiments and not as limitations of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0062] For a thorough understanding of the present application, reference will be made to the following detailed description, taken in conjunction with the accompanying drawings, in which: Embodiments of the present application will be described in detail, with reference to the following detailed description and to the drawings:

[0063] Reference will be made to the following description and drawings to enable those skilled in the art to make and use the present application. Figure 1 An ultrasound imaging system according to an embodiment of the present application is described, Figure 1 A schematic block diagram of an ultrasound imaging system 100 according to an embodiment of the present application is shown.

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

[0065] The ultrasound probe 110 includes a plurality of transducer elements, which can be arranged in a one-dimensional array to form a linear array, or arranged in a two-dimensional matrix to form a planar array, or arranged in a convex array. The transducer elements are used to transmit ultrasound waves according to excitation electrical signals, or convert received ultrasound waves into electrical signals, so each transducer element can be used to realize the mutual conversion between electrical pulse signals and ultrasound waves, so as to realize the transmission of ultrasound waves to the target region of the measured object, and also can be used to receive the ultrasound wave echoes reflected by the tissue. When performing ultrasound detection, it can be controlled by a transmission sequence and a reception sequence which transducer elements are used to transmit ultrasound waves and which transducer elements are used to receive ultrasound waves, or the transducer elements are controlled to be used for transmitting ultrasound waves or receiving ultrasound wave echoes in time slots. The transducer elements participating in the transmission of ultrasound waves can be excited by electrical signals at the same time, so as to transmit ultrasound waves at the same time; or the transducer elements participating in the transmission of ultrasound beams can also be excited by several electrical signals with a certain time interval, so as to continuously transmit ultrasound waves with a certain time interval.

[0066] In 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 excited by the transmitting pulse to emit an ultrasonic beam to the target tissue of the measured object, receives the ultrasonic echo with tissue information reflected from the target tissue after a certain delay, and converts the ultrasonic echo into an electrical signal. The receiving circuit 114 receives the electrical signal converted by the ultrasonic probe 110, obtains the ultrasonic echo signal, and sends the ultrasonic echo signal to the beam synthesis module 122. The beam synthesis module 122 performs focused delay, weighting, and channel summation on the ultrasonic echo data, and then sends the ultrasonic echo data to the processor 116. The processor 116 performs signal detection, signal enhancement, data conversion, logarithmic compression, and the like 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 storage 124.

[0067] Optionally, the processor 116 can be implemented as software, hardware, firmware, or any combination thereof, and can 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 foregoing circuits and / or devices, or other suitable circuits or devices. In addition, the processor 116 can control other components in the ultrasonic imaging system 100 to perform corresponding steps of the method in various embodiments of the present specification.

[0068] The display 118 is connected to the processor 116, and the display 118 can be a touch display screen, a liquid crystal display screen, or the like; or the display 118 can be a liquid crystal display, a television, or the like independent display independent of the ultrasonic imaging system 100; or the display 118 can be a display screen of a smart phone, a tablet computer, or the like electronic device, and the like. The number of the display 118 can be one or more.

[0069] The display 118 can display the ultrasonic image obtained by the processor 116. In addition, the display 118 can provide a graphical interface for human-computer interaction of the user while displaying the ultrasonic image, set one or more controlled objects on the graphical interface, and provide the user with an operation instruction input by a human-computer interaction device to control the controlled objects, so as to perform a corresponding control operation. 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 frame on the ultrasonic image.

[0070] Optionally, the ultrasound imaging system 100 can also include other human-machine interaction devices other than the display 118, which are connected with the processor 116. For example, the processor 116 can be connected with the human-machine interaction devices through external input / output ports, which can be wireless communication modules, wired communication modules, or a combination of both. The external input / output ports can also be implemented based on USB, bus protocols such as CAN, wired network protocols, and / or the like.

[0071] The human-machine interaction devices can include input devices for detecting input information of a user, which can be, for example, control instructions for the ultrasound wave transmission / reception timing, operation input instructions for drawing points, lines, or frames on the ultrasound image, or other instruction types. The input devices can include one or a combination of a keyboard, a mouse, a scroll wheel, a trackball, a mobile input device (such as a mobile device with a touch display, a mobile phone, and the like), a multifunction knob, and the like. The human-machine interaction devices can also include output devices such as a printer.

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

[0073] It should be understood that Figure 1 The components included in the illustrated ultrasound imaging system 100 are only illustrative, and the present application is not limited thereto.

[0074] In the following, the ultrasound contrast imaging method according to an embodiment of the present application will be described with reference to Figure 2 The ultrasound contrast imaging method 200 according to an embodiment of the present application will be described below with reference to Figure 2 is a schematic flowchart of the ultrasound contrast imaging method 200 according to an embodiment of the present application.

[0075] As Figure 2 indicated, the ultrasound contrast imaging method 200 according to an embodiment of the present application includes the following steps:

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

[0077] In step S220, the ultrasound probe is controlled to transmit a second ultrasound wave to the target tissue containing contrast agent and receive echoes of the second ultrasound wave, to obtain second echo signals corresponding to a plurality of receiving channels before beamforming.

[0078] In step S230, half of the array elements in the transmitting aperture of the ultrasound probe are controlled to transmit third ultrasound waves to the target tissue containing the contrast agent, and receive echoes of the third ultrasound waves, to obtain third echo signals corresponding to the multiple receiving channels before beamforming;

[0079] In step S240, the other half of the array elements in the transmitting aperture of the ultrasound probe are controlled to transmit fourth ultrasound waves to the target tissue containing the contrast agent, and receive echoes of the fourth ultrasound waves, to obtain fourth echo signals corresponding to the multiple receiving channels before beamforming;

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

[0081] In step S260, the contrast microbubble echo signals corresponding to the multiple receiving channels are beamformed to obtain contrast image data;

[0082] In step S270, the first echo signals corresponding to the multiple receiving channels are beamformed 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, i.e., the multiple array elements in the ultrasound probe are arranged as a convex array; the first ultrasound waves, the second ultrasound waves, the third ultrasound waves and the fourth ultrasound waves are non-focused ultrasound waves, which are further divergent waves transmitted by the convex array. Alternatively, the ultrasound probe can also be a linear array ultrasound probe or a phased array ultrasound probe, etc., which can perform non-focused ultrasound imaging.

[0085] Before the target tissue is imaged by contrast imaging, the target tissue needs to be injected with a contrast agent containing contrast microbubbles, which can enhance the intensity of reflected echoes and can diffuse to various organs of the human body along with the blood in the human body. Due to the active blood vessels in the lesion area such as tumor, the contrast microbubbles are rich in perfusion, so that 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, so that the contrast image and the tissue image need to be obtained simultaneously in the process of contrast imaging. In order to obtain the tissue image, the ultrasound probe needs to be controlled to emit first ultrasound waves to the target tissue containing the contrast agent and receive echoes of the first ultrasound waves, and first echo signals corresponding to a plurality of receiving channels before beamforming are obtained. Then, the first echo signals corresponding to the plurality of receiving channels are beamformed to obtain tissue image data, and the tissue image is obtained according to the tissue image data. Specifically, all elements in the transmit aperture of the ultrasound probe can be controlled to emit first ultrasound waves to the target tissue, and echoes of the first ultrasound waves are received, that is, the tissue image data is obtained in a non-focusing manner to improve the frame rate of obtaining the tissue image data.

[0087] As shown in Figure 3 To obtain the contrast image data, the embodiment of the present application performs one full-aperture transmission and two half-aperture transmissions. The one full-aperture transmission is to control all elements in the transmit aperture of the ultrasound probe to emit second ultrasound waves to the target tissue containing the contrast agent, receive echoes of the second ultrasound waves, and obtain second echo signals corresponding to a plurality of receiving channels before beamforming. The two half-aperture transmissions are to control one half of the elements in the transmit aperture of the ultrasound probe to emit third ultrasound waves to the target tissue containing the contrast agent, receive echoes of the third ultrasound waves, and obtain third echo signals corresponding to a plurality of receiving channels before beamforming; and to control the other half of the elements in the transmit aperture of the ultrasound probe to emit fourth ultrasound waves to the target tissue containing the contrast agent, receive echoes of the fourth ultrasound waves, and obtain fourth echo signals corresponding to a plurality of receiving channels before beamforming.

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

[0089] Specifically, when the ultrasound waves propagate in the tissue, if they encounter a regular interface, the ultrasound waves will be reflected and refracted, that is, linear propagation. If they encounter an irregular interface, the wave shape will be distorted, the harmonic component will increase, and the sound attenuation coefficient will increase, that is, nonlinear propagation. The nonlinear propagation of the ultrasound waves in the tissue causes the wave shape of the ultrasound waves propagating to the tissue or the contrast microbubble interface to be distorted, which includes both the transmitted fundamental wave component and the harmonic component, and the greater the ultrasound wave energy, the stronger the nonlinear propagation effect, and the more obvious the wave shape distortion of the interface. The fundamental wave is enhanced at a constant ratio, while the harmonic is enhanced at a larger ratio.

[0090] Regardless of the energy of the ultrasonic waves, the ratio of the scattering intensity of the scattering interface of the tissue to the intensity of the ultrasonic waves is constant, and the scattered wave shape does not further distort and is always the same as the transmitted wave shape. In contrast, the scattering ability of the scattering interface of the contrast microbubbles increases with the increase of the intensity of the ultrasonic waves: the greater the intensity of the ultrasonic waves, the greater the ratio of the scattering intensity to the incident intensity, and the scattered wave shape further distorts, and the distortion degree increases with the increase of the intensity of the ultrasonic waves.

[0091] Based on the above principle, the embodiment of the present application performs one full-aperture transmission and two half-aperture transmissions, the intensity of the second ultrasonic wave of the full-aperture transmission is twice the intensity of the third ultrasonic wave and the fourth ultrasonic wave of the half-aperture transmission, and the second echo signal obtained by the full-aperture transmission is subtracted from the third echo signal and the fourth echo signal obtained by the half-aperture transmission. 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 wave signal is completely cancelled, and the harmonic wave signal is partially cancelled, and since the harmonic wave signal generated by the nonlinear propagation is very small, the echo signal generated by the tissue only remains the harmonic wave signal with low intensity.

[0092] For the echo signal of the contrast microbubbles, the second echo signal minus the third echo signal and the fourth echo signal, the result is that the fundamental wave signal is partially cancelled and still has more remaining, and the harmonic wave signal is partially cancelled, and due to the nonlinear scattering and strong scattering properties of the contrast microbubbles, the harmonic wave signal generated has a greater intensity than the harmonic wave signal generated by the tissue, so the echo signal of the contrast microbubbles includes the remaining fundamental wave signal with very high intensity and the remaining harmonic wave signal with slightly high intensity after subtraction.

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

[0094] The superposition and cancellation process of the embodiment of the present application is performed in the receiving channel, that is, the second echo signal, the third echo signal and the fourth echo signal of each receiving channel are superposed and cancelled. Specifically, if a minimum processing region of receiving and reflecting an ultrasonic wave in a target tissue is referred to as a position point in the tissue, different reflections will be generated after the ultrasonic wave reaches each position point in the target tissue, the reflected echo signals are received by the receiving elements, and each receiving element can receive echo signals of multiple position points, the echo signals of different position points received by each receiving element form different channel signals, and the receiving channel corresponds to the receiving element receiving the ultrasonic wave one by one. After the signals corresponding to the same receiving channel in the second echo signal, the third echo signal and the fourth echo signal are superposed and cancelled, the contrast microbubble echo signals corresponding to 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. The beamforming includes corresponding delay and weighted summation processing of the contrast microbubble echo signals corresponding to different receiving channels. Since the distances from the same position point in the tissue to different receiving elements are different, the channel data of the same position point output by different receiving elements have a delay difference, and the delay processing is to phase align the signals of different receiving channels. Then, the data of different receiving channels of the same position point are weighted and summed to obtain the contrast image data after beamforming. After envelope detection, logarithmic compression and other processing of the contrast image data, the contrast image can be obtained.

[0096] Reference Figure 4 The existing contrast imaging scheme is shown. The existing contrast imaging scheme performs one full-aperture transmission and two half-aperture transmissions, respectively performs beamforming on the echo signals obtained by the three transmissions, then performs superposition and cancellation on the beamformed data, extracts the nonlinear components to perform contrast imaging, and at the same time, performs tissue imaging on the echo signals obtained by the full-aperture transmission. The existing contrast imaging scheme needs to perform three times of beamforming when performing one contrast imaging, while the embodiment of the present application only needs to perform two times of beamforming. Since the imaging frame rate of the non-focused wave contrast imaging is mainly limited by the operation speed of the chip, the operation amount of the embodiment of the present application is reduced by 1 / 3, and the imaging frame rate in the contrast imaging mode is effectively improved.

[0097] In one embodiment, as shown in Figure 5 , one half of the elements in the transmitting aperture and the other half of the elements respectively include a plurality of element groups, each element group includes at least one element; the plurality of element groups of one half of the elements and the plurality of element groups of the other half of the elements are alternately arranged, so that the ultrasonic wave uniformly covers the target tissue.

[0098] According to the number of transmitting apertures, the embodiment of the present application can adopt any one of the two transmitting strategies as shown in Figure 6 and Figure 7 .

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

[0100] Specifically, spatial compounding mainly includes spatial alignment of the contrast image data or the tissue image data obtained at different transmission angles, and compounding of the spatially aligned data. Spatial compounding can reduce speckle noise, make the variance of speckles smaller, and increase the visibility of scatterer edges or tissue boundaries, thereby improving image quality. The speckle noise is a speckle produced by the coherent superposition of scattered echoes of uniform tissue. The speckle is not noise in nature, but because the uniform tissue should be a smooth image in an ideal case, the speckles become noise affecting the image quality. If the relative position of the ultrasonic probe and the tissue is fixed, the position of the speckles is fixed, but if the relative position of the ultrasonic probe and the tissue is changed, the position of the speckle image will also change. The spatial compounding technology is based on the above principle. The relative position of the ultrasonic probe and the tissue remains unchanged, but the direction of the sound beam scanning is changed, which is equivalent to the position of the ultrasonic probe and the tissue being changed, thereby obtaining completely different speckle images. After spatial alignment, the speckle noise at different angles does not correspond 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 effect for strong reflection interfaces at different tilt angles. When ultrasonic waves are incident on a strong reflection interface in the tissue, a strong reflection effect is produced, so that the ultrasonic echo signal can only return to the ultrasonic probe when the incident direction is perpendicular to the reflection interface. Scanning at different deflection angles can detect interfaces in different directions; when the tissue interface is a curved surface, different parts of the curved surface are imaged at different deflection angles, so that the continuity of the curved surface can be improved after spatial compounding.

[0102] For example, embodiments of the present invention further improve the imaging frame rate by increasing the deflection angle step size. In one embodiment of the present invention, the angle difference between any two adjacent transmission angles is greater than or equal to 1.5° and less than or equal to 2°, and the angle range of multiple transmission angles is greater than or equal to -15° and less than or equal to +15°. Taking an imaging depth of 17cm as an example, traditional imaging schemes typically deflect transmissions 75 times, with the angle range of multiple transmission angles greater than or equal to -15° and less than or equal to +15°, and the deflection angle step size θ is 0.405° each time, resulting in an imaging frame rate of 10 frames per second. Embodiments of the present invention maintain the original angle range unchanged and increase the angle difference between any two adjacent transmission 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, thereby increasing the theoretical frame rate to over 40 frames per second.

[0103] like Figure 7 As shown, in the second transmission strategy, the ultrasound probe includes multiple transmission apertures, each comprising adjacent array elements within the ultrasound probe. Multiple transmission apertures can slide to transmit ultrasound waves, resulting in better penetration. When performing sliding transmission with multiple apertures, the sliding angle step θ can be increased, or the number of array elements included in each aperture can be increased, thereby reducing the number of transmissions required to form a single frame of imaging image, and thus increasing the frame rate.

[0104] When employing a sliding emission strategy, the superimposed destructive contrast microbubble echo signal and the first echo signal within the receiving channel can be spatially composited, and then beamformed onto the spatially composited signal. Alternatively, beamforming can be performed first, followed by spatial composite of the beamformed contrast image data and tissue image data. Specifically, when spatially composited with the superimposed destructive contrast microbubble echo signal and the first echo signal, multiple emission apertures are controlled to emit first, second, third, and fourth ultrasonic waves, respectively, to obtain the contrast microbubble signal and the first echo signal corresponding to each emission aperture. The contrast microbubble echo signals corresponding to multiple emission apertures under each receiving channel are spatially composited to obtain the composite contrast microbubble echo signal corresponding to each receiving channel. Beamformed onto the composite contrast microbubble echo signals corresponding to multiple receiving channels to obtain contrast image data. The first echo signals corresponding to multiple emission apertures under each receiving channel are spatially composited to obtain the composite first echo signal corresponding to each receiving channel. Beamformed onto the composite first echo signals corresponding to multiple receiving channels to obtain tissue image data. Spatial recombination of the superimposed destructive contrast microbubble echo signal and the first echo signal in the receiving channel can reduce the number of spatial recombination operations and reduce the computational load.

[0105] When spatially combining the beam-synthesized contrast imaging data and tissue image data, multiple emission apertures are controlled to emit first, second, third, and fourth ultrasonic waves, respectively, performing the superposition-destruction and beam combining processes described above to obtain contrast imaging data and tissue image data corresponding to each emission aperture. Subsequently, spatial combining is performed on the contrast imaging data corresponding to multiple emission apertures to obtain a contrast imaging image, and spatial combining is performed on the tissue image data corresponding to multiple emission apertures to obtain a tissue image. The method and principle of spatial combining contrast imaging data and tissue image data can be found in the relevant description above.

[0106] like Figure 8 As shown, in one embodiment, the number of array elements included in each emission aperture can be determined according to a preset number of spatial recombination times and a preset number of emission apertures, wherein the array elements included in each two adjacent emission apertures partially overlap. Figure 8 The preset spatial recombination frequency is twice, meaning each receiving channel needs to obtain two sets of echo signals; the preset number of transmitting apertures is seven. The second transmitting aperture partially overlaps with the first transmitting aperture, and these elements can obtain two sets of echo signals. However, another portion of the elements in the second transmitting aperture do not overlap with the first transmitting aperture; therefore, this portion needs to overlap with the third transmitting aperture to ensure that each element in the second transmitting aperture can obtain two sets of echo signals, and so on.

[0107] In one embodiment, the number of emission apertures is no more than 75, specifically 7 or 17. Limiting the number of emission apertures limits the number of emission times, thereby reducing the number of emission times required to form a single frame of contrast imaging or a single frame of tissue image, and increasing the frame rate of contrast imaging.

[0108] In summary, the ultrasound contrast imaging method 200 of this embodiment performs two full-aperture transmissions and two half-aperture transmissions. The echo signals obtained from one full-aperture transmission and the echo signals obtained from the two half-aperture transmissions are first superimposed and canceled, and then beamformed, thereby reducing the number of beamformation operations and improving the imaging frame rate of contrast imaging.

[0109] This invention also provides an ultrasound imaging system for implementing the aforementioned ultrasound contrast imaging method 200. Now, referring back to... Figure 1 This ultrasound imaging system can achieve the following: Figure 1The illustrated ultrasound imaging system 100 can include an ultrasound probe 110, a transmit circuit 112, a receive circuit 114, a processor 116, and a display 118. Optionally, the ultrasound imaging system 100 can further include a transmit / receive selection switch 120 and a beamforming module 122. The transmit circuit 112 and the receive circuit 114 can be connected to the ultrasound probe 110 through the transmit / receive selection switch 120. The related descriptions of the components can refer to the related descriptions above, and will not be repeated here.

[0110] The transmit circuit 112 is configured to excite the ultrasound probe 110 to transmit ultrasound waves to a target tissue. The receive circuit 114 is configured to control the ultrasound probe 110 to receive echoes of the ultrasound waves to obtain an ultrasound echo signal. The processor 116 is configured to perform the steps of the ultrasound contrast imaging method 200 to obtain a contrast image and a tissue image. The processor 118 is configured 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, refer to the related descriptions of the ultrasound contrast imaging method 200. The ultrasound imaging system of the embodiment of the present application can improve the imaging frame rate of the contrast imaging.

[0112] Although the example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the example embodiments are only exemplary and are not intended to limit the scope of the present application. Those of ordinary skill in the art can make various changes and modifications without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.

[0113] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in connection with the embodiments disclosed herein can be realized by electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on the specific application and design constraints of the technical solution. Those of ordinary skill in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0114] In several embodiments provided by the present application, 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 illustrative. For example, the division of the units is only a logical functional division. In actual implementation, another division manner can be used, for example, a plurality of units or components can be combined or integrated into another device, or some features can be omitted or not executed.

[0115] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been described in detail in order to not obscure the understanding of this description.

[0116] Similarly, it is to be understood that the embodiments of the present application can be readily combined with one another, and the various features of the embodiments of the present application can be interchanged among the embodiments to which the principles of the present application apply. Thus, unless it is specifically otherwise indicated, the description of an embodiment of the present application is intended to apply to all other embodiments of the present application, and the description of the features of an embodiment of the present application is intended to apply to other embodiments of the present application as well.

[0117] Those skilled in the art will appreciate that all features described herein (including all features of the accompanying claims, abstract and drawings) can be taken in combination with any and all other features described herein, and that the ordering of the steps in any method claims is not intended to be limiting (unless otherwise specifically indicated).

[0118] In addition, those skilled in the art will appreciate that, unless otherwise indicated herein, the features described herein can be used in any combination. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0119] Embodiments of the various components of the present application can be implemented in hardware, or as software modules running in one or more processors, or some combination of both. Those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functionality of some of the modules according to embodiments of the present application. The present application can also be implemented as an apparatus program (e.g., computer program and computer program product) for performing part or all of the methods described herein. Such a program implementing the present application can be stored on a computer readable medium, or can have one or more signals. Such signals can be downloaded from an Internet website, or provided on a carrier medium, or in any other form.

[0120] It should be noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present application. While the application has been described with reference to preferred embodiments and illustrative examples, the words which have been used herein are words of description, and thus are used in a descriptive sense and not restrictive. In this detailed description, numerous specific details have been set forth in order to provide a thorough understanding of the application. However, it will be apparent to one skilled in the art that the application can be practiced without the specific details. In other instances, well-known methods have not been described in detail in order not to unnecessarily overshadow an aspect of the present application. Accordingly, the scope of the present application is defined by the appended claims together with their equivalents.

[0121] The specification and drawings should be considered in a descriptive sense only and not limiting on the scope of the present application. Furthermore, the description should not be construed as an exclusion of more than one alternative. Thus, various alternatives are contemplated as being within the scope of the present application. The various aspects of the application are defined by the claims and their equivalents.

Claims

1. An ultrasonic contrast imaging method, characterized by, The method comprises: controlling the ultrasound probe to emit a first ultrasound wave to a target tissue containing contrast agent, and receiving echoes of the first ultrasound wave to obtain first echo signals corresponding to multiple receiving channels before beamforming; controlling all elements in a transmitting aperture of the ultrasound probe to emit a second ultrasound wave to the target tissue containing contrast agent, and receiving echoes of the second ultrasound wave to obtain second echo signals corresponding to the multiple receiving channels before beamforming; controlling half elements in the transmitting aperture of the ultrasound probe to emit a third ultrasound wave to the target tissue containing contrast agent, and receiving echoes of the third ultrasound wave to obtain third echo signals corresponding to the multiple receiving channels before beamforming; controlling the other half elements in the transmitting aperture of the ultrasound probe to emit a fourth ultrasound wave to the target tissue containing contrast agent, and receiving echoes of the fourth ultrasound wave to obtain fourth echo signals corresponding to the multiple receiving channels before beamforming; superimposing and canceling signals corresponding to the same receiving channel in the second echo signals, the third echo signals and the fourth echo signals to obtain contrast microbubble echo signals corresponding to the multiple receiving channels before beamforming; performing beamforming on the contrast microbubble echo signals corresponding to the multiple receiving channels to obtain contrast image data; performing beamforming on the first echo signals corresponding to the multiple receiving channels to obtain tissue image data; obtaining a contrast image according to the contrast image data, and obtaining a tissue image according to the tissue image data.

2. The method of claim 1, wherein, The half elements and the other half elements each comprise multiple element groups, and each element group comprises at least one element; The multiple element groups of the half elements and the multiple element groups of the other half elements are arranged alternately.

3. The method of claim 1, wherein, The transmitting aperture comprises all elements of the ultrasound probe, and the control of the ultrasound probe to emit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave comprises: controlling the ultrasound probe to emit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave respectively under multiple transmitting angles to obtain the contrast image data and the tissue image data corresponding to each transmitting angle; The obtaining of the contrast image according to the contrast image data, and the obtaining of the tissue image according to the tissue image data, comprises: spatially compositing the contrast image data corresponding to the multiple transmitting angles to obtain the contrast image; and spatially compositing the tissue image data corresponding to the multiple transmitting angles to obtain the tissue image.

4. The method of claim 1, wherein, The transmitting aperture comprises all elements of the ultrasound probe, and the control of the ultrasound probe to emit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave comprises: controlling the ultrasound probe to emit the first ultrasound wave, the second ultrasound wave, the third ultrasound wave and the fourth ultrasound wave respectively under multiple transmitting angles to obtain the contrast microbubble signals and the first echo signals corresponding to each transmitting angle; The beamforming of the contrast microbubble echo signals corresponding to the multiple receiving channels obtains contrast image data, and the beamforming includes: The spatial compounding of the contrast microbubble echo signals corresponding to multiple transmitting angles under each receiving channel obtains the compound contrast microbubble echo signals corresponding to each receiving channel, and the beamforming of the compound contrast microbubble echo signals corresponding to the multiple receiving channels obtains the contrast image data; The beamforming of the first echo signals corresponding to the multiple receiving channels obtains tissue image data, and the beamforming includes: The spatial compounding of the first echo signals corresponding to multiple transmitting angles under each receiving channel obtains the compound first echo signals corresponding to each receiving channel, and the beamforming of the compound first echo signals corresponding to the multiple receiving channels obtains the tissue image data.

5. The method of claim 3, wherein, The angle difference between every two adjacent transmitting angles is greater than or equal to 1.5° and less than or equal to 2°, and the angle range of the multiple transmitting angles is greater than or equal to -15° and less than or equal to +15°.

6. The method of claim 1, wherein, The ultrasound probe includes multiple transmitting apertures, each of which includes adjacent partial array elements in the ultrasound probe, and the control of the ultrasound probe to transmit the first, second, third and fourth ultrasonic waves includes: controlling the multiple transmitting apertures to respectively transmit the first, second, third and fourth ultrasonic waves to obtain the contrast image data and the tissue image data corresponding to each transmitting aperture; The obtaining of the contrast image according to the contrast image data and the obtaining of the tissue image according to the tissue image data include: The spatial compounding of the contrast image data corresponding to the multiple transmitting apertures obtains the contrast image; The spatial compounding of the tissue image data corresponding to the multiple transmitting apertures obtains the tissue image.

7. The method of claim 1, wherein, The ultrasound probe includes multiple transmitting apertures, each of which includes adjacent partial array elements in the ultrasound probe, and the control of the ultrasound probe to transmit the first, second, third and fourth ultrasonic waves includes: controlling the multiple transmitting apertures to respectively transmit the first, second, third and fourth ultrasonic waves to obtain the contrast microbubble signals and the first echo signals corresponding to each transmitting aperture; The beamforming of the contrast microbubble echo signals corresponding to the multiple receiving channels obtains contrast image data, and the beamforming includes: The spatial compounding of the contrast microbubble echo signals corresponding to multiple transmitting apertures under each receiving channel obtains the compound contrast microbubble echo signals corresponding to each receiving channel, and the beamforming of the compound contrast microbubble echo signals corresponding to the multiple receiving channels obtains the contrast image data; The beamforming of the first echo signals corresponding to the multiple receiving channels obtains tissue image data, and the beamforming includes: The spatial compounding of the first echo signals corresponding to multiple transmitting apertures under each receiving channel obtains the compound first echo signals corresponding to each receiving channel, and the beamforming of the compound first echo signals corresponding to the multiple receiving channels obtains the tissue image data. The first echo signals corresponding to the plurality of transmitting apertures under each receiving channel are spatially compounded to obtain a compounded first echo signal corresponding to each receiving channel, and the compounded first echo signals corresponding to the plurality of receiving channels are beam synthesized to obtain tissue image data.

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

9. The method of claim 8, wherein, The transmitting aperture number is not greater than 75.

10. The method of claim 1, wherein, The control of the ultrasonic probe to emit the first ultrasonic wave to the target tissue containing the contrast agent and receive the echo of the first ultrasonic wave comprises: The control of the ultrasonic probe to emit the first ultrasonic wave to the target tissue containing the contrast agent and receive the echo of the first ultrasonic wave comprises:

11. The method of claim 1, wherein, 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 non-focused ultrasonic waves.

12. An ultrasound imaging system, characterized by The ultrasonic imaging system comprises: An ultrasonic probe comprising a plurality of array elements; A transmitting circuit for exciting the ultrasonic probe to emit ultrasonic waves to a target tissue containing a contrast agent; A receiving circuit for controlling the ultrasonic probe to receive echo signals of the ultrasonic waves; A processor for generating an ultrasonic image of the target tissue according to the echo signals, the processor further being configured to perform the ultrasonic contrast imaging method according to any one of claims 1-11; A display for displaying the ultrasonic image generated by the processor.

Images