CN108451499B

CN108451499B - Elastography system, method thereof and vibration unit

Info

Publication number: CN108451499B
Application number: CN201710093080.3A
Authority: CN
Inventors: 程刚; 韩晓东; 陈嘉宇
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2017-02-21
Filing date: 2017-02-21
Publication date: 2021-03-16
Anticipated expiration: 2037-02-21
Also published as: CN108451499A

Abstract

The invention discloses an elastography system, which comprises: at least one vibrator unit, wherein each vibrator unit comprises a vibrator for generating shear waves and an attachment unit for attaching the vibrator to a surface. The elastography system further comprises a detector for detecting shear waves. The elastography system also includes a controller for generating an elastography image from an output of the detector. The invention also discloses a method for generating the elastic image, which comprises the following steps: attaching at least one vibrator to a surface; generating shear waves by said at least one vibrator; detecting the shear wave; and generating an elastic image from the detected shear waves.

Description

Elastography system, method thereof and vibration unit

Technical Field

The present invention relates generally to elastography techniques, and in particular to an elastography system and method thereof, and to a vibration unit for an elastography system.

Background

The hardness of the tissue can give diagnostic information on whether the body is suffering from a disease. For example, cancerous tumors are generally harder than the surrounding tissue, while diseased livers are harder than healthy livers. Elasticity, viscosity and viscoelasticity all reflect the hardness properties of soft tissue. Where elastography of shear waves may be used to reflect elasticity, viscosity or viscoelasticity of tissue. Elastic images of the tissue can be generated by measuring the propagation parameters of the shear wave using ultrasound or magnetic resonance imaging.

Shear waves are typically generated by acoustic propulsion methods, or large vibrators and vibrator control systems are used. The penetration of this acoustic push method is very limited due to acoustic power safety regulations and the design of the ultrasound system. The large vibrators are installed on a hospital bed or placed on a portion of the body to be measured, such as the upper part of the thorax, to generate shear waves that penetrate the body, are very heavy and are inefficient to use. There are other designs that add a vibrator around the transducer, but these designs are also heavy and inconvenient to use in a medical environment.

Conventionally, there are two methods for generating shear waves. One approach is to apply a pulsed thrust to the tissue, thereby generating the same fundamental frequency and several harmonic frequencies as the pulse frequency. Another approach is to generate shear waves of different frequencies at different times. The first method can obtain less frequency components although the scanning time is short. The second method, while capable of providing many different shear wave frequency components, takes a relatively long time.

Disclosure of Invention

In one embodiment, the present application provides a vibrator unit for an elastography system, characterized by comprising a vibrator for generating shear waves; and an attachment unit for fixing the vibrator on a surface.

In another embodiment, the present application provides an elastography system, comprising at least one vibrator unit, wherein each vibrator unit comprises a vibrator for generating shear waves, and an attachment unit for securing the vibrator to a surface, a detector for detecting the shear waves; and a controller for generating an elastic image from the output of the detector.

In another embodiment, the present application provides a method of generating an elastic image comprising attaching at least one vibrator to a surface; generating shear waves by said at least one vibrator; detecting the shear wave; and generating an elastic image from the detected shear waves.

Drawings

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic diagram of a vibration unit for an elastography system, according to one embodiment of the present invention;

FIG. 2 is a schematic view of a vibration unit for an elastography system according to another embodiment of the invention;

FIG. 3 is a schematic view of an elastography system according to one embodiment of the present invention;

FIG. 4 is a schematic view of a portion of the elastography system according to one embodiment of the invention shown in FIG. 3;

FIG. 5 is a schematic diagram of an application of a vibration unit of an elastography system according to an embodiment of the invention;

FIG. 6 is a schematic diagram of another application of a vibration unit of an elastography system according to an embodiment of the invention;

FIG. 7 is a schematic diagram of a controller for generating a viscoelastic image in an elastography system, according to an embodiment of the invention; and

FIG. 8 is a flow diagram of a method of elastography according to one embodiment of the present invention.

Detailed Description

To assist those skilled in the art in understanding the claimed subject matter, a detailed description of the invention is provided below along with accompanying figures. In the following detailed description of the embodiments, well-known functions or constructions are not described in detail in order to avoid unnecessarily obscuring the present disclosure.

Unless otherwise defined, technical or scientific terms used in the claims and the specification should have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. As used in this specification and the appended claims, the terms "first," "second," and the like do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms "a" or "an," and the like, do not denote a limitation of quantity, but rather denote the presence of at least one. Unless otherwise indicated, the terms "front," "back," "lower," and/or "upper" and the like are used for convenience of description and are not limited to one position or one spatial orientation. The word "or" and the like are meant to be inclusive and mean one or all of the listed items. The word "comprising" or "having", and the like, means that the element or item appearing before "comprises" or "having" covers the element or item listed after "comprising" or "having" and its equivalent, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections or couplings, whether direct or indirect.

Embodiments of the invention may be described herein in terms of functional components and various processing steps. It should be appreciated that these functional components may be configured by any number of hardware, software, and/or firmware components to achieve the specified functionality. For example, embodiments of the invention may employ various integrated circuit components, e.g., memory elements, digital signal processing elements, logic elements, look-up tables, or the like, which may carry out a variety of functions by a controller under the control of one or more microprocessors or other control devices. In addition, embodiments of the present invention may be combined with any number of data transmission protocols in reality. Moreover, the system described herein illustrates only one exemplary embodiment.

Referring to fig. 1, the present application discloses a vibration unit 10 for an elastography system. The vibrator unit 10 comprises a vibrator 11 capable of generating shear waves, and an attachment unit 19 or attachment unit connecting, attaching or attaching said vibrator 11 to a surface of an object, such as the skin of a patient.

In one embodiment, as shown in fig. 1, the attachment unit 19 includes an elastic cover 12 capable of generating a negative pressure around the vibrator 11. The vibrator 11 is installed in the elastic cap 12 so that the vibrator 11 can be attached to the skin of the patient by the negative pressure generated inside the elastic cap 12. In one embodiment, the elastomeric cover 12 is a rubber bladder.

In one example, the elastomeric cover 12 includes a rubber head 121 having a cavity therein at an upper portion and a cup 122 at a lower portion. The vibrator 11 is connected to the inside of the cup 122. Air in the elastic cover 12 can flow between the cup 122 and the rubber head 121. In one embodiment, cup 122 is also made of a rubber material. In this example, therefore, the rubber head 121 and the cup 122 are integrally formed. In some other embodiments, however, the cup 122 is made of a rigid material, such as glass. In this example, the cup 122 is connected to the rubber head 121 in an airtight manner. For example, the bottom edge of rubber head 121 closely wraps over the upper outer edge of cup 122. When the air in the rubber head 121 is pushed out, the negative pressure inside the cup 122 forms a suction force, thereby attaching the vibrator 11 to the skin of the patient.

In another embodiment of the vibrator unit 18 as shown in fig. 2, the attachment unit 19 comprises an attachment layer 13 connected to the vibrator 11. As shown in fig. 2, in one example, the attachment layer 13 covers the top of the vibrator 11, attaching the vibrator 11 to the skin of the patient. In another example, an attachment layer 13 is provided at the bottom of the vibrator 11 to attach the vibrator 11 to the skin of the patient. In some examples, the adhesive layer 13 comprises a double-sided adhesive tape.

As shown in fig. 1 and 2, the vibrator unit 10 includes a control unit 14 capable of controlling the vibrator 11 to vibrate at a predetermined frequency, phase and amplitude. The vibrator unit 10 includes a wireless communication unit 17 connected to the control unit 14 so as to communicate with the control unit 14. The vibrator unit 10 includes a power supply unit 15 and a power converter 16 to supply power to the vibrator 11, the control unit 14, and the wireless communication unit 17. The power supply unit 15 may be a battery.

The vibrator 11 is a motor or trigger that generates shear waves in the patient's tissue by mechanical motion. In a particular example, the vibrator 11 comprises a coin vibrator motor or a coil motor. The control unit 14 is used to control the movement of the motor or trigger by varying one or more of frequency, phase and amplitude. The wireless communication unit 17 wirelessly connects the control unit 14 to a console unit (see fig. 3) of an elastography system 20, such as an ultrasound system. The control unit 14 is configured to control the vibrator 11 in real time by means of a control signal. The vibrator 11 is directly attached to the patient's skin. Alternatively, the vibrator 11 may be indirectly connected/attached to the patient's skin by a coupling material 24 (see fig. 3), such as a coupling fluid.

The vibrator unit 10 is small and can be attached to any location on the skin of a patient to generate frequency controlled shear waves that can propagate in the target tissue. Shear waves are detected by an ultrasound system and elastic images are generated. One or more of the vibration units 10 may be connected and/or synchronized with the ultrasound system via wireless technology, such as WIFI, bluetooth, and the like.

Referring to FIG. 3, one embodiment of an elastography system 20 is shown. The elastography system 20 comprises at least one vibration unit 10, wherein each vibration unit 10 comprises a vibrator 11 for generating shear waves; an attachment unit 19, which may connect, attach or attach said vibrator 11 to a surface of an object, such as the skin of a patient; a detector 21 for detecting shear waves; and a controller 22 for generating an elastic image from the output of the detector 21.

In one embodiment, the elastography system 20 is an ultrasound system. Therefore, the detector 21 is an ultrasonic detector for detecting the shear wave generated in the tissue by the vibration unit 10. The elastography system 20 comprises a console unit 25 comprising a detector driver 26 for driving the movement of the detector 21. The console unit 25 includes a wireless unit 27 that is connected in wireless communication with the wireless communication unit 17 of the vibrator unit 10 to transmit a control signal to the control unit 14 of the vibrator unit 10. When the wireless communication unit 17 is not present in the vibrator unit 10, the console unit 25 includes a vibrator driver for driving the movement of the vibrator through the cable. In one embodiment, the console unit 25 comprises a controller 22 for calculating viscoelasticity at a target anatomical region, such as a breast, and reconstructing viscoelasticity parameters at the breast from the detected shear wave curves, and finally generating an elasticity image 30. In addition, the elastography system 20 further comprises a probe guide 23 for mounting and guiding the movement of the probe 21.

Turning to fig. 4, one embodiment 29 of the probe guide 23 of fig. 3 is shown. As previously described, the probe guide 23 is used to mount and guide the movement of the probe 21. The probe guide 23 includes a frame 231 and a guide rail 232 provided thereon for mounting the probe 21. The frame 231 and the rail 232 enable the detector 21 to make linear or rotational movements around a target area, such as a breast, along the rail 232, thereby obtaining ultrasound images at different viewing planes. In this embodiment, the probe guide 23 includes a rectangular frame 231 and a linear guide 232 installed in the middle of the rectangular frame 231 so that the ultrasonic probe 21 can move from one end to the other end within the rectangular frame 231 along the linear guide 232. One or more seismic units 10 are disposed around the detector 21 or the guide rail 232. The vibrating unit 10 may also move with the detector 21 during scanning. The placement of the vibratory unit 10 at different locations can increase the distribution of shear waves at the breast.

FIG. 5 is a schematic diagram of an application 32 of one embodiment of the vibration unit 10 of the elastography system 20. In the embodiment of fig. 5, at least two vibrating units 10 are used to generate shear waves of the same frequency and with different other parameters. In one example, the different parameters include at least one of phase and amplitude. In the embodiment of fig. 5, there are two vibration units 10, but more may be used.

Turning now to FIG. 6, a schematic illustration of an application 34 of another embodiment of the vibration unit 10 of the elastography system 20 is shown. In the embodiment of fig. 6, at least two vibratory units 10 are used to generate shear waves of different frequencies. When the vibration unit 10 generates shear waves of different frequencies, elasticity, viscosity and viscoelasticity of the shear waves of the tissue can be obtained. Viscoelasticity measurement is a method of measuring the velocity of shear waves at different frequencies.

Some of the disadvantages of the prior art are solved by providing at least two vibratory units 10, which vibratory units 10 are set to different frequencies. And the two vibrating units 10 are configured to simultaneously generate components of different frequencies, which enables the detector 21 to scan different frequency components in a short time. Shear waves of different frequencies have different penetration forces and therefore the amplitude of the vibrator differs for different frequencies.

The shear wave measurement is related to the detector motion state, so controlling the detector motion is very important for both the shear wave detection and the viscoelastic reconstruction process. There are two typical types of detector motion states. One is to stop and then scan the shear wave, and the other is to scan the shear wave in a state of uniform motion speed. The first method can accurately detect shear waves on a known scan plane, but requires a longer scan time. The second method has a short scanning time, but the detection of shear waves is affected by the motion state of the detector.

Referring to fig. 7, a schematic diagram of one embodiment of a controller for generating a viscoelastic image as shown in fig. 3 is shown. The controller 36 includes an acoustic data collector 221 for collecting acoustic data from the probe 21, and a shear wave calculator 222 for calculating a displacement of shear waves with time from the acoustic data. Further, the controller 36 includes at least one bandwidth filter 223, labeled 223-2 … 223-N for different frequencies, respectively, to obtain the phase and amplitude of the shear wave at the different frequencies. Furthermore, the controller 36 comprises at least one elasticity calculator 224 for reconstructing the elasticity of the shear wave from the phase and amplitude of the shear wave at different frequencies. Further, the controller 36 comprises a viscosity calculator 225 for calculating the viscosity of the shear wave from the elasticity of the shear wave at different frequencies. Controller 36 may determine values for elasticity, viscosity, and viscoelasticity, and generate an elastic image of the tissue from these values.

Furthermore, a method for producing an elastic image is shown according to fig. 8. The method is described by the composition of fig. 1-7.

The method 38 comprises the steps of: at least one vibration unit 10 is attached or affixed to a surface of an object, such as a patient's skin, step 110. And the method 38 comprises a step 120 of generating shear waves by means of said at least one seismic unit 10. In addition, the method 38 includes a step 130 of detecting the shear waves. In addition, method 38 includes step 140, generating an elastic image based on the detected shear waves.

Attaching at least one vibration unit 10 to the surface of the object includes generating a negative pressure around the vibration unit 10. This can be achieved by providing an elastic cover 12 capable of generating a negative pressure inside, and the vibrator 11 is installed inside the elastic cover 12. Thus, the vibrator 11 can be attached to the skin due to the negative pressure generated by the elastic cover 12.

In step 120 of one embodiment, shear waves of different frequencies may be generated by at least two vibratory units 10 (see FIG. 5). In another embodiment, shear waves of the same frequency but different phases are generated by at least two vibratory units 10 (see FIG. 6).

In one embodiment, step 140 of generating an elasticity image includes collecting acoustic data from probe 21, calculating the displacement of the shear wave over time, filtering the acoustic data through at least one bandwidth filter 223 to obtain the amplitude of the shear wave at different frequencies, reconstructing the elasticity of the shear wave at different frequencies, and calculating the viscosity of the shear wave through the elasticity of the shear wave at different frequencies. Elasticity, viscosity, and viscoelasticity can thereby be obtained, yielding an elastic image.

The above-described proposed system and method have the following technical and commercial advantages. Shear waves with a high signal-to-noise ratio can be generated in tissue using these systems, allowing the ultrasound system to measure mechanical properties of the tissue. By using the vibrating unit as a low cost add-on, more elastic image applications can be achieved without changing the ultrasound system. Also, the multi-vibrator system is capable of generating multi-frequency and multi-directional shear waves, thereby generating high quality elastic and viscous signals in the tissue. In addition, the shock unit may be discarded after use.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that many modifications and variations can be made therein. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit and scope of the invention.

Claims

1. A vibration unit for an elastography system, comprising:

a vibrator for generating shear waves; and

an attachment unit for fixing the vibrator on a surface; the attachment unit includes an elastic cover for generating negative pressure around the vibrator;

further comprising:

the control unit is used for controlling the vibrator;

a wireless communication unit for communicating with the control unit; and

the power supply unit and the power converter are used for providing energy for the vibrator.

2. An elastography system, comprising:

at least one vibration unit, wherein each vibration unit includes:

a vibrator for generating shear waves, and

an attachment unit for fixing the vibrator on a surface; the attachment unit includes an elastic cover for generating a negative pressure around the vibrator inside, wherein the vibrator is installed inside the elastic cover; the control unit is used for controlling the vibrator; a wireless communication unit for communicating with the control unit; and a power supply unit and a power converter for supplying energy to the vibrator;

a detector for detecting the shear wave; and

a controller for generating an elasticity image from an output of the detector.

3. The system of claim 2, wherein: the at least one vibratory unit generates shear waves of different frequencies.

4. The system of claim 2, wherein: the at least one vibratory unit generates shear waves of the same frequency and different parameters, wherein the parameters include at least one of phase and amplitude.

5. The system of claim 4, wherein the controller comprises:

an acoustic data collector for collecting acoustic data from the probe;

a shear wave calculator for calculating a time-varying displacement of the shear wave from acoustic data;

at least one bandwidth filter to obtain the phase and amplitude of the shear waves at different frequencies;

at least one elasticity calculator for reconstructing elasticity of shear waves of different frequencies; and

a viscosity calculator for calculating the viscosity of the shear wave from the elasticity of the shear wave at different frequencies.

6. A method of generating an elastic image using the system of any of claims 2-5, comprising:

attaching at least one vibrator to a surface;

generating shear waves by said at least one vibrator;

detecting the shear wave; and

generating an elastic image from the detected shear waves.

7. The method of claim 6, wherein: attaching at least one vibrator to a surface includes generating a negative pressure around the vibrator.

8. The method of claim 6, wherein: generating shear waves by the at least one vibrator includes generating shear waves of different frequencies by the at least one vibrator.

9. The method of claim 6, wherein: generating shear waves by the at least one vibrator comprises generating shear waves of the same frequency and different parameters by the at least one vibrator, wherein the parameters comprise at least one of phase and amplitude.

10. The method of claim 8, wherein:

collecting acoustic data by a detector, wherein the detector is configured to detect the shear waves,

calculating the displacement of the shear wave over time,

filtering the acoustic data through at least one bandwidth filter to obtain phases and amplitudes of shear waves of different frequencies,

reconstructing elasticity of shear waves of different frequencies, and

the viscosity of the shear waves is calculated from the elasticity of the shear waves at different frequencies.