KR102106542B1 - Method and apparatus for analyzing elastography of tissue using ultrasound - Google Patents

Abstract

The method and apparatus for analyzing elasticity of tissue using ultrasound use the ultrasound probe to irradiate ultrasound for diagnosis on a region of interest in which a shear wave is induced, receive echo echo ultrasound, and obtain ultrasound images of the region of interest to obtain tissue of the region of interest. Analyze the elasticity information.

Description

Method and apparatus for analyzing elasticity of tissue using ultrasound

It relates to a method and apparatus for analyzing the elasticity of tissue inside the body using ultrasound.

When a medical institution wants to diagnose a disease, establish a treatment plan, or evaluate treatment progress using ultrasound images, doctors read ultrasound images of patients displayed on a monitor and observe changes in the condition or aging of tumors or cancer tissues, etc. do. However, since the ultrasound image must be manually read by the doctor, even if the same ultrasound image is given, different meanings are given according to the doctor's view, and thus there is a problem that the limit of measurement error is large. In addition, there are many cases in which a doctor's mistake does not recognize abnormal tissue such as tumor or cancer tissue present in the ultrasound image.

However, in recent years, computer-assisted diagnostic systems (CAD, Computer Aided Diagnosis), such as ultrasound images, MRI images, CT images, etc., primarily identify medical images and provide the presence and location of abnormal tissues to doctors, are developed. Is becoming. A computer-assisted diagnosis system is a system that assists a doctor in diagnosis by detecting abnormal tissues by processing the presence or absence of abnormal tissues in a medical image, the size of abnormal tissues, and the location of abnormal tissues and providing detection results to a doctor. It can be used in combination with medical devices such as ultrasound devices, MRI devices, and CT devices.

It is to provide a method and apparatus for analyzing the elasticity of tissue inside the body using ultrasound. In addition, it is to provide a computer-readable recording medium recording a program for executing the method on a computer. The technical problem to be solved by the present embodiment is not limited to the technical problems as described above, and other technical problems may exist.

According to an aspect, a method for analyzing elasticity of tissue using ultrasound includes irradiating ultrasound for diagnosis toward a region of interest in a body where a shear wave is induced using an ultrasound probe having a two-dimensional transducer array; Obtaining 3D ultrasound images of the region of interest using echo ultrasound of the diagnostic ultrasound received by the ultrasound probe; Measuring displacement of the shear wave in the region of interest from the obtained 3D ultrasound images; And analyzing elasticity information of the tissue of the region of interest using the measured displacement of the shear wave.

According to another aspect, there is provided a computer-readable recording medium recording a program for executing an elasticity analysis method of tissue using ultrasound on a computer.

According to another aspect, the apparatus for analyzing elasticity of tissue using ultrasound includes an ultrasound probe that irradiates ultrasound for diagnosis toward a region of interest in a body where a shear wave is induced using a two-dimensional transducer array; An ultrasound image processing unit that acquires 3D ultrasound images of the region of interest using echo ultrasound of the diagnostic ultrasound received from the ultrasound probe; A displacement measurement unit measuring displacement of the shear wave in the region of interest from the obtained 3D ultrasound images; And an elasticity analysis unit that analyzes elasticity information of the tissue of the region of interest using the measured displacement of the shear wave.

According to the above, since 3D ultrasound images of a region of interest (ROI) can be obtained at high speed, it is possible to more accurately measure the displacement of shear waves induced in tissues inside the body. In addition, since the displacement of the shear wave can be measured in three dimensions using 3D ultrasound images, it is possible to more accurately calculate and provide a shear modulus of tissue inside the body. Furthermore, the analyzed elastic information may be used to assist a doctor's decision regarding diagnosis or treatment of a patient's disease.

1 is a configuration diagram of an elastic analysis device 1 for tissue using ultrasound according to an embodiment of the present invention.
2A is a diagram illustrating a shear wave according to an embodiment of the present invention.
2B is a diagram illustrating that shear waves are induced in the region of interest 30 according to an embodiment of the present invention.
3A is a diagram illustrating a case in which ultrasound for diagnosis is irradiated by a 3D volume acquisition method according to an embodiment of the present invention.
FIG. 3B is a diagram illustrating a case where a diagnostic ultrasound is irradiated by a 3D plane scan method according to an embodiment of the present invention.
FIG. 4A is a diagram showing a simulation result obtained by analyzing a modulus of elasticity after acquiring a 2D ultrasound image using an existing ultrasound probe having a 1D transducer array.
FIG. 4B is a diagram illustrating a result of simulating a case where an elastic modulus is analyzed after obtaining a 3D ultrasound image using an ultrasound probe having a 2D transducer array according to an embodiment of the present invention.
5 is a flowchart of a method for analyzing elasticity of tissue using ultrasound according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a configuration diagram of an elastic analysis device 1 for tissue using ultrasound according to an embodiment of the present invention. Referring to FIG. 1, a device 1 for analyzing elasticity of tissue using ultrasound includes a processor 10 and an ultrasound probe 20. In addition, the processor 10 includes an ultrasound image processing unit 110, a displacement measurement unit 120, and an elastic analysis unit 130.

In FIG. 1, only hardware components related to the present embodiment will be described in order to prevent blurring of features of the present embodiment. However, a person having ordinary knowledge in the art that the apparatus 1 for elasticity analysis of tissue using ultrasound according to the present embodiment may include other general-purpose hardware components in addition to the hardware components shown in FIG. 1. Ramen can understand.

Recently, medical images such as ultrasound images, magnetic resonance imaging (MRI) images, and computed tomography (CT) images, such as computer aided diagnosis (CAD) systems, are primarily discriminated to determine the presence and location of abnormal tissue. System is being used. Using such a system, the presence or absence of abnormal tissue in a medical image such as an ultrasound image, the size of the abnormal tissue, the location of the abnormal tissue, etc. are processed by a computer to detect abnormal tissue and provide detection results to a doctor to diagnose a doctor's image Can assist.

The elasticity analysis apparatus 1 for tissue using ultrasound according to the present embodiment is a device that can be used in such a system. Elastic ultrasound (Ultrasound Elastography) technology analyzes the elasticity of tissues and distinguishes the difference between stiffness between normal and abnormal tissues and diagnoses them. In particular, the apparatus 1 for analyzing elasticity of tissue using ultrasound according to the present embodiment analyzes elasticity of tissue using ultrasound, thereby using whether there is abnormal tissue such as cancer or tumor or high intensity focused ultrasound (HIFU). Therefore, when treating tissue, it may be used to determine the state of tissue inside the body, such as whether the treatment is completed.

In general, it is known that abnormal tissues have a difference in stiffness from normal tissues, and by analyzing these differences, abnormal tissues can be discriminated. Therefore, abnormal tissues such as cancer and tumor may have higher elasticity than normal tissues. Due to this, since abnormal tissues such as cancer and tumor have higher elasticity than the surrounding normal tissues, the shear modulus is high. In addition, even when the tissue is treated by necrosis using a therapeutic ultrasound such as HIFU, elasticity is high as the tissue progresses. That is, a change in tissue state can be represented by a change in tissue elasticity. Therefore, if the elasticity of the tissue can be grasped using ultrasound, the condition of the tissue can be monitored non-invasively even if the doctor does not directly see the tissue inside the body.

The apparatus for analyzing elasticity of tissue using ultrasound 1 is a system capable of assisting a doctor in diagnosis of an image in a medical institution, and provides diagnosis results of tissue elasticity using ultrasound images to diagnose a disease, establish a treatment plan, or It can be used to perform treatment progress evaluation, etc. Hereinafter, the configuration and operation of the elastic analysis apparatus 1 for tissue using ultrasound according to the present embodiment will be described in more detail.

Before analyzing the elasticity, the ultrasound probe 20 irradiates diagnostic ultrasound to the region of interest 30 inside the skin of the body to induce a shear wave. In order to quantitatively analyze the elasticity using diagnostic ultrasound, it is necessary to apply an acoustic radiation force impulse (ARFI), such as diagnostic ultrasound, to the inside of the body to cause tissue displacement. As described above, shear waves are induced to the tissues by ARFI, thereby causing displacement of the tissues.

2A is a diagram illustrating a shear wave according to an embodiment of the present invention. Referring to FIG. 2, when the force of the point impulse is applied in the Z-axis direction, a p wave as a longitudinal wave, a s wave as a transverse wave, and a ps wave coupling two waves are generated. Here, the shear wave is a wave that vibrates in a wave propagation direction from a force-applied vibration source and propagates in the Y-axis direction, which means s wave.

As the force (force) of the point impulse for inducing the shear wave, in this embodiment, for convenience of description, it will be described as using diagnostic ultrasound of the ultrasonic probe 20. However, the induction of the shear wave is not limited thereto, and a therapeutic ultrasound device or a vibrator such as a HIFU device provided outside the elastic analysis device 1 may also be used. That is, a person skilled in the art can understand that the means for inducing the shear wave in the region of interest 30 may be various without being limited to any one.

2B is a diagram illustrating that shear waves are induced in the region of interest 30 according to an embodiment of the present invention. Referring to FIG. 2B, the ultrasonic probe 20 or the like induces a shear wave in the region of interest 30 by irradiating diagnostic ultrasound or the like in a depth-axis so that focus is formed on the region of interest 30 in the skin of the body do.

Referring back to FIG. 1, after the shear wave is induced in the region of interest 30, the ultrasound probe 20 is directed toward the region of interest 30 to obtain an ultrasound image around the region of interest 30 and the region of interest 30. Examine the diagnostic ultrasound.

The ultrasound probe 20 may irradiate a plane wave by beamforming ultrasound for diagnosis in a defocusing method. The reason for using the defocusing plane wave is that shear waves can be observed in a wider range.

In more detail, the ultrasound probe 20 can observe the displacement of the shear wave in a wider range than the ultrasound for focusing using the defocusing method. In addition, by using a plane wave whose intensity remains relatively constant even when it reaches deep in the body, it is possible to accurately observe the displacement of the shear wave rather than a spherical wave whose intensity decreases as it reaches deep in the body.

In particular, the ultrasonic probe 20 according to the present embodiment may include a two-dimensional transducer array. The reason why the ultrasonic probe 20 has a two-dimensional transducer array is to acquire three-dimensional ultrasound images at high speed. This will be described with reference to FIGS. 3A and 3B.

3A is a diagram illustrating a case in which ultrasound for diagnosis is irradiated by a 3D volume acquisition method according to an embodiment of the present invention. Referring to FIG. 3A, the ultrasound probe 20 irradiates ultrasound for diagnosis so that a 3D volume around the region of interest 30 and the region of interest 30 can be scanned at one time using an array of 2D transducers. can do.

FIG. 3B is a diagram illustrating a case where a diagnostic ultrasound is irradiated by a 3D plane scan method according to an embodiment of the present invention. Referring to FIG. 3B, the ultrasound probe 20 scans the region of interest 30 and the region of interest 30 in a plane unit using a two-dimensional transducer array, and then the 3D volume of the region of interest 30 Diagnostic ultrasound can be irradiated so that data can be generated.

Referring back to FIG. 1, the ultrasound probe 20 receives echo ultrasound of diagnostic ultrasound waves reflected from the region of interest 30 and the region of interest 30. As described above, the ultrasonic probe 20 according to the present embodiment uses the 2D transducer array to perform diagnostic ultrasound using a 3D volume acquisition method or a 3D plane scan method. Upon irradiation, the ultrasound probe 20 may receive echo ultrasound including 3D information around the region of interest 30 and the region of interest 30.

Usually, the wave speed of the shear wave in the human body is known to be about 1-10 m / s. Therefore, in order to observe this at a resolution of several millimeters, ultrasound images must be acquired in thousands of frames per second. In order to acquire ultrasound images of thousands of frames per second, it is necessary to irradiate and receive diagnostic ultrasound at a rate faster than the moving speed of the shear wave. At this time, since it is impossible to acquire thousands of frames per second of ultrasound images using a conventional 3D line scan method, it may be difficult to accurately measure shear wave movement. Therefore, if the method shown in FIG. 3A or 3B is used, a three-dimensional ultrasound image of thousands of frames per second can be obtained with a two-dimensional transducer array, so that the movement of the shear wave can be accurately measured.

The ultrasound image processing unit 110 processes echo echo received from the ultrasound probe 20 to acquire three-dimensional ultrasound images of thousands of frames per second. In other words, the ultrasound image processing unit 110 obtains thousands of frames of 3D ultrasound images by beamforming and processing the echo ultrasound received from the ultrasound probe 20 to the region of interest 30. Since the general process of processing ultrasound images using echo ultrasound is obvious to those skilled in the art, detailed descriptions thereof will be omitted.

The displacement measurement unit 120 measures the displacement of the shear wave in the region of interest 30 from the obtained 3D ultrasound images. Earlier, since 3D ultrasound images were obtained from the ultrasound image processing unit 110, the displacement of the shear wave measured by the displacement measurement unit 120 corresponds to a measurement of the 3D movement of the shear wave. That is, the measured displacement of the shear wave has displacement components corresponding to the x-axis, y-axis, and z-axis of an arbitrary three-dimensional coordinate space.

Since the general process of measuring the displacement of the shear wave by analyzing the movement of the shear wave displayed on the 3D ultrasound images of thousands of frames is obvious to those skilled in the art, detailed description thereof will be omitted.

The elastic analysis unit 130 analyzes the elastic information of the tissue of the region of interest 30 using the measured displacement of the shear wave. The elastic information analyzed in this embodiment may include a shear modulus.

The elasticity analysis unit 130 uses the displacement components corresponding to each of the three-dimensional coordinate axes (x-axis, y-axis, and z-axis) included in the measured displacement of the shear wave, and the elastic modulus of the tissue of the region of interest 30 (shear) modulus). At this time, the elastic analysis unit 130 may calculate the elastic modulus using a wave equation related to the shear wave.

In more detail, the elasticity analysis unit 130 first calculates the moving speed of the shear wave by using displacement components corresponding to each of the three-dimensional coordinate axes included in the measured shear wave displacement.

Referring to Equation 1, u means the displacement of the shear wave, C _s means the moving speed of the shear wave. In this embodiment, the elastic analysis unit 130 will be described as an example of calculating the moving speed of the shear wave using Equation 1, but the present embodiment is not limited thereto.

Next, the elastic analysis unit 130 calculates the elastic modulus of the tissue of the region of interest 30 using the calculated moving speed C _s of the shear wave.

Referring to Equation 2, G means the elastic modulus (shear modulus), ρ means the density of the medium. Previously, the elastic analysis unit 130 calculated the moving speed (C _s ) of the shear wave using Equation 1, and ρ corresponds to a known value, so the elastic analysis unit 130 uses Equation 2 Elastic modulus (G) can be calculated. In this embodiment, the elastic analysis unit 130 will be described as an example of calculating the elastic modulus using Equation 2, but the present embodiment is not limited thereto.

If the elasticity analysis unit 130 analyzes the elasticity modulus in at least two frame units among the 3D ultrasound images, the elasticity analysis unit 130 may calculate the final elasticity modulus by calculating the average of the calculated elasticity coefficients, respectively. have.

Meanwhile, the elasticity analysis unit 130 may calculate the elasticity coefficient G using Equation 3 below.

That is, the elasticity analysis unit 130 may also calculate the elasticity coefficient G using Equation 3 in which Equations 1 and 2 are combined.

As described above, the ultrasound image processing unit 110 obtained three-dimensional ultrasound images of thousands of frames, and the displacement measurement unit 120 measured the displacement of the shear wave having the three-dimensional displacement components, as the elastic analysis unit 130 ) Can calculate the modulus of elasticity by considering all three-dimensional displacement components. That is, the elastic modulus calculated by the elastic analysis unit 130 according to the present embodiment has a more accurate value than when calculating the elastic modulus by measuring displacement only in two dimensions.

Thus, for example, an ultrasound probe 20 having a two-dimensional transducer array according to the present embodiment is obtained, rather than acquiring a two-dimensional ultrasound image using an ultrasound probe having a one-dimensional transducer array and analyzing elastic modulus based thereon. ), It is possible to more accurately analyze the elastic modulus when acquiring a 3D ultrasound image and analyzing the elastic modulus based on this.

FIG. 4A is a diagram showing a simulation result obtained by analyzing a modulus of elasticity after acquiring a 2D ultrasound image using an ultrasound probe having an existing 1D transducer array. Referring to FIG. 4A, a displacement map representing a two-dimensional displacement of a shear wave and a shear modulus map corresponding thereto are illustrated.

FIG. 4B is a diagram illustrating a result of simulating a case where an elastic modulus is analyzed after acquiring a 3D ultrasound image using an ultrasound probe having a 2D transducer array according to an embodiment of the present invention. Referring to FIG. 4B, a displacement map representing a three-dimensional displacement of a shear wave and a corresponding shear modulus map are illustrated.

In comparison, when a 2D ultrasound image is acquired using an ultrasound probe having a 1D transducer array according to FIG. 4A, since the displacement of the shear wave cannot be considered in all directions in the 3D space, an error occurs, resulting in elasticity Coefficients cannot be analyzed accurately.

However, in the case of acquiring 3D ultrasound images using an ultrasound probe having a 2D transducer array according to the present embodiment of FIG. 4B, the displacement of the shear wave is determined in all directions (x-axis, y-axis, and z of the 3-dimensional space). Axis), the elastic modulus can be more accurately analyzed than in the case of FIG. 4A.

Referring back to FIG. 1, the elasticity analysis unit 130 provides elasticity information based on the calculated elastic modulus. Although not illustrated in FIG. 1, elastic information such as elastic modulus analyzed by the elastic analysis unit 130 is provided to a user, such as a doctor, through a display device (not shown) to grasp the state of the tissue or change in the characteristics of the tissue. Can be utilized.

5 is a flowchart of a method for analyzing elasticity of tissue using ultrasound according to an embodiment of the present invention. Referring to FIG. 5, the method for analyzing elasticity of tissue using ultrasound according to the present embodiment includes steps processed in time series in the apparatus for analyzing elasticity of tissue 1 using ultrasound shown in FIG. 1. Accordingly, even if omitted below, the description of the elasticity analysis apparatus 1 for tissues using ultrasound shown in FIG. 1 is also applied to the elasticity analysis method for tissues using ultrasound according to the present embodiment.

In step 501, the ultrasound probe 20 irradiates ultrasound for diagnosis toward the region of interest 30 in the body where the shear wave is induced using the two-dimensional transducer array.

In operation 502, the ultrasound image processing unit 110 acquires 3D ultrasound images of the region of interest 30 using echo ultrasound of the diagnostic ultrasound received from the ultrasound probe.

In step 503, the displacement measurement unit 120 measures the displacement of the shear wave in the region of interest 30 from the obtained 3D ultrasound images.

In step 504, the elastic analysis unit 130 analyzes the elastic information of the tissue of the region of interest 30 using the measured displacement of the shear wave.

Meanwhile, the above-described embodiments of the present invention can be written in a program executable on a computer and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium. In addition, the structure of the data used in the above-described embodiment of the present invention can be recorded on a computer-readable recording medium through various means. The computer-readable recording medium includes a storage medium such as a magnetic storage medium (eg, ROM, floppy disk, hard disk, etc.), an optical reading medium (eg, CD-ROM, DVD, etc.).

So far, the present invention has been focused on the preferred embodiments. Those skilled in the art to which the present invention pertains will appreciate that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered in terms of explanation, not limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the equivalent range should be interpreted as being included in the present invention.

1: Device for analyzing elasticity of tissue using ultrasound
10: processor 20: ultrasonic probe
30: region of interest 110: ultrasound image processing unit
120: displacement measurement unit 130: elastic analysis unit

Claims (17)

In the elastic analysis method of the tissue performed by the elastic analysis device,
Inducing a shear wave using an ultrasonic probe having a two-dimensional transducer array;
In order to scan an area of interest in the body where the shear wave is induced in a plane unit by using the two-dimensional transducer array of the ultrasonic probe, ultrasound for diagnosis toward the area of interest using a 3D plane scan method Investigating;
Obtaining 3D ultrasound images including a plurality of frames related to the region of interest using echo ultrasound of the diagnostic ultrasound wave received at a speed faster than the shear wave movement speed by the ultrasound probe;
Measuring displacement of the shear wave in the region of interest from the obtained 3D ultrasound images;
Calculating a moving speed of the shear wave using displacement components corresponding to each of three-dimensional coordinate axes included in the measured shear wave displacement;
Calculating a shear modulus of the tissue in the region of interest using the calculated moving speed of the shear wave; And
Displaying the calculated moving speed of the shear wave and elastic modulus of the region of interest together with the 3D ultrasound images on the display unit of the elastic analysis device; Including, method.
According to claim 1,
The measured displacement of the shear wave is
A method for measuring a three-dimensional movement of the shear wave appearing between the obtained three-dimensional ultrasound images.
delete According to claim 1,
The step of calculating the elastic modulus is
And calculating the modulus of elasticity using a wave equation for the shear wave.
delete delete According to claim 1,
The step of irradiating the diagnostic ultrasound
A method characterized by irradiating a plane wave by beamforming the diagnostic ultrasound wave in a defocusing method.
According to claim 1,
Acquiring the 3D ultrasound images
A method of obtaining the 3D ultrasound images by beamforming the echo ultrasound to the region of interest.
According to claim 1,
The step of inducing the shear wave may induce a shear wave in the region of interest using at least one of a diagnostic probe, a therapeutic ultrasound device, and a vibrator.
In order to induce a shear wave in a region of interest in the body and scan the region of interest in a plane unit using a two-dimensional transducer array, the region of interest is used by using a 3D plane scan method. An ultrasonic probe that irradiates ultrasound for diagnosis toward the body;
Acquiring 3D ultrasound images including a plurality of frames for the region of interest by using echo ultrasound of the diagnostic ultrasound received at a speed faster than the moving speed of the shear wave by the ultrasound probe, and the acquired 3D Measure the displacement of the shear wave in the region of interest from ultrasound images, calculate the movement speed of the shear wave using displacement components corresponding to each of the 3D coordinate axes included in the measured shear wave displacement, and calculate A processor for calculating a shear modulus of tissue in the region of interest using the moving speed of the shear wave; And
A display unit that displays the calculated moving speed of the shear wave and the elastic modulus of the region of interest together with the 3D ultrasound images;
A device for analyzing elasticity of tissue using ultrasound.
The method of claim 10,
The measured displacement of the shear wave is
A device for analyzing elasticity of tissue using ultrasound, which measures the three-dimensional movement of the shear wave that appears between the obtained three-dimensional ultrasound images.
delete delete delete The method of claim 10,
The ultrasonic probe
A device for elasticity analysis of tissue using ultrasound, characterized in that a plane wave is irradiated by beamforming the diagnostic ultrasound wave in a defocusing method.
The method of claim 10,
The processor
A device for elastic analysis of tissue using ultrasound, which acquires the 3D ultrasound images by beamforming the echo ultrasound to the region of interest.
A computer-readable recording medium recording a program for executing the method of any one of claims 1, 2, 4 and 7 to 9 in a computer.

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